TUBERCULIN REACTIVITY IN FAMILIES OF INFANTS WHO FAILED TO DEVELOP TUBERCULIN REACTIVITY AFTER BCG IMMUNIZATION AT BIRTH

Setting: Some infants immunized with BCG in the newborn period fail to develop any measurable tuberculin reactivity despite a local reaction at the site of immunization. Objective: We wished to determine the po ssibility of a genetic regulation of this phenomenon by comparing the tuberculin reactivity of BCG-immunized parents and siblings of infants who failed to respond to BCG, and of infants who developed tuberculin reactivity after immunization. Design: We studied 65 parents and sibl ings of 33 nonresponder infants, and 35 parents and siblings of 14 inf ants who had developed tuberculin reactivity. Tuberculin reactivity wa s analyzed by multiple regression analysis considering the BCG immuniz ation status of each individual, and the 2 groups were compared by ana lysis of covariance. Results: 96 of these family members had one or mo re BCG scars. The percentages of tuberculin reactors and non-reactors among BCG-immunized family members of both index infant groups were no t significantly different. Conclusion: These observations suggest that maturational differences among newborns, rather than genetic regulati on, account for the lack of development of cellular immunity against t uberculin after BCG immunization in some infants.