SERODIAGNOSIS OF HELICOBACTER-PYLORI INFECTION IN CHILDREN BY AN INDIRECT IMMUNOFLUORESCENCE TEST

The objective of this study was to evaluate the accuracy of an indirec t immunofluorescence (IIF) test for serodiagnosis of Helicobacter pylo ri infection in children and to determine how the test is affected by the presence of antibodies against Campylobacter jejuni. We studied 65 consecutive children (two with endoscopically confirmed duodenal ulce r) and a series of 18 children with duodenal ulcer. Thirty children we re H. pylori negative, as determined by culture, by the preformed urea se test, and by carbolfuchsin-stained smears. The microorganism was id entified by microbiological methods in 35 of the 65 (53.85%) consecuti ve patients studied and in all children with duodenal ulcer. The titer of the IIF test was greater-than-or-equal-to 1:20 in the sera of all children with duodenal ulcer and in the sera of 30 of 33 H. pylori-pos itive children without duodenal ulcer. No H. pylori-negative children had titers > 1:10. A serum dilution of 1:20 discriminated between H. p ylori-infected and noninfected children. Absorption with C. jejuni did not change the levels of IgG against H. pylori. When five patients wh o had been successfully treated with metronidazole, amoxycillin, and f urazolidone for 7 days were retested, a slight decrease in anti-H. pyl ori IgG levels was noted from the third month on. The decrease was mor e significant 9 months after the eradication of the microorganism.