Detailed description of the study
Helicobacter pylori is a bacterium that affects the gastric mucosa due to its resistance to acidic environments.
It is assumed that infection with this infection occurs at an early age and is transmitted to children from parents or in preschool institutions. The most likely route of infection is considered to be the fecal-oral route of infection when living with an infected person in the same house, as well as during a long stay in a large group.
In addition, the oral route of transmission of infection through saliva and kissing has been recorded. There have been suggestions about the possibility of Helicobacter pylori infection during fibrogastroscopy - an examination through an endoscope that has been insufficiently treated with disinfectants.
After penetration into the stomach, Helicobacter pylori colonizes its mucous membrane, causing gastritis of the antrum of the stomach. The bacterium is protected from exposure to an aggressive acidic environment by producing alkali (ammonia) and some other substances that damage the gastric mucosa.
In response to Helicobacter pylori entering the body, the immune system produces antibodies. Initially, antibodies of class A and M are formed, they are soon replaced by immunoglobulins of class G. In most cases, the body is not able to completely defeat this infection, which predetermines the preservation of a high level of class G antibodies to it.
When combined with other unfavorable conditions, such as stress, poor diet, and infection with this bacterium, it leads to the formation of erosions and stomach ulcers. The following symptoms are noted:
1. pain in the upper abdomen (on an empty stomach);
2. nausea;
3. belching air;
Some people are asymptomatic when infected with Helicobacter pylori. Long-term damage to the gastric mucosa by this bacterium leads to the development of atrophy and decreased acid production. The risk of developing stomach cancer and lymphoma increases. A particularly high risk of developing cancer is observed in those whose relatives suffered from it.
Determining the presence of Helicobacter pylori infection in the body is important for early diagnosis of gastric pathology. Class G antibodies are produced several weeks after infection and are detected throughout life in the presence of bacteria in the body.
This test is relevant, in combination with other antibodies (IgA, IgM), as a primary diagnosis of this infection, but is not recommended for assessing the effectiveness of treatment, because IgG may persist for a long time even after successful therapeutic measures.
Antibodies to Helicobacter pylori IgG, Helicobacter pylori IgG count.
Antibodies to Helicobacter pylori IgG, Helicobacter pylori IgG quantitative
— allows you to quantitatively determine with high sensitivity the presence of IgG antibodies to Helicobacter pylori in the blood, which are an indicator of Helicobacter pylori infection.
Helicobacter pylori
is a spiral-shaped bacterium that infects the stomach and duodenum. This pathogen can lead to various lesions of the gastrointestinal tract, the development of gastric and duodenal ulcers, and chronic gastritis. Helicobacter is sensitive to high temperatures, but persists for a long time in a humid environment. The bacterium itself does not cause ulcers. It leads to stimulation of the formation of hydrochloric acid and disrupts the protection against the effects of acid on the gastric mucosa, leading to the development of an inflammatory process.
IgG antibodies confirm the presence of Helicobacter pylori in the human body. Their presence in the body is detected starting 3–4 weeks after infection. A high level of IgG to Helicobacter persists before and for some time after the elimination of the microorganism. A decrease in the concentration of IgG class antibodies during treatment indicates the effectiveness of the therapy.
Determining IgG in the blood does not require endoscopic examination, therefore it is a safer method of diagnosis. Since the sensitivity of the test is comparable to that of most invasive tests (rapid urease test, histological examination), it is especially useful when endoscopy is not planned. It should be noted, however, that the test does not directly detect the microorganism and depends on the characteristics of the patient's immune response. For example, the immune response of older people is characterized by a reduced production of specific antibodies (any, including to H. pylori), which must be taken into account if a negative test result is obtained for clinical signs of dyspepsia. In addition, the immune response is suppressed when taking certain cytotoxic drugs.
The IgG test can be most successfully used to diagnose primary H. pylori infection (for example, when examining a young patient with new signs of dyspepsia). In this situation, a high titer of IgG allows one to suspect an active infection. Also, a positive test result in a patient (with or without a history of signs of dyspepsia) who has not received therapy will indicate helicobacteriosis.
Indications:
- diagnosis of diseases caused by H. pylori and monitoring of their treatment;
- antral and fundal gastritis;
- ulcers of the duodenum or stomach.
Preparation
It is recommended to donate blood in the morning, between 8 and 11 am. Blood is drawn on an empty stomach, after 4–6 hours of fasting. It is allowed to drink water without gas and sugar. On the eve of the examination, food overload should be avoided.
Interpretation of results
Units of measurement: U/l.
Reference values:
- <0.9 - negative;
- 0.9–1.1 - doubtful;
- > 1.1 - positive.
Exceeding reference values:
- IgG infection with H. pylori (high risk of developing peptic ulcers or peptic ulcers; high risk of developing stomach cancer);
- H. pylori infection cured: period of gradual disappearance of antibodies.
Within reference values:
- IgG - H. pylori infection was not detected (low risk of developing peptic ulcer, but peptic ulcer cannot be excluded);
- the first 3–4 weeks after infection.
"Doubtful":
- It is advisable to repeat the study after 10–14 days.
References
- Ivashkin V.T., Maev I.V., Abdulganieva D.I., Alekseenko S.A., Ivashkina N.Yu., Korochanskaya N.V., Mammaev S.N., Poluektova E.A., Trukhmanov A. S., Uspensky Yu.P., Tsukanov V.V., Shifrin O.S., Zolnikova O.Yu., Ivashkin K.V., Lapina T.L., Maslennikov R.V., Ulyanin A.I. . Practical recommendations of the Scientific Community for Promoting the Clinical Study of the Human Microbiome (NSOM) and the Russian Gastroenterological Association (RGA) on the use of probiotics for the treatment and prevention of gastroenterological diseases in adults. Russian Journal of Gastroenterology, Hepatology, Coloproctology. 2020
- GuevaraB, CogdillAG. Helicobacter pylori: A Review of Current Diagnosticand ManagementStrategies. DigDisSci. 2020
- Choi IJ, Kim CG, Lee JY. Family History of Gastric Cancer and Helicobacter pylori Treatment. N Engl J Med. 2020
Helicobacter pylori (Gag A) toxigenic strain (total) IgA, IgM, IgG
Helicobacter pylori infection is relevant in modern society for patients of any gender and age. Infection with the toxigenic strain of Helicobacter pylori (GagA) is very high, which is associated with an easy transmission mechanism (fecal-oral). Helicobacter pylori causes gastritis, gastric and duodenal ulcers in almost 100% of cases. Also, it can cause stomach cancer (as a result of malignancy of an ulcer or an atrophic process in the intestine).
To determine the presence of infection, as well as the activity of the process, the most popular method is the detection of antibodies of various classes to Helicobacter pylori (total antibodies). Total antibodies of Helicobacter pylori are antibodies of the IgG, IgM and IgA classes. Each of these classes has a specific function and helps in the correct interpretation of the stage of the disease.
IgA to Helicobacter pylori is a class of antibodies that are responsible for local immunity. IgA to Helicobacter pylori is found on the mucous membrane of the gastrointestinal tract. Their quantity is the least informative, but an increase in titer to significant numbers indicates severe inflammation of the mucous membrane.
IgM to Helicobacter pylori are responsible for an acute infection that occurred no more than 2-3 months ago. If IgM antibodies to Helicobacter pylori are detected in the singular, then the infection occurred recently - 2-4 weeks ago. If IgG is also present, then the infection lasts no more than 2-3 months. The absence of IgM to Helicobacter pylori GagA, in the presence of IgG, confirms a long-term chronic infection. The reappearance of IgM antibodies to Helicobacter pylori GagA allows one to judge about re-infection or relapse of infection.
IgG to Helicobacter pylori GagA is produced at 2-3 weeks of infection and remains for a long time. Their concentration slowly decreases during eradication therapy, but they completely disappear only a few months after complete elimination of the pathogen.
Determination of all types of antibodies to Helicobacter pylori - total antibodies, allows you to evaluate the entire spectrum of protective immunoglobulins and make a correct diagnosis.
To identify Helicobacter pylori, the total antibody test is not the only one; invasive techniques and a breath test are often used. But taking the test for antibodies to Helicobacter pylori GagA is the most optimal in terms of speed of execution and minimal invasiveness (blood drawing).
Determination of antibodies to Helicobacter pylori in blood of the IgG class
Detection of class G immunoglobulins (IgG) to Helicobacter pylori in blood serum, used to diagnose antral and fundal gastritis, gastric and duodenal ulcers, as well as to monitor their treatment.
General information about the infection
Helicobacter pylori infection. H. pylori is one of the most widespread infections on earth today. H. pylori-associated diseases include chronic gastritis, gastric and duodenal ulcers. Damage to the gastric mucosa is caused by direct damage by the microorganism, as well as secondary damage to the mucous membrane of the stomach, duodenum and cardiac part of the esophagus under the influence of H. pylori aggression factors. Helicobacter is a spiral-shaped gram-negative bacterium with flagella. The bacterial cell is surrounded by a layer of gel - glycocalyx, which protects it from the effects of hydrochloric acid of gastric juice. Helicobacter is sensitive to high temperatures, but persists for a long time in a humid environment. Infection occurs through food, fecal-oral, and household routes. H. pylori infection is accompanied by the development of a local and systemic immune response. Following a transient increase in the titer of class M immunoglobulins (IgM), there is a prolonged and significant increase in IgG antibodies in the blood serum. Determination of the concentration of immunoglobulins (serological study) is used in the diagnosis of helicobacteriosis. IgG is found in 95-100% of cases of H. pylori infection, and IgM in only 15-20%. Therefore, to confirm H. pylori infection, the concentration of IgG in the blood serum is determined. This analysis has a number of advantages over other laboratory methods for detecting Helicobacter. The IgG test can be used most successfully to diagnose primary H. pylori infection. In this situation, a high titer of IgG allows one to suspect an active infection. Also, a positive test result in a patient (with or without a history of signs of dyspepsia) who has not received therapy will indicate helicobacteriosis. The interpretation of a positive test result if therapy has been carried out (or if antibiotics with activity against H. pylori have been used for other purposes) has some peculiarities. The IgG level remains high for a long time after the complete death of the microorganism (up to 1-1.5 years). As a result, a positive test result in a patient taking antibiotics does not differentiate between an active infection and a history of infection and requires additional laboratory tests. For the same reason, an IgG test is not the main test for diagnosing the effectiveness of therapy. However, it can be used for this purpose if the antibody titer at the time of onset of the disease is compared with the titer after the end of treatment. It is believed that a decrease in IgG concentration by 20-25% within 6 months indirectly indicates the death of the microorganism. At the same time, if this concentration does not decrease, this does not mean the therapy is ineffective. The absence of IgG antibodies during repeated analysis indicates the success of treatment and elimination of the microorganism. The amount of IgG to H. pylori is also one of the components by which the condition of the gastric mucosa is judged (this is the so-called serological biopsy).
Indications for this study:
- when examining a patient with new signs of dyspepsia (primary infection with H. pylori), especially if endoscopy is not planned;
- when examining a patient with a history of dyspepsia, if H. pylori therapy has not been prescribed (or if antibiotics active against H. pylori have not been used for another reason);
- during the initial diagnosis of helicobacteriosis and 6 months after the end of the course of its therapy;
- with peptic ulcer of the stomach and/or duodenum;
- for non-ulcer dyspepsia and gastroesophageal reflux disease;
- with atrophic gastritis;
- with stomach cancer in close relatives;
- newly diagnosed Helicobacter infection in people living together or relatives;
- preventive screenings to identify people at risk of developing stomach ulcers or cancer.
general characteristics
The pathogenic microorganism H. pylori, causing gastritis, duodenitis, gastric ulcer (in 70% of cases) and duodenal ulcer (in 90%). Recent data indicate a close connection between Helycobacter pillory and the development of cancer. Determination of the level of immunoglobulins is the most reliable (specificity 91%, sensitivity 97%), the most accessible, least invasive method for diagnosing Helicobacter pylori infection. These antibodies appear 1-2 weeks after infection and are indicators of an acute process. Used to diagnose the acute period of Helicobacter pylori infection. Women are characterized by higher serum IgA levels. An increase in the proportion of IgA in the IgA/IgG ratio is a prognostic sign in the development of gastric cancer.
