Delayed-type hypersensitivity anergy in human immunodeficiency virus-infected persons screened for infection with Mycobacterium tuberculosis.

A total of 479 human immunodeficiency virus (HIV)-infected persons at an HIV clinic in Florida and a tuberculosis clinic in New Jersey were skin-tested with tuberculin, tetanus toxoid, mumps antigen, and Candida antigen in a study of the prevalence of delayed-type hypersensitivity (DTH) anergy and the usefulness of two-step tuberculin testing in this population. Of the patients tested, 12% had a positive (> or = 5-mm) response to tuberculin; 57%, 45%, and 35% had a positive (> or = 3-mm) response to Candida antigen, tetanus toxoid, and mumps antigen, respectively; and 31% were anergic (< 3 mm of induration in response to each antigen). In a multivariate logistic regression model, anergy was significantly associated with a history of Kaposi's sarcoma, Pneumocystis carinii pneumonia, or oral candidiasis and with White race. Anergy was four times and 15 times as likely for persons with CD4+ T-lymphocyte counts of 200-400/mm3 and < 200/mm3, respectively, as for persons with > 499 CD4+ T lymphocytes/mm3. Of 103 patients who were tuberculin-tested a second time after their initial test result was negative, seven had > or = 5 mm of induration in response to the second test; only one of these patients was anergic at the initial screening. The findings of this study indicate that DTH antigens should be used in conjunction with tuberculin testing and that two-step tuberculin testing is not an alternative to anergy testing but may be useful for the detection of infection with Mycobacterium tuberculosis in nonanergic HIV-infected patients.

Usefulness of skin testing with mycobacterial antigens in children with cervical lymphadenopathy.

One hundred twenty-three children with chronic cervical lymphadenopathy were skin-tested with purified protein derivative (PPD)-B (Mycobacterium intracellulare), PPD-Y (Mycobacterium kansasii), PPD-G (Mycobacterium scrofulaceum) (nontuberculous mycobacterial antigens (NTMags)) and PPD-T (Mycobacterium tuberculosis). Children with culture-confirmed mycobacterial disease had significantly larger reactions to NTMags and were 6 times more likely to have PPD-B responses of greater than or equal to 10 mm than those with negative microscopy/culture results. Children with acid-fast bacilli present in clinical specimens but with negative culture results were 3 times more likely to have greater than or equal to 10 mm induration to PPD-B than those with negative microscopy/culture results. In all groups except those with culture-confirmed M. tuberculosis, responses to PPD-T were significantly smaller than those to the NTMags. We conclude that NTMags, particularly PPD-B, may be useful in diagnosing childhood mycobacterial cervical adenopathy; however, their usefulness in distinguishing disease caused by M. tuberculosis from that resulting from other mycobacteria is unknown.

Evaluation of the clinical usefulness of mycobacterial skin test antigens in adults with pulmonary mycobacterioses.

A double-blind, multicenter study was conducted to evaluate the usefulness of mycobacterial skin test antigens for the specific diagnosis of adult pulmonary mycobacterial disease. The skin test antigens used were PPD-T (M. bovis) and PPD-B (M. intracellulare), made bioequivalent to 5 TU PPD-S through bioassay in human subjects. Of the 192 adults (18 yr of age or older), those with disease caused by M. tuberculosis (MTB) had significantly larger reactions to PPD-T than did those with disease caused by nontuberculous mycobacteria (NTM) or those with negative culture results (NEG)(13.41 mm versus 4.87 and 4.96 mm, respectively, p less than 0.001). The mean induration to PPD-B in NTM was not different from that in MTB or NEG. Defining a "positive" to be greater than or equal to 10 mm induration and a size difference of greater than or equal to 3 mm between PPD-T and PPD-B, the sensitivity, specificity, and positive predictive value (PPV) for PPD-T in diagnosing MTB versus NTM was 29, 90, and 75%. Corresponding values for PPD-B and NTM disease were 70, 61, and 64%. Dual testing was less useful in distinguishing disease caused by any of the mycobacteria from NEG. Although the sensitivity of PPD-B, made bioequivalent to PPD-S, was high, the specificity and PPV were low. We conclude that this preparation of PPD-B is no more useful in distinguishing adult pulmonary disease caused by NTM than is PPD-T alone.