An IgG M-component reacting with both anti-kappa and anti-gamma light chains in multiple myeloma.

A patient with multiple myeloma who has an IgG-IM-component in serum reacting with both kappa and lambda light chains in immunoelectrophoresis is presented. The possibility of "hybrid molecule (H2LkappaLlambda)" is strongly suspected. The absorption studies of the patient's serum employing anti-kappa and anti-lambda light chains, however, support the view that this apparently single M-component consists of two M-components, IgG 1-kappa and IgG 1-lambda. The reason why these two M-components possessed the identical electrophoretic mobility is unclear. The possibility is high that these two M-components are produced in the same cell.