LAUSR

Sir, In adult patients with haemolytic anaemia and marked spherocytosis in the peripheral blood smear, a distinction has to be made between a late presentation of a hereditary anaemia such as hereditary spherocytosis (HS) and acquired haemolysis due to autoimmune haemolytic anaemia (AIHA). A positive family history, the presence of gallstones and splenomegaly is in favour of the former diagnosis, while a short history in combination with an underlying haematological or immunological disease favours the latter. The laboratory diagnosis of HS is commonly based on screening tests such as an acidified glycerol lysis test (AGLT) or osmotic fragility test (OFT) in combination with flow cytometric analysis of eosin5’maleimidelabelled intact red blood cells (EMA binding test).1,2 Subsequent quantification of individual membrane proteins by sodium dodecyl sulphatepolyacrylamide gel electrophoresis (SDSPAGE) or molecular genetic analysis is recommended in a selected number of cases, as the initial screening tests cannot identify all cases of HS because of the widely variable phenotypes.1-3 AIHA is generally diagnosed by a polyspecific direct antiglobulin test (DAT) containing antiIgG, antiIgM and anticomplements. In cases in which the phenotype is compatible with AIHA and the standard DAT is negative, testing for sensitization with an antiIgA reagent should be performed.4,5 Although IgAmediated AIHA is rarely seen, it can also be easily overlooked. We report a case of idiopathic IgAmediated AIHA with marked spherocytosis in which osmotic fragility persisted despite successful treatment with prednisolone with resolution of haemolysis and disappearance of the IgA antibody. In view of the profound spherocytosis at presentation and the incomplete normalization of the OFT, we hypothesize that an underlying hereditary membrane disorder is associated with the persisting osmotic fragility. A 44yearold Hindustani female was admitted because of severe haemolytic anaemia. Her medical history revealed a laparoscopic cholecystectomy. She presented with a 10day history of fatigue, progressive dyspnoea and chest pain upon exertion. She suffered from pain in her left calf since one day. There was no history of fever or sign of infection. She did not use medication, and the family history was unremarkable. On physical examination, we noticed obvious jaundice without lymphadenopathy or hepatosplenomegaly. The left calf was tender without swelling or redness. Laboratory studies showed severe haemolysis with a haemoglobin level of 5.4 g/dL (RR 11.515.2), reticulocytosis of >400/nl (RR 25120), elevated lactate dehydrogenase of 989 U/L (RR <248), elevated bilirubin of 153 umol/L (RR <19) of which 94% was unconjugated and undetectable levels of haptoglobin <58 mg/L (RR 1602000). The peripheral blood smear showed marked spherocytosis of 80%. The polyspecific DAT containing antiIgG, antiIgM and antiC3d was negative (including in eluate). With HS in the differential diagnosis, we performed additional screening tests. The AGLT showed 50% lysis after 63 seconds (RR >1800 seconds), and the OFT showed increased fragility as can be seen in HS, but also in warmantibody type (WAT) AIHA (Figure 1). As the phenotype was compatible with WATAIHA we performed a monospecific antiIgA DAT, which appeared to be strongly positive and led to our diagnosis of idiopathic IgAmediated AIHA. The EMA binding test revealed normal membrane