Sensitivity to tuberculin and sensitins from atypical mycobacteria (M. chelonae subsp. abscessus, M. avium, M. intracellulare, M. scrofulaceum) in 100 Danish school children.

One hundred non-BCG vaccinated Danish school children aged 7.3-14.9 yrs (median 12.8 yrs) were studied with regard to the size of skin induration 72 hrs following intracutaneous injections of 1 unit of tuberculin PPD and 0.1 microgram of four different sensitins produced from M. chelonae subsp. abscessus. M. avium, M. intracellulare and M. scrofulaceum. Fifteen children showed at least one significant reaction (i.e. skin induration greater than 6 mm). Of these children, 13 had two or more significant reactions. None of the children showed primary reactions to tuberculin; but the tuberculin reaction in one child was significant, whereas five other children had detectable tuberculin reactions, all being due to cross reactions to atypical mycobacteria. In addition to the atypical mycobacteria, the following frequencies of significant reactions were found: M. chelonae subsp. abscessus (6%), M. avium (11%), M. intracellulare (13%), M. scrofulaceum (12%). The reactions to the 5 skin tests were significantly different (p less than 0.001). However, the skin reactions to M. avium, M. intracellulare and M. scrofulaceum (i.e. the MAIS complex) were similar, and they correlated significantly (p less than 0.001). On the other hand, the members of the MAIS complex correlated with neither M. tuberculosis nor with M. chelonae subsp. abscessus, and the reactions to these two atypical mycobacteria were significantly different (p less than 0.01). This seems to indicate extensive cross reactions between the members of the MAIS complex. Consequently, cutaneous testing for this complex in epidemiological surveys only requires a skin test with one of the members.(ABSTRACT TRUNCATED AT 250 WORDS)