Difference Between H.pylori IGG and IGA | H.pylori IGG vs IGA


Key Difference – H.pylori IGG vs IGA
 

Helicobacter pylori are spiral-shaped bacteria that cause gastrointestinal infections. H. pylori infection is one of the most common bacterial infection known to mankind across the world. World Health Organization has declared the Helicobacter pylori bacteria to be a Class 1 carcinogen which leads to gastrointestinal cancers and lymphoma. H. pylori cause infection by invading the mucous lining of the stomach and it is also the cause of up to 95% of duodenal ulcer and up to 75% gastric ulcers.

Different tests are performed in order to diagnose H. pylori infection. The types of tests include gastroscopy, urea breath test and stomach biopsy tests. Serology deals with the body’s serum. In the serology test for H. pylori, patients’ blood is screened for the presence of antibodies to H. pylori which indicates an immune response to the bacteria. Two such tests are termed as H. pylori IGG and IGA test. The key difference between H. pylori IGG and IGA is that, in H. pylori IGG test, the presence of Immunoglobulin G is tested in the blood whereas, in H. pylori IGA test, the presence of Immunoglobulin A is tested in blood.

CONTENTS

1. Overview and Key Difference
2. What is H.pylori IGG
3. What is H.pylori IGA
4. Similarities Between H.pylori IGG and H.pylori IGA
5. Side by Side Comparison – H.pylori IGG vs H.pylori IGA in Tabular Form
6. Summary

What is H. pylori IGG?

IGG is the most common type of immunoglobulin present in the immune system. It is the main form of circulatory Immunoglobulin in the body. IGG has four major sub classes due to its wide functions. These consist of IGG1, IGG2, IGG3 and IGG4. IGG is the immediate antibody response produced in the body to an infection caused by a bacterial or a viral agent. Since IGG is produced in response to a bacterial agent, this test is done to identify the presence of bacterial agents such as H. pylori. IGG is reported to be produced and appeared first as a primary immune reaction in individuals who are infected for the first time. But in re-infected individuals, IGG appears late in the serum.

Difference Between H.pylori IGG and IGA | H.pylori IGG vs IGA

Figure 01: H. pylori

IGG is tested via Enzyme Linked Immunosorbent Assay (ELISA). However, this is not a highly accurate test to detect early infection. IGG test is performed in both adults and children, and have shown to have wide application in the diagnosis of H. pylori infections.

What is H. pylori IGA?

Immunoglobulin A is found commonly in high concentrations in the mucous membranes. It is especially found in those lining the respiratory passages and gastrointestinal tract. As H. pylori infection is characterized by the destruction of gastrointestinal mucosa, the elevated production of IGA is a possible immune response during H. pylori infection. IGA appears to be an early occurrence in the individuals who contact the infection for the first time. But in re-infected individuals it is not prominently identified.

Difference Between H.pylori IGG and IGA | H.pylori IGG vs IGA

Figure 02: IGG and IGA

The key difference between H. pylori IGG and IGA test is that, in H. pylori IGG test, the presence of Immunoglobulin G is tested in the blood while, in H. pylori IGA test, the presence of Immunoglobulin A is tested in blood.

What are the Similarities Between H. pylori IGG and IGA?

  • Both are tests for the presence of antibodies in response to pylori infection.
  • Both are a type of serological test.
  • Immunological testing methods such as ELISA and Radio Immuno assay are used for diagnosis for both tests.
  • Both are in vitro testing methods.
  • The serum sample used is blood for both tests.
  • Both tests are not very specific.

What is the Difference Between H. pylori IGG and IGA?

 H.pylori IGG vs IGA

H.pylori IGG test is a serological test which is done to check the presence of Immunoglobulin G in the blood following an infection. H.pylori IGA test is a serological test which is done to check the presence of Immunoglobulin A in blood following an infection.
Function of the Immunoglobulin
IGG is produced in response to a bacterial agent and thus, it can be tested for pylori which is a bacterium. IGA is produced in response to mucosal lining damage of the gastrointestinal tract which is a characteristic feature of the infection.

Summary – H. pylori IGG vs IGA

Helicobacter pylori or H. pylori infection is considered to be the most common gastrointestinal bacterial infection. This infection is found worldwide and infects both adults and children equally. The infection results in gastric ulcers and increased bile acidity leading to gastritis. This can also lead to gastrointestinal cancers. Thus, anti-bacterial treatment should be administered at an early stage to prevent the severity of the infection. Hence, the antibody testing is used much widely to detect the presence of H. pylori in the immune system. Immunoglobulin types IGG and IGA are widely used in detecting H. pylori as they are produced against bacterial infections that causes mucosal damage in the gastrointestinal tract.

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Image Courtesy:

1.”Ulcer-causing Bacterium (H.Pylori) Crossing Mucus Layer of Stomach” by Zina Deretsky, National Science Foundation – NSF Flickr photostream, (Public Domain) via Commons Wikimedia
2. “Mono-und-Polymere” by Von Martin Brändli (brandlee86) – Eigenes Werk,(CC BY-SA 2.5)  via Commons Wikimedia

Reference:

1. Rosemary C., and Andrew R. Wilson2, “Clinical and Vaccine Immunology”, 1 Aug. 2009, cvi.asm.org/content/16/8/1253.full. Accessed 21 Sept. 2017.
2.“Blood Test: Immunoglobulins (IgA, IgG, IgM).” YaminiDurani ed, KidsHealth, The Nemours Foundation, Aug. 2014, kidshealth.org/en/parents/test-immunoglobulins.html. Accessed 21 Sept. 2017.
4.“Immunoglobulin A IgA Blood Test.” Request A Test, requestatest.com/immunoglobulin-a-iga-blood-test. Accessed 21 Sept. 2017.