OVEREXPANDED B-CELL CLONE MEDIATING LEUKEMIC ARTHRITIS BY ABUNDANT SECRETION OF INTERLEUKIN-1-BETA - A CASE-REPORT

The role of cytokines in leukemic arthritis is unknown. The presentati on of a patient with B cell chronic lymphocytic leukemia and destructi ve arthritis of the wrist joints prompted us to study the synovial cyt okine pattern by immunohistologic analysis. In addition, rearranged V- H and V-L immunoglobulin genes were sequenced to assess B cell clonali ty, Heavy infiltrations of CD20+ cells with lambda light chain restric tion were found in the synovial tissue. Sequencing demonstrated overex pansion of a single B cell clone (DP58/D/J(H)4b and IGLV3S2/J(lambda)2 -J(lambda)3 for V-H and V-L, respectively) in the peripheral blood. Id entical V-H and V-L rearrangements were found in the synovial infiltra tes. Somatic mutations were found in both the peripheral blood and the synovial clone. Immunohistologic study revealed the presence of abund ant interleukin-1 beta (IL-1 beta) and, to a lesser degree, tumor necr osis factor beta (TNF beta) (lymphotoxin), In contrast, TNF alpha, int erferon-gamma, IL-4, IL-6, and IL-10 were rarely found in the synovial infiltrates. Therefore, IL-1 beta secreted in great amounts by leukem ic B cells appears to be the major cytokine that mediates joint destru ction in leukemic arthritis.