Clinicopathologic, Immunophenotypic, Cytogenetic, and Molecular Features of γδ T-Cell Large Granular Lymphocytic Leukemia: An Analysis of 14 Patients Suggests Biologic Differences With γδ T-Cell Large Granular Lymphocytic Leukemia

Objectives: T-cell large granular lymphocytic (T-LGL) leukemia is a rare disorder in which the neoplastic cells usually express the αβ T-cell receptor (TCR). To determine the significance of γδ TCR expression in this leukemia, we compared the clinicopathologic, immunophenotypic, and genetic features of patients with T-LGL leukemia expressing γδ TCR or αβ TCR. Methods: We used the World Health Organization classification criteria to confirm the diagnosis. All patients were diagnosed and treated at our institution. Results: We identified 14 patients with γδ T-LGL leukemia, 11 men and three women; six (43%) patients had a history of rheumatoid arthritis, 10 (71%) had neutropenia, four (29%) had thrombocytopenia, and three (21%) had anemia. Eight (67%) of 12 patients had a CD4−/CD8− phenotype, and four (33%) had a CD4−/CD8+ phenotype. The median overall survival was 62 months. Patients with γδ T-LGL leukemia were more likely to have rheumatoid arthritis ( P = .04), lower absolute neutrophil count ( P = .04), lower platelet count ( P = .004), and a higher frequency of the CD4−/CD8− phenotype ( P < .0001). However, there was no significant difference in overall survival between the two groups ( P = .64). Conclusions: Although patients with γδ and αβ T-LGL leukemia show some different clinical or phenotypic features, overall survival is similar, suggesting that γδ TCR expression does not carry prognostic significance.