Tfh cell subset biomarkers and inflammatory markers are associated with frailty status and frailty subtypes in the community-dwelling older population: a cross-sectional study

We conducted a cross-sectional study investigating community-dwelling older population to determine association between immunoscenescence marker, inflammatory cytokines and frailty. Frailty status was classified with 33-item modified frailty index and latent class analysis was applied to explore the latent classes (subtypes) of frailty. In multivariable analysis, higher Tfh2 cells were associated with a higher risk of frailty [1.13(1.03–1.25)] in females, but a lower risk of cognitive and functional frail [0.92(0.86–0.99)] and physiological frail [0.92(0.87–0.98)]. Additionally, a greater risk of multi-frail and physiological frail correlated with low Tfh1 [0.77(0.60–0.99); 0.87(0.79–0.96)] and Tfh17 cells [0.79(0.65–0.96); 0.86(0.78–0.94)], respectively. Higher B cells were associated with decreased frailty/pre-frailty both in females [0.89(0.81–0.98)] and males [0.82(0.71–0.96)], but did not correlate with frailty subtypes. Regarding inflammatory markers, participants in the TGF-β 2(nd) quartile showed a decreased risk of pre-frailty/frailty in females [0.39(0.17–0.89)] and psychological frail [0.37(0.16–0.88)], compared with those in the top tertile. Moreover, we found participants in the 2(nd) tertile for IL-12 levels showed a decreased risk of physiological frail [0.40 (0.17–0.97)]. Our study highlights the importance of Tfh cell subsets and inflammatory markers in frailty in a sex-specific manner, particularly in terms of frailty subtype.