Comprehensive profiling of phenotypic features of memory T- and B-cells from birth to the onset of old age.

Introduction: Human aging is accompanied by profound and continuous remodeling of the immune system, characterized by rhythmic, stage-specific patterns. These features are characterized by waves of cellular differentiation, network reorganization, and functional recalibration, a phenomenon encompassed by the concept of immunobiography. Methods: This study focuses on T- and B-cell memory immunophenotypes that shape adaptive immunity, including interferon-activated cells from healthy volunteers of both sexes, aged 9 months to 65 years, stratified into 12 consecutive age subgroups. Significant shifts were concentrated in intermediate age subgroups, particularly at 5-6 years, 10-19 years (the most pronounced), and 20-29 years. Results: Although women exhibited an earlier onset of changes, men demonstrated greater lifelong variability in differentiated subsets, especially for early effector CD4 Discussion: Our findings indicate that immune memory remodeling across the human lifespan occurs in discrete, sex-dependent waves, probably shaped by cumulative antigen exposure and endocrine transitions. These trajectories may differentially balance adaptive immunity and inflammatory differentiation, potentially influencing long-term immune resilience and susceptibility to chronic inflammatory conditions.