Immunosuppression following alloantigen exposure: a role for lymphocyte Fc gamma-receptor blocking antibodies.

In this study we have shown that IgG class, noncytotoxic, Fc gamma-receptor blocking antilymphocyte antibodies can de detected in a high proportion of patients who have previously been exposed to alloantigens, i.e. multiple transfused uraemic patients, haemophiliacs and male homosexuals. These antilymphocyte antibodies appear to cross-react with human spermatozoa. Monomeric IgG preparations from these patients were also found to significantly impair T-cell responsiveness in vitro. Depression of cell mediated immunity by these antibodies may contribute to prolonged graft survival in uraemic patients but may also predispose to infection.