Women are less susceptible to infectious diseases than men, but are more often prone to autoimmune diseases. This higher prevalence is partly attributable to the X chromosome, which has many genes relating to the immune system. It is advantageous for women to have two X chromosomes, but the price is a greater tendency to develop autoimmunity.
Women are healthier and live longer than men. They are less susceptible to infectious diseases, but on the other hand 80% of individuals with autoimmune diseases are women. These diseases affect 5–10% of the population, are often chronic, and represent a considerable burden on healthcare budgets.
The autoimmune diseases are a heterogeneous group with multifactorial causes. The common denominator is an immunological reaction that leads to the breakdown, either systemic or organ-specific, of tolerance for the subject’s own tissue.