Impact of CMV-serostatus on frequency and differentiation status of γδ T-cells. The frequency of Vδ2- and Vδ2+ γδ T-cells within total T-cells (A), CD27+CD28+ early-differentiated (B) and CD27-CD28- late-differentiated cells (C) within Vδ2+ and Vδ2- cells as well as the differentiation index (CD27+CD28+/CD27-CD28-) for each subset (D) were compared between CMV-seronegative (CMV-) and CMV-seropositive (CMV+) individuals between 21 and 89 years of age. Each symbol represents a single donor. Horizontal bars represent the median of the group. P values were calculated using the Mann-Whitney U-test. Y: young 21 to 38 years, 10 female, 4 male; O: old, 55 to 89 years, 11 female, 8 male).