2015 Volume 3 Issue 1 Pages 9-17
Pneumocystis jirovecii pneumonia (PCP) is a life-threatening fungal infection seen in immunocompromised patients. In 1980s, with the worldwide epidemic of human immunodeficiency virus (HIV) the prevalence of PCP has dramatically increased. Because of the progress in the anti-retroviral therapy and the use of routine prophylaxis against PCP, the incidence of PCP in HIV-infected population was reduced in most of the industrialized countries. Instead, PCP has now emerged as a threat to immunocompromised patients, such as those receiving novel immunosuppressive therapeutics for malignancy, organ transplantation, or connective tissue diseases. Clinical manifestations of PCP are quite different between patients with and without HIV infections. In patients without HIV infection, PCP rapidly progresses, is difficult to diagnose correctly, and causes severe respiratory failure with a poor prognosis. These differences in clinical features are the result of severe or dysregulated inflammatory responses evoked by a relatively small number of Pneumocystis organisms in patients without HIV infection. In recent years, the usefulness of PCR and serum b-D-glucan assay for noninvasive diagnosis of PCP has been revealed. Although corticosteroid adjunctive to anti-Pneumocystis agents has been shown to be beneficial in some populations, the optimal dose and duration remain to be determined. Recent investigations revealed that Pneumocystis colonization is prevalent, and that asymptomatic carriers are at risk for developing PCP and can serve as the reservoir for the spread of Pneumocystis by person-to-person transmission. These findings suggest the need for chemoprophylaxis in immunocompromised patients without HIV infection, although its indication and duration are still controversial.
