title: Anti-Helicobacter pylori immunoglobulin G (IgG) and IgA antibody responses and the value of clinical presentations in diagnosis of H. pylori infection in patients with precancerous lesions.
abstract: OBJECTIVE
  To determine the prevalence of Helicobacter pylori (H. pylori) infection, the serum anti-H. pylori immunoglobulin G (IgG) and IgA antibody responses, and the value of clinical presentations in diagnosis of H. pylori infection in patients with gastric atrophy, intestinal metaplasia and dysplasia.
  
  
  METHODS
  H. pylori infection was detected by histology in 209 patients with mild chronic atrophic gastritis (CAG, n=76), severe CAG (n=22), mild intestinal metaplasia (IM, n=22), severe IM (n=58), or dysplasia (DYS, n=31). Serum anti-H. pylori IgG and IgA were double sampled and evaluated by enzyme-linked immunoadsordent assays. 35 clinical presentations were observed and their relationship with H. pylori infection was analyzed by the k-means cluster method.
  
  
  RESULTS
  Both IgG and IgA levels in H. pylori positive patients were significantly higher than those negative for H. pylori (P<0.001-0.01). The prevalence of H. pylori was highest in severe IM (84.5 %), and lowest in mild CAG (51.3 %) (P<0.01). They were similar in severe CAG (68.2 %), mild IM (72.7 %), and DYS (67.7 %). In H. pylori positive patients, the IgG levels in severe CAG were significantly higher than those in mild CAG (P<0.01). In H. pylori negative patients, both IgG and IgA levels increased remarkably in severe IM, compared to those in mild IM (P<0.01-0.05). H. pylori infection exhibited no association with patient's gender (62.1 % in males; 71.7 % in females) and age (r=0.0814, P=0.241). The diagnostic accuracy based on 35 clinical presentations was 65.7 %. It could be improved by 5.7 % when only the assemblage of digestive symptoms were engaged, or by 8.6 % when the pathogenic factors, general status and grossoscopy were combined. The diagnostic accuracy could be decreased when only the general symptoms were engaged, or when the pathogenic factors were accompanied with some common digestive symptoms.
  
  
  CONCLUSIONS
  H. pylori infection is a major risk factor for the process from atrophy, IM to DYS of gastric mucosa. Serum IgG and IgA are good indicators to evaluate this progress with a certain arrearage. Investigation on the effective assemblages of clinical presentations may provide a better understanding in the pathogenesis, diagnosis and treatment for H. pylori infection.
authors.affiliation: Institute of Basic Theory, China Academy of Traditional Chinese Medicine, Dongzhimen, Beijing 100700, China.
authors.forename: Shao
authors.initials: S
authors.lastname: Li
authors.forename: Ai-Ping
authors.initials: AP
authors.lastname: Lu
authors.forename: Lian
authors.initials: L
authors.lastname: Zhang
authors.forename: Yan-Da
authors.initials: YD
authors.lastname: Li
mesh_terms: D000368:Aged; D000907:Antibodies, Bacterial / Q000097:blood*; D000917:Antibody Formation; D005260:Female; D005756:Gastritis / Q000097:blood / Q000276:immunology / Q000382:microbiology; D016481:Helicobacter Infections / Q000097:blood / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011230:Precancerous Conditions / Q000097:blood / Q000276:immunology / Q000473:pathology; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000097:blood / Q000276:immunology / Q000473:pathology
chemical_list: D000907:Antibodies, Bacterial; D007070:Immunoglobulin A; D007074:Immunoglobulin G