Tixocortol pivalate contact allergy in the GPMT: frequency and cross-reactivity

In spite of their intrinsic anti-inflammatory properties, corticosteroids c an induce contact allergy. When studying the allergenic properties of corti costeroids it has to be considered that both the allergenic and anti-inflam matory effect may influence the induction phase as well as the elicitation phase and that such effects may be dose-dependent. A multiple dose guinea p ig maximization test (GPMT) was therefore used to study the dose-response r elationship of tixocortol pivalate. The GPMT was conducted according to OEC D guideline #406, using a multiple-dose design and test results were analys ed with logistic regression analysis. There was a significant tixocortol pi valate sensitization of the test animals compared to the control group (p < 0.05), after both challenge and re-challenge. The challenge with 1% tixoco rtol pivalate gave more positive reactions than the challenge with 3%. The highest frequency of positive animals was observed when the animals were tr eated with low to intermediate induction concentrations and intermediate to high challenge concentrations with tixocortol pivalate in the TRUE Test(TM ) Cross-reactivity was found between tixocortol pivalate and hydrocortisone , which was expected from their close molecular resemblance, whereas no cro ss-reactivity was seen between tixocortol pivalate and the 3 other corticos teroids: amcinonide, budesonide, and hydrocortisone-17-butyrate.