Clinical and immunologic aspects of B chronic lymphocytic leukemia associated with autoimmune disorders

Autoimmune disorders often develop during the course of B chronic lymphocytic leukemia. The source of the autoantibodies is still uncertain: either uncontrolled production of the malignant B cells or disturbances of the residual normal B and T cells involved in the immune system.

To evaluate immunologic parameters in B-CLL associated with autoimmune disorders. As a hypothesis we postulated that in those cases, the malignant B cells might disclose an activated phenotype pattern leading to the production of autoantibodies.

In the Registry of the Israel Study Group on CLL that includes 964 patients, we found 115 cases showing a single or a complex of autoimmune disorders. We evaluated the lymphocyte morphology, immunoglobulin G and beta-2-microglobulin serum levels and positivity of the CD38 and FMC7 markers, and compared these values with those of a matched CLL population without autoimmune disorder.

The main autoimmune disorders encountered were autoimmune hemolytic anemia (55 patients), Evan's syndrome (n=7), Hashimoto's thyroiditis (n=15), vasculitis (n=5) and rheumatoid arthritis (n=4). We found atypical prolymphocytic morphology in 22%, high expression of the activation antigens CD38 and/or FMC7 in 30%, and high level of immunoglobulin G (> 1000 mg/dl) and beta-2-microglobulin in 57% and 78% respectively. When compared with a matched CLL population without an autoimmune disorder, these values were statistically significant.

Our data, which show activated lymphocyte morphology, high levels of IgG and beta-2-microglobulin, and increased expression of CD38 and/or FMC7 in a significant number of cases, suggest that some degree of activation of B cells may lead to the occurrence of an autoimmune disorder in CLL.