Anaemia due to a red blood cell membrane defect

Transcription

1 Anaemia due to a red blood cell membrane defect BHS training course

2 Red blood cell membrane defect Pathologies Clinical signs Diagnostic criteria Treatment (HS) 2

3 The pathologies Structural organisation Hereditary spherocytosis Hereditary elliptocytosis Transport function Stomatocytosis The other hereditary forms: CDA II The other acquired forms PNH Zieve, 3 Mohandas, 2008 Br J Haematol

4 Hereditary spherocytosis (HS) RhAG B3 B3 4.2 Ankyrin Spectrins < 1% 15-20% < 5% 50-60% 20% 4

5 Hereditary elliptocytosis (HE) Pyropoïkylocytosis (PPE) Junction complex > 90% Auto-association sites 5

6 Hereditary «Stomatocytosis» (HSt) Cryohydrocytosis B3 B3 Dehydrated form (DHSt) ou xerocytosis Overhydrated (OHSt) ou hydrocytosis Intermediate forms: Cryohydrocytosis Familial pseudohyperkaliemia 6

7 Congenital dyserythropoïesis (CDA) CDA II Deglycosylation B3 B3 B3 Mutation SEC23B Gene: protein involved in maturation, proliferation and division of erythroblasts 7

8 Caucasians ++ Hereditary spherocytosis The pathologies Sub-Saharan Africa (caucasians) Hereditary elliptocytosis?? Stomatocytosis CDA 8

9 Caucasians ++ Hereditary spherocytosis The pathologies Sub-Saharan Africa (caucasians) Hereditary elliptocytosis 1/2000-1/5000 1/100 West Afr.?? Stomatocytosis CDA 1/ (DHSt) (Cryohydrocytosis, OHSt: a few families) < 1/

10 Caucasians ++ Hereditary spherocytosis The pathologies Sub-Saharan Africa (caucasians) Hereditary elliptocytosis 65-75% dominant 70% dominant?? Stomatocytosis Dominant OHSt de novo CDA Recessive 10

11 Red blood cell membrane defect Pathologies Clinical signs Paediatric/adult Splenomegaly/biliary lithiasis Diagnostic criteria 11

12 Paediatric/adult First visit at what age? Depends on the degree of decompensation of anaemia Variable age at diagnosis, but HS ± 65% with neonatal icterus Each stress on the RBCs = decompensated anaemia Birth Infection (i.e. Parvovirus B19) Pregnancy 12

13 Red blood cell membrane defect Pathologies Clinical signs Paediatric/adult Splenomegaly/biliary lithiasis Diagnostic criteria 13

14 Splenomegaly/ biliary lithiasis Haemolysis ± compensated Differential diagnosis (MCV, AutoImmune Haemolytic Anaemia) Measurement RBC enzymes (G6PD, PK, GPI, ) Hb fractions Screen for Hb H Heat and isopropanol tests Screen for Heinz bodies Enzyme deficiency Haemoglobinopathy HbCC, HbSC, Unstable Hb

15 Red blood cell membrane defect Pathologies Clinical signs Paediatric/adult Splenomegaly/biliary lithiasis Diagnostic criteria 15

16 Diagnostic criteria RBC membrane pathology MCV SH EH DHSt OHSt CDA I CDA II N or N or N 16

17 Reticulocytes x 10³ Reticulocytes x 10³ Diagnostic criteria RBC membrane pathology Membrane defect = regenerative Hb g/dl Except CDAs Hb g/dl 17

18 Diagnostic criteria CDA II Aniso-poikylocytosis Fex spherocytes Binuclearity of bone marrow erythroblasts CDA II 18

19 Diagnostic criteria RBC membrane pathology Electrophoresis (SDS-PAGE) CDA II Band 3 19

20 Diagnostic criteria CDAs Heimpel H, ENERCA white book 20

21 Diagnostic criteria HE and HPP HE HPP Study of the parents 21

22 Diagnostic criteria Hereditary spherocytosis -spectrin Bande 3 22

23 Diagnostic criteria Screening tests for HS Cryohaemolysis test Osmotic fragility Eosin-5-maleimide binding test: decrease fluorescence Membrane protein defect 23

24 Diagnostic criteria Osmotic gradient ektacytometry Control HS 24

25 Diagnostic criteria Electrophoresis (SDS-PAGE) HS -spectrin -spectrin ankyrin band 3 protein 4.1 protein 4.2 actin Confirmation of diagnosis (± 80%)

26 Hereditary spherocytosis Clinical Individual and family history First line tests Confirm haemolysis and erythropoietic answer Exclude AIHA, enzymopathy, other Search for HS characteristics Second line tests Search for osmotic fragility and RBC membrane deficiency (Cryohaemolysis, EMA binding test) In any doubt, diagnostic tests (Ektacytometry, SDS-PAGE) 26

27 Follow-up Hereditary spherocytosis Childhood: annual visit unless new symptoms, acute event Chronic haemolysis: look for co-inheritance of a haemochromatosis gene Treatment Folate therapy in severe and moderate HS Splenic conditioning: Further membrane loss Splenectomy (HS confirmed) Indications depends on symptoms and complications (individual tolerance) 27

28 Treatment Hereditary spherocytosis Splenectomy (HS confirmed) Lifelong small risk of overwhelming sepsis (grade 1 recommendation, grade B evidence) National guidelines for immunization; reimmunization when and how? Duration of AB prophylaxis? (grade 2 recommendation, grade C evidence) No indication for extended thrombosis prophylaxis after splenectomy. Adults should receive perioperative thromboprophylaxis in the usual way; To be avoided in patients with some forms of hereditary stomatocytosis (grade 1 recommendation, grade B evidence). 28

29 Red blood cell membrane defect Home message The most frequent in Belgium: hereditary spherocytosis Haemolysis ± compensated except for CDAs= dyserythropoiesis Differential diagnosis with other causes of haemolysis Clue: clinical features, screening tests Final diagnosis Simple (family history) Complex: diagnostic tests available un expert centres Treatment Symptoms, complications Eliminate the amplifier (spleen) 29

30 RBC membrane pathology Summary: diagnostic criteria SH EH DHSt OHSt Cryohydro. Cryohemolysis or EMA, ektacytometry, SDS-PAGE Morphology (Parents), EMA, ektacytometry Ektacytometry SDS-PAGE (absence of stomatin) MCV, MCHC and K + after 2H on ice CDA II SDS-PAGE (no glycosylation of Band 3) 30

31 Red blood cells enzyme deficiencies 31

32 Red blood cell enzyme disorder If persistent haemolytic anaemia and Normocytic Regenerative Haemoglobinopathies excluded Negative Coombs test Acute haemolytic anaemia 32

33 Enzymatic equipment of the RBC Other deficiencies Very rare Sometimes other symptoms (TPI) Inheritance: Autosomal recessive Consanguinity? Pyruvate Kinase < 1/ Inheritance: Autosomal recessive Consanguinity? Chronic haemolytic anaemia 33

34 Enzymatic equipment of the RBC G6PD First step of the pentoses pathway: production of NADPH which gives protection against oxydatives agents 34

35 G6PD deficinecy Epidemiology (classification II et III) 35

36 G6PD deficiency Malaria Mechanisms of R against malarial infection RBC infection equal in RBC with and without the deficiency RBC with G6PD deficiency: Alterations of the parasites and the RBCs Phagocytosis++ and earlier: lowered parasitaemia Probably not a decrease of the parasite growth (discordant literature) Gene 2010; 467:1-36

37 Question Do you think that women are affected by G6PD deficiency? 37

38 G6PD deficiency X-linked recessive inheritance Men affected : 1/20 Women affected (homozygosity/compound heterozygosity/x inactivation): ±1/400 XY XX XY XY XX XX 38

39 Class I (very rare) Neonatal icterus Chronic haemolytic anaemia G6PD deficiency Class II (Asia, Med. Bassin) Neonatal icterus Severe haemolytic crisis when exposed to any oxydant (drugs, infection, ) Class III (Sub-Sahar. Africa) Neonatal icterus if preterm newborn Haemolytic crisis when exposed to any oxydant (drugs, infection, ) G6PD MED (II) G6PD A- (III) +jaundice +++ if Gilbert s disease 39

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41 G6PD deficiency Biological diagnosis Regenerative haemolytic anaemia Measuring the enzyme activity glucose-6-p + NADP + G6PD 6-P-gluconate + NADPH + H + 6-P-gluconate + NADP + 6PGD ribulose-5-p + CO 2 + NADPH + H + Suivi à 340 nm G6PD activity/reticulocytes Patient 1 Patient 2 Patient 3 G6PD ( ) 7,5 9,6 < 0,5 HK ( ) 2,0 7,2 2,9 41

42 Prevention of crisis To avoid the trigger G6PD deficiency Treatment Transfusion if necessary (+ Folic acid) Life expectancy similar to the general population 42

43 G6PD deficiency Home message X-linked recessive inheritance (BUT not only boys) Resistance against malarial infection (BUT sometimes in individuals from North Europe) Haemolytic anaemia (trigger) Intravascular++ Regenerative, normocytic Final diagnosis Measurement of the enzyme activity Treatment Removal of the trigger and its avoidance Class I = chronic haemolytic anaemia (rare) No relationship with endemic zones for malarial infection 43