Release and clinical significance of soluble CD83 in chronic lymphocytic leukemia.

Soluble CD83 (sCD83), a potent immunosuppressive agent, circulates at elevated levels in some chronic lymphocytic leukemia (CLL) patients. We report that CLL patients with elevated plasma sCD83 levels had significantly shorter (P=0.038) treatment free survival. Culture of CLL cells with solid phase CD83 mAb+IL-4 significantly increases sCD83 release (23-117-fold, P=0.013) and ligation of normal donor PBMC with solid phase CD83 mAb alone induces similar significant increases in sCD83 release (P=0.003). RT-PCR analysis detected the presence of a transcript for sCD83 in 2/3 CLL samples. These results suggest sCD83 release may play a regulatory role in CLL progression.