Why is the thyroid so prone to autoimmune disease?

The thyroid gland plays a major role in the human body; it produces the hormones necessary for appropriate energy levels and an active life. These hormones have a critical impact on early brain development and somatic growth. At the same time, the thyroid is highly vulnerable to autoimmune thyroid diseases (AITDs). They arise due to the complex interplay of genetic, environmental, and endogenous factors, and the specific combination is required to initiate thyroid autoimmunity. When the thyroid cell becomes the target of autoimmunity, it interacts with the immune system and appears to affect disease progression. It can produce different growth factors, adhesion molecules, and a large array of cytokines. Preventable environmental factors, including high iodine intake, selenium deficiency, and pollutants such as tobacco smoke, as well as infectious diseases and certain drugs, have been implicated in the development of AITDs in genetically predisposed individuals. The susceptibility of the thyroid to AITDs may come from the complexity of hormonal synthesis, peculiar oligoelement requirements, and specific capabilities of the thyroid cell's defense system. An improved understanding of this interplay could yield novel treatment pathways, some of which might be as simple as identifying the need to avoid smoking or to control the intake of some nutrients.

[Neonatal immune system changes caused by phototherapy]. / Promene u imunskom sistemu novoredjenceta izazvane fototerapijom.

It is noticed that phototerapy may cause disturbance in the behavior and higher incidence of infections in neonate. Moreover an electromagnetic radiation may influence different functions of cells. We examined the effects of pototherapy on the immune system of neonates applied because of hyperbilirubinemia. The examined healthy patients, without signs of infection, anoxia or birth injury. Physical examination, white blood cell count, surface differentiation markers on peripheral blood lymphocytes,and hemiluminescent response of peripheral blood leukocytes were performed before and immediately after phototerapy. Our results showed an increase in the total number of peripheral white blood cells: polymorphonuclears, lymphocytes and monocytes as well as a delay in the chemilumonescence response of the peripheral blood phagocytes with lower values of the pick, suggesting a decrease of their functional ability to respond by respiratory burst. This might be important in the case of bacteriemia when phothoterapy may complicate the existing infection. Those findings are temporary.