STAT3 and Autoimmunity: Taken together, data suggest that much caution should be exercised in efforts to modulate STAT3 pathways as therapy for inflammatory diseases as its role in inducing differentiation of pathogenic Th17 cells has to be weighed against its role in promoting cell survival and in suppressing proinflammatory costimulatory molecules or inhibitory receptors that restrain exuberant T cell activities that can cause autoimmunity.