Recent studies have revealed several characteristic clinical features, including predominance see more in middle-aged to elderly men, frequent association with IgG4-related

conditions in other organs, high levels of serum IgG and IgG4, a high frequency of hypocomplementemia, a high serum IgE level, eosinophilia, characteristic radiologic findings in the kidney, and a good initial response to corticosteroids. However, it still remains ambiguous whether IgG4 antibody may behave as tissue-destructive immunoglobins, or just a result of overexpression in response to unknown primary inflammatory stimulus. A specific antigen render naïve CD4+ T cells activated and differentiate into distinct effector T cell subsets. T helper Type 1 (Th1) cells induced by IL-12 are mainly responsible for cell-mediated immunity, while Th2 cells induced

by IL-4 are responsible for humoral immunity. A subset of IL-17–producing PXD101 T cells (Th17 cells) distinct from Th1 and Th2 cells was shown to play a crucial role in the induction of autoimmunity and allergic inflammation. These Th subsets are then mutually controlled by the cytokine that each produces. Exaggeration of responses by Th1, Th2 and Th17 cells induce tissue inflammation and regulatory T cells (Treg cells) controls these Th cells for maintenance of the immune response and prevents autoimmune and inflammatory reaction. Various types of Treg cells have been described that mediate these regulatory

second functions. IgG4 is a Th2-dependent IgG isotype, and plays a central role in ‘alternative Th2 responses’, which was a proposed term for a modified Th2 response not associated with clinical allergy. In fact for instance of alternative Th2 response, an allergen-specific immunotherapy has elucidated that extended and high-dose exposure to allergens can induce an increase in IgG and IgG4 antibodies with a decrease in IgE antibodies. For another instance it is known that helminth parasites asymptomatic infections are correlated with high levels of IgG4, and it has been shown that parasite-specific IgG4 antibody can inhibit IgE-mediated degranulation of effector cells. In these responses it is accepted that Treg cells are activated by excessive immune reactions to prevent a Th2-type immune response.