Women and Autoimmune Disease
I wanted to dig deeper about women and increase in autoimmune disease (AID). In fact, autoimmune disease affects about 8% of the population, and 78% are women (Fairweather, Frisancho-Kiss, & Rose, 2008). Women are known to respond to infection, vaccination, and trauma with increased antibody production and a more TH-2-mediated immune response, whereas a Th1 response and inflammation are usually more severe in men. In addition, AID that manifest men usually occur before the age of 50, and are characterized by a pro-inflammatory TH1 immune response. In women, the clinical age is typically over 50 and is associated with a TH-2 mediated response (Fairweather et al., 2008). Females also present with increase in neutrophil inflammation and chronic fibrosis. “Women respond to infection, vaccination, and trauma with increased antibody production, whereas inflammation is usually more severe in men resulting in an increased mortality in men and protection against infection in women” (Fairweather et al., 2008).
According to Fairweather et. al, the number of different autoantibodies present in an individual is a good predictor of the risk of developing an autoimmune disease, which also increases as we age, regardless of your gender. Male-predominant autoimmune diseases that manifest during the early, proinflammatory phase are associated with acute inflammation, whereas female-predominant diseases that manifest during the early, acute phase are associated with primarily antibody-mediated pathology. Autoimmune diseases that manifest later in life (past age 50) are characterized by chronic inflammation, fibrosis, increased number of autoantibodies, and a TH-2 mediated response.
So why are women shown to have more autoimmune disease? There are two theories that work in concert. First, females exhibit a TH2 immune response to infection which can increase both chronic and acute antibody-mediated pathology. An IL-4 mediated TH2 response may protect females from severe acute inflammation by inhibiting IFN-gamma and increasing Treg populations (Fairweather et al., 2008). Unfortunately, this makes them more susceptible to autoimmune mechanisms. Second men die at an earlier age from heart disease, diabetes, cancer and other diseases. Thus, the heightened proinflammatory Th1 response to infection made by males increases the severity of acute inflammation and the risk of early death so that males susceptible to develop chronic autoimmune diseases might not survive to develop disease (Fairweather et al., 2008).
Fairweather, D., Frisancho-Kiss, S., & Rose, N. R. (2008). Sex differences in autoimmune disease from a pathological perspective. Am J Pathol, 173(3), 600-609. doi:10.2353/ajpath.2008.071008