Autoimmunity in IgA Deficiency: Revisiting the Role of IgA as a Silent Housekeeper
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Both systemic and organ-specific autoimmune diseases are major manifestations of IgA deficiency (IgAD), the most common primary immunodeficiency. In addition, to discuss the clinical findings of IgAD patients, we proposed a hypothesis to explain the high association with autoimmune phenomena. Based on observations, interactions of monomeric IgA with FcαRI result in a partial phosphorylation of FcRγ-associated FcαRI, notably in the immunoreceptor tyrosine-based activation motif (ITAM) inducing the recruitment of the SHP-1 tyrosine phosphatase. This leads to deactivation of several activating pathways of the immune system including immunoreceptors that bear ITAM motif and ITAM-independent receptors. Consequently, inflammatory reactions and auto-immune process would be prevented.
KeywordsIgA deficiency autoimmunity clinical evolution Fc receptor physiopathology
This work is supported by Fundação de Amparo à Pesquisa do Estado de São Paulo-FAPESP-grant 2002/05880-4.
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