Class‐Specific Anti‐IgA Associated with Severe Anaphylactic Transfusion Reactions in a Patient with Pernicious Anaemia

Abstract

Abstract. The case history and investigations of a 32‐year‐old man with pernicious anaemia and selective absence of IgA in serum and saliva are presented and discussed. On two occasions, the patient, who had not previously been exposed to foreign human serum, developed severe anaphylactic shock after blood transfusion of a few millilitres. A precipitating antibody to IgA was identified in his serum. It was of class‐specific type reacting not only with the donors' sera, but also with other normal sera. The patient had no apparent chromosome abnormality, and no close family members had similar IgA lack. Lymphocyte transformation in vitro with PHA was normal: no stimulation followed exposure to IgA. On fluorescent microscopy, very few IgA‐containing cells were seen in the gastric mucosa.