Pneumocystis pneumonia in liver transplant recipients

The clinical course of Pneumocystis pneumonia in liver transplant recipients has not been well investigated. Therefore, we collected and analyzed the clinical, epidemiological, and molecular data from patients with Pneumocystis pneumonia as well as paired controls (Chinese Clinical Trial Registry, ChiCTR2100046028; www.chictr.org.cn). There were a total of ten patients diagnosed with Pneumocystis pneumonia containing prospectively included six patients and retrospectively collected four patients, of which seven were transferred to the surgical intensive care unit and four died. The transmission map revealed that inter-patient transmission of Pneumocystis jirovecii was impossible; P. jirovecii detection was negative in all air samples. It was positive only in one sample from the twelve healthcare workers who had close contact with diseased patients. Five out of 79 liver transplant recipients during the outbreak were colonized with Pneumocystis jirovecii compared to 2 out of 94 after the outbreak upon admission (P>0.05). Liver transplant recipients with Pneumocystis pneumonia had totally different genotypes based on multilocus sequence typing. Additionally, we found an unreported mutation in the cytochrome b gene. The absolute CD19⁺ B-cell counts (odds ratio: 1.028; 95% confidence interval: 1.000-1.057; P=0.049) were defined to be the only significant independent risk factor. At a cut-off value of 117.16/µL, the sensitivity and specificity were 100% and 70%, respectively. Pneumocystis pneumonia is a severe complication following liver transplantation. The outbreak may not be caused by nosocomial transmission. A decrease in absolute CD19⁺ B-cell counts may be associated with the development of Pneumocystis pneumonia.