Characterization of T-cell large granular lymphocyte leukemia associated with Sjogren's syndrome-an important but under-recognized association

Patients with T-cell (CD3+) large granular lymphocyte (LGL) leukemia have a high prevalence of autoantibodies and associated autoimmune diseases. Sjogren's syndrome may not be diagnosed unless specifically looked for. We set to determine the prevalence of Sjogren's syndrome in LGL leukemia and its cytokine profile.

Every patient with a confirmed diagnosis of LGL leukemia diagnosed at a single academic medical center over the last 15 years was evaluated for Sjogren's syndrome by questioning about sicca symptoms. In symptomatic patients, Schirmer's test, rose bengal corneal staining, salivary flow rate measurement, autoantibody screening, and minor salivary gland biopsy were performed. Supernatants obtained from T-LGL leukemic cells following phytohemagglutinin (PHA) activation were analyzed for cytokine production by enzyme-linked immunosorbent assay and patients with or without Sjogren's syndrome were compared with controls.

Of 48 patients, 21 reported sicca symptoms and were enrolled in the study. In 8 patients Sjogren's syndrome was ruled out. Thirteen patients had clear evidence of Sjogren's syndrome according to accepted criteria (27%). None had rheumatoid arthritis, but 1 had limited scleroderma. Thus, 12/48 patients had primary Sjogren's syndrome. Other autoimmune diseases were frequently present, in particular, immune cytopenias (n=7) or thyroid autoimmunity (n=6). Supernatants of T-LGL leukemia cells incubated with PHA revealed markedly increased levels of multiple cytokines (especially soluble interleukin 2 receptor, tumor necrosis factor alpha, IL-6, IL-8) compared with healthy controls. However, this increase was common to LGL leukemia patients with or without Sjogren's syndrome.

Sjogren's syndrome was commonly identified in the patients with T-cell LGL leukemia in this study. Upregulated cytokine production by the neoplastic cells may underlie some of the immune-mediated disorders common in these patients.