Abstract: Objective To study the clinical characteristics, diagnosis and treatment strategy of pneumocystis pneumonia (PCP) in non-hematopoietic stem cell transplantation (HSCT) patients with hematological diseases, in order to improve the understanding of the disease. Methods The clinical manifestations, laboratory examinations, imaging features, treatment strategies and clinical outcomes of 7 non-HSCT patients with hematological diseases complicated with PCP confirmed from September 2014 to September 2019 in the hospital were retrospectively analyzed. Results 1 Basic diseases were hematological malignancies in 5 cases and autoimmune hematological diseases in 2 cases. All received immunosuppressive therapy. 2 The incubation period for the disease was between 5 and 30 days, and the main clinical manifestations include fever, dry cough and labored dyspnea. 3 Increased lactate dehydrogenase was found in 7 cases and hypoxemia in 5 cases. 4 Pulmonary high-resolution CT showed diffuse ground-glass shadow in both lungs, accompanied by bronchial inflation sign and air sac cavity. The ground-glass shadow fused into pieces in the late stage of the disease. 5 Pneumocystis jirovecii (PJ) cysts were found in bronchoalveolar lavage fluid in 7 cases. PJ nucleic acid was positive in 5 cases by polymerase chain reaction. Serum 1-3-β-D glucan level was increased in 5 cases. 6 Methoxypyrimidine-sulfamethoxazole was the first choice for treatment in all cases. Five cases were also treated with caspofungin, 2 cases received mechanical ventilation. Five cases recovered and 2 died. Conclusions PCP might be a fatal disease for patients received immunosuppressive agents. Early diagnosis and early treatment could improve the curative effect, and high-risk patients need preventive medication.

Key words: hematological malignancies, immunocompromised host, pneumocystis pneumonia, clinical analysis