Expression of shared idiotypes in chronic lymphocytic leukemia and small lymphocytic lymphoma

The expression of shared idiotypes (Slds) has been studied on malignant CD5+B cells from patients with chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) using a panel of 37 murine monoclonal antibodies previously demonstrated to be reactive with Slds derived from follicular B-cell lymphomas. Thirteen anti-Slds identified tumor cells from 31 of 105 (30%) CLL patients and 4 of 6 SLL patients. In comparison, the same panel of anti-Slds is reactive with 33% of follicular and diffuse B-cell lymphomas. Ten of these anti-Slds reacted with CLL cases at similar frequencies to that of the B-cell lymphomas. Two anti-Slds, which are known to react with autoantibodies, were significantly more prevalent in CLL than in B-cell lymphomas. These data confirm the presence of Slds in CLL and provide further evidence of an association between CLL and autoimmunity. The identification of a panel of antibodies reactive with a significant number of CLL and SLL patients will facilitate the application of anti-idiotype antibody therapy in these diseases.