CD4 and cystic fibrosis: - Comparison of Tregs (CD4+ CD25+ FOXP3+):→ higher percentages in CFAct and CFPast groups compared to the CFControl→ in elderly cohort were higher in NTM patients compared to healthy controls.- CD25+, CTLA-4, and PD-1 on CD4+ T cells revealed a common fingerprint in CFAct and CFPast groups which was distinct from the CFControl group- no difference between CF patients with active or past NTM-PD and HC in terms of T cell fingerprint