Lymphocyte transformation test in healthy contacts of patients with leprosy. II. Influence of consanguinity with the patient, sex, and age.

The study was carried out in the Gurage area of Ethiopia, where 53 household contacts of lepromatous patients, 37 household contacts of tuberculoid patients, and 91 control persons were examined with the lymphocyte transformation test (LTT) for their responses to whole and sonicated antigen preparation from M. leprae to BCG, M. avium, M. gordonae and phytohemagglutinin. The potential influence of host factors, namely the state of consanguinity with the leprosy patient, sex and age on the LTT responses was evaluated. In the 35 household contacts of "active," i.e., highly bacilliferous, lepromatous patients, consanguinity with a lepromatous patient was not associated with a significant depression of the LTT responses to M. leprae antigens. Male household contacts of active lepromatous patients showed significantly greater LTT responses to M. leprae antigens than female household contacts. Possible confounding factors for this finding are discussed. Sensitization of M. leprae antigens was present already in a high proportion of the 6 to 14 year old household contacts of active lepromatous patients, which was the youngest age group examined in our study. No significant results were found in any of the other patient contact groups with regard to the host factors examined.