Helicobacter Pylori

Helicobacter Infection

Helicobacter pylori is a gram-negative, spiral-shaped, motile bacterium that parasitizes in the folds of the gastric mucosa. Infection with Helicobacter pylori is the main cause of chronic gastritis and peptic ulcer disease. Recent epidemiological studies have also confirmed its link to an increased risk of stomach cancer. This infection tends to be persistent, making it a significant long-term health concern.

In addition, this bacterium is responsible for the majority of cases of lymphoma (a type of oncological and hematological disease characterized by the proliferation of lymphoid tissue cells associated with the gastrointestinal mucosa). It has been established that H. pylori infection is quite common even among very young age groups — including children and adolescents. The main reservoir of infection is individuals who test positive for H. pylori, and intra-family contact is the most important transmission route, especially during early childhood.

In developing countries, other transmission routes may occur — for example, through contaminated water. The infection often develops without noticeable symptoms. However, when clinical symptoms do appear, patients typically experience dyspeptic disorders: discomfort, abdominal pain, nausea, heartburn, belching, and a feeling of fullness after eating.

Detection of H. pylori IgG antibodies is a standard tool for studying the epidemiology of the infection. This test is used for screening asymptomatic cases in individuals from families where others suffer from H. pylori-related diseases. H. pylori strains are extremely heterogeneous and are divided into two major groups:

• Type I strains — express both VacA and CagA antigens;
• Type II strains — do not express these antigens.

Type I strains dominate in patients with duodenal ulcers and gastric cancer. The CagA protein enters epithelial cells of the mucous membrane and disrupts mitosis, inducing chromosomal instability. When a person is infected with H. pylori strains expressing the CagA protein, the body produces specific antibodies against this antigen.

Antibodies to the CagA protein are found in 80–100% of patients with duodenal ulcers and in 94% of patients with gastric cancer. Therefore, the presence of anti-CagA antibodies serves as an informative marker in diagnosing duodenal ulcers and gastric cancer.

Type II H. pylori strains, which do not express CagA and VacA antigens, are not associated with severe gastric or duodenal damage, particularly peptic ulcers or cancer.

Infection with H. pylori can be diagnosed using both invasive and non-invasive methods.

Invasive diagnostic methods include histological and culture-based analysis of mucosal biopsies, as well as rapid urease testing. However, uneven distribution of H. pylori in tissues often leads to false-negative results.

Non-invasive diagnostic methods include serological tests for detecting specific H. pylori antibodies in blood serum and the urea breath test, which uses radiolabeled urea. ELISA (Enzyme-Linked Immunosorbent Assay) for detecting specific IgG/IgA/IgM antibodies is a minimally invasive, fast, highly sensitive, and informative method for diagnosing H. pylori infection.