Three monoclonal immunoglobulins, an IgG2(kappa), an IgM(kappa) and an IgM/A hybrid, in one patient. I. Isolation and characterization.

Three monoclonal immunoglobulin components were identified in the plasma of a patient exhibiting a multiple gammopathy. These were an IgG2(κ) and IgM(κ) and an IgM/A hybrid molecule containing mu, alpha, and kappa antigenic determinants. This is the first report of an immunoglobulin hybrid which consists of portions of two different heavy-chain classes, and the significance of this observation in terms of our present concept of immunoglobulin gene arrangement is discussed.