A 56-year-old human immunodeficiency virus (HIV)-infected man presented with progressive interstitial lung disease (ILD) and lymphocyte infiltration of the salivary glands which mimicked autoimmune disease. Pneumonia, which was very likely caused by Pneumocystis carinii, developed after 3 courses of monthly methylprednisolone pulse therapy for ILD. Both enzyme immunoassay and Western blot analysis confirmed the HIV infection. After antibiotic treatment, the pneumonia gradually resolved. Autoimmune manifestations such as ILD and xerostomia may be initial presentations of HIV infection. Immunosuppressive drugs must be used cautiously in these patients. Screening for HIV is mandatory in the differential diagnosis of patients with ILD or xerostomia.