THE HUMORAL IMMUNE-RESPONSE TO HELICOBACTER-PYLORI INFECTION IN CHILDREN WITH RECURRENT ABDOMINAL-PAIN

The systemic humoral immune response to Helicobacter pylori antigens w as investigated in 36 children with recurrent abdominal pain (RAP). H. pylori was cultured and Helicobacter-like organisms (HLO) were seen i n six children, three of whom had active and two inactive chronic gast ritis. None of these children had endoscopic abnormalities. All sex ch ildren had increased IgG antibodies to heat-stable H. pylori antigens which were of the IgG1 and IgG3 subclasses. Using six other IgG tests, four of which were commercially available, two to five H. pylori-posi tive children were found seropositive. Five of six H. pylori-negative children with inactive chronic gastritis and no endoscopic abnormaliti es had increased IgM antibody levels in addition to increased or borde rline increased IgG antibody levels to H. pylori, indicating activity in a chronic H. pylori infection. Five children without H. pylori and with no morphological changes, but with gastritis or duodenitis by end oscopy, had significantly lower IgG and IgA antibody levels compared t o other groups. Six of nineteen children without H. pylori, and with n o morphological or endoscopic changes had increased IgG and IgM antibo dy levels to H. pylori. All H. pylori-negative children were seronegat ive by the four commercial kits. Overall, 12 (33%) of 36 children with RAP were either H. pylori positive by culture and microscopy or had i ncreased IgG antibody levels to H. pylori, which is significantly diff erent from the 10-14% seropositive rate of asymptomatic children. H. p ylori may therefore be a cause of RAP in one quarter to one third of t he children with RAP in whom other etiologies of RAP are excluded. Fur ther studies on a large number of children are needed for an extended evaluation of the humoral immune response to H. pylori and for further examination of commercial kits which seem to give a high number of fa lse-negative results.