HORMONAL INFLUENCE ON AUTOIMMUNE DISEASES

Abstract

A central function of the immune system is to distinguish foreign antigens, such as infectious agents, from self­ components of body tissues. The immune system normally acquires self- tolerance by clonal deletion of autoreactive cells in the thymus in the perinatal period and by functional suppression of autoreactive T- and B- cells at later stages of development. Nevertheless, there is failure in the maintenance of self-tolerance and an autoimmune response, characterized by activation and clonal expansion of autoreactive lymphocytes and the production of autoantibodies, is produced against autologus antigens of normal body tissues. •

Autoimmune diseases can be classified into two broad, but overlapping groups: organ-specific and systemic autoimmune diseases. In the first mentioned, local injury or dysfunction is produced; clinical examples include autoimmune haemolytic anaemia, Hashimoto thyroiditis, Graves's disease and myasthenia gravis. In systemic autoimmune diseases, in contrast, tissue injury occurs in multiple sites in organs. SLE and RA are classical examples of an IC-mediated systemic autoimmune disease.

It is well known that there is greater incidence of many autoimmune diseases in women, therefore it has been inferred that sex steroid hormones (including estrogen, progesterone and androgens), particularly estrogen, are factors in the susceptibility to autoimmune disorders. Hormones affect the immune cell functions and consequently the immune system activities. In general, progesterone and androgens suppress the immune system, prolactin stimulates it, and estrogen can do