Defective Regulation of the Protective IgE Response against Intestinal Helminth Ascaris lumbricoides in Malnourished Children

• Published in: Journal of tropical pediatrics (1980) 2003-06, Vol.49 (3), p.136-142
• Main Authors: Hagel, I., Lynch, N.R., Puccio, F., Rodriguez, O., Luzondo, R., Rodríguez, P., Sánchez, P., Cabrera, M., Di Prisco, M. C.
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Animals; Antibodies, Helminth - biosynthesis; Antigens, CD - metabolism; Antigens, Differentiation, T-Lymphocyte - blood; Ascariasis - immunology; Ascaris lumbricoides - immunology; Biological and medical sciences; Child; Feces - parasitology; Flow Cytometry; Humans; Immunoglobulin E - biosynthesis; Immunoglobulin E - blood; Interleukin-4 - blood; Lymphocyte Count; Medical sciences; Metabolic diseases; Nutrition Disorders - epidemiology; Nutrition Disorders - immunology; Nutrition Disorders - parasitology; Other nutritional diseases (malnutrition, nutritional and vitamin deficiencies...); Parasite Egg Count; Radioimmunosorbent Test; Tropical medicine; Venezuela - epidemiology
• ISSN: 0142-6338; 1465-3664
• DOI: 10.1093/tropej/49.3.136

It is well established that malnutrition affects the immune response and increases the susceptibility to parasitic infection. In the present study we evaluated some aspects of the cellular and cytokine network that regulate the IgE responses, which are important components of host defence mechanisms against helminthic parasites in children infected with the intestinal helminth Ascaris lumbricoides, and with differing degrees of malnutrition. We found a defective T cell response in malnourished children, as indicated by diminished levels of circulating total (CD3+), helper (CD4+), IL‐2‐receptor‐bearing (CD4+CD25+) and memory helper T cell responses (CD4+CD45RO+) in keeping with the decreased specific IgE levels against Ascaris lumbricoides. In contrast, the proportions of total B cells (CD20+), and those bearing the low‐affinity IgE receptor (CD23+) were increased in the moderated malnourished children. Moreover, serum IL‐4 levels and total IgE were also increased in these children. We suggest that malnutrition can cause an imbalance in T cell subpopulations that may lead to a defective T cell maturation and a decreased specific anti‐Ascaris IgE response thus increasing the susceptibility to such infections. The high levels of total IgE observed may be related to a non‐specific stimulation of the proliferation of activated B cells, probably caused by helminthic parasites and other infectious agents that are frequent in malnourished children.