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Background Preserving physical function is central to healthy aging, and declines in handgrip strength are strong predictors of frailty, disability, and mortality. Although immunosenescence has been implicated in age-related functional decline, the contribution of specific B-cell subsets to longitudinal changes in muscle strength remains poorly understood. Objective To examine whether baseline B-cell phenotypes are associated with 1-year changes in handgrip strength in community-dwelling older adults. Methods Sixty-two adults aged ≥60 years from the Magallanes Region, Chile, underwent baseline and 1-year follow-up assessments of handgrip strength and body composition. Peripheral B-cell subsets were characterized by flow cytometry, identifying CD45 + CD19 + lymphocytes and classifying subsets according to CD21 and CD11c expression. Associations between baseline B-cell subsets and 1-year change in handgrip strength were evaluated using robust linear regression adjusted for age, sex, and change in muscle mass. Results Participants showed a significant 1-year decline in handgrip strength (mean change: −2.02 kg), whereas muscle mass remained stable. Higher baseline frequencies of CD19 + CD21 + CD11c + B cells were independently associated with greater decline in handgrip strength over 12 months (βstd = −0.31, CI95% -0.60, −0.03, p = 0.031). No other B-cell subset was associated with changes in handgrip strength or muscle mass. Conclusion Baseline levels of CD19 + CD21 + CD11c + B cells were associated with a subsequent decline in handgrip strength in community-dwelling older adults, independent of change in muscle mass. These findings support a potential link between B-cell phenotypes and functional decline, warranting further investigation in larger cohorts.
Mabe-Castro et al. (Fri,) studied this question.