Similarly, young recipients of aged kidneys develop a senescent T cell phenotype, characterized by loss of CD28 and shortened telomeres in CD8+ T cells, closely mirroring the features observed in juvenile idiopathic arthritis (JIA), where oligoarticular patients (n = 62) show elevated frequencies of CD31+CD28− CD8+ T cells with reduced proliferative capacity and expression of senescence markers γH2AX and p16 [34]. Here, CD28 is linked to juvenile idiopathic arthritis.