Rapid evolution in the immunochemical findings of a gamma heavy chain disease.

We noted the following major immunochemical changes in the final course of a gamma heavy-chain disease associated with a myelomonocytic leukemia: an important oligoclonal increase of IgG1/kappa, during sepsis development, whereas the lambda molecules decreased and IgG2 and IgG3 completely disappeared in a one-month interval. Initial concentrations of IgG4 were stable during that period, and gamma 1 heavy chains were slightly increased. This is a very unusual observation of the successive immunochemical events terminating a gamma heavy-chain disease.