Thrombocytopenia and leucopenia with mianserin-dependent antibodies.

By indirect immunofluorescence specific mianserin-dependent antibodies were detected against platelets but not against granulocytes in the serum of a patient with thrombocytopenic purpura and mild leucopenia. A complement-mediated cytotoxicity assay demonstrated 70% lysis of granulocytes but no lysis of platelets, only when mianserin was added to the medium. We suggest that, at least in some patients, mianserin may cause blood disorders by an immunologically-mediated mechanism.