Chronic lymphocytic leukemia associated with bone marrow fibrosis: possible role of interleukin 1 alpha in the pathogenesis.

B-cell chronic lymphocytic leukemia (B-CLL) associated with bone marrow fibrosis is described. The conditioned medium of the CLL cells contained a high quantity of interleukin 1 alpha (IL-1 alpha), and showed growth promoting activity for marrow fibroblasts which was partially inhibited by anti IL-1 alpha antibody. In addition, the conditioned medium as well as IL-1 alpha stimulated the growth of marrow fibroblasts from the patient. These results strongly suggested the marrow fibrosis occurred by the secretion of IL-1 alpha from the CLL cells and its growth stimulation of marrow fibroblasts. As far as we know, this is the first case in which B-CLL was associated with marrow fibrosis, and its mechanism was investigated.