Effect of High Dose Natural Ionizing Radiation on the Immune System of the Exposed Residents of Ramsar Town, Iran

Iran is one of several countries that has regions of high dose natural ionizing radiation. two wellknownvillages in the suburb of ramsar town in the caspian sea strip, taleshmahaleh and chaparsar,have background radiation that is 13 times higher than normal. this radiation is the result of radium226 and radon gas both of which are highly water soluble.while people living in these regions do not suffer from any major health problems, we decided tostudy the their immune responses to infection and inflammation in order to determine if their habitataffects their immune defense mechanisms as a way of compensating for their exposure to high doseenvironmental ionizing radiation.our results showed that the total serum antioxidant level in the exposed people was significantlylower than the individuals not exposed to high dose natural ionizing radiation. the exposedindividuals also had higher lymphocyte-induced il-4 and il-10 production, and lower il-2 and ifn-مproduction. in addition, neutrophil nbt, phagocytosis, and locomotion were higher in the exposedgroup. in contrast, lymphocyte proliferation in response to pha was unaffected.we conclude that the immune system of individuals exposed to high dose ionizing radiation hasadapted to its environment by shifting from a type 1 to a type 2 response to promote antiinflammation.this may be because inflammatory type 1 responses generate more free radicals thantype 2 responses, in addition to the free radicals generated as a result of high environmental radiation.thus, the serum total antioxidant level in the exposed residents was lower than the unexposed group.