Gold induced thrombocytopenia: platelet associated IgG and HLA typing in three patients.

Three patients who developed thrombocytopenia while taking gold therapy are reviewed. Bone marrow examinations at the time of thrombocytopenia revealed adequate numbers of megakaryocytes. Elevated levels of platelet associated IgG (PAIgG) were demonstrated in relationship to the thrombocytopenia. A response to prednisone therapy was seen with a rise in platelet count and a fall in PAIgG. All 3 patients were found to have the following alloantigens of the major histocompatibility complex, HLA-B8, DR3. These findings suggest that gold induced thrombocytopenia is immunologically mediated and possibly related to the genes of the major histocompatibility complex.