Acute graft pyelonephritis and long-term kidney allograft outcome

Long-term graft function is the result of multiple parameters, including both immune and non-immune components, which have a beneficial or detrimental potential. Among these, despite its frequency and theoretical interest (expression of "danger signals" in the graft itself), the effects of acute graft pyelonephritis (AGPN) on immediate and long-term outcome have not been studied in a large series. This article reviews a cohort of 1387 consecutive primary renal transplant recipients.

The objective of the study was to define the risk factor for AGPN, the risk profile for recurrence, and the impact of AGPN on long-term graft survival. According to a higher risk for AGPN in females during their follow-up, statistical analyses (Cox model, and multiple regression analysis) were performed by recipient sex strata.

Multivariate analysis showed that CMV infection was the only risk factor for AGPN occurrence. AGPN occurred in 13% of the graft recipients during their follow-up. Taken as a whole, AGPN was not associated with a significantly poor long-term outcome. However, when assessed in more detail, the outcome of this population was found to be more complex and to depend on several factors. Early AGPN (during the first 3 months) was significantly detrimental for graft outcome, independently of acute rejection episodes. Moreover, E. coli involvement in a first episode was linked to an increased AGPN recurrence.

This analysis did not support the concept that with current immunosuppression, strong "danger signals" such as those derived from bacteria within an allograft, are instrumental in initiating acute or chronic rejection.