Serum and intestinal fluid immunoglobulins and jejunal IgA secretion in Crohn's disease.

Immunoglobulins in serum and proximal intestinal fluids and secretion of IgA by cultured jejunal mucosa were measured in 12 healthy subjects and 36 patients with Crohn's disease. Concentrations of IgA, IgG, IgM, and IgE in serum and intestinal fluids were similar in the two groups, except for increased serum IgA concentrations in the patients. Elevation of IgA and chronicity of disease were correlated, which suggests that the IgA alteration was a response to duration of disease rather than a primary pathogenetic factor. IgA secretion by cultured jejunum was similar in control and patient groups. Thus, no evidence was found that abnormalities of secretory immunoglobulins are pathogenetically involved in Crohn's disease.