TCRγ δ⁺ cells expressing Vγ 9Vδ 2, which normally predominate the blood, are found in the spleens of patients with hairy cell leukemia

Abstract

T cell receptor γδ⁺ (TCRγδ⁺) cells are present in all lymphoid tissues, but at lower frequencies than TCRαβ⁺ cells. In normal spleens, they account for about 15–20% of CD3⁺ cells. In hairy cell leukemia (HCL), a B cell malignancy with a characteristic involvement of the spleen, splenic T cells of approximately 40% of the examined patients showed a remarkable increase in CD3⁺TCRγδ⁺ cells. Therefore, we studied the TCRγδ phenotypes in blood and spleen of 12 HCL patients in comparison with normal samples. In normal blood (n = 6) the majority of TCRγδ⁺ cells expressed the Vγ 9Vδ 2 phenotype, while in normal spleens (n = 9) a different population was found expressing Vδ 1. In contrast, six of eight paired blood and spleen samples of individual HCL patients demonstrated the same phenotype with predominantly Vγ 9Vδ 2 expression. This change in splenic TCRγδusage in patients with HCL might be the result of cell-trapping, or an infiltration of TCRγδ⁺ cells from the blood.