Targeting cytokines of the interleukin-12 family in autoimmunity

In the past, autoimmunity was thought to be mediated by antibodies and immune complexes. It has now become clear that many autoimmune diseases, especially tissue specific, are T cell-mediated, or at least T cell-dependent. The pathogenesis of cell-mediated autoimmune diseases, including multiple sclerosis, uveitis, diabetes, arthritis, and others, is now thought to be, in a large measure, driven by interferon-γ-producing, antigen-specific T cells, which are polarized toward the T helper type 1 (Th1) phenotype. Interleukin (IL)-12 and the more recently discovered IL-23 and IL-27 constitute a unique family of structurally-related, heterodimeric cytokines, which regulate cell-mediated immune responses and Th1-type inflammatory reactions. Thus, these cytokines may have a central role in the development and progression of cell-mediated autoimmune diseases. Therefore, pharmacologically targeting cytokines of the IL-12 family would be useful in the modulation of several autoimmune diseases. This review summarizes the recent findings concerning IL-12 family cytokine-mediated autoreactive inflammatory responses, and also describes some possible therapeutic interventions, including medicinal compounds at mitigating autoimmune inflammation.