Distribution of Pneumocystis jirovecii in lungs from colonized COPD patients

Abstract

Pneumocystis jirovecii has been detected in lung tissue from patients with chronic obstructive pulmonary disease (COPD) and is associated with disease severity. The regional distribution of the organism in lungs is unknown, but differences in distribution of Pneumocystis could affect estimates of colonization prevalence. We examined the distribution of Pneumocystis in the lungs of 19 non-HIV-infected patients with COPD who were undergoing lung transplantation. DNA was extracted from explanted lungs. We found Pneumocystis colonization in lung tissue of 42.1% of patients with advanced COPD; however, there was significant regional variation in colonization between lung segments of individual patients. Colonization was detected more commonly in the lower and middle lobes than the upper lobes. These findings suggest that single samples from an individual may underestimate the prevalence of Pneumocystis colonization and future studies may obtain a higher yield of Pneumocystis colonization detection when sampling the lower lobes.

Prospective Multicenter Study of Pneumocystis jirovecii Colonization among Cystic Fibrosis Patients in France

“…Despite technical factors that can influence the reported prevalence of Pneumocystis colonization, and according to the abovecited studies (including our results), it appears that CF is associated with lower Pneumocystis colonization rates than are other chronic pulmonary diseases (14,20,22,24,26,27,32). Three studies have reported the association of P. jirovecii and P. aeruginosa in CF patients (14,22,25), but whether Pneumocystis infection/colonization complicated CF-associated lung disease remains unclear.…”

Neither Classical nor Alternative Macrophage Activation Is Required for Pneumocystis Clearance during Immune Reconstitution Inflammatory Syndrome

“…Pneumocystis also infects patients receiving long-term immunomodulatory therapy for rheumatoid arthritis and other inflammatory diseases (4) as well as cancer patients undergoing chemotherapy (5). Furthermore, Pneumocystis infection or colonization has been associated with chronic obstructive pulmonary disease in both HIV and non-HIV patients (6).…”

“…The host's immune response against this pathogen often contributes to severe PcP-related lung injury (6,7). Clinical studies suggest that the intensity of pulmonary inflammation, rather than organism lung burden, correlates with the severity of PcP (8)(9)(10).…”

ExperimentalPneumocystislung infection promotes M2a alveolar macrophage-derived MMP12 production

“…Although the mechanism(s) for this is unknown, it has been hypothesized that subclinical pulmonary infections could be involved. In turn, the atypical fungal organism Pneumocystis jirovecii is increasingly becoming associated with COPD in both non-HIV and HIV patients (26,27,36). We have recently determined that HIV-positive individuals colonized with Pneumocystis had worse airway obstruction in the presence of higher levels of MMP12, but not MMP1, MMP2, or MMP9, in sputum compared with noncolonized HIV-positive individuals (25).…”