[Clinical Characteristics of Pneumocystis Jiroveci Pneumonia after Allogeneic Hematopoietic Stem Cell Transplantation].

Objective: To summarize the clinical characteristics of patients with combined pneumocystis jiroveci pneumonia (PJP) after allogeneic hematopoietic stem cell transplantation (allo-HSCT).

Methods: The clinical manifestations, laboratory tests, imaging findings, and treatment outcomes of 21 allo-HSCT patients with PJP diagnosed at the First Affiliated Hospital of Soochow University and Soochow Hopes Hematology Hospital from July 2018 to July 2023 were retrospective analyzed.

Results: Among the 21 patients, the male -to-female ratio was 2.5∶1, and the median age was 36 years old with a range of 15-62 years. The median time to diagnosis of PJP after transplantation was 225 days. The clinical manifestations lack specificity, and the main clinical symptoms include respiratory symptoms (dyspnea, cough, sputum, etc.) and fever. Laboratory examination revealed peripheral blood lymphocyte counts decreased in 15 cases, CD4⁺ T lymphocyte absolute values less than 200 cells/μl in 19 patients, C-reactive protein levels significantly increased in 20 patients, lactate dehydrogenase levels increased in 14 patients, and 1,3-β-D-glucan detection levels increased in 14 patients. Chest CT manifestations can be divided into three types: ground glass type, nodular type, and mixed type. Among them, the incidence of ground glass type was the highest (18/21), with 2 cases of nodular type and 1 case of mixed type. The sequence number of Pneumocystis jiroveci was detected through mNGS (15-57 570), and 11 patients had mixed infections. In terms of treatment, TMP-SMX, Caspofungin, and methylprednisolone were administered, and 17 patients achieved improvement in their condition. Four patients died, all of whom died from respiratory failure.

Conclusion: PJP is a critically ill condition after hematopoietic stem cell transplantation, and diagnosis is difficult. Early diagnosis can achieve better prognosis. The sensitivity of mNGS in diagnosing PJP is high, providing the possibility of early and accurate diagnosis for clinical practice, which is worthy of application and promotion.