Cytotoxic CD4+ Pool
25.4%
+8.4x over older adults
Lysis Clearance Rate
0 /min
0 targets eliminated
Granzyme B / Perforin
0.88 RFU
High cytolytic index
Exhaustion Barrier
Low (0.18)
PD-1 / KLRG1 Suppressed
Single-Cell Transcriptional Gate
scRNA-seq
Microenvironment Parameters
1.0x
25%
Longevity Mechanism Evidence
Key Discovery: Supercentenarians avoid typical age-related immunodeficiency not by preserving fragile naive T-cell pools, but through robust clonal expansion of cytotoxic CD4+ T-lymphocytes (up to ~25-30% of total CD4+ compartment). These cells express high levels of GZMB and PRF1, providing de novo direct tumor and viral target cell lysis.