[Gamma-1 heavy chain disease with the demonstration of Bence-Jones proteins].

We describe a 61-year-old patient suffering from gamma-1-heavy-chain disease (gamma 1-HCD) associated with Bence-Jones-lambda proteinemia and proteinuria. The analysis of the patients gamma 1-HCD protein (WIN) shows a deletion of the complete Fd fragment. The N-terminal seven amino-acid residue does not resemble any of the known immunoglobulin-heavy-chain variable regions. Unexpectedly, in PBL-DNA and in DNA from EBV-immortalized cells we found in addition to the expected predominantly rearranged Ig-lambda-light-chain gene a predominant rearrangement of an Ig-kappa gene. These findings show that the gamma-1-heavy-chain disease of the patient involves a defective regulation of Ig-light-chain-gene activation as well.