Identification of human immunodeficiency virus-infected individuals by delayed type hypersensitivity skin testing.

OBJECTIVE To determine if more useful information could be derived from delayed type hypersensitivity skin testing of human immunodeficiency virus (HIV)-infected patients by measuring the amount of induration in response to skin testing in contrast to assessing for the presence of anergy. DESIGN Prospective, double-blind trial. SETTING Two HIV clinics. PATIENTS A sample of 60 ambulatory, HIV-infected patients and 18 normal controls. INTERVENTIONS Delayed type hypersensitivity skin testing with a panel of recall antigens. MAIN OUTCOME MEASURES Anergy, total induration in response to the panel of antigens, and CD4 lymphocyte count. RESULTS Anergy was present in only 28 of 60 (46.7 percent) HIV-infected subjects. A low skin test score (under 20 mm of total induration) was present in 43 of 60 (71.7 percent) HIV-infected subjects (p < 0.01 vs anergy). One control patient was anergic, while two had a low skin test score (p = NS). Among HIV-infected subjects, there was poor correlation between CD4 lymphocyte count and skin test score (R2 = 0.12). CONCLUSIONS Skin testing by this method identifies more HIV-infected patients than does assessing the presence or absence of anergy.