Development of humoral immunity system of the small bowel.

The study was performed in 24 children aged 2 months to 6 years, without intestinal or immunological diseases. Intestinal biopsies were obtained by a Crosby's capsule, pediatric size. The number of immunoglobulin forming cells of lamina propria was measured by planimetry. Under 12 months of age there are increased levels of IgM forming cells and a low IgA forming cells/IgM forming cells quotient, but over 1 year the difference disappears. This suggests that the maturity process is very rapid. There are no correlation between serum IgA, IgM, and IgG levels and its respective forming cells number of lamina propria. It seems to support that the participation of intestinal lymphoid tissue in serum pool of immunoglobulin is very poor and that systemic and intestinal immunity maturation are completely independent.