thymic-factor--circulating and zinc-chloride

Abnormalities in the immune system and zinc homeostasis in patients with beta-thalassemia major (TM) have been reported. Since zinc ion is essential for the efficiency of the immune system and is required to induce biological activity to thymulin (Zn-FTS), a biochemically defined thymic hormone, we investigated the plasma levels of zinc and both active thymulin (Zn-FTS) and total zinc saturable thymulin (Zn-FTS+FTS) in 18 patients with TM aged between 2 and 31 years and 22 normal controls of the same age. Inhibitory molecules anti-thymulin and the distribution of lymphocyte subsets were also analyzed. Patients with TM presented significantly lowered plasma zinc and thymulin levels when compared to normal subjects. The significant enhancement of the active form of the hormone after zinc addition in vitro suggests that low thymulin values found in TM are due not to a thymic failure in synthesizing and secreting the thymic hormone, but a defect in zinc saturation of the hormone. An impairment of cell subset distribution was also demonstrated. This study shows that zinc and thymulin deficiency contribute to the complex mechanisms underlying immune dysfunction in TM.

Topics: Adolescent; Adult; Antigens, CD19; Autoantibodies; beta-Thalassemia; CD3 Complex; CD4-Positive T-Lymphocytes; CD56 Antigen; CD8-Positive T-Lymphocytes; Child; Child, Preschool; Chlorides; Female; Humans; Lymphocyte Count; Lymphocyte Subsets; Lymphocytes; Male; Thymic Factor, Circulating; Zinc; Zinc Compounds

Thymulin is a well defined nonapeptide produced by thymic epithelial cells, and plays an important role in thymocyte differentiation. We investigated the restorative effect of thymulin on the stress-induced reduction in the production of antibodies against SRBC in mice. Antibody production in stressed mice was reduced to about 50% of that in normal mice. A 3-day period of administration of thymulin (1 ng/kg) restored antibody production to close to the normal level, whereas thymulin (1 ng-1 microgram/kg) did not affect antibody production in normal mice. These results indicated that thymulin normalizes the altered thymus-dependent immune responses.

Topics: Animals; Antibody Formation; Chlorides; Female; Mice; Mice, Inbred BALB C; Restraint, Physical; Stress, Physiological; Thymic Factor, Circulating; Thymus Gland; Zinc Compounds

In 36 children with nephrotic syndrome (NS) a significant decrease of their serum levels of the thymic-hormone--thymulin--was found, in parallel with a diminution of their mean blood zinc levels as compared to 33 control children. The serum level of thymulin normalized after the in vitro addition of ZnCl2. Similar results have previously been reported in mice subjected to a long term zinc deficient diet. It can therefore be assumed that the decreased biological activity of the thymic hormone noted in NS is secondary to a low serum zinc level. These data could explain certain anomalies of T lymphocytes described in childhood NS.

Topics: Adolescent; Child; Child, Preschool; Chlorides; Humans; Infant; Nephrosis, Lipoid; Nephrotic Syndrome; Thymic Factor, Circulating; Thymus Hormones; Zinc; Zinc Compounds