IgA1, IgA2 or secretory piece containing antigliadin antibodies in the sera of coeliac patients.

A study was made of the gliadin antibodies containing secretory piece (SP) found in 73 sera samples obtained from 38 children with coeliac disease (CD); simultaneously an intestinal biopsy was carried out. In 32 cases the mucosa was flat and the remaining 41, following a gluten-free diet, had a normal intestinal histology. Thirty chronic non-coeliac gastrointestinal patients and 22 normal children were used for a control. An enzymoimmunoassay technique with monoclonal IgA1 and IgA2, and SP polyclonal antibodies was used. The antigliadin antibodies containing SP in serum were above normal limits in 24/32 (75%) active CD patients, but also in 22/41 (54%) patients with normal biopsy and in 20/30 (66%) chronic non-coeliac gastrointestinal patients. There was a multivariant correlation (p less than 0.002) among antigliadin, ovoalbumin and lactoglobulin antibodies containing SP. These results are probably due to non-specific intestinal damage. Nevertheless, antigliadin antibodies containing SP in the sera of gluten-free CD cases lasted longer than antiovoalbumin and antilactoglobulin antibodies. The IgA1 antigliadin antibodies were increased in 19/30 (64%) of active CD patients and 0/8 of inactive CD patients (p less than 0.0005). Nevertheless IgA2 antibodies were increased in only 2/30 (7%) of active CD patients (p less than 0.05). According to this study the IgA antigliadin antibodies in serum are the result of a systemic response, although another interpretation could be that gliadin mainly stimulates IgA1 subclass antibodies in the gut.