Analysis For Antibodies IgG, IgE To Roundworm

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Analysis For Antibodies IgG, IgE To Roundworm
Analysis For Antibodies IgG, IgE To Roundworm

Video: Analysis For Antibodies IgG, IgE To Roundworm

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Video: Antibody Testing: IgG and IgM explained 2023, February
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types of antibodies
types of antibodies

Ascariasis is an intestinal invasion of ascaris worms. The helminth itself does not pose a direct danger to the human body, but having a high migratory activity (the pathogen is able to penetrate with the blood and lymph flow into almost any organ), it can cause severe complications in the foci of skidding: lesions of the lung tissue, heart muscle, liver. The situation is aggravated by the difficulty of making a diagnosis.

At any stage, helminths secrete waste products to which the immune system reacts. Metabolic products are foreign to our body and are antigens.

Antigens are protein molecules that normally cannot be found in the body. When they get hit, the immune system turns on protective mechanisms for the production of neutralizing factors - antibodies.

Content

  1. Antibodies for helminth infection
  2. Infection
  3. Migration
  4. Intestinal invasion
  5. Enzyme immunoassay (ELISA) for ascariasis
  6. Preparation for the test
  7. Interpretation of ELISA results
  8. Conclusion

Antibodies for helminth infection

Antibodies are a special class of factors in the immune system. These are immunoglobulins, which are produced in response to the appearance of a certain pathogen in the body. They "attack" the pathogen, leading to its death.

The life cycle of ascaris in the body has several phases.

Infection stages:

  • Infection
  • Migration
  • Intestinal invasion

Infection

Ascaris eggs, getting into the intestines, lose their shell. A larva emerges from them, which penetrates into the intestinal wall and enters the lymphatic and blood vessels.

At this stage, clinical manifestations and changes in laboratory parameters are not observed.

Ascaris eggs under the microscope
Ascaris eggs under the microscope

Migration

With the flow of blood and lymph, the larvae can enter any organ, causing inflammatory and destructive changes in it. The products of their vital activity cause intoxication of the body with the corresponding symptoms and signs of organ damage to which the larvae have gotten with blood and lymph flow. The maturation process outside the intestine lasts up to 3.5 months.

With a general blood test, an increase in the number of eosinophils is determined.

In response to the production of toxins, IgM and IgE appear within a week. These are non-specific markers for the appearance of any helminthic invasion. Antibodies to the roundworm allergen IgE are noted for two weeks after the parasite enters the body. After that, IgG antibodies to ascaris antigens appear, which retain their activity for up to three months.

Intestinal invasion

After maturation, ascaris again enters the intestine in the lumen of which it can live up to a year. During this period, the patients show signs of intoxication due to the absorption of waste products of ascaris and stool disorders.

Enzyme immunoassay (ELISA) for ascariasis

A simple and affordable way to detect ascaris is to detect the eggs of the pathogen in the feces. But it is informative only in 30% of cases at the stage of intestinal localization of ascaris.

During the migration period, only a test for immune markers will confirm the presence of helminthic invasion. The enzyme-linked immunosorbent assay allows detecting antibodies to allergens (IgE) and antigens (IgG) of ascaris in the blood plasma and assessing the stage of infection. This method reliably determines the fact of infection within 5-10 days after the pathogen enters the body.

Preparation for the test

Blood for antibodies to helminths for analysis is taken from a vein on an empty stomach. The last meal should be no later than 8 hours before visiting the laboratory. For the next 3 hours before taking blood, smoking and drinking carbonated drinks are prohibited.

Interpretation of ELISA results

According to the results of the enzyme immunoassay, the level of IgE and IgG is assessed.

Normally, the level of antibodies to allergens in a child under one year old is up to 30 IU / ml, from one to 9 years old - up to 50 IU / ml, over 9 years old and in adults - up to 90 IU / ml. IgE is not a specific marker. An increase in its content in plasma is noted with any helminthic invasion or allergic disease.

An increase in IgG titer - confirms the presence of the pathogen in the body.

Antibodies to ascaris in a titer of more than 1/100 indicates the presence of the pathogen in the body - a positive answer.

IgG titer less than 1/100 - negative answer.

Antibodies to roundworm titer 1/100 - the answer is doubtful. In this case, after 10 - 14 days, a second analysis is performed for roundworms.

To increase the reliability of diagnostic measures, an algorithm for evaluating several criteria is used.

Criterion Stage of infection Invasion stage (first 14 days) Invasion stage (after day 14) Intestinal localization
ELISA Not informative Increase in IgE titer Increase in IgG titer Increased IgG titer upon re-invasion of larvae
General blood analysis Moderate increase in eosinophils Elevated eosinophil levels, signs of intoxication Elevated eosinophil levels, signs of intoxication Elevated eosinophil levels, signs of intoxication
Clinical symptoms Not defined or the symptoms are erased Signs of intoxication: weakness, irritability. Signs of intoxication and damage to internal organs. Signs of intoxication, stool disorder
Determination of pathogen eggs in feces Not determined Not determined Not determined It is determined in 30-40% of cases.

Conclusion

Infection of the body with ascaris has no specific manifestations. Establishing a reliable diagnosis of ascariasis is possible only when an increased antibody titer is confirmed. After that, the doctor has the right to prescribe treatment by prescribing anthelmintic drugs.

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