Anti-CagA antibodies in Helicobacter pylori-positive patients and blood donors from Nigeria

Prevalence of cagA in relation to clinical presentation of Helicobacter pylori infection in Egypt

Helicobacter pylori infection, peptic ulcer and gastric cancer are common problems in Egypt. We investigated the prevalence of cagA-positive Helicobacter pylori infections among Egyptian adults in relation to presentation (e.g. dyspepsia vs asymptomatic controls) in Minofyia, Egypt. Patients included men or women seeking care for at least 3 months of upper gastrointestinal symptoms. Helicobacter pylori status was determined by rapid urease test and gastric histopathology in patients and by anti-Helicobacter pylori IgG antibodies in controls. CagA status was determined using an anti-cag A ELISA. 99 Helicobacter pylori infected patients were entered including 90 dyspeptic patients (30 each with gastric cancer, peptic ulcer, and non-ulcer dyspepsia) and 9 non-dyspeptic healthy controls. Age ranged from 27 to 78 y (mean 49.5 y); 50% were men. Anti-cagA antibodies were present in 62.2% of dyspeptic patients compared with 11% of asymptomatic controls (p = 0.004). Anti-cagA antibodies were more prevalent among dyspeptic patients with gastric cancer or peptic ulcer (73.3%) compared to those with non-ulcer dyspepsia (40%) (p = 0.004). The prevalence of cagA in Egypt was related to the clinical presentation of Helicobacter pylori infection being lowest in asymptomatic controls (11.1%) and increasingly prevalent in non-ulcer dyspepsia (40%), peptic ulcer (66.7%), and gastric cancer (89%).

Specific serum immunoglobulin G to H pylori and CagA in healthy children and adults (south-east of Iran)

AIM: To evaluate the serologic IgG response to H pylori and CagA across age groups and in healthy children and adults.

METHODS: Totally, 386 children aged 1-15 years and 200 adults aged 20-60 years, were enrolled to study. The serum samples of participant were tested for presence of anti-H pylori and anti-CagA IgG by using ELISA method.

RESULTS: The seroprevalence of H pylori in adults was significantly higher than that observed in children (67.5% vs 46.6%; P < 0.000003). In children, the seropositivity rate in males (51.9%) was significantly (P < 0.05) higher than that observed in females (41.7%). The prevalence of serum anti-CagA antibody was 72.8% and 67.4% in infected children and adults, respectively. The mean titer of serum anti-CagA antibodies was significantly higher among children in comparison to adults (64.1 Uarb/mL vs 30.7; P < 0.03). In infected children and adults the prevalence of serum anti-CagA antibody was higher in males compared to females (78.4% vs 66.3%; P = 0.07 and 75.6% vs 54.71%; P < 0.04, respectively). The age-specific prevalence of anti-H pylori and anti-CagA antibody (in infected subjects) was 37.6% and 59.57% at age 1-5 years, 46.9% and 75% at age 6-10 years, 54.9% and 79.45% at age 11-15, 59.01% and 83.33% at age 20-30 years, 66.6% and 60.52% at age 31-40 years, 73.46% and 63.88% at age 41-50 years and 75.75% and 60% at age 51-60 years with mean titer of anti-CagA antibody of 75.94, 63.32, 57.11, 52.06, 23.62, 21.52 and 21.80 Uarb/mL, respectively. There was significant difference between mean serum anti-CagA antibody in age subgroups (P < 0.001).

CONCLUSION: These results showed that anti-H pylori and anti-CagA antibodies were common in the children and adults. The H pylori-specific antibodies influenced by age and sex of subjects. Moreover, it seems that males are more susceptible to infection with CagA⁺ strains compared to females. The seroprevalence of anti-CagA antibody was increased with age, up to 30 years and then decreased. It was also found that the magnitude of the IgG response to CagA decreased with advanced age.

Helicobacter pylori virulence factors in duodenal ulceration: A primary cause or a secondary infection causing chronicity

Reports from countries with a high prevalence of Helicobacter pylori (H pylori) infection do not show a proportionately high prevalence of duodenal ulceration, suggesting the possibility that H pylori cannot be a primary cause of duodenal ulceration. It has been mooted that this discrepancy might be explained by variations in the prevalence of virulence factors in different populations. The aim of this paper is to determine whether the published literature gives support to this possibility. The relevant literature was reviewed and analyzed separately for countries with a high and low prevalence of H pylori infection and virulence factors. Although virulent strains of H pylori were significantly more often present in patients with duodenal ulcer than without the disease in countries with a low prevalence of H pylori infection in the population, there was no difference in the prevalence of virulence factors between duodenal ulcer, non - ulcer dyspepsia or normal subjects in many countries, where the prevalence of both H pylori infection and of virulence factors was high. In these countries, the presence of virulence factors was not predictive the clinical outcome. To explain the association between virulence factors and duodenal ulcer in countries where H pylori prevalence is low, only two papers were found that give little support to the usual model proposed, namely that organisms with the virulence factors are more likely than those without them to initiate a duodenal ulcer. We offer an alternative hypothesis that suggests virulence factors are more likely to interfere with the healing of a previously produced ulcer. The presence of virulence factors only correlates with the prevalence of duodenal ulcer in countries where the prevalence of H pylori is low. There is very little evidence that virulence factors initiate duodenal ulceration, but they may be related to failure of the ulcer to heal.

Duodenal gastric metaplasia and Helicobacter pylori infection in high and low duodenal ulcer-prevalent areas in India

BACKGROUND

Previous reports, based on surgery, showed duodenal ulcer (DU) to be more common in the rice-eating areas of southern India than in the northern wheat-eating areas.

AIMS

Does this difference persist? Can it be explained by risk factors other than diet?

METHODS

A total of 20 053 records from patients undergoing endoscopy for dyspepsia, and 590 endoscopy patients from two northern and two southern centers in India were studied prospectively. Records were scrutinized to determine the relative incidence of DU and non-ulcer dyspepsia in wheat- and rice-eating areas. Age, sex, length of history, smoking and medication were recorded. Three antral biopsies and one from each duodenal quadrant were taken. A rapid urease test was carried out on one of the antral biopsies; the others were examined for Helicobacter pylori, gastritis, duodenitis and duodenal gastric metaplasia.

RESULTS

The difference in diet-associated prevalence persisted. No differences in smoking, Helicobacter pylori infection or duodenal gastric metaplasia were found between the two regions, but all three were more common in DU than in non-ulcer dyspeptic patients from both dietary areas.

CONCLUSIONS

The dietary differences between the regions remain the only factor to account for the differences in DU prevalence. A strong interrelationship between duodenal gastric metaplasia and cigarette smoking is demonstrated.