Helicobacter pylori: Pathology and Diagnostic Strategies

Detection rate of Helicobacter pylori stool antigen in newborn infants and small children

AIMS

To investigate the prevalence of H. pylori antigen in the stools of Norwegian neonates and small children.

METHODS

A total of 249 children aged 0 days-3 years were tested for the presence of H. pylori antigen in feces using the HpSA immunoassay. For verification purposes, a selection of samples were analyzed with PCR targeting the 16 S rDNA Helicobacter gene.

RESULTS

H. pylori antigen in stool was detected in 52% (36/69) of the neonates, in 15% (7/46) of infants aged 7 days-1 month, and in 5% (7/134) of children aged 1 month-3 years. In neonates, H. pylori antigen detection was significantly associated with mode of delivery: 59% (30/51) with uncomplicated vaginal births were HpSA positive compared to only 10% (1/10) of infants delivered by cesarean section (P=0.02). Positive PCR results were found in 35% (9/26) of HpSA positive samples. Sequencing of PCR products revealed 97-100% homology with gene sequences from both H. pylori and other Helicobacter species.

CONCLUSIONS

The low H. pylori antigen detection rate in children >1 month of age is in accordance with previous prevalence studies from Western countries. The unexpected finding of a high H. pylori antigen detection rate in neonates suggests that transient colonization may occur in the neonatal period.

Expression of NF-kappaB in Helicobacter pylori infection

Helicobacter pylori colonizes the gastric mucosa in humans and causes chronic gastritis. NF-kappaB has a key role as a mediator in mucosal inflammation. In this study, we examined the expression of NF-kappaB in the antral epithelial cells of H. pylori-infected and H. pylori-uninfected biopsies and examined these processes in relationship with grade and activity of gastritis, density of H. pylori, presence of the intestinal metaplasia, and atrophy. Fifty biopsies (35 H. pylori-positive patients and 15 H. pylori-negative controls) were studied. NF-kappaB immunohistochemical stain was performed. NF-kappaB activity in H. pylori-infected biopsies were markedly enhanced compared with uninflamed biopsies (P = 0.001). We also found positive correlation NF-kappaB expression with severity of gastritis (according to Sydney score) (P = 0.001), activity of gastritis (P = 0.046) and H. pylori load (P < 0.001), and atrophy (P = 0.004). We did not find a significant relationship between NF-kappaB and the presence of intestinal metaplasia (P = 0.355). These findings suggested that expression of NF-kappaB has an important role in H. pylori gastritis.