Abstract
Serological tests are practical, with low cost, but no noninvasive tests are available for diagnosing Helicobacter pylori (H. pylori) infection in Brazil. The aim here was to develop and validate enzyme-linked immunosorbent assay (ELISA) serological tests to detect anti-H. pylori immunoglobulin G antibodies, based on cultured strains from Brazilian patients. Cross-sectional, diagnostic accuracy study comparing a locally developed and validated ELISA and invasive tests among dyspeptic patients at two public hospitals in São Paulo, Brazil. An ELISA test was prepared using whole-cell antigen from 56 strains. After genotypic characterization, it was standardized and optical density (OD) cutoffs were determined based on the serum antibody response of 100 H. pylori-negative samples, compared with 82 H. pylori-positive samples. Validation was performed on 174 symptomatic patients. The optimal OD cutoffs established (for monoclonal and polyclonal tests, respectively) were 0.167 and 0.164; overall ELISA sensitivity: 84.3%, 78.9%; specificity: 88.6%, 90.6%; positive predictive value (PPV): 75.4%, 80%; negative predictive value (NPV): 93.1%, 81.8%; accuracy: 87.3%, 86.2%; child and adolescent ELISA sensitivity: 74.2%, 81.8%; specificity: 90.8%, 86.7%; PPV: 66.6%, 84.3%; NPV: 95.8%, 84.8%; accuracy: 88.5%, 84.6; adult ELISA sensitivity: 84.4%, 75%; specificity: 86.9%, 93%; PPV: 81.8%, 78.3%; NPV: 88.9%, 91.8%; accuracy: 85.9%, 88.5%. The polyclonal serological test developed using local strains presented better diagnostic performance among children and adolescents, while the monoclonal test was better among adults. The results from both tests suggest that these in-house serological tests could be used to detect anti-H. pylori antibodies in our population, for screening purposes.
Highlights
Helicobacter pylori (H. pylori) colonizes the stomach of more than half of the world’s population, mainly in developing countries.[1,2] the burden of H. pylori infection is mostly borne by developing countries and specific high-risk groups in poor communities.[3]This infection is associated with chronic gastritis, peptic ulcer disease and mucosa-associated lymphoid tissue (MALT) lymphoma in children and adults, and with development of gastric cancer, which occurs typically in adulthood.[4]
The polyclonal serological test developed using local strains presented better diagnos‐ tic performance among children and adolescents, while the monoclonal test was better among adults
A university hospital, and Hospital Infantil Cândido Fontoura, a secondary-level children’s hospital, which are both in the city of São Paulo, Brazil
Summary
Helicobacter pylori (H. pylori) colonizes the stomach of more than half of the world’s population, mainly in developing countries.[1,2] the burden of H. pylori infection is mostly borne by developing countries and specific high-risk groups in poor communities.[3]This infection is associated with chronic gastritis, peptic ulcer disease and mucosa-associated lymphoid tissue (MALT) lymphoma in children and adults, and with development of gastric cancer, which occurs typically in adulthood.[4]. The aim here was to develop and validate en‐ zyme-linked immunosorbent assay (ELISA) serological tests to detect anti-H. pylori immunoglobulin G an‐ tibodies, based on cultured strains from Brazilian patients. CONCLUSION: The polyclonal serological test developed using local strains presented better diagnos‐ tic performance among children and adolescents, while the monoclonal test was better among adults. The results from both tests suggest that these in-house serological tests could be used to detect anti-H. pylori antibodies in our population, for screening purposes
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