Comparison of Different Criteria for Interpretation of Immunoglobulin G Immunoblotting Results for Diagnosis of Helicobacter pylori Infection

Abstract

Gastric infection withHelicobacter pylori is one of the most common chronic infections in humans, causing substantial morbidity and mortality. The diagnosis of H. pylori infection usually involves upper endoscopy with biopsy since the only noninvasive method of comparable accuracy, the [ 13 C]urea breath test, requires technical equipment that is not available in most gastroenterological units. Serological methods for detection of H. pylori infection have reached sufficient accuracy to be used as screening tests before endoscopy or for seroepidemiological surveys. In the present study we evaluated different interpretation criteria for use with immunoglobulin G immunoblotting for the diagnosis of H. pylori infection. We applied five different sets of interpretation criteria, four of which had been published previously, to the Western blot results of 294 patients with different gastrointestinal symptoms. Since it is known that less than 2% of patients who are infected with H. pylori fail to seroconvert, an optimally sensitive Western blotting system should be able to detect approximately 98% of active infections. When the different criteria were applied to our patient population, it became apparent that the abilities of the systems to detect active H. pylori infection were quite varied. The results for the sensitivity and specificity, according to the different applied criteria, ranged from 62.8 to 95.9% and from 85.7 to 100.0%, respectively. Positive predictive values and negative predictive values, according to the published criteria, ranged from 97.2 to 100.0% and from 37.7 to 82.4%, respectively. Recommendations for the optimal use of the different interpretation criteria are discussed.

Helicobacter pyloriDetection and Antimicrobial Susceptibility Testing

“…In spite of these potential advantages and the widespread availability of blotting equipment in clinical laboratories, Lepper et al (305) reported that immunoblot for H. pylori antibodies is not common practice and that this was possibly due to discrepant recommendations for interpretation. Indeed, most of the publications concerning this subject are merely descriptive (9,90,138,195,261,298,560), and only four proposed interpretation criteria (219, 407, 527, 559).…”

“…Indeed, the immunoblot is most likely used as a second-step technique to identify false-positive cases detected by ELISA, in which case, the criteria proposed by Nillson et al (407) and Trautmann et al (527) leading to 100% specificity must be used. In contrast, when immunoblotting is used for preendoscopy screening, the criteria of Lepper et al, which emphasize sensitivity, are more suitable (305). A commercial immunoblot test is now available, which is an important advance toward standardization, Helicoblot 2.1 (Genelabs, Singapore) (305,383,432).…”

“…In contrast, when immunoblotting is used for preendoscopy screening, the criteria of Lepper et al, which emphasize sensitivity, are more suitable (305). A commercial immunoblot test is now available, which is an important advance toward standardization, Helicoblot 2.1 (Genelabs, Singapore) (305,383,432).…”

Pathogenesis ofHelicobacter pyloriInfection

“…The finding that Lewis antigen expression enhances bacterial internalization by epithelial cells (374) suggests that Lewis antigen expression potentially affects the innate immune response. H. pylori LPS stimulates NF-B and IL-8 production in both epithelial cells and immune cells in a CagA-independent manner (53,359,384), but the NF-B activation observed in epithelial cells upon stimulation with H. pylori is not mediated by LPS (445). Compared to other gram-negative bacteria, the LPS of H. pylori is a poor activator of the innate immune response (59,446).…”

Analysis of immune responses againstH pyloriin rabbits

“…Strains carrying the genes encoding the cytotoxin-associated protein (Cag-A) cause chronic active gastritis [2] . Gastric infection with H pylori is one of the common chronic infections in humans, causing substantial morbidity and some mortality [3] . Before an active protective response occurs, the gut must first be exposed to H pylori, which is a slowly growing microaerophilic, highly motile, Gramnegative spiral organism whose most striking biochemical characteristic is the abundant production of urease [4] .…”