Zinc deficiency, depressed thymic hormones, and T lymphocyte dysfunction in patients with hypogammaglobulinemia

Zinc, its biological role and use in dermatology

This literature review detines the biological role ot zinc in the human body, immune homeostasis and skin physiology as well as pathophysiology ot skin diseases. It describes the current range ot systemic and topical zinc preparations and their pharmacological characteristics. The review also describes skin diseases that may be treated with the use ot zinc preparations on a grounded basis, and discloses the clinical experience ot the use ot these drugs described in the world literature. It sets out certain recommendations tor using zinc preparations in clinical practice.

Treatment of patients with refractory giardiasis

Giardia lamblia is one of the most common parasitic infections. Although standard treatments are usually curative, some immunocompromised patients, including patients with acquired immunodeficiency syndrome as well as healthy patients, have giardiasis that is refractory to recommended regimens. We report our experience with 6 patients with giardiasis, for whom therapy with a combination of quinacrine and metronidazole resulted in cures for 5 of the 6 patients.

Decreased expression of CD73 (ecto-5'-nucleotidase) in the CD8+ subset is associated with zinc deficiency in human patients

We used flow cytometry to observe the changes in T cell populations resulting from zinc deficiency in subjects with sickle cell anemia (SCA) and in healthy human volunteers without SCA. Zinc deficiency was associated with significant decreases in cellular zinc concentration, CD4+/CD8+ ratio, and percentage of CD73+ cells in the CD8+ population. The decrease in the percentage of CD73+ cells in the CD8+ subset was significantly correlated with lymphocyte zinc concentration and was accompanied by essentially no change in the percentage of CD11b+ cells in the CD8+ subset. Daily oral zinc supplementation in nine zinc-deficient human volunteers (25 mg elemental zinc) and in seven zinc-deficient SCA subjects (50 mg elemental zinc) resulted in increases in the absolute lymphocyte count and significant increases in the CD4+/CD8+ ratio and in the percentage of CD73+ cells in the CD8+ subset. In zinc-supplemented subjects, the increase in the percentage of CD73+ cells was accompanied by a significant decrease in the percentage of CD11b+ cells in the CD8+ subset. Changes in the CD4+/CD8+ and CD73+/CD11b- cell ratios in the CD8+ subset after treatment may provide a useful diagnostic criterion for zinc deficiency in humans.

Nutrition and cellular immunity

We have investigated the influence of nutrition on immune function in animals and man over the past two decades. The profound impairment of immune function that had not been observed in children in developing countries could not consistently be reproduced in the laboratory setting; paradoxically, moderate nutritional restriction could even enhance T-cell-based cell-mediated immune responses in experimental animals. Studies of the crucial role of the element zinc in maintenance of vigorous cellular immunity provided at least a partial explanation of this paradox. Zinc, shown to be absolutely crucial for development and expression of both T- and B-cell functions, was commonly deficient as were other micronutrients under many conditions of protein-calorie malnutrition. Indeed, administration of adequate zinc alone could correct some of the T-cell-mediated immune functions in children with protein-calorie malnutrition. In later investigations we found that as long as all essential nutrients were supplied in adequate amounts, 40% chronic energy (calorie) restriction will regularly extend lifespan and maintain vigorous immunologic function while preventing numerous cancers and immunologically based diseases of aging, such as profound and destructive autoimmune diseases in genetically short-lived mice strains, as it was known to do for moderately long-lived rats and long-lived strains of mice. Such undernutrition without malnutrition appears to influence a wide range of critical metabolic and physiologic processes in both short-lived and long-lived animals. One of the most challenging of these influences was a down-regulation of cellular proliferation and cell turnover in each of the rapidly replicating tissues studied.(ABSTRACT TRUNCATED AT 250 WORDS)

Nutrition, the gastrointestinal tract and the Acquired Immune Deficiency Syndrome. Facts and perspectives

Diarrhoea and malnutrition are common findings in patients with the Acquired Immune Deficiency Syndrome (AIDS). In this disease, enteropathy leads to fat and D-xylose malabsorption and chronic non-specific inflammation of the small bowel. Moreover, gastrointestinal infection can induce severe diarrhoea. Depletion in real body cell mass, body fat content, and weight loss have been observed. Nutritional therapy is mandatory when weight loss is 10% or greater. Enteral feeding is not easily achieved. Parenteral feeding including fat as a nonprotein calorie source improves general condition. The use of intravenous fat emulsions has been hypothesized to have several beneficial effects. Fluidisation of human immunodeficiency virus membranes by lipid emulsions through cholesterol extraction could decrease the infectivity of the virus. Long term intravenous nutrition may be more than a treatment for malabsorption and depletion; it may possibly have direct pharmacological effects.

In vivo and in vitro studies of thymulin in marginally zinc-deficient mice

Thymulin (or serum thymic factor, FTS-Zn), a well-defined thymic hormone previously shown to be a nonapeptide binding the metal zinc, was studied in mice subjected to a long-term marginally Zn-deficient diet. In spite of the absence of thymic atrophy, we observed a significant decrease in the serum levels of thymulin as early as two months after the onset of treatment. However, these levels could be consistently restored after in vitro addition of ZnCl2. The analysis of thymuses from Zn-deficient mice showed that, despite the apparently normal network of epithelial cells, there was a progressive increase in the number of thymulin -containing cells (assessed by immunofluorescence with anti- thymulin monoclonal antibodies) that was already significant after two months of treatment. These results are in keeping with those of previous investigators, showing a specific, altered, thymic endocrine function following Zn deprivation. Nonetheless, our results strongly suggest that the nonactive Zn-deprived peptide is secreted under these experimental conditions. Furthermore, the fact that the augmented numbers of thymulin -containing cells were observed in the thymuses following a decrease in the peripheral thymulin (biologically active) brings further evidence for the existence of a feedback mechanism for the secretion of this hormone.