Infection timing and immuno-inflammatory profiles determine prognosis of Pneumocystis jirovecii pneumonia in kidney transplant recipients

BACKGROUND: Pneumocystis jirovecii pneumonia (PJP) is a severe opportunistic infection in kidney transplant recipients (KTRs). Clinical presentation varies widely among patients. We aimed to identify key prognostic factors for PJP in KTRs, build a visual nomogram to predict outcomes, and examine the effect of infection timing on survival. METHODS: We analyzed data from 169 KTRs diagnosed with PJP at a single center between July 2019 and October 2025. Using multivariate Cox regression with restricted cubic spline (RCS) analysis, we identified independent prognostic factors. Using these factors, we developed a predictive nomogram and an online calculator. Model performance was assessed using the concordance index (C-index), ROC curves, calibration plots, and decision curve analysis (DCA). We also compared survival in patients with PJP within six months of transplantation versus after six months. RESULTS: Thirty-three patients (19.5%) died or required ICU admission. Multivariate Cox regression analysis showed that low CD4 + T-lymphocyte counts, high C-reactive protein (CRP) levels, and high serum 1,3-β-D-glucan (G-test) levels were key risk factors for adverse outcomes. The nomogram based on these indicators demonstrated high accuracy and clinical usefulness, with AUC values of 0.884 (4 months), 0.793 (9 months), and 0.877 (12 months) for predicting adverse outcomes. Patients with late-onset PJP (after 6 months) had a lower risk of adverse outcomes than those with early-onset PJP (within 6 months) (OR 0.36, P = 0.013). CONCLUSION: PJP outcomes in KTRs depend heavily on immune status and inflammatory response. Infection timing matters: early-onset PJP often leads to a higher risk of death. Our dynamic nomogram helps clinicians identify high-risk patients early, supporting a shift from standard treatment to stepwise precision care.