HEMOGLOBIN-SPECIFIC ANTIBODY IN A MULTIPLY TRANSFUSED PATIENT WITH SICKLE-CELL DISEASE

Human hemoglobins (Hbs) are known to be immunogenic, and both normal a nd variant forms of Hb have been shown to stimulate antibody formation in a variety of animal species, In patients who are homozygous for th e sickle Hb (HbS) mutation, transfusion of normal, HbA-containing eryt hrocytes provides a potential stimulus for HbA alloimmunization. We te sted serum samples for the presence of anti-Hb antibody by a solid-pha se enzyme-linked immunosorbent assay (ELISA) using Hb-coated polystyre ne microtiter plates, Hb-bound antibody was identified using an antihu man IgG antibody. Serum samples from 89 patients with sickle cell dise ase were initially tested for evidence of Hb antibody. The serum from three individuals exhibited antibody activity against HbA with little or no activity against HbS, Only one of them, a multiply transfused ad ult with HbSS, was available for further study. When this patient's an tibody was tested against a variety of normal and mutant Hbs using ant ibody either to human IgG or to kappa chains, the anti-Hb antibody dem onstrated specificity for the region of the Hb beta chain correspondin g to the site of the amino acid substitution of HbS. The level of acti vity of the patient's anti-HbA showed no significant change over 1.5 y ears of observation, The transfusion of erythrocytes containing Hb str ucturally different from that of the recipient appeared to be capable of stimulating the production of Hb-specific alloimmune antibody. (C) 1997 by The American Society of Hematology.