Age-Related Differences in T-Cell Subsets in a Nationally Representative Sample of People Older Than Age 55: Findings From the Health and Retirement Study

Abstract

Though T-cell immunosenescence is a major risk factor for age-related diseases, susceptibility to infections, and responses to vaccines, differences in T-cell subset counts and representation by age and sex have not been determined for a large sample representative of the national population of the United States. We evaluated the counts of T-cell subsets including total, CD4+, and CD8+ T cells and their naïve (Tn), effector memory (Tem), and effector subsets, in the context of age, sex, and exposure to cytomegalovirus (CMV) infection among 8 848 Health and Retirement Study participants, a nationally representative study of adults older than 55 years. Total T cells (CD3+) and CD4+ cells declined markedly with age; CD8+ T cells declined somewhat less. While CD4+ T cell declines with age occurred for both CMV-seropositive and CMV-seronegative groups, total T cells and CD8+ cells were both substantially higher among the CMV-seropositive group. Numbers of Tn CD4+ and CD8+ cells were strongly and inversely related to age, were better conserved among women, and were independent of CMV seropositivity. By contrast, accumulation of the CD8+ and CD4+ Tem and effector subsets was CMV-associated. This is the first study to provide counts of T-cell subsets by age and sex in a national sample of US adults older than the age of 55 years. Understanding T-cell changes with age and sex is an important first step in determining strategies to reduce its impact on age-related diseases and susceptibility to infection.

Keywords: Aging; CMV seropositivity; Older adults.

Figure 1.

Distribution of absolute counts (mean [±SEM]) of CD4+ T cells and subsets by age in sex and CMV serostatus categories in Health and Retirement Study 2016 survey participants: (A) Total CD4+ cells, (B) CD4+ T cells: Effector, (C) CD4+ T cells: Effector memory (Tem), (D) CD4+ T cells: Central memory (Tcm), and (E) CD4+ T cells: Naïve (Tn). *p ≤ .001 for CD4+ T-cell subsets change across age groups based on NPAR1WAY test for p for trend.

Figure 2.

Distribution of absolute counts (mean [±SEM]) of CD8+ T cells and subsets by age in sex and CMV serostatus categories in Health and Retirement Study 2016 survey participants. (A) Total CD8+ cells, (B) CD8+ T cells: Effector, (C) CD8+ T cells: Effector memory (Tem), (D) CD8+ T cells: Central memory (Tcm), and (E) CD8+ T cells: Naïve (Tn). *p ≤ .001 for CD8+ T-cell subsets change across age groups based on NPAR1WAY test for p for trend.