Pneumocystose chez les patients immunodéprimés non infectés par le VIH

Abstract

Pneumocystis jiroveci (formerly P. carinii) is an opportunistic fungus responsible for pneumonia in immunocompromised patients. Pneumocystosis in non-HIV-infected patients differs from AIDS-associated pneumocystosis in mostly two aspects: diagnosis is more difficult, and prognosis is worse. Hence, efforts should be made to target immunocompromised patients at higher risk of pneumocystosis, so that they are prescribed long-term, low-dose, trimethoprime-sulfamethoxazole, highly effective for pneumocystosis prophylaxis. Patients at highest risk include those with medium and small vessels vasculitis, lymphoproliferative B disorders (chronic or acute lymphocytic leukaemia, non-Hodgkin lymphoma), and solid cancer on long-term corticosteroids. Conversely, widespread use of prophylaxis in all patients carrier of inflammatory diseases on long-term corticosteroids is not warranted. The management of pneumocystosis in non-AIDS immunocompromised patients follows the rules established for AIDS patients. The diagnosis relies on the detection of P. jiroveci cyst on respiratory samples, while PCR does not reliably discriminate infection from colonization, in 2015. High-doses trimethoprim-sulfamethoxazole is, by far, the treatment of choice. The benefit of adjuvant corticosteroid therapy for hypoxic patients, well documented in AIDS patients, has a much lower level of evidence in non-HIV-infected patients, most of them being already on corticosteroid by the time of pneumocystosis diagnosis anyway. However, based on its striking impact on morbi-mortality in AIDS patients, adjuvant corticosteroid is recommended in hypoxic, non-HIV-infected patients with pneumocystosis by many experts and scientific societies.