Impact of age, gender, and race on circulating γδ T cells

A major subset of human peripheral blood gamma delta T cells expresses the V gamma 2V delta 2 T cell receptor and responds to malignant or infectious diseases. We noted significant differences in the numbers of V gamma 2V delta 2 T cells in blood samples from healthy Caucasian CA or African American (AA) donors. On average, CA donors had 3.71% +/- 4.37% V delta 2 cells (as a percentage of total lymphocytes) compared with 1.18% +/- 2.14% V delta 2 cells for AA donors (p < 0.0001). Age and race had the greatest impact on V delta 2 cell levels; the effect of age was similar for both racial groups. The V delta 2 cell population was dominated, for both donor groups, by cells expressing the V gamma 2-J gamma 1.2 V delta 2 T cell receptor, an apparent result of strong positive selection and there was substantial overlap in the public V gamma 2 clonotypes from both racial groups. Mechanisms for selection and amplification of V delta 2 cells are nearly identical for both groups, despite the significant difference in baseline levels. These data show that appropriate controls, matched for age and race, may be required for clinical studies of V gamma 2V delta 2 T cells in infectious disease or cancer and raise important questions about the mechanisms regulating the levels of circulating V delta 2 cells. (C) 2010 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.