Immunoglobulins in jejunal mucosa and serum from patients with adult coeliac disease.

Immunoglobulin (Ig)-containing cells were quantitated immunohistochemically in biopsy specimens from the proximal jejunal mucosa. The numbers of IgA, IgM, and IgG immunocytes in a defined "mucosal tissue unit" were, on the average, raised 2.4, 4.6, and 6.5 times, respectively, when 13 adult patients with untreated coeliac disease (CD) were compared with 15 patients who had a histologically normal mucosa. The IgA-:IgM-:IgG-cell ratios averaged 66:28:6 in untreated CD and 79:18:2.6 in the controls. Similar quantitative data in 10 patients with treated CD were intermediate. IgD- and IgE-containing cells were rare in all patient groups. Most patients in a heterogeneous malabsorption group showed a jejunal Ig-containing cell population similar to that seen in CD, indicating that the local immunocyte pattern may not be specific for the latter disease. The only significant alteration in serum Ig levels related to CD was a raised concentration of IgA compared with normal. This was consistent with the increased amounts of extracellular IgA revealed in the mucosa. However, there was no indication of a defect in the transport of dimeric IgA and IgM through SC-producing cells, which in the CD mucosa were present in both crypt and surface epithelium.