Effect of malnutrition on the expression of cytokines involved in Th1 cell differentiation.

Cristina González-Torres,Angel Miliar,Haydeé González-Martínez,Verónica Firo,Oralia Nájera,Catalina Alvarez,Leonor Rodríguez,Edmundo Bonilla,Jaime Graniel

doi:10.3390/nu5020579

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.

Highlights

Malnutrition is either directly or indirectly responsible for 54% of the 10.8 million deaths per year in children under five in developing countries [1]
The aim of this study was to evaluate the expression levels of the cytokines involved in Th1 cell differentiation (IL-12, IL-18 and IL-21) by PCR and flow cytometry and to correlate this with the plasmatic levels of two Th1 cytokines (IL-2 and IFN-γ) in malnourished and well-nourished children hospitalized for bacterial infection
The expression results were standardized with respect to the reference gene β-actin, and the relative expression levels of IL-12, IL-18 and IL-21 for children in groups WN-I, MN-1, MN-2 and MN-3 were analyzed

Summary

Introduction

Malnutrition is either directly or indirectly responsible for 54% of the 10.8 million deaths per year in children under five in developing countries [1]. Malnutrition is a common cause of secondary immune deficiency and has been linked to an increased susceptibility to infection in humans [2]. It is well-known that malnutrition affects T-cell-mediated immune responses. Diminished T-cell immunological responses are generally associated with increased susceptibility to infections. This susceptibility is likely related to alterations in the production or expression of specific cytokines [3,4]

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