QUANTITATION OF SALIVARY, URINARY AND FECAL SIGA IN CHILDREN LIVING IN DIFFERENT CONDITIONS OF ANTIGENIC EXPOSURE

A sandwich-type ELISA was developed to quantify salivary, urinary and faecal secretory IgA (sIgA). The assay is based on binding of sIgA to microplates coated with anti-SC antibodies and reaction with peroxidas e-labelled anti-IgA. The sensitivity of the technique was approximatel y 5 mug/L. Children, 1-6 years old (n = 142), were divided into two gr oups. Group 1 (n = 80) was composed of children living in a place with presumably low antigenic exposure conditions. Group 2 (n = 62) was co mposed of well-nourished (2A, n = 53) and malnourished children (2B, n = 9) living in a Sao Paulo slum with presumably high antigenic exposu re. The subgroup 2A had salivary levels higher than group 1 and the ra nges were similar to those found in the literature for older children and adults. The same subgroup presented a high incidence of undetectab le faecal sIgA; their levels of urinary sIgA did not differ from group 1. The subgroup 2B did not have levels of salivary, urinary and faeca l sIgA different from subgroup 2A. Our results suggest that environmen tal factors influence the ontogenesis of sIgA system.