Pubertal stage specific changes in T-cell subpopulations in healthy individuals.

This study investigates how puberty affects T-cell subpopulations in healthy individuals, aiming to understand why kidney transplant outcomes are worse during adolescence. We hypothesize that pubertal maturation shifts the immune system towards a more pro-inflammatory phenotype. To explore this, we examined T-cell subtypes in individuals aged 8-30y. Pubertal maturation was assessed in 66 healthy individuals (median age: 17y, 42% male) using skeletal age and Tanner stage, and individuals were subsequently classified into one of four pubertal stages (pre-: n = 10, early-: n = 8, late-: n = 6, and post-puberty: n = 42). Multiple differentiation stages of CD4, CD8, and TCRγδ T-cells subpopulations were determined in peripheral blood samples using flow cytometry. Our results showed that absolute naïve CD4 T-cell and recent thymic emigrant CD4 T-cell counts generally decreased over the course of puberty (p = 0.004, p = 0.015), while absolute CD4 effector memory cell counts increased (p = 0.002). Notably, higher absolute naïve CD4 T-cell counts were observed during early-puberty compared to post-puberty which could not be explained by aging (p = 0.19). These findings indicate a developmental shift during puberty from a naïve to a more mature T-cell profile, supporting the idea that pubertal maturation affects the composition of the immune system.