Efficacy of immunohistochemical staining in detecting <em>Helicobacter pylori</em> in Saudi patients with minimal and atypical infection

Abstract

Gastric Helicobacter pylori infection is diagnosed based on histopathological evaluation of gastric mucosal biopsies, urease test, urea breath test, H. pylori culturing, or direct detection using polymerase chain reaction (PCR). This study aimed to evaluate the efficacy of immunohistochemical (IHC) staining in detecting H. pylori in gastric biopsies from patients with chronic gastritis and minimal or atypical infection. Gastric biopsies from 50 patients with chronic gastritis were subjected to routine haematoxylin and eosin (H-E), modified Giemsa, and IHC staining. The results of staining were compared with those of quantitative real-time PCR (qRT-PCR). The qRT-PCR analysis identified 32 (64%) H. pylori-positive cases, whereas IHC, H-E, and modified Giemsa staining identified 29 (58%), 27 (54%), and 21 (42%) positive cases. The sensitivity of IHC staining (87.50%) was higher than that of H-E (59.38%) and modified Giemsa (43.75%) staining. The specificity of H-E, modified Giemsa, and IHC staining was 55.56%, 61.11%, and 94.44%, respectively. IHC staining exhibited the highest diagnostic accuracy (90%), followed by H-E (58%) and modified Giemsa (50%) staining. Active gastritis, intestinal metaplasia, and lymphoid follicles were detected in 32 (64%), 4 (8%), and 22 (44%) cases, respectively, and all of these cases were H. pylori positive. In contrast to routine H-E and modified Giemsa staining, IHC allows for the accurate H. pylori detection in cases with minimal or atypical infection. Moreover, IHC can be an alternative diagnostic method to qRT-PCR for detection of H. pylori in such cases.

Figure 1.

Gastric biopsies specimens showing: A-C) superficial gastritis with minimal colonisation of gastric mucosal glands with few scattered H. pylori taking typical S-shaped bacilli (arrows); D,E) superficial gastritis with minimal colonisation with H. pylori taking atypical coccoid and irregular shapes (arrows) (H&E; Magnification, 400x); F,G) chronic gastritis with intestinal metaplasia and presence of papillary configuration (thick arrows) with mucous-secreting cells (thin arrows); H) H. pylori associated follicular gastritis with lymphoid follicles (thick arrows) situated deeper in the gastric mucosa and associated with intestinal metaplasia (thin arrows) (H&E; magnification 200x).

Figure 2.

Gastric biopsies specimens showing: A-C) gastric mucosal glands with minimal colonization with H. pylori (arrows) (modified Giemsa stain; magnification 400x). D-F) H. pylori observed using immunohistochemistry staining; D) minimal colonization with typical spiral S-shaped bacilli (arrows); E) minimal colonisation with atypical coccoid forms; F) enhanced colonization with coccoid and irregular forms (IHC, magnification, 400x).

Figure 3.

Gastric biopsies specimens showing gastric mucosal glands with different degrees of colonisation with H. pylori (arrows) demonstrated by immunohistochemistry staining (IHC, magnification 800x).