Th17 lymphocytes in anti-infectious immunity: What have we learnt from the studies in primary immunodeficiencies?
Abstract
Recently discovered Th17 lymphocytes differentiate from naive T cells in the presence of IL-1, IL-6 and IL-23 produced by activ ated antigen presenting cells. Soon after their initial discovery, Th17 cells have been implicated in the pathogenesis of autoimmune disease s.
Activation of the Th17 axis (overproduction of IL-23, amplification of Th17 cells and excessive production of Th17 effector cytokines) has be en implicated in patients with autoimmune diseases and it has been shown that Th17 cells are highly proinflammatory and that they promote tissue inflammation. Efforts then have been made to characterize the role of Th17 cells in protective immunity in humans.
With regard to the role of Th17 cells in protective immunity, the intriguing question has been which pathogens require the appropriate function of Th17 cells for elimin ation. In this review, we summarize current knowledge about the function of Th17 lymphocytes in the context of three primary immunodeficiencie s with disturbed development of Th17 immune response, CARD9 deficiency, hyper IgE syndrome and chronic granulomatous disease.
Disturba nces in the development or function of Th17 immune response result in chronic infections with Candida albicans and Staphylococcus aureus .