Cytokine expression profiles during murine contact allergy: T helper 2 cytokines are expressed irrespective of the type of contact allergen

We have investigated the cytokine response pattern following sensitisation (induction) of BALB/c mice with different chemicals (dinitrochlorobenzene. dinitrofluorobenzene, oxazolone, glutaraldehyde, formaldehyde, trimellitic anhydride, croton oil) and elicitation (challenge) of contact allergy in se nsitised animals. The results of our investigations showed that different c hemicals induced both T helper (Th) 1 cytokines [interleukin (IL) 2, interf eron beta (IFN beta)] and Th2 cytokines (IL-4, IL-10) at different stages d uring murine contact allergy. We also confirmed our previous findings that IL-4 and IL-10 release were up-regulated during the challenge phase regardl ess the contact allergen used, whereas the release of IFN beta did not show a clear preference for being up- or down-regulated. In our hands, the incr eased expression of Th2 cytokines after challenge exposure to contact aller gens appeared as a stable marker of secondary contact allergenic responses. Quantitative differences in the expression of IL-4 were observed between d ifferent contact allergens. The present results clearly indicate that skin sensitisers were able to elicit cytokine response patterns, which could not be related to a clearcut Th1 or Th2 type of cytokine response. Furthermore , dermal application of contact allergens produced different kinetics of cy tokine secretion upon induction and challenge. In our hands. the co-express ion of Th1 and Th2 type cytokines appeared as a universal consequence of de rmal application of contact allergens to responsive mice. Our results indic ate that co-expression of Th1 and Th2 cytokines during contact allergy is a n important feature of murine contact allergy in responsive mice and that c hemicals differ in their potency to induce the expression of these cytokine s. Furthermore, the results do not support the view that different chemical s induce Th1 or Th2 cytokines in a mutually exclusive manner depending on t heir preference for inducing either contact or respiratory allergy. The res ults are expected to renew the discussion about the usefulness of the Th1/T h2 paradigm in certain areas of immunotoxicology.