Results of the use of dilute Mitsuda antigen.

In his study of the immunological. relations between leprosy and tuberculosis, Floch (1) performed von Pirquet and Mitsuda tests on 128 children of the Marchoux School and of the B. de Cayena Dispensary. Their ages varied from 6 to 14 years. Forty-three of them suffered from tuberculoid leprosy, while 85 had the indeterminate form. In carrying out the Mitsuda test Floch used as his antigen, not the classical 1 :20 preparation of Hayashi, but a 1 :750 dilution. He stated that in this way he economized antigen, for he had discovered by means of a series of experiments that the positive reaction to the antigen thus diluted was as prompt as when much less dilute preparations were used. The reactions, he stated, could be correlated with those to ordinary lepromin by adding one plus ( 1 +) to the readings. As this was an interesting observation, we undertook to repeat the experiment with diluted lepromin to compare the results obtained with it and those obtained with the classical 1 :20 antigen. The tests were made on a group of 216 children of both sexes, varying in age from 2 to 16, interned in the Sao Tarcisio Preventorium in this state. Most of them had been treated with BCG. We also tested 40 young boys, varying in age from 12 to 16, at the Technical School for Apprentices. These boys had not been treated with BCG. The total number of individuals tested was 256.