T-lymphocytes expressing CC chemokine receptor-5 are increased in frail older adults

Abstract

Objectives: To evaluate the frequencies of T-lymphocytes expressing CC chemokine receptor-5 (CCR5(+) T-cells) and their relationship with frailty in older adults.

Design: Case-control study with an age-, race-, and sex-matched design.

Setting: General Clinical Research Center.

Participants: Community-dwelling adults aged 72 and older from Baltimore, Maryland.

Methods: Frailty was determined using five validated criteria: weakness, slow walking speed, fatigue, low physical activity, and weight loss. Those meeting three or more of these five criteria were defined as frail and those with none as nonfrail. Complete blood counts were performed to obtain peripheral lymphocyte counts using an automated (Coulter) counter. Peripheral blood was collected for surface immunofluorescent staining of CCR5 and other T-cell markers.

Results: Twenty-six frail and matched nonfrail participants (mean age+/-standard deviation 83.8+/-5.3, range 72-94) completed the study. Frail participants had higher CCR5(+), CCR5(+)CD8(+), and CCR5(+)CD45RO(-) T-cell counts than matched nonfrail controls (349+/-160/mm(3) vs 194+/-168/mm(3), P=.02; 208+/-98/mm(3) vs 105+/-62/mm(3), P=.02; and 189+/-149/mm(3) vs 52+/-36/mm(3), P=.01; respectively). Furthermore, there was a trend toward graded increase in these T-cell counts across the frailty scores in frail participants (e.g., CCR5(+)CD8(+) counts of 123+/-52/mm(3), 248+/-115/mm(3), and 360+/-215/mm(3) for those with frailty scores of 3, 4, and 5, respectively).

Conclusion: These initial results suggest an expansion of the CCR5(+) T-cell subpopulation in frailty. They provide a basis for further characterization of CCR5(+) T-cells and their role in frailty, with potential therapeutic implications.

Figure 1

Trend of graded increase in CCR5⁺ T-cell counts across frailty scores. Each bar represents the mean count of CCR5⁺T-cells (A), CCR5⁺CD8⁺ T-cells (B), and CCR5⁺CD45RO⁻ T-cells (C) in each of the frail participant groups with a frailty score of 3, 4, or 5. The numeric data of mean ± standard deviation are shown above each bar. The number of frail participants in each group is indicated (in parenthesis) along with the frailty score.