γδ T‐cell large granular lymphocyte (LGL) leukemia with spontaneous remission

T-cell large granular lymphocyte (LGL) leukemia is a clonal disorder with an indolent clinical course. In July 1995, a 46-year-old Japanese man was admitted to our hospital because his anemia had progressed. He had a white blood cell count of 3.9 × 109/L with 75% lymphocytes, which were intermediate to large and had almost round nuclei and azurophilic granules, and anemia with a red blood cell count (RBC) of 2.69 × 1012/L, hemoglobin (Hb) of 9.5 g/dL, and hematocrit (Hct) of 28.3%. Electron microscopic examination showed that most of the lymphocytes had a parallel tubular array and dense core granules in their cytoplasm. Flow cytometry and Southern blotting of the T-cell antigen receptor (TCR) genes using the peripheral blood species showed monoclonal proliferation of LGLs with a CD3+, TCRγδ+, CD4−, CD8−, CD16+, CD56−, CD57−, HLA-DR+ phenotype, and a TCR γ gene rearrangement, respectively, suggesting that the patient was diagnosed as having γδ T-cell LGL leukemia. He had no symptoms, organomegaly, or skin lesions. About 1.5 years after diagnosis, the anemia gradually improved with disappearance and appearance of a rearranged band in the TCR-γ gene and TCR-β gene, respectively. About 7 years after diagnosis, the anemia improved completely with a RBC of 5.01 × 1012/L, Hb of 14.8 g/dL, and Hct of 44.3%, and he was in complete remission without TCR-β and -γ gene rearrangements. He had received no therapy. This is the first report of spontaneous remission of γδ T-cell LGL leukemia. Am. J. Hematol. 75:168–172, 2004. © 2004 Wiley-Liss, Inc.