An autoantibody to Rh-Ce protein causing positive direct antiglobulin test in a healthy blood donor.

A positive direct antiglobulin test (DAT) is of diagnostic feature for the patient with autoimmune hemolytic anemia (AIHA). However, on rare occasions, for obscure reasons, it is found among healthy blood donors. The present report is aimed to elucidate serological and immunological characteristics of such autoantibody in a healthy donor aged 62 years found with positive DAT. There was no history of Leishmaniasis, nor having a significant illness. His red blood cells (RBCs) showed incompatible cross-match results with every recipient tested in the antiglobulin phase. He was found to be DAT+. As his plasma had very little presence of autoantibody, hence was augmented by elution from his in vivo sensitized RBCs for the study. Autoantibody with immunoglobulin IgG showed predominant specificity of anti-Ce. It is certainly a rare case of autoantibody to RhCe compound antigen yet being innocuous in a healthy blood donor with a positive DAT.