Monoclonal immunoglobulinaemia associated with glomerulopathy.

Four patients with benign monoclonal immunoglobulinaemia and associated glomerulopathy are described. Immunohistochemical investigations of the immunoglobulin-containing cells in the bone marrow revealed an unexpectedly pronounced predominance of monoclonal over polyclonal cells as typically seen in macroglobulinaemia and multiple myeloma, but in contrast to the malignant plasma cell proliferations the percentage of immunoglobulin-containing cells only constitued 6-12% of the nucleated cells. The possible pathogenetic mechanisms relating monoclonal immunoglobulinaemia and glomerulopathy are unknown. The sera did not contain antibodies to glomerular basement membrane, cryoglobulins, antinuclear factors or antiglobulins. The immunohistochemical technique certainly offers a clear advantage over conventional bone marrow cytology in the study of patients with monoclonal immunoglobulinaemia.