Rheumatoid arthritis associated with transient gamma 2-heavy chain disease

This paper describes the clinical history of a patient (F.-O.) with longstanding rheumatoid arthritis (RA), who subsequently developed a transient gamma 2-heavy chain disease (gamma 2-HCD). Immunochemical studies comprised serial determinations of serum levels of intact IgG, the gamma-HCD protein, IgA, and IgM. New applications of the rocket immunoselection and the radial immunodiffusion were used for the quantitation of the gamma-HCD protein and intact IgG, respectively, in the presence of one another. Immunofluorescent microscopy on bone marrow cells showed cells containing gamma-heavy chains but devoid of light chains. Protein studies of the isolated gamma-HCD protein revealed a molecular weight of 72 000 in the dimeric form, a carbohydrate content of 9.7%, and a PCA-Val-Gln NH2-terminal amino acid sequence. The literature on the rare coexistence of RA and gamma-HCD in a single patient is reviewed.