“…In vivo skin tests of cellmediated immunity (CMI) have not been reported (except to gluten) but several groups (Winter et al, 1967;Blecher et at., 1969;Housley et al, 1969;Ansaldi et al, 1970;Popovic et al, 1970;Maclaurin et at., 1971;Morganroth et at., 1972), have studied lymphocyte transformation in response to PHA which Received for publication 29 June 1976 is the usual in vitro test of CMI. It can be seen (Table 1) that the results are inconclusive.…”