Immunological Theory of Aging

What it proposes

Roy Walford in the 1960s–70s argued aging arises from progressive immune-system dysfunction:

• Reduced immune capacity: weakened response to infection and cancer surveillance.
• Increased autoimmunity: failure to distinguish self from non-self.
• Cross-reactive damage: low-grade autoimmune attack on host tissues drives age-related decline.

Modern reformulation

The theory has been refined into two intertwined concepts:

• Immunosenescence: progressive thymic involution, T-cell repertoire contraction, memory-cell expansion, exhausted phenotypes.
• Inflammaging: chronic low-grade systemic inflammation (high IL-6, hsCRP, TNF-α) that drives most age-related diseases.

Together these produce the pattern Walford described, but the mechanism is broader than autoimmunity alone.

Evidence

• Centenarian cohorts show preserved naive T-cell populations and better inflammaging profiles.
• Thymic regeneration interventions (FOXN1 overexpression, sex-hormone modulation) restore immune function in mice and humans.
• CMV infection accelerates immunosenescence in many adults.
• IL-1β blockade (canakinumab in CANTOS) reduces both cardiovascular events and lung-cancer incidence — consistent with immunosurveillance loss.

Therapeutic implications

• Inflammaging is a tractable target (statins, GLP-1, colchicine, canakinumab, exercise, Mediterranean diet).
• Thymic regeneration is an active research area.
• CMV vaccination may emerge as preventive longevity intervention.

Related entries

Chronic inflammation, Inflammaging (concept), Immunosenescence (concept), CANTOS.