These results demonstrate that a substantive proportion of eligible blood donors at our institution have antibodies specific for T. cruzi and that a commercially available assay can be used to detect these antibodies. Our data suggest that the risk of transmission of T. cruzi by transfusion could be eliminated by serologic testing limited to persons born in or transfused in countries in which Chagas' disease is endemic.

No abstract

Using age-fractionated erythrocytes, warm autoantibodies can be classified into two distinct categories, depending on their reactivity with reticulocyte-enriched (younger) or reticulocyte-poor (older) red cell fractions. The strength of the direct antiglobulin test (DAT) on the age-fractionated red cells of 24 patients indicated that 19 (79%) had an IgG warm autoantibody that reacted preferentially with older red blood cells. In 7 of these 19 patients (37%), the DAT was negative using reticulocyte-enriched red cell fractions. We have termed this preferential reactivity of warm autoantibodies with older red cells as type I. Five of the 24 patients studied (21%) had an IgG warm autoantibody that demonstrated no preference for young or older red cells. We have termed this pattern of warm autoantibody reactivity as type II. All 5 patients having type II warm autoantibodies had severe anemia. In contrast, 6 of 19 patients having type I warm autoantibody did not have clinical evidence of anemia when tested, and 11 of the 19 had only slight to moderate anemia. Additionally, our results using type I warm autoantibody raise questions regarding the blood group specificity of warm autoantibodies. The antigen recognized by type I warm autoantibody may be a cryptantigen. Rh specificity or relative Rh specificity, often associated with warm autoantibodies, may simply be a coincidental finding.