Differences in the clinical characteristics of Pneumocystis jirovecii pneumonia in immunocompromized patients with and without HIV infection

Background and objective: The incidence of Pneumocystis jirovecii pneumonia (PCP) in patients with predisposing immunodeficiencies other than AIDS is growing. Knowing the different characteristics and outcomes of PCP according to HIV status would help physicians manage and treat patients with PCP. Methods: The medical charts of all patients with a proven first episode of PCP, diagnosed between 1997 and 2007 were retrospectively reviewed, and clinical and laboratory data abstracted. Results: Of the 35 patients with PCP, 18 were HIV-positive and 17 were HIV-negative with other immunosuppressive conditions. HIV-negative patients were significantly older than HIV-positive patients. The WCC (10 952 +/- 5669 vs 9750 +/- 3133/mu L; P = 0.015), neutrophil counts (9631 +/- 5421 vs 5680 +/- 2628/mu L; P = 0.01) and CD4+ lymphocyte counts (329 +/- 502 vs 47 +/- 50/mu L; P < 0.001) were significantly higher in HIV-negative patients. Six of the 17 HIV-negative patients had a CD4+ lymphocyte count > 300/mu L. Serum IgG levels were lower in HIV-negative patients (943 +/- 379 vs 1635 +/- 657 mg/dL; P = 0.017). Mortality was higher in HIV-negative (52.9%) than in HIV-positive patients (0%). On univariate analysis, risk factors for mortality from PCP were the presence of underlying pulmonary disease (odds ratio 4.000, 95% CI: 1.501-10.658) and HIV-negative status (odds ratio 2.125, 95% CI: 1.283-3.518). Conclusions: The characteristics and outcomes of PCP differ significantly depending on HIV status. The existence of underlying pulmonary diseases may be associated with the prognosis of HIV-negative patients with PCP.