Distribution in various clinical groups of antibody to C. pylori detected by enzyme-linked immunosorbent assay, complement fixation and microagglutination tests

An enzyme-linked immunosorbent assay (ELISA), complement fixation test (CFT) and a microagglutination (Magg) test have been evaluated for serodiagnosis of C. pylori associated gastritis. The three methods detected elevated antibody titres (ELISA-IgG ≥ 1 in 640, CFT ≥ 1 in 2, Magg ≥ 1 in 320) in 93-100% of patients with organisms detected and gastritis in comparison to 22-32% of patients without organisms and without gastritis. Seventy-three percent of patients with duodenal or gastric ulcers and 86% of patients with acute pancreatitis also showed elevated antibody titres. The IgG, IgM and IgA response was determined by ELISA and elevated titres (IgG ≥ 1 in 640 and IgA ≥ 1 in 80) were demonstrated in patients with C. pylori and gastritis. In comparison IgM titres were not of diagnostic value. The most sensitive test was the ELISA-IgG (100% for presence of organisms and 95% for gastritis). This assay was of similar specificity (73-74%) to the other methods. Antibody titres in different age groups were determined by ELISA and CFT. Fifteen percent of children < 5 years had raised antibody titres by ELISA-IgG and CFT. The proportion with elevated titres increased with age to 36% and 48% in adults as determined by ELISA-IgG and CFT respectively. In those patients with gastritis, C. pylori detected and elevated C. pylori antibody titres 65% and 45% also showed raised titres to C. jejuni and C. jejuni subsp 'doylei' respectively.