Factors Involved in Thymic Atrophy in Severely Malnourished Children: A Systemic Review and Meta-Analysis

To determine leptin's effect on the thymus, we gathered data on leptin levels, ghrelin, cortisol and cytokine levels. The aim of the study was to map leptin's effect on the thymus when malnourished. Pubmed and Embase were searched for articles by the search terms 'malnutrition' and 'leptin'. The risk of bias was assessed by using JBI critical appraisal tools. Results were presented in tables and forest plots generated using STATA. A total of 16 articles were included. All articles included in the study are researching leptin, cortisol, or ghrelin, as well as cytokines. Forest plots were created for leptin, ghrelin, cortisol, Interleukin 10 (IL-10) and Interferon gamma (IFN-γ). Leptin had an overall effect size of 3.01 (95% CI 0.51; 5.51), ghrelin had an overall effect size of -1.71 (-2.97, -0.45), cortisol had an overall effect size of -1.16 (-1.49, -0.83), IL-10 had an overall effect size of -0.34 (95% CI -0.54; -0.14) and IFN-γ had an overall effect size of -0.02 (95% CI -0.25; 0.22), respectively. Our data revealed a decrease in leptin levels and an increase in cortisol, ghrelin and IL-10 when compared with control. This review displayed a relationship between leptin, cortisol, ghrelin and thymus atrophy. The change in T-helper cells contributes to the increased thymocyte depletion seen when severely malnourished. Leptin cannot explain all the changes observed, but may give insight into how it is a contributing factor in the changes the thymus undergoes.