Histoplasmosis is a serious opportunistic (AIDS-related) infection that responds well to antifungal medications. Before anti-HIV drugs, patients with histoplasmosis required lifelong antifungal therapy. Patients who take anti-HIV drugs for a long time may see an improvement in their immune system functions. Improved immune function may eliminate the need for long-term preventive treatment with antifungal agents. Doctors want to see if the improved immune functions allow preventive treatment for histoplasmosis to be stopped. (This study has been changed to include histoplasmosis treatment with drugs other than itraconazole.)