COMPARISON OF THE MANTOUX INTRADERMAL REA CTION PRODUCED WITH 2 TUBERCULINS IN BCG-VACCINATED AND NON BCG-VACCINATED CHILDREN

The intradermal Mantoux tuberculin test is the most reliable test for the detection of tuberculous infection in children. We compared the re sponses to tuberculin Merieux (TM), regularly used in France, with tho se to tuberculin RT 23 supplied by the Serumstatens Institut, Copenhag en, a product carefully standardized in a wide range of subjects and c onditions. The study was carried out within 2 years, and included 92 c hildren (56 boys, 36 girls) aged 4 months to 15 years 8 months (mean : 61.5 months), referred to our department either for a positive tuberc ulin skin test and tuberculin conversion without BCG-vaccination, or a n increase of post vaccinal allergy (46 cases were BCG-vaccinated). Sk in tests were performed simultaneously on each forearm following the s tandard Mantoux procedure using tuberculin RT 23 (2 TU/0.1 mi) and TM (10IU/0.1 mi). The reactions were read on the 3rd day by measuring the largest diameter of induration in mm. Our subjects were divided into 3 groups regarding the final diagnosis : A- tuberculous infection and disease or preventive treatment (n = 15), B- sensitization by non tube rculous mycobacteria (NTM) (n = 25), C- child not belonging to the two previous groups (n = 52). Variance analysis showed that, whatever the tuberculin used, tuberculin reactions differed significantly between groups (p < 0.001) and that, whatever the group considered, the reacti ons to TM were greater than to RT 23 (p < 0.001) without interaction b etween parameters (p < 0.13). BCG-vaccination has no influence on the results. This more intense reactivity could lead to difficulties in th e interpretation of the tuberculin reaction, particularly in non BCG-v accinated children, in the cases of non specific reactions due to NTM sensitization usually responsible for reaction of intermediate strengh t (between 5 and 10 mm). The risk is to suspect wrongly a tuberculous infection and to set up an unwarranted antituberculous treatment.