Distinct follicular T cell subsets regulate lymphoma progression and outcomes

follicular T cell subsets that expand in FL. These subsets exhibit enhanced anti-tumorigenic properties and form unique spatial niches. Their phenotypes were replicated under interleukin-21-predominant conditions, revealing discrete self-regulatory cellular ecosystems that generate these subsets and may underlie FL clinical behaviors. Furthermore, these subsets robustly stratify FL prognoses, independently of existing prognostic markers. Our findings highlight previously unrecognized immunity that could advance our understanding of lymphoma and improve patient management.