Cell-bound immunoglobulin on peripheral blood mononuclear cells of patients with myeloma.

Four patients who had myeloma were examined for monoclonal lymphocytes in the peripheral blood using anti-idiotype antibodies. All the patients had received treatment and two were in apparent complete remission. In no case was there any evidence of peripheral blood mononuclear cells (PBMC) with endogenous surface idiotypic determinants, even in patients with active disease. It was found, however, that substantial cytophilic IgG may remain bound to Fc receptors on PBMC even after extensive incubation and washing at 37 degrees C.