Utility of immunohistochemistry in demonstrating Helicobacter pylori

Background: Helicobacter pylori is the causative organism for chronic active gastritis, duodenal ulcer and also for malignancies like gastric adenocarcinoma and mucosa associated lymphoid tissue lymphoma. It is essential to mention the presence of H. pylori in gastric biopsies as it has an important role in patient care. Though there are several special stains to detect H. pylori in histological sections, their specificity and sensitivity vary greatly. Immunohistochemically H. pylori can be detected by using anti H. pylori antibody, which reacts with somatic antigens of the whole bacteria. The aim of this study was to compare the reliability of routine hematoxylin and eosin (H and E), Giemsa, Warthin-Starry (WS) silver stain and immunohistochemical technique in diagnosing H. pylori. Materials and Methods: In this retrospective 1-year (2009) study, endoscopic gastric biopsies taken from patients during gastrointestinal-endoscopy with histopathological diagnosis of gastritis were studied. Standard H and E staining was performed on 5-μm-sections from paraffin block of each specimen. Microscopic sections of biopsy specimens of patients showing features of gastritis histopathologically in routine H and E stain and where the presence of H. pylori was suspected were also stained with Giemsa, WS, and immunohistochemistry (IHC) using purified polyclonal H. pylori antiserum (BioGenex). We have not included gastric resection specimens in our study. Results: Of the 29 cases, 26 (32.9%) showed presence of H. pylori on H and E, Giemsa and WS stains, whereas 49 (62.0%) cases demonstrated H. pylori on IHC stain. Conclusion: We conclude that H. pylori detection by IHC has advantage over routine H and E staining. However, in the developing countries with financial constraints, routine H and E staining in combination with special staining are fairly reliable in demonstrating H. pylori.