To analyze the clinical manifestation, diagnosis and treatment of Pneumocystis jirovecii pneumonia (PCP) in immunocompromised patients without human immunodeficiency virus (HIV) infection, and investigate the clinical characteristics of PCP in kidney transplant recipients.

Forty-Two patients with PCP who were hospitalized between January 2013 and December 2016 in a tertiary teaching hospital were included in a retrospective study.They were divided into kidney transplantation group (21 cases) and non-kidney transplantation group (21 cases), their clinical data were collected and analyzed.

The patients included 19 males and 23 females, with median (quartile) age of 49.0(27.0) years.The mainly underlying disease was kidney transplantation which accounted for 50.0%, followed by non-transplant kidney disease (19.0%) and connective tissue disease (14.3%). Most of patients (97.6%) received immunosuppressive therapies.Fever (100.0%), cough (64.3%) and dyspnea (59.5%) were the most common symptoms.Diffuse ground-glass opacity (83.3%), patchy and/or consolidation were the most common manifestations on chest CT scan.All patients received first-line treatment for PCP with 14 patients adjusted to alternative regimens because of clinical failure or untolerable side effects.The regimens were mainly sulfamethoxazole/trimethoprim (SMZ/TMP)(48.2%) or combination therapy with SMZ/TMP (35.7%), non-SMZ/TMP regimens were only accounted for 16.1%(caspofungin or caspofungin combined with clindamycin). The mortality was 7.1%(3/42 cases). Compared with non-kidney transplantation group, the patients in kidney transplantation group were mainly male (61.9% vs 28.6%, P=0.030) and younger [41.0(18.0) vs 52.0(27.0) years old, P=0.015], most of them had low-grade fever(low-grade fever, moderate fever and high fever were 66.7%, 28.6% and 4.7%, respectively vs 14.3%, 38.1% and 47.6%, respectively, P=0.001) and PaO₂/FiO₂ ration>300(PaO₂/FiO₂ ration>300, ≤300, ≤200, ≤100 were 71.4%, 19.1%, 9.5%, 0, respectively vs 19.1%, 23.8%, 38.0%, 19.1%, respectively, P=0.003), total lymphocyte count was significantly decreased [0.6(0.8)×10⁹/L vs 1.0(2.1)×10⁹/L, P=0.036], serum creatinine level was significantly increased [160.0(105.5) vs 77.0(36.0) μmol/L, P=0.001], fewer patients reiceived respiratory support therapy (non-invasive positive pressure ventilation and mechanicalventilation were 1 and 0 case, respectively vs.8 and 2 cases, respectively, P=0.007), 3 cases who were all non-kidney transplant patients died.

PCP in kidney transplant recipients is characterized as mild clinical manifestation and better prognosis.Kidney transplant recipients with lymphopenia and renal insufficiency are at high risk of PCP.

Pneumonia; Pneumocystis jiroveci; Pneumocystis jirovecii pneumonia; Immunocompromised host