Smoldering gamma delta T-cell granular lymphocytic leukemia associated with pure red cell aplasia.

We present a case of granular lymphocytic leukemia (GLL) associated with pure red cell aplasia (PRCA). Twenty-seven percent of the peripheral blood mononuclear cells (PBMC) were positive for TCR delta 1, but not for delta TCS1 (V delta 2), and a rearrangement of the TCR chain (J delta 1) gene was detected. The PBMC and serum from the patient slightly suppressed CFU-E but not BFU-E colony formation in vitro. These findings suggest that monoclonal proliferation of TCR gamma delta-positive granular lymphocytes (GL) can be associated with PRCA even in a patient having a small proportion of leukemia GL, which we propose to designate as 'smoldering GLL'.