[Influence of helminthic infections and nutritional status on immune response in Venezuelan children]

We investigated the influence of nutritional status, as determined from anthropometric measurement, and of helminthic infections on the immune response of children of low socioeconomic status in two rural communities in Venezuela: El Cardón in the state of Nueva Esparta and San Daniel in the state of Miranda. A total of 125 boys and girls between 2 and 15 years old participated in the study. Their socioeconomic stratum was determined by a modified Graffar method. A physical examination was performed, as was also an anthropometric evaluation that took into account three indicators--weight-for-height, weight-for-age, and height-for-age--according to parameters established by the World Health Organization. Other examinations included feces, secretory IgA in saliva, total serum IgE, and anti-Ascaris-specific immunoglobulins. The children in both of the communities were in strata IV and V of the of Graffar scale, with a significantly greater number of stratum V inhabitants in San Daniel (P < 0.001). The results suggest that exposure level and individual susceptibility to the parasites are determining factors in parasitic infection and immune system behavior. The intensity of the parasitic burden plays an important role in stimulating polyclonal IgE, which diminishes the effectiveness of the specific response to those infections. On the other hand, nutritional deficiencies could change the immune mechanisms of the mucous membranes, negatively influence the synthesis of secretory IgA, and stimulate the production of polyclonal IgE. Poor sanitary and socioeconomic conditions promote more exposure to gastrointestinal parasites and a deficient nutritional status, which modulates the immune response and affects serum IgE and secretory IgA production mechanisms.