Role of Progesterone in HIV and Parasitic Infections

Progesterone (P4) plays different physiological roles, including reproductive and non-reproductive actions. Most of P4 effects are mediated by its interaction with its nuclear receptor (PR). Among the non-reproductive functions of P4, the regulation of the immune response, particularly during pregnancy, is remarkably important. P4 is able to modulate the immune response during normal physiological processes, as well as in infectious diseases, including parasitic and viral infections. During parasitic infections, P4 not only exerts its action upon the immune system, but also directly acts on the parasite, as it has been shown for helminthes and protozoans. Variations of P4 levels during the menstrual cycle could be involved in changes in susceptibility to infection, such as that caused by the human immunodeficiency virus (HIV). P4 could be involved in the acquisition and development of HIV disease, regulating infection susceptibility. Further investigations could open new application fields, where the differential effects of P4 upon the immune response represent the keystone of a successful hormonal therapy as well as the design of new drugs with more specific actions on parasites and