Six-month risk of Pneumocystis pneumonia following acute cellular rejection: A case-control study in solid organ transplant recipients.

Background: Solid organ transplant (SOT) recipients are at risk of Pneumocystis pneumonia (PCP). PCP is associated with significant morbidity and mortality. The effect of acute T cell-mediated rejection (TCMR) on post-transplant PCP has not been determined yet.

Methods: In this case-control study, we estimated the risk of PCP following acute TCMR during a lookback period of 180 days. We also determined the effects of contributing factors such as CMV infection.

Results: We compared 15 SOT (8 kidney, 4 heart, 2 liver, and 1 kidney-pancreas) recipients with PCP with 60 matched recipients who did not develop PCP (control group) during the study period (December 2013 to February 2016). PCP occurred after a complete course of prophylaxis (ie, late-onset PCP) in 60% of patients. Patients with PCP frequently required intensive care unit (ICU) admission (73.3%). Post-transplant PCP was associated with considerable allograft loss (53.4%) and mortality (26.7%). In the 6-month lookback period, acute TCMR (OR: 13.1, 95% CI: 3.2, 53.2), and CMV infection (OR: 15.1,95% CI: 4.0, 53.2.1) were significantly associated with post-transplant PCP.

Conclusions: Post-transplant PCP is associated with substantial risk of ICU admission, allograft failure, and mortality. Anti-Pneumocystis prophylaxis for at least 6 months following acute TCMR may reduce the risk.