ISOTYPIC ANALYSIS OF SPECIFIC ANTIBODY-RESPONSE IN SERUM, SALIVA, GASTRIC AND RECTAL HOMOGENATES OF HELICOBACTER PYLORI-INFECTED PATIENTS

The relationship between systemic and local humoral immune response to Helicobacter pylori is poorly understood. To further address this iss ue we measured, using ELISA, H. pylori-specific IgG and IgA antibodies in serum, saliva, gastric and rectal homogenates of H. pylori-infecte d patients. A total of 107 patients who underwent upper GI endoscopy a nd/or sigmoidoscopy were studied. The isotypic pattern of H. pylori-sp ecific antibodies appeared to differ at the serum, salivary, gastric a nd rectal mucosa level, Serum H. pylori IgG titers were higher than th ose of the serum-specific IgA. On the contrary, in saliva samples H. p ylori IgA titers were higher than specific IgG titers. In gastric homo genates, specific IgG and IgA titers were similar. H. pylori-specific IgG were detectable in rectal homogenates but no or very low H. pylori -specific IgA were found in the same material. Furthermore, no differe nce was found in H. pylori IgG and IgA in serum, saliva and gastric ho mogenates between duodenal ulcer and non-ulcer dyspepsia patients. Dat a of the present study indicate that, in H. pylori-infected patients, the specific immune response is as follows: (1) it involves the secret ory immune system; (2) it is paralleled by the specific salivary IgA; (3) it does not differentiate duodenal ulcer from non-ulcer dyspepsia patients; and (4) it does not take place in the large bowel.