THE Rh BLOOD TYPES AND SOME OF THEIR APPLICATIONS*

Transcription

1 THE Rh BLOOD TYPES AND SOME OF THEIR APPLICATIONS* ALEXANDER S. WIENER, M.D. From the Transfusion Division, Department of Laboratories, Jewish Hospital of Brooklyn, and the Serological Laboratory of the Office of the Chief Medical Examiner of New York City. The field of the Rh factors and their applications has become so extensive and complex, that it was with some misgivings that I accepted the kind invitation to present the topic before this society. Inasmuch as a detailed and comprehensive review like those prepared by Potter, " Broman lb and Boyd lc is hardly possible in the time allotted, I shall merely attempt to present the highlights of the subject. Until recently it was generally believed that no dangerous transfusion reactions could occur if patient and donor belonged to the same Landsteiner blood group, and indeed almost all hemolytic reactions could be traced to errors in blood grouping of patient or donor or both. During the decade 93-39, with the increasing use of blood transfusion, authenticated reports began to appear of hemolytic reactions despite the use of blood of the correct blood group. In most of these cases, no explanation for the reactions could be found; but in a few instances the patient's serum was reported to contain irregular isoagglutinins or isohemolysins acting on the blood of the donor used for the transfusion as well as certain other human bloods, independently of the blood groups. Among the most carefully studied instances of this sort were those reported by Zacho, 2 Culbertson and Ratcliffe, 3 Neter, and Levine and Stetson. 6 However, no attempt was made to correlate these cases with one another and this was the way the subject remained until a new period was opened by the discovery of the Rh factor. EARLY HISTORY OF THE Rh BLOOD FACTOR In 937, while studying the evolution of the properties M and N of human blood, Landsteiner and I demonstrated the presence of M-like agglutinogens in the blood of anthropoid apes and old-world monkeys. This led us to try immunization of rabbits with blood of rhesus monkeys, and it was found that in this way potent anti-m immune sera could be obtained. It then occurred to us that in the same way antibodies might possibly be produced against hitherto undiscovered individual blood factors in human blood. Pursuing the studies further, we succeeded in obtain- * Aided by a Grant from the United Hospital Fund of New York City. Paper read (with additions) before the Medical Society of Pennsylvania, September 2, 9. 6 ing antiserums which reacted with the bloods of approximately 85 per cent of all white individuals, independently of the blood groups. 7 The property of human blood detected by these anti-rhesus serums proved to be different from M, N and P, and was named Rh to indicate the manner in which it had been discovered. Some time after the Rh factor was discovered, I reported with Peters 8 three hemolytic transfusion reactions, one fatal, which proved to be due to isoimmunization against this new blood property. These cases indicating the clinical importance of the Rh factor prompted Landsteiner and myself to report our findings early in 9, 7 more than two years after we had obtained our first anti-rhesus serum. The patients, who were all Rh negative, had been given repeated transfusions of blood of the homologous blood group, but Rh positive. As a result, the patients became sensitized to the Rh factor, so that reactions occurred upon repetition of the transfusions, at first mild, then progressively more severe, until finally a dangerous hemolytic reaction directed attention to the true nature of the phenomenon. When within the short space of a year, as many as ten additional examples of reactions caused by isoimmunization against the Rh factor were encountered by me, 9 it became clear that this must be the usual explanation for hemolytic reactions when blood of the correct group is transfused. The accepted estimate is that approximately 9 per cent of intragroup hemolytic reactions are due to Rh. Careful study, in the light of modern knowledge, of the cases previously reported by Zacho, Culbertson and Ratcliffe, Levine and Stetson, and others, during the preceding decade, leave little doubt that these were also examples of Rh isoimmunization, and in 9, when Katzin retested the case of Levine and Stetson, he was able to confirm the correctness of this assumption. Analysis of the intragroup transfusion reactions encountered by me and Peters, as well as those previously described in the literature, revealed that these fall into two groups: () instances in which the patients had been given repeated blood transfusions, and as a result became sensitized to the Rh factor, and (2) intragroup hemolytic reactions occurring after an initial transfusion. In the latter group, it was observed that the patients had all been pregnant recently, and this suggested that the fetus in utero was the source of the antigen which had sensitized the patient, Downloaded from on 9 December 27

2 Rh BLOOD TYPES 7 as had previously been suggested by Levine and Stetson to explain the intragroup transfusion reaction their patient had had. It was also noticed that in many instances where the patients had had hemolytic reactions, their infants were stillborn or had erythroblastosis, and this suggested the solution to a second medical mystery (Levine et al., Bumham"). If an Rh-negative woman has an Rh-positive husband, the fetus in utero may also be Rh positive, by inheriting the Rh factor from its father. 7 In this way, the woman might become sensitized to the Rh factor, so that if she is given a transfusion of Rh-positive blood, a dangerous hemolytic reaction could result. Moreover, the Rh isoantibodies produced by the mother could pass through the placenta into the fetus and destroy its blood, giving rise to one or another manifestation of erythroblastosis fetalis. This theory of Levine and his associates 2 is now well established ; and is the basis for the suggestion that the name, "hemolytic disease of the fetus and newborn," be substituted for "erythroblastosis fetalis," although the latter term is still convenient to use because of its brevity. In view of the clinical importance of the Rh factor, it may seem surprising that the Rh factor was not discovered sooner. One contributing reason is that instances of intragroup hemolytic reactions and erythroblastotic infants are rather uncommon. While one out of ever}' seven individuals is Rh negative, not every Rh-negative individual becomes sensitized to the Rh factor when transfused with Rh-positive blood or when pregnant with an Rh-positive fetus. There evidently are wide differences among Rhnegative individuals in the ease with which they can be sensitized, so that only one in 25 or 5 are readily sensitized. The remainder might possibly require as many as to 2 or more transfusions or pregnancies before sensitization occurred, so that under ordinary conditions no isoimmunization would result. The small size of modern families would therefore explain why the incidence of hemolytic disease of the newborn is only approximately in 25 to 5 pregnancies, 3 instead of in, as would be expected if every Rhnegative individual became sensitized upon exposure to the Rh antigen. Another reason why the Rh factor was not discovered sooner is the difficulty of demonstrating the existence of Rh sensitization by in vitro tests. The usual method of testing for Rh sensitization is to examine the patient's serum for anti-rh isoagglutinins, as was first done by me and Peters. 8 Due to peculiarities of the anti-rh isoagglutinins and the Rh antigens," a special technic must be employed, or the antibodies will be overlooked. Only exceptionally, will the agglutinins be demonstrable by the common slide technic. Moreover, not infrequently, no anti-rh agglutinins can be detected by any technic, even though the patient is strongly sensitized to the Rh factor. Cases of the latter sort have been explained at least in part by the recent discovery of the blocking Rh antibodies, 6 - u which will be discussed later on. From the foregoing, it is evident that the specialist in blood grouping and blood transfusion must now be equipped to perform tests for the Rh factor, as an aid in diagnosing and preventing intragroup hemolytic transfusion reactions, and for the diagnosis and treatment of cases of hemolytic disease of the fetus and newborn. In addition, a complete transfusion service must now include a panel of blood donors who have been classified for the Rh factor. THE Rh BLOOD TYPES Anti-Rh serums can be obtained by immunizing guinea-pigs with the blood of rhesus monkeys, 7 ' 8,9 or from Rh-negative patients who have had hemolytic transfusion reactions or 8, l2 borne infants with hemolytic disease. Serums of the former type had the advantage that they could be produced at will (an advantage which now exists to a lesser degree on account of the scarcity of rhesus monkeys caused by the war), and most of the earlier studies on the Rh factor were carried out with anti-rhesus guinea-pig immune serums. They have the disadvantage that more technical skill is required for their accurate use than tests with better human anti-rh serums from mothers of erythroblastotic babies available at the present time. Another disadvantage of the anti-rhesus guinea-pig serums is that they cannot be used for typing infants' bloods because, as Fiske and Foord 2 have shown, the sera strongly agglutinate the blood of all infants regardless of Rh type. 37 ' lb Direct comparative study of different anti-rhesus guinea-pig serums and different human anti-rh serums has revealed that while the former all give parallel reactions, human serums vary in their specificities 9,2, so, 2i. 22,23 with the aid of human anti-rh serums, it has been discovered that there are five major varieties of Rh factors instead of ; only one, and that these five Rh factors give rise to eight types of human blood. 2,25,26 Since the Rh blood types have proved to be of clinical importance, 27 and, in any event, a knowledge of the subject is essential for the precise performance even of the ordinary.rh tests, they will now be briefly described. The differences among human anti-rh serums have been found to be due to the existence of three sorts of anti-rh agglutinins; the most common variety of agglutinin corresponds exactly with the standard 85 per cent positive, anti-rhesus immune animal Downloaded from on 9 December 27

3 8 ALEXANDER S. WIENER serums (Landsteiner and Wiener 7 ), and is designated reacts. Thus, blood reacting only with agglutinin 28 anti-rho; the second variety of anti-rh anti-rh', but not anti-rho or anti-rh" is said agglutinins clumps approximately 7 per cent of bloods from white individuals (Wiener 9 ) and is to belong to type Rh'; blood reacting only with agglutinin anti-rho belongs to type Rho; etc. designated as anti-rh'; the third and rarest Blood reacting with anti-rho and anti-rh' variety of anti-rh agglutinin gives only 3 per but not with anti-rh" is said to belong to type cent positive reactions 25,29,3 and is known as Rho instead of type RhoRh' for reasons which anti-rh". The situation is somewhat complicated will become clear when the heredity of the Rh because the agglutinins anti-rh' and anti-rh" types is discussed; similar reasons exist for the usually occur in association, with agglutinin designations of types Rho and RhoRho. For anti-rho, giving rise to two additional common these three types, the alternate designations Rhi, varieties of human anti-rh serums: one variety RI2 and RhiRli2 are also used. In fact, while which contains anti-rho and anti-rh' together is the designations Rho, Rho and RhoRho should be designated as anti-rh Rh' (or better anti-rho) used whenever necessary for the sake of clarity and gives about 87 per cent positive reactions on or to avoid ambiguity, the simpler designation the bloods of white individuals in New York City; Rhi. Rh 2 and RhiRh 2 will usually be found the second variety, which contains anti-rho preferable. 28 and anti-rh" together and is designated anti- RhoRh" or anti-rho, gives about 85.5 per cent It is of interest to mention briefly at this point the striking differences in the distributions of the 26, 28 positive reactions. It is clear that serums Rh blood types among individuals of different anti-rho, anti-rho and anti-rho give parallel races. In table, for example, are given the contrasting reactions except for a small percentage of bloods; distributions of these types among Whites for this reason, they are difficult to differentiate, and Negroes in New York City. 32 It will be seen and methods of doing so will be described later on. Still other varieties of anti-rh serums, e.g., sera that the most common type among white individuals is type Rhi to which slightly more than containing both anti-rh' and anti-rh", 3 or all half of all white individuals belong, but only one three agglutinins together, are also possible fifth of Negroes. On the other hand, type Rho, theoretically, but appear to be extremely rare for which is relatively rare (2.6 per cent) in Whites, reasons pointed out elsewhere. 26 is the most common type (.7 per cent) among Any one who thoroughly understands the four Negroes. Some races, such as American Indians, 33 Landsteiner blood groups and their heredity can Chinese 3,35 and Australian aborigenes, 36 are quickly learn the serology and genetics of the characterized by the virtual absence of the Rhnegative type. eight Rh blood types. First, considering the reactions of agglutinins anti-rh' and anti-rh" alone, four sorts of blood quite analogous to the HEREDITY OP THE Rh BLOOD TYPES four blood groups are possible. 25 Blood not The heredity of the eight Rh blood types can be agglutinated by either anti-rh' or anti-rh" learned quickly by any one familiar with the (analogous to group O) is said to belong to class heredity of the four blood groups. As was done W; blood reacting with anti-rh' but not anti-rh" when discussing the serology of the Rh types, let belongs to class U; blood clumped by anti-rh" us first consider only the agglutinins anti-rh' but not anti-rh' belongs to class V; while blood and anti-rh" and the four classes, W, U, V, and clumped by both antiserums (analogous to group UV, which they determine. These four classes AB) belongs to class UV. Now, when the reac- are inherited just like the four blood groups by tions of the anti-rh agglutinin are taken into' triple allelic genes which we may designate as account, each class is subdivided into two types,, giving rise to what amounts to a double blood W, U, and V, where U determines the agglutinogen reacting with agglutinin anti-rh', V group scheme of four types each. The resulting determines the agglutinogen reacting with antieight Rh types, their relationships to the four classes and their reactions with the three varieties Rh", and W is the recessive gene, analogous to gene of the A-B- series of allelic genes. When of anti-rh agglutinins are shown in table. It agglutinin anti-rh is brought into the picture, it will be seen that each Rh type has been named to correspond with the antiserums with which it becomes necessary to postulate the existence of six allelic genes instead of three, because each of Downloaded from on 9 December 27

4 Rh BLOOD TYPES 9 the genes W, U, and V comprises two Rh genes as follows: W = rh Rh U = Rhi Rh' V = Rhi Rh" The Rh genes postulated under this theory of six allelic genes are all named after the agglutinogens which they determine, as shown in table 2. To determine the phenotype corresponding to each of the 2 genotypes possible under the theory, it is only necessary to combine the effects of the pair of genes making up the genotype. In this way one can easily ascertain which genotypes correspond to each of the eight Rh blood types, as shown in table 3. (or Rho) were always caused by separate genes, as in genotype R/i'Rho, then it would be expected that half the children of the mating Rh-negative x Rhi would belong to type Rho and half to type Rh'. Actually, this variety of family has not been encountered to date, because genes Rho and Rh' are both relatively rare. This is the reason for the designation of blood reacting with agglutinins anti-rho and anti-rh' as Rho or Rhi instead of RhoRh'; namely, that only with rare exceptions, these reactions represent the effect of a single gene. Incidentally, this situation is of interest to the geneticist because it demonstrates that single genes, like Rhi and Rhi can produce effects indistinguishable from the combined effects of two genes (Rho and Rh', and Rho and Rh", respectively). 26 TABLE CLASSIFICATION OF Rh BLOOD TYPES AND DISTRIBUTION AMONG WHITES AND NEGROES IN NEW YORK CITY BLOODS LACKING Rho FACTOR BLOODS CONTAINING Rho FACTOR CLASSES vv u V uv Anti- Rho Reactions with antiserums _ - Anti- Rh' _ Anti- Rh" - Designation of types Neg. Rh' Rh" Rh'Rh" Distribution (per cent) Whites* Negroest Anti- Rho Reactions with antiserums Anti- Rh' - Anti- Rh" Designation of types Rho Rhi (Rh'o) Rh 2 (Rho) RhiRh 2 (Rh Rh"o) Distribution (per cent) Whites* Negroest * Based on tests. Calculated gene frequencies: rh = 35.9 per cent; Rh = 3. per cent; RIh = 3.7 per cent; Rh = 3.5 per cent; Rh' =.2 per cent; Rh" =. per cent. D = - VRh = =.9 per cent. t Based on tests on 223 Negroes from Harlem Hospital. Calculated gene frequencies: rh = 28. per cent; Rh =.7 per cent; Rh =. per cent; Rh = 2. per cent; Rh' = 2.7 per cent. D = - XRhi = =.7 per cent It is now a relatively simple matter to determine to which types the children must belong, when the Rh types of the parents are known. For example, if both parents are Rh negative, obviously all the children must be Rh negative; if one parent is Rh negative and the other belongs to type Rh'Rh", half the children will belong to type Rh' and half to type Rh". The mating Rh-negative x Rhi is more complicated because there are five possibilities depending on the genotype to which the Rhi parent belongs. In most families either all the children are Rhi, or half belong to type Rhi and half are Rh negative, because the most common genotypes in type Rhi are Rh\Rli\ and Rhirh. If the two reactions (with anti-rho and anti-rh') which characterize agglutinogen Rhi TABLE 2 THE SIX Rh GENES AND THE REACTIONS THEY DETERMINE Rh GEKES rh Rh' Rh" Rho Rh Rh Anti-Rho Neg. Neg. Xeg. Pos. Pos. Pos. REACTIONS WITH ANTISERUMS Anti-Rh' Neg. Pos. Xeg. Xeg. Pos. Xeg. Anti-Rh' Neg. Neg. Pos. Xeg. Xeg. Pos. The accuracy of the theory of six allelic genes has been established by investigations on the Rh Downloaded from on 9 December 27

5 ALEXANDER S. WIENER types in families, and by the statistical analysis of data on the distribution of the Rh types in the TABLE 3 THE EIGHT Rh TYPES AND THEIR GENOTYPES Rh TYPES Neg Rh' Rh" Rh'Rh" Rh Rh,(Rh ) Rh 2 (Rh?) RhiRh 2 (RnSRhiO GENOTYPES rhrh Rh'Rh' and Rh'rh Rh"Rh" and Rh'rh Rh'Rh" RhoRho and Rh&h RhRh, Rhrh, RhRh', RhRh, and Rh'Rh RhRh, Rhrh, RhRh", RhRh, and Rh"Rh RhRh, RhRh", and Rh'Rh the table. Here there are three possibilities depending on which of the three genotypes,i?/ti.r/t2, RhiRh" or Rh'Rh 2, the type RhiRh 2 parent belongs to. However, genotypes Rh\Kk" and Rh'Rhz are rare compared to RhiRht, so that ordinarily one would expect half the children to belong to type Rhi and half to type Rh2. It will be seen that the families in table actually yielded 8 type Rhi and 8 type Rh 2 children and none of any other type. Further evidence demonstrating the accuracy of the six gene theory has been obtained by Race et al. 38, working independently with anti-rh serums obtained in England. As pointed out by these authors, their arriving at the same scheme suggests the essential correctness of Wiener's six gene theory. TABLE HEREDITY OF THE Rh BLOOD TYPES IN 97 FAMILIES* NO. OF FAMILIES Neg. Rhi CHILDREN OF TYPES Rh 2 RhiRhs Rho Rh' Neg. X Neg. Neg. X Rhj. Neg. X Rh 2... Neg. X RruRhj Neg. X Rh... Neg. X Rh'... Rhi X Rhi Rhi X Rh 2 Rhi X RhiRh Rh 2 X Rh, Rh 2 X Rh Rh a... Rh 2 X Rh RhiRh, X RhiRh 2. RhiRh 2 X Rh.... Rh,Rh 2 X Rh' Totals * From Wiener, Sonn and Belkin. 37 general population. As an example of the former, one may consult table from the study by Wiener, Sonn and Belkin. 37 This series of 97 families with 275 children does not contain a single exception to the genetic theory. A particular striking case is the mating Rh-negative x RhiRh2, in TECHNIC OF THE Rh TESTSf Before returning to the discussion of the technic of the Rh tests, a few remarks concerning the t Because of lack of time, the tests with guinea-pig anti-rhesus serums will not be discussed here. Downloaded from on 9 December 27

6 Rh BLOOD TYPES blocking antibodies would be in order. As suggested by the name, 5 these blocking Rh isoantibodies have the capacity of combining with Rh-positive cells without producing a visible reaction,}: so that if subsequently a good anti-rh agglutinating serum is added, no clumping occurs because the combining sites on the erythrocytes have been blocked by the first antibody 5,6 (cf. fig. ). The blocking antibodies are sometimes quite potent as can be shown by titrating them. 5 The situation is somewhat complicated ' because, as has just been shown, there are at least manner, anti-rh o blocking antibodies can be used to "convert" Rh 2 cells to Rh", RhiRh 2 to Rh'Rh" and Rho to Rh-negative. 5 Before human anti-rh serums can be used for Rh-typing, their specificity must be determined, that is, whether they correspond to anti-rh o, anti-rh', anti-rh", anti-rho or anti-rho'. For this purpose, all one requires is group O bloods of types Rhi, Rhi2 and Rh-negative and some anti-rho blocking serum. By treating some of the Rhi and RJ2 blood with the blocking serum, one obtains artificial controls of types Rh' and Rh Agglutinogen u * Rh Cells Anti-Rh Agglutinin Anti-Rh Blocking Antibody Agglutination Blocking FIG.. DIAGRAMMATIC REPRESENTATION OF Rh AGGLUTINATION AND BLOCKING REACTIONS three sorts of Rh antigen, Rho, Rh' and Rh". The blocking antibodies found to date have invariably given reactions corresponding to anti- Rh o; thus, if type Rhi blood cells are mixed with serums containing such blocking antibodies, the blood suspension now behaves like type Rh' blood, because the Rho site of the Rhi (or Rho) agglutinogen has been blocked. In a similar t For a description of a similar phenomenon in tests with agglutinating serums for Pfeiffer bacilli, see Coca and Kelley. 69 Rh", respectively, and this is a very convenient procedure, because individuals of types Rh' and Rh" are rare. The serum to be standardized is merely tested against the cell suspensions, Rhnegative, Rhi and RI2, and natural or artificial Rh' and Rh" cells, and its specificity is readily determined as shown in table 5. For example, if the type Rhi and RI2 cells are clumped but not Rh', Rh" or Rh-negative, the serum contains an anti-rho agglutinin; if Rhi and Rh' are the only cells agglutinated, the specificity of the serum corresponds to anti-rh', etc. For Rh typing, Downloaded from on 9 December 27

7 2 ALEXANDER S. WIENER serums containing only one of the three agglutinins anti-rh o, anti-rh' and anti-rh" are obviously the most valuable; serums anti-rho and anti-rho are less useful. Serums anti-rho and anti-rho can be readily converted to anti-rh' and anti-rh" by adding to them a small amount of anti-rho blocking serum. 39 In fact, most, if not all, natural anti-rh' serums seem to contain anti-rho blocking isoantibodies,, 39 which would conceal any anti-rho agglutinins which might be present, so that natural anti-rh' serums may actually be more complicated rather than simpler than anti-rho serums. To be useful, anti-rh serums must not only be of known specificity but of sufficient potency or titer to give clear-cut reactions. The technic of titrating anti-rh serums is no different from that of titrating anti-a and anti-b serums, except SERUM NUMBER TABLE 5 STANDARDIZATION OF ANTi-Rh SERUMS Rh neg. - REACTIONS WITH TEST CELLS Type Rhi Type Rh 2 - Artificial or natural Type Rh' _ Type Rh" _ - - DIAGNOSIS anti-rho anti-rh' anti-rh" anti-rho anti-rh" that the former must always be done in testtubes as will be explained for the tests proper, later on. Finally, unless the serums are derived from a group AB individual, the anti-a and anti-b agglutinins present in the sera must be absorbed or neutralized so that the serums can be used for testing blood of individuals of all four blood groups This can be accomplished by absorbing the serum with pooled, washed Rh-negative cells of groups Ai and B. A simpler and more satisfactory procedure is to neutralize the isoagglutinins with pooled saliva of groups Ai and B from secretors (or with solutions of Witebsky's group substance ). If saliva is used, it should be placed in boiling water for minutes immediately after it is collected, in order to destroy the blood group enzymes, and coagulated material is removed by centrifugation. An example of a satisfactory formula that can be used for converting a potent (titer or more) group O, anti-'rho serum into an anti-rh' reagent is the following: 39 mix one part of the stock serum, with one part each of boiled Ai and B saliva and a potent anti-rho blocking serum and with 6 parts of saline solution. The dilute reagent should only be prepared immediately before use as the stock serum is far more stable than the dilute reagent. (The boiled Ai and B saliva should retain their potency indefinitely if stored in the refrigerator. Preservatives, such as merthiolate, should be avoided because these appear to damage the anti-rh isoagglutinins. 2 The actual tests are performed by mixing one drop of a fresh 2 per cent (in terms of blood sediment) suspension of the blood being tested with a drop of the diluted anti-rh serum in a small, narrow (inside diameter 7-8 mm:) test-tube and incubating the mixture in a water-bath at body temperature. (Most human anti-rh serums give more satisfactory reactions at body temperature than at room or refrigerator temperatures.) Such tests should be set up, using all three serums, anti-rho, and anti-rh' and anti-rh", if possible. (For clinical purposes, however, tests with the standard anti-rho serum alone are usually sufficient.) After the mixtures have stood for 3 to 6 minutes (or until sedimentation is complete) the reactions are read by observing with the naked eye the appearance of the sediment in each tube. For the interpretation of the reactions, consult figures. 2-7 The tubes are genlly shaken and the presence or absence of agglutination is determined with the naked eye and under the low power of the microscope. If any doubt remains, another reading may be taken after the mixtures have stood for an additional 2 hours at room temperature or after the tubes have beencentrifuged for one minute at low speed (about 5 r.p.m.). The type to which the blood belongs can readily be ascertained by- comparing the reactions obtained with the anti-rho anti-rh' and anti-rh" serums with those recorded in table. MEDICOLEGAL APPLICATIONS The Rh types, like the other individual properties of human blood, have two applications in legal medicine, namely, for individual identification and in cases of disputed parentage. It will be recalled 3 that the Landsteiner blood groups together with the subgroups of A andab give rise to six varieties of blood, O, Ai, As, B, AiB and A 2 B. When the three types M, N and Downloaded from on 9 December 27

8 Rh BLOOD TYPES 3 MX are taken into account, 6 x 3 or 8 combinations are possible. Since every person is either P positive or P negative, this doubles the number of possibilities. Finally, if the 8 Rh types are included, a total of 36 x 8 or 288 varieties of human blood can be distinguished. Of course, these 288 varieties vary considerably in their frequency in the general population. The most common combination among white persons would be group O, type MM, P positive and type Rhi, with a frequency of (.3) (.S) (.75) (.5) =.87 or approximately 8.7 per cent. The rarest combination would be group A 2 B, type N, P negative and type Rh'Rh", with a frequency of (.5) (.2) (.25) (.) or.,,75 or o FIGS SEDIMENTIVE METHOD OF TESTING FOR THE Rh FACTOR (After Landsteiner and Wiener.) Reproduced from the Journal of Experimental Medicine, 7: 32, 9. Magnification :2. FIGS. 2 AND 3. NEGATIVE REACTIONS: THE INNER LIGHT DISC IN FIG. 2 IS DUE TO SLIGHT CONVEXITY IN THE BOTTOM OF THE TUBE FIG.. FAINTLY POSITIVE REACTION FIG. 5. WEAK REACTION FIGS. 6 AND 7. TYPICAL POSITIVE REACTIONS less than in millions. The type Rh'Rh" itself is rare, with an incidence of one in ten thousand, and no individual of this type has yet been encountered by the speaker. Stratton 3 stated that he has encountered four persons of this type, two of them siblings. It should be mentioned that the number of identifiable varieties of human blood is actually considerably more than 288, because in the calculations given above, no account has been taken of the blood factor Hr, or the rare agglutinogens A 3, N», etc. The individual properties of human blood can be used only to prove that a certain bloodstain did not come from a certain person; they can never be used as evidence that a blood stain contains the blood of a specific person. Thus, if the combination of blood factors in the blood stain is not. identical with that of a given person, that would prove that the stain does not contain his blood;, mere identity of types only means that the stain contains blood of the same type as the person in question, but the possibility of coincidence can never be excluded. In a similar way, blood tests may in certain cases prove that a certain man or woman is not the parent of a certain child, they can never prove parentage, because compatibility of types may be accidental. With regard to the Rh blood types the following 37, rules of heredity holds: () The properties Rh, Rh' and Rh" cannot appear in the blood of a child unless present in the blood of one or both parents. (2) A class W (type Rh or type Rh-negative) parent cannot have a class UV (type RhiRh2 or type Rh'Rh") child, and a class UV parent cannot have a class W child. The most common type of case where blood tests are used involve children born out of wedlock, and the mother accuses a certain man of the paternity of her child, a charge which he denies. If the accused man is innocent of the charge, his innocence can be established in a certain percentage of cases by means of the blood tests. The chances of excluding an innocent man by tests for the Rh types vary with the Rh type of the accused man and the distribution of the Rh types in the general population. With the aid 5, 6 it of general formulae published elsewhere, can readily be shown that the average chances of proving non-paternity for white persons in New York City are approximately 6 per cent and the chances of exclusion for persons of each of the eight Rh types is given in table 6. When one considers, that by means of tests for the A-B groups, the subgroups of A and AB, and the M-N types, a falsely accused man has approximately a 35 per cent chance of proving his innocence, the Rh tests have now raised the chances of exclusion to approximately 5 per cent. CLINICAL APPLICATIONS OF THE Rh TYPES As already mentioned, natural sensitivity to the Rh types apparently never occurs. At any rate, no instance of an intragroup hemolytic transfusion reaction has ever been reported in a man not previously transfused, or a woman who has had no previous transfusion or pregnancy. Downloaded from on 9 December 27

9 ALEXANDER S. WIENER Theoretically, individuals might be considered capable of being sensitized against any of the Rh factors, Rho, Rh' and Rh" absent from their blood. Actually, as already mentioned, individuals differ widely in the ease with which they can be sensitized, so that only one in every 25to SO Rh-negative persons are apt to have an intragroup hemolytic transfusion reaction or an erythroblastotic infant. Moreover, the properties Rho, Rh' and Rh" differ considerably in their antigenicity for man, and Rho is by far the most important factor clinically. For this reason, persons of types Rh' and Rh" are practically equivalent to Rh-negative persons clinically, because such patients lack Rho and are therefore 27, 3Q capable of producing anti-rho isoantibodies. Instances of Rhi persons being sensitized against TABLE 6 APPROXIMATE CHANCES OP EXCLUDING PATERNITY OF A FALSELY ACCUSED MAN, BY MEANS OF THE Rh BLOOD TYPES (WHITE INDIVIDUALS, N. Y. C.) CLASSES w u V uv Rh TYPES Rh neg. Rh' Rh" Rh'Rh" CHANCES OF EXCLDSION % Rh TYPES Rh Rh, Rh 2 Rh,Rh 2 Average chances of exclusion (type of accused man not known) CHANCES OF EXCLUSION % ' Rh" or Rh2 patients being sensitized to Rh' are quite rare; 39,7 in fact, when an Rh-positive woman of type Rhi has an erythroblastotic infant, then, as will be explained later, this will more likely be due to the Hr factor than to factor Rh". 8-9 In order to illustrate the clinical application of the Rh factors in transfusions, a few cases, not previously reported, will be described briefly: Case : This case, referred by Dr. I. M. Westing, involved a 3 year old woman with anemia due to lymphosarcoma, treated at a hospital in Brooklyn. A first blood transfusion had been well tolerated, but a second transfusion given 5 days later had to be discontinued because of chills and shock, and a third transfusion 3 weeks later was terminated after cc. were given because of a chill, rise in temperature to 6 F. and marked tachycardia (pulse rate 22). Tests on the patient's blood showed her to belong to group B, type MN and Rh-negative, and anti-rh agglutinins (titer 5) were present in her serum. Two transfusions of bank blood, supposedly group B, Rh-negative were then given. The first was uneventful; the second was terminated at cc. because of chills, fever, hemoglobinemia and hemoglobinuria, followed by profuse bleeding from the gums. Retests of the latter sample of bank blood showed that it belonged to group AB (subgroup A 2 B), type Rh,, so there had been a double error in typing. Luckily the patient survived the reaction. A subsequent transfusion of group B, Rh-negative bank blood resulted in a satisfactory response. Case 2: A young woman (Jewish Hospital ) was under treatment for subacute bacterial endocarditis. At another hospital, she had received three transfusions, the third being interrupted because of a reaction. Upon admission she was given a transfusion without apparent reaction; a second transfusion 3 days later caused a mild reaction and the hemoglobin instead of rising, dropped from 6 per cent to 2 per cent. A third transfusion 2 weeks later caused a severe chill and rise in temperature to 3 F. Tests on the patient's blood showed that she belonged to group B, type N and type Rh-negative with weak anti-rh agglutinins in her serum. For subsequent transfusions only group B, Rh-negative donors were used, with satisfactory response. In both cases, sensitization to the Rh factor was largely, if not entirely due to repeated transfusions of Rh-positive blood to an Rh-negative patient. Though both patients were female there was no evidence that previous pregnancies contributed to the Rh sensitization. An example will now be described of a hemolytic reaction to an initial blood transfusion. Case 3: This patient was a married woman 9 years of age, admitted to service of Dr. Leo M. Davidoff for an operation for pituitary tumor. During the operation the patient was given a transfusion of 5 cc. of apparently compatible blood, and at the close of the operation it was noticed that there was marked oozing from the incision. The patient was then given 5 cc. of plasma and an additional 5 cc. of blood because of shock. While pre-operatively the hemoglobin concentration had been 85 per cent, post-operatively the hemoglobin concentration dropped to 5 per cent. After the transfusions, the patient passed only cc. of dark red urine; then she became anuric, comatose and the blood urea N rose to 62 mg. per cc. A sample of blood obtained at this time yielded a deeply icteric serum (icteric index 25), and the patient's blood was found to be group B, type MN and type Rh-negative. No anti-rh isoantibodies (either blocking or agglutinating) were detected in the serum, but Downloaded from on 9 December 27

10 Rh BLOOD TYPES 5 this was not significant because the patient was in the negative phase. One of the donors whose blood was available proved to be group B, type MN, type Rhi. The patient died 8 hours after the operation and blood transfusions. The marital history of the patient revealed that she had been pregnant 5 times. The first pregnancy resulted in a normal boy, who died from pneumonia when years old. One child died in infancy following a circumcision, a second infant was jaundiced and died after 3 days, and two pregnancies terminated in stillbirths. Obviously, the pregnancies were the cause of the patient's sensitivity to the Rh factor, which in turn was responsible for the fetal and neonatal deaths as well as the hemolytic transfusion reaction. The most remarkable aspect of the case was the prolonged duration of the sensitivity to the Rh factor. Another unusual aspect is the hemorrhagic symptoms exhibited by the patient as a result of the hemolytic reaction. Obviously, this complication is particularly dangerous in surgical cases. For example, in another intragroup hemolytic reaction due to Rh sensitization recently referred to the author, in a woman subjected to a Cesarean operation in a hospital in New York City, the patient died within six hours from the resulting loss of blood and shock. Case : This patient was a woman, 5 years of age, admitted to the 3rd Surgical Ward at Bellevue Hospital with a diagnosis of bleeding duodenal ulcer. Transfusions of 5 cc. each of group, compatible bank blood on May 23, 9, May 27, and June were followed by no reactions. Following a transfusion on June 9, temperature rose from to 3 F., and three weeks later the author was requested to determine the cause of this reaction. Tests showed that she belonged to group O, type MN, type Rh' and there were anti-rho agglutinins (titer 5) in her serum. This case illustrates the clinical importance of knowledge of the Rh blood types. Had only typing serum anti-rh^ (87 per cent positive) been used, the patient would have been classed as Rh-positive, and the cause of the reaction might have been overlooked. Though this patient had had 5 pregnancies, it is not likely that these were the cause of the sensitivity to the Rh factor because all S children were normal; besides no reactions occurred until the fourth transfusion, indicating that the first three transfusions had been responsible for the sensitization. The patient's husband was dead, but of her 5 children were available for testing. (The oldest child was 28 years old, the youngest 6 years old.) Their types proved to be: AMNRI2, AiMRh', AiMN Rh-negative and BMNRh', so that the husband obviously must have belonged to group AiB, type MN or M and type RJ2 (genotype Rhnrh). Of these four children only one (the type Rii2 child) could have offered an opportunity for Rh isoimmunization. Incidentally, this family supplies an example of the heredity of the Rh types involving the rare gene Rh'. In view of the observations cited, ideally all patients who are to be transfused should be tested for the Rh factor as well as the blood groups and all Rh-negative patients should only be given Rh-negative blood. This is not practicable, however, because of the shortage of good anti-rh serum, Rh-negative donors, and properly trained technicians. Fortunately, it is adequate merely to take the Rh factor into account in pregnancy cases,- or patients who have had previous transfusions. In any event, any woman who has had a stillbirth or an erythroblastotic infant should only be given Rh-negative blood unless tests prove that she is not Rh-negative or, at least, not sensitive to the Rh factor, and the same applies to a patient who has had a previous transfusion that was followed by a reaction. Where the search for Rh-negative donors would unduly delay an urgent transfusion, Wiener's biological test with 5 cc. of Rh-positive blood of a compatible A-B group can be tried, since experience has shown that only a small percentage of Rhnegative patients are sensitive to the Rh factor. 5,6l If no clinical symptoms and no darkening in the color of the patient's plasma occur within one to two hours after the injection of the test dose of 5 cc. of blood, the patient can be given any quantity of Rh-positive blood without danger, (cf. figure 8) THE Hr FACTOR As has already been mentioned, about 9 per cent of all instances of intragroup transfusion reactions or erythroblastosis are due to Rh sensitization. With regard to the remainder of the cases, a few may be due to isoimmunization to other factors, such as M, 2 ' - lb P, 8 - i - M A! 53 or O. 5 One must also bear in mind the possibility of multiple sensitization, so that, for example, a patient could be sensitive to factors M and Rh simultaneously, and such a patient would. I Downloaded from on 9 December 27

11 6 ALEXANDER S. WIENER have to be given type N, Rh-negative blood, of a compatible group. The most common cause of intragroup incompatibility in Rh-positive individuals seems to be the Hr factor. The Hr factor was first described by Levine, Javert and Katzin 2 ' 65 who found that the serum of an Rh-positive mother of an erythroblastotic infant agglutinated all Rh-negative bloods and those Rh-positive bloods which did not react with anti-rh' serum. The symbol Hr was selected to indicate that the factor in question was opposite to Rh because it is present in all Rh-negative bloods. Race and Taylor 55 observed a similar agglutinin in an Rh-positive mother of an erythroblastotic infant, which differed from Levine of genotype Rh'Rh', for practical purposes this means that the only Hr negative individuals are persons of type Rhi, homozygous for gene Rh\ (or far less commonly, of genotype Rh\Rh'). The anti-hr serums encountered to date have been of much lower titer than the better anti-rh serums. The anti-hr serums also have the peculiarity that they give three grades of reactions, strong, weak or moderate, and negative. When the serum deteriorates, the more weakly reacting bloods are no longer agglutinated, while the strongly reacting blood still show distinct clumping. This accounts for the discrepancy between the percentage of positive reactions reported by Levine et al. and by Race and Taylor. FIG. 8. BIOLOGICAL TEST FOR INTRAGROUP INCOMPATIBILITY A. Appearance of patient's serum before test. B. Patient's serum one hour after injection of Rh-negative blood. C. Patient's serum one hour after the injection of Rh-positive blood: positive reaction. (From Weiner's Blood Groups aud Transfusion, 93. Courtesy of Charles C. Thomas, Publisher, Springfield, Illinois.) et al's in the higher percentage of positive reactions (8 per cent instead of 3-5 per cent). Race and Taylor's factor, designated by them St, is almost certainly the same as Hr, the apparent differences reported being due to the fact that Levine et al.'s anti-hr serum was weaker and gave many false negative reactions. According to the hypothesis of Race et al. 38 the blood factors determined by genes RI2, Rh", Rho, and rh react with anti-hr serum, while the blood factors determined by genes Rhi and Rh' do not react. It would therefore be expected that only bloods of genotypes Rh\Rhi, Rh\Rh' and Rh'Rh' would fail to react with anti-hr serum. In view of the rarity of gene Rh' and particularly The peculiarities of the Hr reactions can be explained simply as follows: If we assume that the Hr factor is inherited as a Mendelian dominant by a pair of allelic genes, Hr and hr, then as shown in table 7. Hr = rh Rh Q Rh 2 Rh" or W V and hr =R/n Rh' or U Strongly reacting bloods will presumably be of genotype HrHr and as shown in table 8, should therefore include all bloods of types Rh2, Rh", Rho and Rh-negative. Weakly reacting bloods, of genotype Hrhr, will include type Rl^Rhs, Downloaded from on 9 December 27

12 Rh BLOOD TYPES 7 type Rh'Rh", type Rhi (genotypes Rh\rh, RhiRho and RhoRh') and heterozygous individuals of type Rh'. Negatively reacting blood, as already mentioned, can only occur in type Rhi or very rarely in type Rh'. This theory has been confirmed by studies on families by Race and Taylor, 57 and by studies on the distribution of the Hr factor among Negroes and Whites by Wiener, Davidsohn and Potter. 58 For example, Hrnegative-individuals were encountered in approximately 25 per cent of the white population, but in only 2 per cent of the Negro population, as was to be expected from the differences in the distribution of the Rh types. TABLE 7 THE Hr FACTOR AND THE Rh GENES REACTION WITH ANTI-Hr SERUM Positive Negative Hr GENES Hr hr Rh GENES rh, Rho, Rhi and Rh" Rh,. and Rh' panel of Hr-negative donors as well as Rh-negative donors. When a type Rhi patient has an intragroup hemolytic reaction, and incompatibility to factors such as M or P can be excluded, a biological test with Hr-negative blood would be worth trying. TRANSFUSION THERAPY OF HEMOLYTIC DISEASE OF THE NEWBORN The discovery of the role of isoimmunization in pregnancy in the pathogenesis of hemolytic disease of the newborn has made possible a more rational transfusion therapy of the disease. The general principle when selecting donors for these infants is the same as that for transfusing their mothers, or any patient who has had previous intragroup hemolytic reactions, except that the infants have been passively instead of actively sensitized to the Rh factor. The severity of the disease in the infant depends upon the amount of Rh isoantibodies that pass into its body through the placenta from the mother. The disease may TABLE 8 THE Hr TYPES AND GENOTYPES IN RELATION TO THE Rh TYPES AND GENOTYPES Hr GENOTYPE REACTION WITH ANTI-Hr SERUM Rh GENOTYPES Rh TYPES HrHr Strong rhrh, Rharh, Rh Rh, Rhrh, RhRh, RhRh", RhRh, Rh"Rh, Rh"rh and Rh"Rh" Rh neg., Rh, Rh 2 and Rh" Hrhr Weak or Medium Rhrh, Rh t Rho, Rh'RIh, Rh'rh, RhRh, Rh'Rh" Rh,Rh", Rh'Rh and Rh,, Rh', Rh,Rh 2 and Rh'Rh" hrhr Negative RhRh, RhRh' and Rh'Rh! Rhi and Rh' A common misconception that arose from the earlier vague reports on the Hr factor is that in cases of erythroblastosis due to the Hr factor, the mother is Rh positive and the child Rh negative. Actually the child is never Rh-negative in such cases, because the mother who must be Hr negative, and therefore must belong to genotype RhiRhi, RhiRh' or Rh'Rh', must transmit either an Rhi or an Rh' gene to every child. In cases of hemolytic disease caused by Hr sensitization, the mother belongs to type Rhi; there is no restriction on the Rh type of the father since Hr positives occur in all the 8 Rh types, but the child's blood cannot belong to type Rh2, Rh", Rho or Rh-negative. A complete transfusion service should include a be so mild that spontaneous recovery occurs and the condition may be entirely unnoticed or confused with physiologic icterus of the newborn; or the disease may be so severe that the infant is stillborn. In severe cases where the infant is born alive, death may occur within a few hours or days; or else the infant may appear entirely normal at birth, and develop an insidious anemia which may result in death within the week. The mysterious lack of correlation between the titer of the maternal Rh isoantibodies and the severity of the disease in the infant 55, 59, 6 has apparently been solved, at least in part by the discovery of the Rh blocking isoantibodies. 5 For transfusing infants with hemolytic disease, maternal blood should not be used, because the Downloaded from on 9 December 27

13 8 ALEXANDER S. WIENER additional isoantibodies injected into the infant may increase the severity of the disease. The father's blood or any blood sensitive to the action of the- maternal isoantibodies should not be transfused, because the infant's body may contain enough isoantibodies to hemolyze all its own blood and any additional blood injected, so this would prolong and aggravate the disease. As Levine and Katzin have suggested, in the usual case involving the Rh factor, Rh-negative blood is to be preferred. 6 Wiener and Wexler 62 have cited case reports illustrating the life-saving value of Rh-negative blood and similar experiences have been described by Gimson. 63 When Rhnegative donors are not available, the mother's citrated blood can be washed twice with saline solution to free the cells of plasma, and the washed cells resuspended in compatible plasma can be used for the transfusion. This procedure has the advantage that it can always be used; also in problem cases involving Rh-positive mothers, while Rh-negative blood will be satisfactory only in the common case of Rh sensitization involving an Rh-negative mother or a mother of type Rh' or Rh". 27 In emergencies, where neither Rh-negative nor maternal blood is available, any donor of a compatible group should be taken in order to tide the infant over until a more suitable donor can be found. As part of the treatment, breast feeding should be interdicted, because additional Rh isoantibodies may be ingested by the infant in the milk , 66 ' Direct evidence of the superiority of Rhnegative blood for treating the usual case of hemolytic disease has been obtained by Mollison 67 who traced the fate of the donor's blood in the infant's circulation by the method of differential agglutination. While Rh-negative blood survived for periods up to three months, Rh-positive blood was often eliminated within or 5 days. Similar observations have been made by me. 62 Since the average newborn infant weighs about 7 lbs. and has a blood volume of 25 cc, two transfusions of 75 cc. will usually be sufficient because they will maintain the infant's hemoglobin above 6 per cent. In mild cases, a single transfusion may be sufficient, while in the more severe cases a third or even a fourth transfusion maybe required. The following case taken from the paper of Wiener, Wexler and Gamrin 68 is cited to illustrate the dramatic, life-saving effect of proper transfusion treatment in hemolytic disease of the newborn. Case 6: A woman, pregnant for the second time, was near term and gave the history that her first child, a boy now 3 years old, had become anemic shortly after birth (delivery by Cesarean section), and had required a number of transfusions over a period of a month. Blood tests on the woman, her husband and child revealed the following: Blood of Group M-N Type Rh-Type Woman N Negative Husband ' MN Rh,Rh 2 Son (3 yrs. old) MN Rh! These findings supported the diagnosis of erythroblastosis and the woman was evidently sensitized to the Rh factor. Moreover, it was evident that the expected child had to be group, and Rh-positive (type Rh! or Rh 2 ) and therefore susceptible to the maternal isoantibodies. Accordingly, blood was drawn from a group O, Rh-negative donor in preparation for transfusing the expected infant. This precaution proved life-saving, because the infant when it was delivered by Cesarean section, was extremely pale (subsequent tests indicate that the hemoglobin concentration at birth must have been approximately 2 per cent), breathed poorly and was very feeble. The transfusion was started at once and 6 cc. of blood were transfused because of the infant's poor condition. This revived the infant in a spectacular fashion and the infant was sent to its room in good condition. The subsequent course was practically uneventful except that another transfusion of 75 cc. of blood was necessary when the infant was one month old. The results of repeated hemoglobin determinations are charted in figure 9; while the total hemoglobin concentration did not show striking changes, the partition of this value into the patient's and donor's blood yielded illuminating results. It is of interest to note how for a period of about a month, the only blood in the infant's circulation was that derived from the donor. Then, gradually, as the donor's blood was eliminated, it was replaced by newly formed blood of the infant. When last seen at the age of 3 months, the infant was normal, having recovered.completely from the hemolytic disease. CONCLUSIONS Within the short space of four years, the discovery of the Rh factor has served to open an interesting but intricate subject with important applications in clinical and legal medicine. Since the subject is apparently still in its growth phase, it is difficult to prepare a comprehensive review, entirely up-to-date. Observations may even be made, while this review is in press, that may render obsolete some of the statements or ideas included in the review. We may all look forward, therefore, with pleasant anticipation to the next Downloaded from on 9 December 27