ANTIBODIES TO CAGA PROTEIN ARE ASSOCIATED WITH GASTRIC ATROPHY IN HELICOBACTER-PYLORI INFECTION

Strains of Helicobacter pylori which express the product of the cytoto xin associated gene A(CagA) are associated with duodenal ulceration. A lso there is evidence that the presence of serum IgG antibodies to Cag A is associated with an increased risk of gastric cancer of the intest inal type. Gastric atrophy is a precursor of intestinal-type gastric c ancer so we have investigated whether antibodies to CagA are associate d with gastric atrophy. In H. pylori infected patients, IgG antibodies to CagA were present in 24/38 (63%) of non-ulcer patients with atroph y compared with 13/40 (33%) of patient-controls with neither atrophy n or ulcer (P<0.02). CagA antibodies were also more prevalent in patient s with duodenal ulcers; 15/20 (75%) or gastric ulcers 5/5 (100%) than in the patient-controls (P<0.005 and <0.02 respectively). These result s show that circulating IgG antibodies to CagA are associated with gas tric atrophy, as well as peptic ulcer disease. Atrophy is a precursor of gastric cancer so these results support the hypothesis that certain strains of H. pylori are more likely to cause gastric cancer.