The use of dilute antigens in lepromin tests

ABSTRACT

In a study of the value of dilute antigens for the lepromin reactions, a group of 40 tuberculoid leprosy cases has been used. According to earlier lepromin tests with normal antigens (MItsuda-Hayashi integral, 120, or the Dharmendra bacillary antigen, 11000), 28 of them were classed as strong reactors, and 12 as weak reactors. The dilute antigens used for comparison were integral, 1100 and 1750; bacillary, 15000. Both the early and the late reactions were observed, and on the basis of the results seen the followin conclusions are arrived at 1- Dilute antigens have value or practical use only in strong (2+ and 3+) reactors, in which they give the same percentages of positivity with the dilute antigens as with the normal ones although in lesser intensity. 2- Dilute antigens should not be used with weak (1+) reactors, because the results are virtually always negative and may lead to error. 3- With every individual who is lepromin tested for the first time, or whose capability to respond is not known, a normal antigen should always be used. 4- Dilute antigens should be used only with strong reactors, for the periodical examinations which are usually made to determine thhe immunological curve. In this way we would save antigen material, besides avoiding the residual scars which often occur after strong lepromin reactions.