Systemic lupus erythematosus and chronic lymphocytic leukemia: rare coexistence in three patients, with comments on pathogenesis.

We describe three patients with coexistent chronic lymphatic leukemia (CLL) and systemic lupus erythematosus (SLE). In two patients, the CLL was present before or coexistent with the SLE when the SLE was diagnosed, while in the third, the CLL developed 5 years after the diagnosis of SLE was first made. Although the association of autoimmune diseases and lymphoproliferative disorders is well established, only a few patients with coexistent CLL and concomitant SLE have been reported. The possible pathogenesis of this rare association is discussed.