Objective: To compare the clinical characteristics and outcomes of Pneumocystic carinii pneumonia (PCP) infection between patients with acquired immunodeficiency syndrome (AIDS) and patients with other immunodeficiencies.

Materials and methods: The medical records of patients with PCP infection in Songklanagarind Hospital between 1 January 2003 and 31 August 2008 were reviewed.

Results: Out of fifty-three patients with PCP infection, median age 37 years (range 20-58 years), 28 patients were male and 25 patients were female. Thirty-eight were human immunodeficiency virus (HIV)-related patients and 15 were patients with other immunodeficiencies. All patients with other immunodeficiencies group had received corticosteroids. There were no statistical differences in sex, age, clinical presentations and chest roentgenography between HIV and patients with other immunodeficiencies. However, mortality and intensive care unit admission rates were higher in patients with other immunodeficiencies (60.0% vs. 28.9%, p=0.036 and 66.7% vs. 36.8%, p=0.049, respectively)

Conclusion: Although the clinical characteristics of PCP infection were similar between the HIV and patients with other immunodeficiencies, the mortality rate was higher in the patients with other immunodeficiencies.