ABO Hemolytic Disease of the Newborn

Transcription

1 ABO Hemolytic Disease of the Newborn A Retrospective Analysis of 5 Cases D. ROBERT DUOUR,.D. AND W. PATRICK ONOGHAN, PH.D. Dufour, D. Robert and onaghan, W. Patrick: ABO hemolytic disease of the newborn. A retrospective analysis of 5 cases. Am J Clin Pathol 7: 69-7, 980. ABO hemolytic disease of the newborn is the single most common cause of neonatal jaundice, with an incidence of 5. per,000 births; it occurs almost exclusively in infants of groups A or B having mothers of group O. Previous studies have shown a poor correlation between serologic tests on cord blood and clinical course in affected infants. In a retrospective analysis of 5 cases of ABO hemolytic disease of the newborn the relation of laboratory parameters to incidence and severity of jaundice was studied. Sixty-five per cent of the infants who had positive direct antiglobulin tests experienced jaundice, compared with approximately 5% of control infants or infants who had ABO hemolytic disease of the newborn with negative direct antiglobulin test results. Infants who had ABO hemolytic disease of the newborn with positive direct antiglobulin test results also had greater severity of jaundice than control infants or infants who had ABO hemolytic disease of the newborn with negative direct antiglobulin test results (P <.000). Thus, the direct antiglobulin test is a good screening test for ABO hemolytic disease of the newborn. Sex, race, gravidity, birth weight, and blood type of the infant did not have significant relationships to clinical outcome. The combined results of the direct antiglobulin test and the strength of reaction in a heat eluate may be of use in prognosis; although differences were not significant, infants who had stronger eluates had higher bilirubin values and were more likely to require therapy. Serologic analysis of cord blood can be useful in the early detection of infants having the risk of severe jaundice. (Key words: Erythroblastosis fetalis; Blood group incompatibility.) THE IRST REPORT of a possible association between maternal-fetal ABO incompatibility and neonatal jaundice was made by Halbrecht in 9. 7 Rosenfield reported the first controlled study in 955, and showed that a positive direct antiglobulin test identified a group of ABO-incompatible infants showing laboratory evidence of hemolytic disease due to alloantibodies detected on their erythrocytes. Since then, numerous studies have attempted to establish other laboratory tests useful in evaluating ABO hemolytic disease; these Received November, 978; received revised manuscript and accepted for publication April 9, 979. Address reprint requests to Dr. Dufour: LT, C, USNR, National Naval edical Center, Box 99, Bethesda, aryland 00. Department of Laboratory edicine, National Naval edical Center, Bethesda, aryland studies have recently been reviewed by Gold and Butler. 5 While it has been recognized that maternal-fetal ABO incompatibility is the most frequent cause of hemolytic disease of the newborn, the clinical course is often benign, and therapy is required in approximately 0% of the affected infants. 5 With the declining incidence of Rh hemolytic disease since the introduction of Rh immune globulin, ABO incompatibility has become the most common cause of hemolytic disease of the newborn requiring therapy at many institutions. These observations emphasize the major unsolved problem in ABO hemolytic disease of the newborn: while serologic tests (usually the direct antiglobulin test can detect antigen-antibody interactions, they may not predict the clinical course of affected infants. Although the studies of Rosenfield have shown that infants having a positive direct antiglobulin test result, as a group, have evidence of increased hemolysis, few studies have attempted to compare the course of these infants with that of otherwise normal infants. In an attempt to evaluate these unanswered questions, a retrospective study was undertaken to identify any correlation between clinical severity of ABO hemolytic disease of the newborn and the various laboratory parameters tested. This report is an analysis of 5 cases of ABO hemolytic disease of the newborn seen over a 6-month period. aterials and ethods The National Naval edical Center serves as both a primary-care hospital for routine obstetric cases and a tertiary-care center for complicated obstetric cases. Prenatal blood analysis for each fetus includes ABOgroup and Rh-type determination, and an indirect antihuman globulin test for detection of atypical alloantibodies. A specimen of cord blood, collected by syringe, is obtained after delivery for each infant and /80/000/069 $00.75 American Society of Clinical Pathologists 69 Downloaded from on ebruary 08

2 70 DUOUR AND ONAGHAN A.J.C.P. arch 980 Table. Incidence of Hemolytic Disease of the Newborn Total deliveries,706 aternal-fetal ABO incompatibility 98 others of group O 665 ABO Hemolytic Disease of the Newborn present 5 ABO Hemolytic Disease of the Newborn absent others of groups A and B 6 ABO Hemolytic Disease of the Newborn present ABO Hemolytic Disease of the Newborn absent 6 Hemolytic disease other than ABO Hemolytic Disease of the Newborn Due to anti-d 6 Due to other Rh antibodies Due to non-rh antibodies (anti-kell, anti-jk" twins) is sent to the Blood Bank for ABO-group, Rh-type, and direct antiglobulin test determinations. To determine antibody specificity, a heat eluate is performed on each cord specimen having a positive direct antiglobulin test result. All test procedures are listed in the Technical anual of the American Association of Blood Banks. Permanant records of cord-blood results are maintained in the Blood Bank; a review of these records for the previous 6 months indicated a total of 5 cases of ABO hemolytic disease of the newborn. In addition, the distribution of maternal blood group and maternal-fetal blood group pairs was tabulated. Criteria for making this diagnosis varied slightly during the study. rom 97 to 976, only infants who had a positive direct antiglobulin test result and a heat eluate positive for either anti-a or anti-b or both, were included. alse-negative results had been reported in ABO hemolytic disease of the newborn; therefore, in the final 6 months of the study, infants with a heat eluate positive for either anti-a or anti-b, or both, were included, regardless of the results of the direct antiglobulin test. Hospital records of infants diagnosed as having ABO hemolytic disease of the newborn were reviewed, and the following information was obtained: sex, race, gestational length, gravidity, birth weight, maternal blood group and type, peak bilirubin level, day of peak bilirubin, hemoglobin, reticulocyte count, prenatal or postnatal complications, and length of hospital stay. Therapy for hyperbilirubinemia, when given, was also noted. Immunohematologic analyses recorded for infants included: blood group and type, direct antiglobulin test result, and antibody present in the heat eluate. In the first months of the study, the strength of reaction in a heat eluate was not graded; in the last 0 months, it was graded as recommended in the Technical anual of the American Association of Blood Banks. As a control group, all term infants admitted during a two-month period were studied in the same way that patients who had ABO hemolytic disease of the newborn were studied. Results During the 6 months of the study, there were,99 deliveries. Complete records of maternal and fetal blood groups and types infant direct antiglobulin test results and maternal antibody screens were available in,706 cases (95.%). The remaining cases most frequently lacked test results of maternal group and type; this may have been owing to the transfer of a small percentage of patients from other medical facilities. The incidence of laboratory evidence of ABO hemolytic disease of the newborn during the study is given in Table. aternal-fetal ABO incompatibility is defined as the presence of a maternal alloantibody that in reaction with fetal erythrocytes, could cause agglutination or hemolysis. aternal-fetal ABO-incompatible pairs included: mothers of group O with infants of group A or B, mothers of group A with infants of group B or AB and mothers of group B with infants of group A or AB. All other maternal-fetal blood group pairs were considered ABO compatible. Of ABO-incompatible infants with mothers of group O, 7.9% had laboratory evidence of ABO hemolytic disease of the newborn. Of ABO-incompatible infants with mothers of groups A or B, only 0.8% had laboratory evidence of ABO hemolytic disease of the newborn. This difference appears to be highly significant (x = 0.6, P <.00000). Three sets of infants were evaluated in this study. The first two sets were of infants showing laboratory evidence of ABO hemolytic disease of the newborn. One set consisted of 08 infants who had positive direct antiglobulin test results and anti-a or anti-b identified in a heat eluate of cord erythrocytes; the second set consisted of 8 infants who had negative direct antiglobulin test results, but who had anti-a or anti-b, or both, in a heat eluate. The third set (controls) consisted of all 7 full-term infants born in this institution during a two-month period near the end of the study. Table. Results of Direct Antiglobulin Test in ABO Hemolytic Disease of the Newborn Correlated with Clinical Course Negative Control Total No Group I (No Clinical Evidence of Jaundice) Group ("Physiologic Jaundice") 80 5 Group III (arked Jaundice) 5 9 Downloaded from on ebruary 08

3 Vol. 7 No. ABO HEOLYTIC DISEASE O THE NEWBORN 7 Patient, Patient, Patient, Patient, Patient 5, Patient 6, Patient 7, Patient 8, Patient 9, Patient 0, Patient, Patient, Patient, Patient, Patient 5, Patient 6, Patient 7, Patient 8, Patient 9, Patient 0, Patient, Patient, Patient, Patient, Patient 5, Patient 6, Patient 7, Patient 8, Table. Infants Receiving Therapy for ABO Hemolytic Disease of the Newborn Gravidity Group and Type B B B B A Negative B B Eluate* Weak positive Weak Weak Weak positive * Weak positive indicates microscopically positive; positive indicates positive but strength of reaction not given. The records of all infants were evaluated in the same manner. No significant differences (P >.05) were found among the three sets of infants when comparisons were made for sex, race, birth weight, or gravidity of the mother. An additional eight infants idenified as having laboratory evidence of ABO hemolytic disease of the newborn were not included in this study; four infants' charts were not available for review, and another four infants had coexisting disease processes which made evaluation of the ABO hemolytic extremely difficult (two being extremely premature, one having hereditary spherocytosis, one having Rh hemolytic disease ofthe newborn). Since one of the major manifestations of ABO hemolytic disease of the newborn is hyperbilirubinemia, the infants were evaluated for degree of jaundice. Because ofthe wide range of bilirubin values, it was necessary to group the infants for purposes of analysis. Infants who had no clinical evidence of jaundice were placed in group I; infants who had "physiologic" jaundice (bilirubin values less than.0 mg/dl), in group II; and infants with jaundice above the physiologic range (marked jaundice), in group III. A comparison ofthe courses ofthe three sets of infants is given in Table. As can be seen from the table, infants who had positive direct antiglobulin test results had a much higher incidence of both "physiologic" Therapy, exchange transfusion Begun on Day and marked jaundice (groups II and III) than did either control infants or infants who had negative direct antiglobulin test results and positive eluates. Among infants who had positive direct antiglobulin test results, 6% had some degree of jaundice and 6% had marked jaundice; this was significantly higher {P <.000) than for control infants or infants who had negative direct antiglobulin test results. The incidence of jaundice in infants who had negative direct antiglobulin test results (% jaundiced, 8% marked) was not significantly different from that in control infants (7% jaundiced, 7% marked). A total of 8 infants (.%) required therapy for ABO hemolytic disease. The laboratory and clinical features of these infants are given in Table. our infants received only exchange transfusions: 7 received only phototherapy, and seven received both exchange transfusions and phototherapy. Although criteria for treatment varied slightly during the course ofthe study, infants received treatment when the serum bilirubin level exceeded the albumin binding capacity. ost ofthe infants who received exchange transfusions were treated during the early years of the period studied, before phototherapy was adopted as the preferred primary means of therapy at this institution; in the last three years, only infants failing to respond adequately to phototherapy, or those having critically Downloaded from on ebruary 08

4 7 DUOUR AND ONAGHAN A.J.C.P. arch 980 Table. Results of Cord Blood Eluates in ABO Hemolytic Disease of the Newborn and Correlation of Eluate Strength* with Clinical Course Group I (No Clinical Re- Evidence Group II Group III ceived of ("Physiologic (arked Ther- Jaundice) Jaundice") Jaundice) apy Weakly positive (microscopic orl+) Strongly positive (-+) * Etuate strength of reaction was measured by the procedure recommended in the Technical ethods anual of the American Association of Blood Banks. low hemoglobin levels, were treated by exchange transfusion. In comparison with the remaining infants who had ABO hemolytic disease of the newborn and the control group, infants requiring therapy showed no significant differences of clinical features, with the exception of the earlier onset of jaundice (x = 9.0, P <.0) and, by definition, more severe jaundice. Among infants who had positive direct antiglobulin test results, the strength of the reaction of a heat eluate was recorded in cases. The clinical course of these infants is given in Table. Infants who had strongly positive eluates had a slightly higher incidence of jaundice than those who had weakly positive eluates and higher mean bilirubin levels (. mg/dl vs. 0. mg/dl); however, these differences are not significant. In addition, a higher proportion of infants who had strongly positive eluates required therapy than did infants who had weakly positive eluates (6% vs. 0%, 0. > P >.05). Thus the eluate strength appeared to give additional information to that provided by a positive direct antiglobulin test result. or infants who had negative direct antiglobulin test results, the eluate strength had no relation to the clinical course. Race, sex, gestational age, birth weight, gravidity of mother, and blood group also had no relations to the clinical course. Cord-blood bilirubin, hemoglobin, and reticulocyte count were recorded in too few cases to allow any correlations to be made. Discussion ABO hemolytic disease of the newborn occurs relatively frequently and can be a significant cause of neonatal morbidity. While the incidence of clinically significant jaundice in ABO-compatible infants varies from 6.5% (our series) to 8.% (other series 9 ), it is in the range of 5-0% in ABO-incompatible infants having positive direct antiglobulin test results. 9 In our series, ABO hemolytic disease of the newborn was responsible for jaundice in approximately 0% of all infants who had clinically significant jaundice; in other series, it has been as high as 0%. 9 Although ABO hemolytic disease of the newborn is known to be a cause of neonatal jaundice, its prevalence as a major etiologic factor has not previously been emphasized. Because of the decline in hemolytic disease of the newborn due to anti-rh 0 (D), ABO hemolytic disease of the newborn has become the most common cause of hemolytic disease of the newborn requiring therapy. During the period studied, 8 infants who had ABO hemolytic disease of the newborn required therapy, compared with only infants who had hemolytic disease of the newborn due to any other antibody. This trend is likely to continue in the future. ABO hemolytic disease of the newborn is found almost exclusively among infants having mothers of group O. In our series, the incidence of ABO hemolytic disease of the newborn among ABO-incompatible infants of mothers of group O was 7.9%; this is similar to the incidence published in previous reports., In ABO-incompatible infants of mothers of group A or B, the incidence was only 0.8%. Rosenfield, in 955, was the first to note the marked preponderance of group O mothers of infants having ABO hemolytic disease of the newborn; since then, many studies have been done to try to explain this fact. Rosenfield and Ohno have shown that, whereas 90% of group O individuals have IgG anti-a and anti-b, only % of group A or B individuals have IgG anti-b or anti-a. In a later paper, Kochwa and co-workers 0 showed that, whereas 70% of group O mothers had titers of IgG anti- A or anti-b greater than :, no mother of group A or B did. While this would appear to explain the marked preponderance of group O mothers of infants having ABO hemolytic disease of the newborn, it does little to explain the manner of sensitization. Pregnancy does not seem to be a major stimulus, since infants of primigravida mothers may be affected as severely or more severely than infants of multigravida mothers. 5 Our series confirmed these findings; infants of multigravida and primigravida mothers were affected to a similar extent. Of the three women who had more than one infant during the study, two had infants who had similar degrees of jaundice: the third mother's first infant was more severely affected than her second. There has been much interest in the early prediction of the occurrence and severity of ABO hemolytic disease of the newborn. Voak and Bowley screened a large number of women of group O for the presence of high titer IgG anti-a and anti-b and followed them to delivery. Although they considered this characteristic to define a "high risk" group, the incidence Downloaded from on ebruary 08

5 Vol. 7 No. ABO HEOLYTIC DISEASE O THE NEWBORN 7 and severity of jaundice in the infants in their study were not different from those reported by other authors who studied an unscreened population. Carpella-de Luca, Pacioni, and Tonelli found a high titer of IgG anti-a and anti-b to be correlated with a positive direct antiglobulin test result; however, this high titer had no apparent correlation with a need for therapy. Graham, orrison, and candrew 6 used Sephadex separation of IgG anti-a and anti-b followed by titration, to define a "high risk" group. However, the incidence and severity of jaundice in infants in their screened series were only slightly higher than in infants in our series, and the differences were not significant. Thus, at best, prenatal studies have a limited value in the prediction of ABO hemolytic disease of the newborn. Previous authors have indicated a racial difference in the incidence of ABO hemolytic disease of the newborn, with black infants being more frequently affected than white infants.,8,9 Our data do not support these findings, but the small number of black infants in our series may have prevented our observation of this association. Because of the failure or prenatal tests, serologic tests on cord blood may be the first useful tests available for predicting the clinical course of affected infants, if a correlation can be shown to exist. Our data seem to show such a relationship. irst, infants having positive direct antiglobulin test results have significantly greater incidence and severity of jaundice than do infants having laboratory evidence of erythrocytic sensitization (a positive heat eluate) and negative direct antiglobulin test results. In fact, infants with negative direct antiglobulin test results do not show differences from the control infants, and thus either have subclinical or compensated hemolytic disease or do not have true hemolytic disease. Hence, it would appear that the direct antiglobulin test has few, if any, falsenegatives results, making it a good screening test for all newborn infants of group O mothers. Infants whose direct antiglobulin test results are negative and control infants appear to have the same likelihood of experiencing jaundice. On the other hand, like most screening tests, the direct antiglobulin test lacks specificity; that is, it is not very useful for predicting severity of disease. In our experience, and in that of others,,9 approximately 0% of infants having positive direct antiglobulin test results will have more than "physiologic" jaundice, with one-third to one-half of these requiring therapy. A semi-quantitative test, the reaction strength in a heat eluate of cord cells, may be of some value in predicting severity of disease, since infants who had tests showing stronger reactions had higher bilirubin values and were more likely to require therapy, although differences were not significant. These tests, obviously, do not absolutely predict the course of the infants, but may permit the laboratory to adivse the clinician, who can closely monitor infants whose test results indicate an unusual risk of jaundice. Acknowledgment. s. Sondra Gandler Getz provided editorial assistance. References. American Association of Blood Banks: Technical anual. Seventh edition. Philadelphia, J. B. Lippincott Co., 977, pp Bucher KA, et al: Racial difference in incidence of ABO hemolytic disease. Am J Pub Health 66:85-858, 976. Carapella-de Luca E, Pacioni C, Tonelli C: The titre of IgG anti-a/b in the serum of group O mothers of incompatible infants with early neonatal jaundice. Vox Sang 0:00-0, 976. Clifford JH, et al: Screening for hemolytic disease of the newborn by cord blood Coombs' testing-analysis of a five year experience. Clin Pediatr 7:65-69, Gold ER, Butler NR: ABO hemolytic disease of the newborn. tendon, John Wright and Sons, Ltd., 97, pp Graham H, orrison, candrew R: A simple method for fne prediction of ABO incompatibility using Sephadex A-50. Vox Sang 9:7-77, Halbrecht I: Role of hemagglutinins anti-a and anti-b in the pathogenesis of jaundice of the newborn (icterus praecox neonatorum). Am J Dis Child 68:8-9, 9 8. Kaplan E, Herz, Scheye E: ABO hemolytic disease of the newborn without hyperbilirubinemia. Am J Hematol :79-8, Kirkman HN: urther evidence for a racial difference in frequency of ABO hemolytic disease. J Pediatr 90:77-7, Kochwa S, et al: Isoagglutinins associated with ABO erythroblastosis. J Clin Invest 0:87-88, 96. Orzalesi, et al: ABO system incompatibility: relationship between direct Coombs' test positivity and neonatal jaundice. Pediatrics 5:88-89, 97. Rosenfield RE: A-B hemolytic disease of the newborn. Blood 0:7-8, 955. Rosenfield RE, Ohno G: A-B hemolytic disease of the newborn. Rev Hematol 0:-5, 955. Voak D, Bowley CC: A detailed serologic study on the prediction and diagnosis of ABO hemolytic disease of the newborn. Vox Sang 7:-8, 969 Downloaded from on ebruary 08