Do infectious diseases after kidney re-transplantation differ from those after first kidney transplantation?

Infectious diseases (ID) are highly relevant after solid organ transplantation in terms of morbidity and mortality, being among the most common causes of death. Patients undergoing kidney re-transplantation (re-K-Tx) have been already receiving immunosuppressive therapy over a prolonged period potentially facilitating subsequent infections. Comparing ID events after re-K-Tx and first kidney transplantation (f-K-Tx) can delineate patterns and risks of ID events associated with prolonged immunosuppression. We included adult patients with records on the f-K-Tx and re-K-Tx in the Swiss Transplant Cohort Study. We analyzed ID events after f-K-Tx and re-K-Tx within the same patients, and compared infection rates, causative pathogens and infection sites. Recurrent time to event analyses were performed for comparison of infection rates. A total of 59 patients with a median age of 47 years (range = 18 - 73) were included. Overall, 312 ID events in 52 patients occurred. In multivariable recurrent event modelling, the rate of ID events was significantly lower after re-K-Tx (HR = 0.70, p = 0.02). More bacterial (68.9% versus 60.4%) and fungal (4.0% versus 1.1%) infections were observed after f-K-Tx, but less viral infections (27.0% versus 38.5%) as compared to after re-K-Tx (p = 0.11). After f-K-Tx, urinary tract and gastrointestinal tract infections were more frequent; after re-K-Tx, respiratory tract and surgical site infections were more frequent (p < 0.001). Infectious disease events were less frequent after re-K-Tx. Affected sites differed significantly after f-K-Tx compared to after re-K-Tx.