ObjectiveTo explore the clinical value of next-generation sequencing (NGS) in the diagnosis of Pneumocystis jirovecii pneumonia (PCP).MethodsTwo patients with Pneumocystis jirovecii pneumonia after lung transplantation were detected by NGS in the sputum and bronchoalveolar lavage fluid. The clinical data, imaging features, laboratory examination and treatment of the two patients were reported. A systematic literature review was performed for similar published cases in PubMed database, using the keywords "lung transplantation/solid organ transplantation" and "Pneumocystis jirovecii".ResultsThere were six references based on the keywords of "lung transplantation " and " Pneumocystis jirovecii ", of which three were case report. Sixty-six lung transplant patients were complicated with Pneumocystis jirovecii in total. The clinical manifestations of Pneumocystis jirovecii pneumonia were fever and dyspnea of different degrees. The diffuse "ground glass" infiltration could be shown on imaging. Computer tomography scan of chest was a sensitive method to detect PCP. Combined immunofluorescence microscope/PCR/serum 3-β-D-glucan could effectively improve the accuracy of microbiology detection. In addition, NGS could quickly and accurately identify pathogenic bacteria, give guidance for treatment and improve prognosis so as to benefit patients well. Trimethoprim/sulfamethoxazole (TMP/SMZ) was the preferred choice for the treatment of PCP patients.ConclusionsPneumocystis jirovecii pneumonia is more common in patients with immunodeficiency or immunosuppression. NGS can help rapid and accurate diagnosis, and the treatment should be early and sufficient.
Objective To investigate the colonization, risk factors and prognosis of Pneumocystis jirovecii (P.jirovecii) colonization in patients with Pulmonary alveolar proteinosis (PAP). Methods The patients with Pulmonary alveolar proteinosis who were admitted to the Department of Respiratory and Critical Care Medicine, Nanjing Drum Tower Hospital from March 2019 to December 2022 were retrospectively analyzed. Polymerase chain reaction/next-generation metagenomic sequencing were used to detect the colonization of P. jirovecii in bronchoalveolar lavage fluid, and then to investigate the colonization rate, risk factors and outcome of P. jirovecii in PAP patients. Results A total of 25 patients were included in the study, of which 7 were colonized by P. jirovecii (28.0%). The rate of using antibiotics before admission in the colonizing group was significantly higher than that in the non-colonizing group (85.7% vs 33.3%, P=0.030). Total blood lymphocytes (1.4×109/L vs. 1.8×109/L, P=0.048), CD3+T cells (0.83×109/L vs. 1.34×109/L, P=0.010), CD4+T cells (0.48×109/L vs. 0.85×109/L, P=0.010) were significantly lower than those in the non-colonizing group, lactate dehydrogenase (469.9 U/L vs. 277.3 U/L, P=0.005) was significantly higher than those in the non-colonizing group. A higher proportion of colonizing group required combination therapy (57.1% vs. 11.1%, P=0.032); but there was no significant difference in the percentage of whole-lung ground-glass opacification, lung function, oxygen index and outcome. Lactate dehydrogenase was positively correlated with the percentage of whole-lung ground-glass opacification of PAP, but negatively correlated with oxygen index, percentage of predicted forced vital capacity and percentage of predicted diffusion capacity for carbon monoxide. Conclusions The colonization rate of P. jirovecii in PAP patients was high. Reduced lymphocyte count in peripheral blood of PAP patients and antibiotic use before diagnosing were risk factors for P. jirovecii colonization.