Stat6-independent tissue inflammation occurs selectively on the ocular surface and perioral skin of IkappaBzeta-/- mice.

PURPOSE: IkappaBzeta(-/-) mice have been reported to be affected by allergic dermatitis. This study was conducted to analyze the pathophysiological role of IkappaBzeta and to address the functional relevance of Th2-mediated immune responses in the development of ocular surface inflammation and dermatitis by IkappaBzeta(-/-) mice.

METHODS

BALB/c background IkappaBzeta(-/-) mice were established without individual differences; IkappaBzeta/Stat6 double-knockout (WKO) mice unable to produce Th2 cytokine were created; and microscopic-, histologic-, and immunochemical studies were performed. In IkappaBzeta(-/-) mice the serum IgE levels were examined by ELISA, and quantitative PCR was used to study the gene expression of IFN-gamma, IL4, IL10, TNFalpha, IL6, IL17alpha, and CCL11 in eyelid tissue.

RESULTS

IkappaBzeta(-/-) mice exhibited a severe inflammatory phenotype on the ocular surface and perioral skin. The inflammatory infiltrates in the perioral skin consisted primarily of CD4(+) and CD8(+) cells; CD4(+) and CD45R/B220(+) cells were mainly detected in the conjunctiva. In eyelid and perioral skin tissue, the expression of IL-17alpha and of Th1 and Th2 cytokines, but not of CCL11, was augmented. IkappaBzeta(-/-) and IkappaBzeta(+/-) mice did not differ significantly in their serum total IgE levels before, 0 to 4 weeks, and 5 to 9 weeks after disease onset. IkappaBzeta/Stat6 WKO mice showed the same or slightly more severe inflammation than did IkappaBzeta(-/-) mice.

CONCLUSIONS

IgE and Stat6 are not responsible for the immune pathologic response leading to the development of ocular surface and perioral skin inflammation in IkappaBzeta(-/-) mice. IkappaBzeta(-/-) mice may be a suitable model for Stevens-Johnson syndrome, but not for atopic dermatitis.