Clinical features and prognosis of pneumocystis pneumonia in patients treated with rituximab for autoimmune diseases

Abstract

Objective: To determine the clinical features and outcomes of pneumocystic pneumonia (PCP) in patients treated with rituximab for autoimmune diseases. Methods: PCP patients with autoimmune diseases as underlying diseases from January 2009 to April 2019 in Peking University First Hospital (male 67 cases, female 35 cases, age 17-79) were retrospectively reviewed. Patients were grouped as rituximab group and non-rituximab group based on the fact if they were treated with rituximab before the onset of PCP. Demographic data, clinical features, and outcomes of the two groups were analyzed. Results: There were 102 cases altogether, and 7 patients were treated with rituximab before the onset of PCP. Patients in rituximab group were relatively younger than that in non-rituximab group [(32.0±18.7) vs (52.4±14.9) years, P=0.010]. Patients in rituximab group had more CD3(+), CD4(+), CD8(+)T lymphocytes in peripheral blood samples than that in non-rituximab group [(1 306±596) vs (546±439)/μl, (674±401) vs (243±232)/μl, (616±249) vs (282±256)/μl, respectively, all P<0.01]. However, the B lymphocyte count and plasma level of IgG and IgM were significantly lower in rituximab group than that in non-rituximab group [0 (0, 0.2) vs 72 (50.0, 124.4)/μl, 4.0 (2.6, 5.8) vs 9.4 (5.3, 12.0) g/L, 0.3 (0.2, 1.0) vs 1.1 (0.6, 1.8) g/L, respectively, all P<0.05]. The incidence of Cytomegalovirus (CMV) pneumonia was significantly lower in rituximab group (0/7 and 57/95, P=0.007). Other demographic data, the use of corticosteroids, the incidence of severe PCP, mechanical ventilation, intubation, pneumothorax and mediastinal emphysema complications, as well as hospital mortality and length of stay in hospital in the two groups were comparable. Conclusions: In patients treated with rituximab for autoimmune diseases, the number of B lymphocytes in peripheral blood and the plasma level of immunoglobulins but not CD3(+), CD4(+), and CD8(+)T lymphocyte counts may play an important role in the pathogenesis of PCP. These patients are not vulnerable to be complicated with CMV pneumonia.