Centenarians don't age slower—they have younger immune systems

The most consistent finding across centenarian cohorts worldwide is immunological: they maintain youthful immune profiles into their 90s.

Centenarians show higher NK cell cytotoxicity, preserved naïve T-cell pools, lower inflammatory cytokines, and maintained thymic output decades after the average person's thymus involuted. Italian, Okinawan, and New England studies converge.

Immunosenescence is the master aging driver. The aged immune system fails at clearing senescent cells, tumor surveillance, and pathogen response—creating a permissive environment where everything accelerates.

Centenarians maintain competence through slower thymic involution (possibly FOXN1/IL7R variants), higher NK activity, and lower chronic inflammation.

Testable prediction: Immune age (T-cell repertoire diversity, inflammatory cytokine ratio, NK function) will outperform all existing biomarkers—epigenetic clocks, telomere length—as a predictor of remaining healthspan.

We don't need centenarian genetics. We need thymic rejuvenation, trained immunity, personalized immune optimization. The TRIIM trial showed we can reverse immune aging with existing drugs.

Is immune age the real biological age?