CD4 and AIDS: Among the HIV-infected prisoners, the median CD4 count was 384 (IQR 257-591) lymphocytes/μL; 23 (16.8%) subjects had CD4 lymphocyte count <200 cells/μL (AIDS-defining diagnosis and in need of preventive therapy against Pneumocystis jiroveci pneumonia) and 63 (45.6%) had CD4 ≤350 lymphocytes/μL (eligible for antiretroviral therapy; ART).