Some aspects of tuberculoid leprosy and chemotherapeutic trials.

The author describes the progress made in our knowledge of tuberculoid leprosy since the original case of Jadassohn in 1898. The numerical importance of T patients in different parts of the world is reviewed and their role in the transmission of the disease discussed. An analysis is made of the subgroups into which T leprosy is divided according to the clinical symptoms, bacteriology, histopathology and immunology in the Madrid classification as well as in the Souza-Lima-Souza Campos and Ridley-Jopling studies. The author concludes that a majority of T patients are immunologically stable and belong to two well defined groups, the first called T annular in the Souza-Lima-Souza Campos study and TT in the Ridley-Jopling classification and the second called T reactional by S.L.-S.C. and BT by R.J. Taking into account the high proportion of T cases in most epidemiological situations, their generally accepted good prognosis under treatment and the present availability of several drugs of proved efficacy, the author suggests to carry out in T leprosy under controlled conditions a trial of a number of therapeutic regimens of not more than 12 months duration. Follow-up periods will make possible medium and long-term evaluation of results after 3 and 5 years respectively of the initiation of the chemotherapeutic regimens. The practical implications of effective and well tolerated short-term therapy in T leprosy is stressed. Its widespread use in field programmes will represent among other advantages a considerable economy in personnel and drugs costs. The use of a single protocol is recommended. The one worked out by THELEP for therapeutic trials in lepromatous leprosy could be adopted with a few changes made necessary because of the morphological and bacteriological differences between L and T leprosy. It is suggested that, if the results of the trial are successful, similar regimens could be tried in indeterminate leprosy.