Salivary SIgA and SIgA 1 in coeliac disease, inflammatory bowel disease and controls

Levels of secretory IgA1 (SIgA1) in the saliva have not been measured previously in either coeliac disease (CD) or inflammatory bowel disease (IBD). Saliva was collected from coeliacs, IBD patients and controls. The concentration of total SIgA in saliva was measured by enzyme linked immunosorbent assay (ELISA) with an anti-human SIgA antibody as the bound phase and human SIgA isolated from colostrum as the standard. The concentration of SIgA1 was determined using an ELISA with a lectin with a high affinity for human SIgA1. The IBD patients have a significantly higher concentration of SIgA1 than the controls. The rate of secretion of saliva and %SIgA1 was significantly lower in coeliacs than in the control and IBD groups. The rate of secretion of SIgA1 was significantly higher in the IBD than in the coeliacs. We describe hitherto unreported levels of SIgA1 in CD and IBD.