Cross‐reactivity between sesquiterpene lactones related to parthenin in parthenin‐sensitized guinea pigs

The naturally‐occurring sesquiterpene lactone, parthenin, is responsible for a high incidence of allergic contact dermatitis in India. Cross‐sensitivity tests on guinea pigs sensitized to parthenin indicate a relatively high immunological specificity for this low molecular weight hapten. Coronopilin and damsin, sesquiterpene lactones most similar to parthenin, gave positive reactions but other structurally related lactones such as dihydroisoparthenin, tetra‐hydroparthenin, tetraneurin‐A, hysterin, helenalin, and tenulin, or hymenin, a diastereoisomer of parthenin, were negative.