Long term serological surveillance after treatment of Helicobacter pylori infection.

Fifteen patients with type B gastritis caused by Helicobacter pylori infection were treated with 'triple' therapy consisting of colloidal bismuth subcitrate, amoxycillin, and metronidazole. All were followed up as outpatients every three months for at least one year. After 'triple' therapy a significant (p less than 0.01) and persistent reduction in IgA and IgG antibody levels against H pylori was detected. In three patients recurrent active infection with H pylori at nine and 12 months was detected by a rise in IgA (three patients) and IgG (two patients) antibody levels against H pylori and worsening of symptoms, and was confirmed by culture and histology. In 11 patients, the absence of infection at 12 months was confirmed by culture and histology. In a control group of 13 patients with type B gastritis who received no antibacterial treatment, specific IgA and IgG antibody levels against H pylori remained unchanged during 12 months of follow up. Although specific IgG against H pylori is the most widely used serological test for screening, our data indicate that specific IgA is also valuable in monitoring treatment. These serological tests are easy to perform, relatively inexpensive, devoid of radioactivity and are very acceptable to patients. It is concluded that serological testing is the preferred method for follow up after treatment for H pylori infection and will probably replace endoscopy or the urea breath test.