STAT1 and Immunodeficiency: However, current studies merely suggest that potential immune deficiency mechanisms in AIGA might be related to the fact that AIGA syndrome patient serum can inhibit STAT1 phosphorylation and IL-12 production in peripheral blood mononuclear cells (PBMCs) (12) and damage the antimicrobial function of macrophages (13) by impeding the IL-12/IFN-γ axis, causing microbial clearance failure.