Arthritis associated with primary agammaglobulinemia: new clues to its immunopathology

Primary agammaglobulinemia is a rare disorder which is associated with articular symptoms in 11% of patients. Septic arthritis may occur, but often patients complain of chronic oligoarthritis and have a clinical presentation similar to rheumatoid arthritis. We report 2 cases of primary agammaglobulinemia in adults, associated with non-erosive chronic arthritis. Peripheral blood lymphocyte phenotyping showed a predominance of CD8 lymphocytes with a CD4/CD8 ratio < 1. We did not find any abnormalities in cellular immunity. A histological study of the synovium showed chronic synovitis with perivascular CD8 lymphocyte infiltrates. Intravenous infusion of immunoglobulins resulted in a dramatic improvement in the arthritis in both cases. In one patient we noticed a decrease in CD8 lymphocytosis. These results suggest that CD8 lymphocytes are involved in the pathogenesis of the arthritis associated with agammaglobulinemia.