The role of the pineal- thymus system in the regulation of autoimmunity, aging and lifespan

Thymus is an immunoendocrine organ, the hormones of which mainly influence its own lymphatic elements. It has a central role in the immune system, the neonatal removal causes the collapse of immune system and the whole organism. The thymic nurse cells select the bone marrow originated lymphocytes and destroy the autoreactive ones, while thymus originated Treg cells suppress the autoreactive cells in the periphery. The involution of the organ starts after birth, however, this truly happens in the end of puberty only, as before this it is overcompensated by developmental processes. From the end of adolescence the involution allows the life, proliferation and enhanced functioning of some autoreactive cells, which gradually wear down the cells and intercellular materials, causing the aging. The enhanced and mass function of autoreactive cells lead to the autoimmune diseases and natural death. This means that the involution of thymus is not a part of the organismic involution, but an originator of it, which is manifested in the lifespan-pacemaker function. In this case aging can be comprehended as a thymus-commanded slow autoimmune process. The neonatal removal of pineal gland leads to the complete destruction of the thymus and the crashing down of the immune system, as well as to wasting disease. The involution of the pineal and thymus runs parallel, because the two organs form a functional unit. It is probable that the pineal gland is responsible for the involution of thymus and also regulates its lifespan determining role. The data reviewed do not prove the exclusive role of pineal-thymus system in the regulation of aging and lifespan, however, calls attention to the suitability of solving this problem alone.