Anti-Helicobacter pylori antibodies IgA, Microblot (CagA, VacA, UreA, NAP, HpaA, HcpC, GroEL)

Helicobacter pylori IgA antibodies, Microblot is a serological test designed to detect IgA immunoglobulins against specific Helicobacter pylori antigens using the immunoblot (microblot) method. The assay evaluates the immune response to a broad spectrum of bacterial antigens and is used as an additional laboratory tool in the diagnosis of H. pylori infection.

Helicobacter pylori is a Gram-negative bacterium that colonizes the human gastric mucosa. Infection is primarily transmitted via fecal-oral and oral-oral routes and is one of the most common bacterial infections worldwide.

H. pylori is the main etiological agent of chronic gastritis and a significant pathogen associated with the development of gastric and duodenal peptic ulcer disease. Persistent infection is also associated with an increased risk of gastric adenocarcinoma and MALT lymphoma.

The Microblot method allows the detection of IgA antibodies to individual H. pylori antigens, including CagA, VacA, UreA, NAP, HpaA, HcpC, and GroEL.

• CagA (p120) - major virulence factor associated with more severe gastric inflammation, peptic ulcer disease, and increased cancer risk
• VacA (p87) - cytotoxin involved in epithelial cell damage, mitochondrial dysfunction, apoptosis, and immune modulation
• UreA (p29) - urease subunit enabling bacterial survival in the acidic gastric environment
• NAP - neutrophil-activating protein involved in inflammation and oxidative stress
• HpaA - adhesin responsible for bacterial attachment to gastric epithelium
• HcpC - immunogenic protein associated with chronic infection
• GroEL - heat shock protein (chaperonin) involved in bacterial survival and immune response

The presence of IgA antibodies reflects a local mucosal immune response to H. pylori antigens.

This test is used as an additional method in the complex diagnosis of H. pylori infection and should be interpreted together with clinical data and other laboratory or instrumental findings.

Indications

• suspected Helicobacter pylori infection
• chronic gastritis
• gastric and duodenal ulcer disease
• dyspeptic symptoms (epigastric pain, heaviness, heartburn, nausea)
• suspected active or chronic H. pylori infection
• inconclusive or conflicting results from other diagnostic methods
• comprehensive assessment of upper gastrointestinal tract disorders

Procedure

Venous blood sample collection.

Investigation method

Immunoblot (Microblot), detection of IgA antibodies to Helicobacter pylori antigens.
 

Sources:
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https://www.nature.com/articles/nrmicro3016
https://www.ncbi.nlm.nih.gov/books/NBK2412/
https://www.mdpi.com/2072-6651/8/6/17
https://pubmed.ncbi.nlm.nih.gov/15074390/