Validation of a Commercial Enzyme-Linked Immunosorbent Assay to Detect Anti-CagA Antibodies in Children With Helicobacter pylori Infection

Rocha, Gifone A.; Am, Rocha; Queiroz, Dulciene Maria Magalhães; E, Nogueira Mendes; Am, Nogueira; As, Teles de Carvalho

doi:10.1097/00005176-200110000-00021

Cited by 4 publications

(5 citation statements)

References 20 publications

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“…As we previously observed for children (16), this commercial ELISA showed high sensitivity for the detection of anti-CagA antibodies in adults from Brazil. Employing commercial ELISAs, similar results were observed by other authors in a developed country (2,9).…”

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confidence: 72%

Accuracy of a Commercial Enzyme-Linked Immunosorbent Assay for CagA in Patients from Brazil with and without Gastric Carcinoma

Rocha

Santos

et al. 2003

J Clin Microbiol

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We validated a commercial enzyme-linked immunosorbent assay for the detection of anti-CagA antibodies in Brazilian patients with Helicobacter pylori infection. The test presented high sensitivity (97.4%) and specificity (88.9%) when employed in patients without gastric carcinoma. However, in gastric carcinoma patients, the test was neither sensitive nor specific enough to detect cagA-positive H. pylori infection.Among the Helicobacter pylori putative virulence factors, the cag pathogenicity island, which includes cagA, has been associated with peptic ulcer and distal gastric carcinoma in human beings (3,6,14). cagA status may be determined by detection of the cagA gene in the bacterium strain or gastric mucosa by molecular methods or by evaluation of serum anti-CagA antibodies (7,8). Although anti-CagA antibodies have been evaluated by enzyme-linked immunosorbent assay (ELISA) in several studies, in most of them (4, 10, 13), the test had not been previously validated for the population. Besides this factor, all of those studies were conducted in developed countries, where the low prevalence of the infection may have a negative effect on the positive predictive value of the test. In addition, becausethe serum response to CagA may depend on factors linked to the patient, such as H. pylori-associated disease (15), or the genetic diversity of the bacterium worldwide (18), validation of the tests employed to detect anti-CagA antibodies in different geographic regions should be done (8,19).Therefore, from 1995 to 1997, we studied 123 patients (64 male and 59 female; mean age, 48.2 Ϯ 15.8 years; range, 19 to 95 years) who underwent endoscopy for the evaluation of symptoms involving the upper gastrointestinal tract (n ϭ 86) or had been treated for gastric carcinoma (n ϭ 37) at the Surgical Clinic of the University Hospital/Universidade Federal de Minas Gerais (UFMG), at Luxemburgo Hospital, and at Mário Penna Hospital of Oncology. Part of the sera tested in the present study were from patients with gastric carcinoma included in a previous study (15). This project was approved by the Ethics Committee of Hospital das Clínicas, UFMG, Brazil, and informed consent was obtained from all patients.At endoscopy, biopsy specimens were obtained from the antral and oxyntic gastric mucosa for culture, preformed urease test, and carbolfuchsin-stained smears. In patients with gastric carcinoma, gastric mucosa fragments from the antrum and body were obtained from stomachs removed by gastrectomy. Patients were considered to be H. pylori positive if at least two of the three test results were positive or if the culture alone was positive and negative if the three test results were negative.As a "gold standard," the presence of the cagA gene was evaluated by PCR. Genomic DNAs from the bacterial strains (n ϭ 92) or the gastric mucosa (n ϭ 5 each from H. pyloripositive or -negative patients) were extracted with QIAamp (Qiagen, Germany) and PCR amplified with two sets of oligonucleotide primers as previously described (11, 12). The PCR produ...

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confidence: 72%

Accuracy of a Commercial Enzyme-Linked Immunosorbent Assay for CagA in Patients from Brazil with and without Gastric Carcinoma

Rocha

Santos

et al. 2003

J Clin Microbiol

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“…23 We evaluated the CagA status of our HP-infected children by measuring anti-CagA antibodies by ELISA. Rocha et al 24 have already shown the reliability of this technique in determining the CagA status in HP-infected children. Our present study showed that most HP strains isolated in Turkey were positive for CagA proteins (90/121, 74.4%).…”

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confidence: 95%

CagA positivity and its association with gastroduodenal disease in Turkish children undergoing endoscopic investigation

et al. 2006

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“…As shown in Table 1, 11 pediatric studies have been published so far that have examined the association between cagA-positive status detected by genetic tests and gastric mucosal pathology. Interestingly, some authors (14,15,18,25,26) have described a significant correlation between the severity of histological changes and the presence of the cagA gene in the H pylori genome, whereas others (17,19,22,24,29,33) have been unable to confirm this association. A strong correlation was found in our study between cagA-positive status and the density of H pylori colonization, as well as the severity of acute and chronic inflammation.…”

Section: Discussionmentioning

confidence: 99%

“…Furthermore, a distinct geographic distribution of the virulence genes has also been demonstrated (20,21). Data concerning virulence genotypes and genetic variations among different geographic regions in the pediatric population are still limited (13)(14)(15)(16)(17)(18)(19)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33). To the best of our knowledge, 19 studies have so far been published in pediatric populations concerning the prevalence of H pylori genotypes and a possible association between polymerase chain reaction (PCR)-detected genotypes and gastric mucosal damage (reviewed in Table 1).…”

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Prevalence and Clinical Relevance of cagA, vacA, and iceA Genotypes of Helicobacter pylori Isolated From Slovenian Children

Homan

Luzar²,

Kocjan³

et al. 2009

J. pediatr. gastroenterol. nutr.

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Validation of a Commercial Enzyme-Linked Immunosorbent Assay to Detect Anti-CagA Antibodies in Children With Helicobacter pylori Infection

Cited by 4 publications

References 20 publications

Accuracy of a Commercial Enzyme-Linked Immunosorbent Assay for CagA in Patients from Brazil with and without Gastric Carcinoma

Accuracy of a Commercial Enzyme-Linked Immunosorbent Assay for CagA in Patients from Brazil with and without Gastric Carcinoma

CagA positivity and its association with gastroduodenal disease in Turkish children undergoing endoscopic investigation

Prevalence and Clinical Relevance of cagA, vacA, and iceA Genotypes of Helicobacter pylori Isolated From Slovenian Children

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