A unique CD4+ large granular lymphocytosis occurring in patients treated with tumor necrosis factor α inhibitors: report of 2 cases.

We report 2 cases of CD4(+) large granular lymphocyte (LGL) lymphocytosis occurring in patients being treated with a monoclonal antibody against tumor necrosis factor α for underlying autoimmune disorders. CD4(+) LGL lymphocytosis is a rare subset of LGL disease that has previously only been described in patients without underlying autoimmune disorders, and most demonstrate uniform coexpression of CD56 on the atypical T cells. The clinical features, with both cases occurring in patients with autoimmune disease, and immunophenotypic features, with both cases showing dim CD8 coexpression without CD56 in the CD4(+) LGLs, suggest that the reported cases are distinct from those previously described and may represent a novel T-cell LGL lymphocytosis emerging from iatrogenic immune modulation of patients with underlying autoimmune disorders.