T-cell ageing in end-stage renal disease patients:Assessment and clinical relevance

End-stage renal disease(ESRD) patients have a defective T-cell-mediated immune system which is related to excessive premature ageing of the T-cell compartment.This is likely to be caused by the uremia-associated pro-inflammatory milieu,created by loss of renal function.Therefore,ESRD patients are highly susceptible for infections,have an increased risk for virus-associated cancers,respond poorly to vaccination and have an increased risk for atherosclerotic diseases.Three ageing parameters can be used to assess an immunological T-cell age.First,thymic output can be determined by assessing the T-cell receptor excision circlescontent together with CD31 expression within the naive T cells.Second,the telomere length of T cells and third the T-cell differentiation status are also indicators of T-cell ageing.Analyses based on these parameters in ESRD patients revealed that the immunological T-cell age is increased by on average 20 years compared to the chronological age.After kidney transplantation(KTx) the aged T-cell phenotype persists although the pro-inflammatory milieu is diminished.This might be explained by epigenetic modifications at hematopoietic stem cells level.Assessment of an immunological T-cell age could be an important tool to identify KTx recipients who are at risk for allograft rejection or to prevent over-immunosuppression.