Testing for serum IgG antibodies to Helicobacter pylori cytotoxin-associated protein detects children with higher grades of gastric inflammation

Background: Little information is available about the relationships between Helicobacter pylori cytotoxin-associated protein (CagA) and clinicopatholo gic features in children. The purpose of this study was to test whether det ermining serum IgG antibodies to CagA is a useful tool for detecting more s evere disease. Methods: One hundred twenty-seven consecutive children (age range, 0.75-17. 8 years; median, 9.4 years) referred for gastroscopy were included in the s tudy. Antral and corpus biopsies were taken for gastric histology and H. py lori detection. Major symptoms and endoscopic findings were recorded. A ser um sample was drawn from each child and assayed for Ige antibodies CagA by a commercial enzyme-linked immunosorbent assay. Results: Sixty-three (50%) children had no evidence of H. pylori infection, 28 (22%) were H. pylori positive/CagA positive, and 36 (28%) were H. pylor i positive/CagA negative. There were no differences in clinical diagnosis a nd occurrence of any predominant symptom according to H. pylori and CagA st atus. Findings of antral nodularity were more frequent (p = 0.003) in H. py lori-positive/CagA-positive children than in H. pylori-positive/CagA-negati ve children. The gastritis score was significantly higher in PI. pylori-pos itive/CagA-positive children than in H. pylori-positive/CagA-negative child ren (5.7 +/- 1.9 vs. 3.8 +/- 1.6, respectively; p = 0.0003), either in the antral (p = 0.0002) or in the corpus (p = 0.001) mucosa. Inflammation (p = 0.0001) and activity (p = 0.0001) scores were both higher in H. pylori-posi tive/CagA-positive children than in H. pylori-positive/CagA-negative childr en, but the H. pylori density score was not significantly different (p = NS ). In no case was normal gastric mucosa found in H. pylori-positive/CagA-po sitive children. Lymphocytic gastritis (p = 0.0008) and lymphoid follicles (p = 0.000003) were a more frequent finding in H, pylori-positive children than in H, pylori negative children, irrespective of CagA status. Conclusion: Testing for serum IgG to CagA detects higher grades of gastric inflammation among children with H. pylori infection. It may be useful in t argeting H. pylori-positive/CagA-positive children for antimicrobial therap y while reducing the need for endoscopy and gastric biopsy.