Sp ecialist Leprologist, Uganda and M. M. STONE, S.R.N., S.C.M. Kumi Ongino Leprosy Settlement 215 The work of de Farial (1950), Kooij and Gerritsen2 (1956), Floch) (1956) and Davey4 (1958) has shown that a local response can be elicited in some individuals by the intradermal injection of a saline suspension of normal skin taken from a non-leprous person. An early reaction at 24 -48 hours or a late infiltration at three weeks is possible. This phenomenon might be taken to mean that the

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... and Mi tsuda reactions to lepromin are only incidental and have little direct relationship to prognosis ; alternatively, that an antigen prepared from n o rmal skin might for practical purposes be substituted for that prepared from bact�riologically positive tissue. The response to normal skin, however, was generally much smaller, comparable with that to a very weak lepromin. It is allowed for in the standard method of calibrating the results of the usual lepromin test, by not regarding as positive any reaction that is less than a certain diameter. We have already reported the use of depot lepromin injection by the multipuncture route, the results of which are easily correlated with those obtained with the standard saline suspension by the usual intradermal method (Kinnear Brown and Stone5,6,7, 1958-9). The modified test has the advantages that the reaction is less violent, the method is economical, and the lepromin is retained in the skin sufficiently long to indicate if there is conversion from negative to positive within a fe w weeks. A number of children whose depot tests were negative at three, fo ur and five weeks showed °a change to positive within fo ur weeks of BeG vaccination, whilst others who were not BeG vaccinated showed no change whatever. Apart from the inference that BeG vaccination was the cause of the conversions, the investigations showed that this method eliminates the need for a second test and, therefore, the complicating effect of a second dose of antigen. We now decided to investigate by the multipuncture route the results of using various skin preparations suspended in the depot medium, and the subsequent effect of BeG vaccination. We first tested 25 patients who were known to be positive to lepromin, the majority strongly so, with a I :20 depot 'lepromin' made from the skin of an active tuberculoid lesion which was bacteriologically negative on st aining by Ziehl N eelsen. Eight were