Role of thymic hormones in neuroimmunomodulation. Their use in patients with phobic disorders

Many evidences support the existence of a bilateral connection between the thymic gland and the hypothalamic-pituitary-adrenal axis (HPAA). In this respect, neurohormones such as the adrenal corticotropin hormone and glucocorticoids cause thymic involution, while the growth hormone and the prolactin upregulate thymic functions. On the other hand, a thymic hormone, the thymosin fraction 5, activates the HPAA, thus closing-up the regulatory loop between immune system and nervous system. In this review, a clinical trial with two thymic hormones (Timostimolina and Thymopentin) in agoraphobic patients with phagocytic dysfunctions is reported. Results obtained indicate that both substances lead to a partial and temporary immunological recovery, since a further depression of phagocytic activities occurs in coincidence with panic attack. The use of alternative immunomodulators in these patients is discussed.