[Show abstract][Hide abstract] ABSTRACT: Malnutrition is a common cause of secondary immune deficiency and has been linked to an increased susceptibility to infection in humans. Malnutrition specifically affects T-cell-mediated immune responses. The aim of this study was to assess in lymphocytes from malnourished children the expression levels of IL-12, IL-18 and IL-21, molecules that induce the differentiation of T cells related to the immunological cellular response (Th1 response) and the production of cytokines related to the immunological cellular response (Th1 cytokines). We found that the expression levels of IL-12, IL-18 and IL-21 were significantly diminished in malnourished children compared to well-nourished children and were coincident with lower plasmatic levels of IL-2 and IFN-γ (Th1 cytokines). In this study, we show for the first time that the gene expression and intracellular production of cytokines responsible for Th1 cell differentiation (IL-12, IL-18 and IL-21) are diminished in malnourished children. As expected, this finding was related to lower plasmatic levels of IL-2 and IFN-γ. The decreased expression of Th1 cytokines observed in this study may contribute to the deterioration of the immunological Type 1 (cellular) response. We hypothesize that the decreased production of IL-12, IL-18 and IL-21 in malnourished children contributes to their inability to eradicate infections.
[Show abstract][Hide abstract] ABSTRACT: Protein-calorie malnutrition represents a significant worldwide health problem and is associated with an increased risk for infections. The purpose of this study was to evaluate possible changes in type 1/type 2 responses balance in malnourished children.
The data obtained in the present study showed that the expression levels of tumor necrosis factor-alpha, interleukin (IL)-4, and IL-10 were more highly, in contrast IL-2, gamma interferon, and IL-6 genes were expressed less in all groups of malnourished children compared with the well-nourished infected children. It is important to indicate that the data collected in the present work agree with the results obtained by different authors, who showed differences in the production of cytokines in malnourished children.
In conclusion, the results suggest that alterations in the balance of type 1/type 2 immune responses exist in malnourished children, and this could be the reason that the immunological system of the malnourished children is incapable of eradicating infections.