High Incidence and Mortality of Pneumocystis Jiroveci Infection in Anti-MDA5-Antibody Positive Dermatomyositis: Experience From a Single Center
Abstract Background Idiopathic inflammatory myopathies (IIM) was associated with a significantly higher risk of opportunistic infections that including Pneumocystis jiroveci pneumonia (PJP), a potentially fatal opportunistic infection. However, no prior studies have evaluated the PJP infection in subtypes of IIM. Objectives To investigate the incidence rate and mortality rate of PJP infection in subgroups of Idiopathic inflammatory myopathies (IIM) patients according to myopathy specific antibodies. Methods In the first part, 463 consecutive patients with IIM were prospectively followed up for a period of at least one year to analyze incidence of PJP. In the next part, we enrolled 30 consecutive PJP patients with any rheumatic disease were to identify the mortality rate and risk factors by Cox regression. Kaplan-Meier curve with log-rank test was used to access differences in survival. Results We found that the incidence rate of PJP in IIM patients is 3.0/100 person-year, while in MDA5+DM patients is 7.5/100 person-year and in MDA5−IIM patients is 0.7/100 person-year. (P < 0.05). PJP typically happened in the first two months for MDA5 + DM patients who have a significant decrease in the CD4+ T cell counts and Lymphocyte counts (P < 0.05). In PJP + patients, the mortality was lethally higher in MDA5+DM patients than those with other rheumatic diseases (83.3% VS. 38.9%, P < 0.05). Unlike patients with other rheumatic diseases, MDA5 + patients seemed not to benefit from prompt anti-PJP treatment. For patients with other rheumatic diseases, anti-PJP treatment within 6 days was confirmed to crucially increased the survival (P < 0.05). Conclusion PJP has alarming high incidence and mortality in MDA5+DM patients. Timely treatment for PJP does not improve the prognosis of this particular subtype. Therefore, the necessity of further study of PJP prophylaxis treatment in MDA5+DM patients is verified.