IgG and IgA antibodies in Helicobacter pylori infections.

We compared Helicobacter pylori-specific IgG and IgA antibodies in serum, salivary and gastric juice of H. pylori-infected and noninfected patients using the ELISA method. Serum and salivary anti-H. pylori IgG and IgA titres were higher in H. pylori-positive than H. pylori-negative patients. Serum H. pylori IgG titres were higher than those of serum-specific IgA. In contrast, H. pylori IgA titres in saliva samples were higher than those of specific IgG. In all patients, the levels of IgG antibodies were very low in gastric juice. H. pylori-positive patients with increased levels of IgA in sera, also exhibited increased IgA levels in gastric juice. The determination of IgA antibodies in serum and saliva may be used as a test that complements the IgG antibody assay.