Effect of age, malnutrition and renutrition on free secretory component and IgA in secretions.

The development of free secretory component (FSC) was studied in the tears of normal infants, children and adults. The level of FSC in tears was higher in older adults than in children. Free secretory component was also measured in the tears of normal, moderately and severely malnourished Colombian children. Children suffering from kwashiorkor, combined protein-calorie malnutrition or marasmus were studied before and after renutrition. No change was detected in the concentration of FSC in tears of moderately malnourished (Grade I and II) children. There was a significant difference between normal and severely malnourished children which improved with renutrition. The levels of tear IgA were decreased in the moderately malnourished children. These results indicate that reduction in secretory IgA levels in moderate malnutrition may not be explained by a lack of available free secretory component in tears, but that severe malnutrition may impair the S-IgA system by significantly reducing the availability of free secretory component.