Lymphocyte transformation assays as a diagnostic tool in tuberculosis in children.
Lymphocyte transformation (LT) assays were evaluated as a diagnostic aid in tuberculosis of children. Skin tests and LT assays were performed in 6 children with culture-proved tuberculosis (Group I), 32 children suspected of having tuberculosis (Group II), and 20 healthy children (Group III). Five of 6 children in Group I, 16 of 32 in Group II, and 8 of 20 in Group III had positive skin test reactions to PPD. The correlation between skin test reactivity and LT responses to PPD was highly significant (p less than 0.0001). Four (80%), 14 (88%), and 6 (75%) of the 29 subjects with positive skin test reactions in Groups I, II, and III showed a significant LT response to PPD. Only 2 (13%) of 16 tuberculosis suspects with negative skin test reactions in Group II exhibited an LT response to PPD. One (8%) of 12 healthy children with negative skin test reactions had a positive reaction in LT assays. All but 4 (7%) of 58 children in Groups I, II, and III were skin test reactive to PPD and/or 1 or more of 5 nonmycobacterial antigens. One (2% of 58) of these failed to exhibit an LT response to nonmycobacterial antigens. The strong correlation between LT responses and skin test reactivity to PPD and our finding that only 2 of 16 tuberculosis suspects had positive reactions in LT assays in the absence of PPD skin test reactivity argues against the likelihood that LT assays will prove useful in the diagnosis of this disease.