[Positive Pneumocystis jirovecii PCR in immunocompromised patients with a systemic disease: infection or colonisation?].

PURPOSE: Pneumocystis pneumonia is a serious opportunistic infection that frequently occurred in HIV-seropositive patients, prior to the advent of highly active antiretroviral therapy. This infection can also occur in patients with systemic diseases. The diagnostic value of a positive Pneumocystis jirovecii PCR in patients with systemic diseases has not yet been clearly defined.

METHODS: We conducted a retrospective study of patients with a systemic disease who presented clinical symptoms consistent with Pneumocystis pneumonia to assess the diagnostic value of a positive P. jirovecii PCR in respiratory samples.

RESULTS: During a 10-year period, 73 patients with respiratory symptoms underwent respiratory sampling with tests for the presence of P. jirovecii. P. jirovecii PCR was positive in 20 patients: Pneumocystis pneumonia was diagnosed in nine patients and for six of these nine patients, the microscopic examination was negative. Patients with Pneumocystis pneumonia differed from those who were solely colonized in that they had a lower CD4+ T lymphocyte count, were more likely to have received immunosuppressive treatment, and were not receiving primary prophylaxis against Pneumocystis pneumonia. Chronic pulmonary involvement was more frequent among colonized patients.

CONCLUSION: A positive P. jirovecii PCR does not always indicate overt infection. However, in a context of severe immunosuppression and in the absence of prophylaxis against Pneumocystis pneumonia, a specific treatment should be considered.