T-cell large granular lymphocytic leukemia and pure red cell aplasia in a patient with type I autoimmune polyendocrinopathy: response to immunosuppressive therapy.

Clonal proliferations of large granular lymphocytes (LGLs) of T-cell origin characterize T-cell LGL leukemia. This disorder has been described in association with rheumatoid arthritis and other autoimmune phenomena. The presence of endocrinologic abnormalities in patients with T-cell LGL leukemia has not been previously reported, nor has T-cell LGL leukemia been described in patients with endocrinologic abnormalities. Herein we describe a young woman with type I autoimmune polyendocrinopathy, in whom pure red cell aplasia developed in association with clonal proliferation of LGLs. Immunosuppressive therapy with cyclophosphamide resulted in remission of pure red cell aplasia, transient improvement in hypocalcemia, and disappearance of the LGL clone. Clonal proliferation of LGLs may be associated with autoimmune endocrinopathies. Clinicians who are responsible for the care of such patients should be aware of this possible association.