DIAGNOSIS OF HELICOBACTER-PYLORI INFECTION BY SPECIFIC GASTRIC-MUCOSAL IGA AND IGG PYLORI ANTIBODIES

Aims-To investigate the diagnostic value of mucosal IgA and IgG Helico bacter pylori antibodies. Methods-The study population comprised 209 c onsecutive patients with severe dyspeptic complaints referred for uppe r gastrointestinal endoscopy. A positive culture or histological ident ification of H pylori in gastric biopsy specimens, or both, were used to confirm infection. Specific IgA and IgG H pylori antibodies were de termined using a modified ELISA technique. Results-Of the 209 patients , 137 were infected with H pylori. The diagnostic value of systemic Ig A and IgG H pylori antibodies was confirmed. Systemic IgA antibodies h ad a sensitivity of 76.6% (95% confidence interval 69.5-83.7) and a sp ecificity of 94.4% (89.1-99.7). The sensitivity and specificity for sy stemic IgG antibodies were, respectively, 97.1% (94.3-99.9) and 98.6% (95.9-100). A moderate but clinically important correlation was found between local and systemic IgA and IgG. Mucosal IgA H pylori antibodie s had a sensitivity of 98.5% (96.5-100) and a specificity of 91.7% (85 .3-98.1), while for IgG these figures were, respectively, 88.3% (82.9- 93.7) and 98.6% (95.9-100). As a diagnostic test mucosal IgA H pylori antibodies were comparable with culture and histology. Conclusion-Dete rmination of local IgA and IgG H pylori antibody levels is a highly se nsitive and specific test for the diagnosis of H pylori infection.