Differences in laboratory diagnostics of less common types of viral hepatitis D and E

With the help of modern diagnostic equipment, it has become possible to determine various types of viral hepatitis, such as D and E. Laboratory tests are an integral part in the diagnosis of hepatitis, the result of which will allow timely treatment of hepatitis. At the same time, the measures taken in the republic to prevent and reduce viral hepatitis require improvement not only of anti-epidemiological measures, but also of effective laboratory diagnosis of viral hepatitis.

Keywords: epidemiological surveillance, viral hepatitis, types of hepatitis, laboratory diagnostics, etiological diagnosis, serological markers.

С помощью современного диагностического оборудования стало возможным определять различные типы вирусных гепатитов, таких как D и Е. Проводимые лабораторные исследования — неотъемлемая часть в диагностике гепатита, результат которой позволит своевременно провести лечение гепатита. При этом, в республике проводимые мероприятия по профилактике и снижению вирусных гепатитов нуждаются в совершенствовании не только противоэпидемиологических мер, но и эффективной лабораторной диагностики вирусных гепатитов.

Ключевые слова: эпидемиологический надзор, вирусный гепатит, виды гепатитов, лабораторная диагностика, этиологический диагноз, серологические маркеры.

In Uzbekistan, much attention is paid to the study of cause-and-effect relationships, monitoring the level of morbidity, timely diagnosis and hospitalization of patients, and most importantly, the prevention of the occurrence of viral hepatitis from both medical and preventive medical institutions of the republic. Thus, according to the Resolution of the President of the Republic of Uzbekistan dated May 16, 2022 № PP-243 “On improving measures to counter the spread of some current viral infections” in Uzbekistan, the incidence of viral hepatitis tends to dynamically decrease. At the same time, with the updating and equipping laboratories with modern diagnostic equipment, various types of viral hepatitis, including D and E, began to be identified. However, despite this, measures to combat viral hepatitis require further improvement of laboratory differential diagnosis. In addition, in this regard, the republic pays special attention to the prevention of viral hepatitis.

Considering that viral hepatitis, including D and E are the most common, special attention is paid to blood tests, which can provide comprehensive information about these diseases. Various instrumental research methods using special installations, such as ultrasound, computed tomography and magnetic resonance imaging for diagnosing hepatitis are ineffective, therefore many researchers and clinicians believe that the basis for laboratory diagnosis of viral hepatitis is knowledge about the causative agents of viral hepatitis, markers of infection, modern immunochemical and molecular biological methods for determining antigens, antibodies and nucleic acids [3, 4].

It is known that diagnosing viral hepatitis is necessary not only to determine the type of viral infection and timely treatment, but also to exclude possible other types of jaundice, somatic and oncological diseases of the gastrointestinal tract, blood diseases, etc. In this case, the criteria for the etiological diagnosis of viral hepatitis are serological markers, for each type of hepatitis of which they are individual. Thus, with viral hepatitis D the following are determined: HBsAg, anti-HDV IgM and HDV RNA; hepatitis E — anti-HEV IgM, HEV RNA (anti-HEV IgG — a sign of past disease, persists throughout life) [1, 2].

Determination of markers of infection with hepatitis viruses is carried out only when using certified standardized diagnostic kits approved for use in the territory of the Republic of Uzbekistan. Research is carried out using enzyme immunoassay, chromatographic method, and polymerase chain reaction. If there are positive indicators, it is necessary to examine the patient additionally presence of serological and virological markers of viral hepatitis to establish a final etiological diagnosis [5].

Hepatitis D virus is a defective virus that contains single-stranded ribonucleic acid, and does not belong to any of the known families of animal viruses, and is close to viroids and satellite viruses of plants. Most often, laboratory diagnosis is carried out by detecting serological markers, including the presence of an antigen, antibodies to it, and RNA in the blood serum or liver tissue, indicating the presence of an active infection. A marker of active replication of viral hepatitis D is also a marker of the IgM class. Serological markers of infection depend on how the virus was acquired—as coinfection with hepatitis B virus. The anti-hepatitis D virus titer usually declines to virtually undetectable levels after recovery, and there remains no serological marker that the person was ever infected with hepatitis D virus. It has been established that the viral hepatitis D antigen is detected in only 25 % of patients [3].

Currently, a number of special kits consisting of the necessary components and reagents are used to carry out diagnostics and make a final diagnosis. In these diagnostic preparations, it is widely accepted to use delta antigen, the source of which is the liver of marmots, isolated through experimental laboratory infection with hepatitis D, and also obtained by genetic engineering. In addition, it is possible to obtain the antigen from the liver of deceased carriers of viral hepatitis D [1, 2].

More over, there are other diagnostic methods that involve the use of immunofluorescent antibodies to determine the hepatitis E viral antigen in feces and enzyme-linked immunosorbent assay to determine antibodies to type E hepatitis: anti-HEV class IgM and IgG. In addition, methods for determining hepatitis E viral RNA are often used for diagnostic purposes.

Thus, when determining antibodies to antigens in the acute stage of viral hepatitis D, the analysis shows a high content of IgM antibodies, after which other antibodies, IgG, can be detected over a period of time. In addition, determining the RNA of the virus using the PCR method allows detection even at low concentrations and provides information not only about the type of virus, but also about the stage of the disease.

For viral hepatitis E, a diagnostic test to determine antibodies is the main diagnostic method, which shows the presence of IgM and IgG antibodies in the patient’s blood.

Taking into account the above, we can conclude that laboratory tests are an integral and important part of conducting diagnostic studies for hepatitis, the results of which completely determine the scheme and effectiveness of treatment for these diseases.

References:

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2. Лабораторная диагностика инфекционных вирусных заболеваний. 2-е издание // Коллектив авторов СПб ГУЗ «Городской диагностический центр (вирусологический)», Экспертная лаборатория Минздрава РФ. — СПб., 2004. — 94 с.
3. Лобзин Ю. В., Жданов К. В., Волжанин В. М., Гусев Д. А. Вирусные гепатиты: клиника, диагностика, лечение. — СПб.: «Фолиант», 2003. — 192 с.
4. Серов В. В., Апросина З. Г. Хронический вирусный гепатит. — М.: Медицина, 2002. — 384 с.

5. Сокурова А. М. Специфическая лабораторная диагностика вирусных гепатитов // Педиатр. — СПб., 2014. — Том 5. — № 3. — С. 96–100.