Interferon-gamma-deficient mice are resistant to the development of alopecia areata.
Animals, Autoimmune-Diseases, CD4-Positive-T-Lymphocytes, CD8-Positive-T-Lymphocytes, Hair-Follicle, Histocompatibility-Antigens-Class-I, Histocompatibility-Antigens-Class-II, Interferon-Type-II, Lymph-Nodes, Lymphocyte-Activation, Mice-Inbred-C3H, Mice-Knockout, Skin, Skin-Transplantation, Th1-Cells, Up-Regulation
see Reprint Collection
Br J Dermatol 2006 Sep; 155(3):515-21.
BACKGROUND: Alopecia areata (AA) is a T-cell mediated putative autoimmune disease of hair follicles, which can be transferred by CD4(+) T cells. However, whether T-helper (Th) 1 or Th2 cytokines are predominant has not yet been defined. OBJECTIVES: To elucidate the importance of Th1 cells in the pathogenesis of AA we investigated the functional role of interferon (IFN)-gamma in the experimental induction of AA. METHODS: AA was experimentally induced by grafting full-thickness skin from AA-affected C3H/HeJ mice on to C3H/HeJ mice with a targeted deletion of the Th1 cytokine IFN-gamma gene (IFNgamma(-/-)) and on to wild-type mice (IFNgamma(+/+)). RESULTS: While 90% of wild-type mice developed AA, none of the IFNgamma(-/-) mice exhibited hair loss. Immunohistochemistry of skin sections revealed a dense perifollicular and intrafollicular infiltrate of CD4(+) and CD8(+) T cells in controls, while in IFNgamma(-/-) mice skin-infiltrating CD8(+) T cells were absent and the number of CD4(+) cells was significantly reduced. Aberrant expression of major histocompatibility complex class I and II molecules in the putative immune-privileged infrainfundibular site of the hair follicle was found to be weaker in AA-resistant IFNgamma(-/-) mice than in control mice with AA. Flow cytometry revealed that leucocytes of IFNgamma(-/-) mice did not respond to the transfer of AA-affected skin. As distinct from IFNgamma(+/+) mice, neither T-cell activation markers nor Th1 cytokines were upregulated in draining lymph node cells or skin-infiltrating leucocytes of AA-resistant IFNgamma(-/-) mice. However, there was no evidence for a shift towards a Th2 cytokine profile, nor for upregulation of regulatory T cells in IFNgamma(-/-) mice. CONCLUSIONS: IFNgamma(-/-) mice fail to activate Th1 cells in response to the transplanted (auto)antigens, which suggests an essential requirement for IFN-gamma-mediated Th1 activation in the induction of AA.
Interferon-gamma-deficient mice are resistant to the development of alopecia areata. Br J Dermatol 2006 Sep; 155(3):515-21.