Suppression of one monoclonal immunoglobulin in the presence of another in multiple myeloma. Evidence for benign B-cell neoplasia.

The case of a 77-year-old man with two monoclonal proteins, IgG lambda and IgG kappa, is presented. The IgG kappa protein increased in concentration, and, after two years, overt multiple myeloma developed with anemia and suppression of polyclonal immunoglobulins. The IgG lambda protein at first remained constant, but disappeared when overt myeloma developed. The disappearance of the IgG lambda protein suggests suppression of one neoplastic immunoglobulin clone by another, more aggressive, clone. This indicates that idiopathic monoclonal gammopathy can result from a benign neoplasm of B-cells that is responsive to regulatory factors and is not an early stage of myeloma.