Russian scientists figured out how to detect hidden hepatitis B

Named after Pasteur Rospotrebnadzor, St. A new test system for the diagnosis of latent hepatitis B was developed by specialists from the St. Petersburg Research Institute of Epidemiology and Microbiology. According to the creators of the diagnostic method, it allows you to determine the disease even with minimal viral load. Currently, the test system is in the testing and preparation phase of registration documents.

“Our method is based on our analysis in two steps using the polymerase chain reaction (PCR) method: in the first step we obtain the complete genome of the virus, and in the second step, based on the obtained genome, three parts of this genome – S, X and Core – three regions / genes corresponding to the virus. “In the second step, we use control samples – plasmids that carry the same sequences of the viral genome, which allows us to make sure that we have fully identified the desired/desired parts.”

In addition, the patient’s genetic material is used – its detection in the sample indicates that the DNA extraction went correctly. If, in addition to the patient’s genetic material, nothing else was found in the sample, then he does not have latent hepatitis.

“There are patients with cryptogenic hepatitis, also known as hepatitis of unknown etiology,” Ostankova says. –

A person develops hepatitis, fibrosis, cirrhosis, and doctors cannot find the reasons for this. As our studies show, more than 80% of such cases are occult hepatitis B cases. If doctors could detect this in time, treatment would be aimed not only at keeping the patient’s condition as stable as possible, but also at combating the virus. symptomatic treatment » .

For the primary diagnosis of hepatitis B in both acute and chronic forms, serological methods are used – the Australian HBsAg antigen acts as a diagnostic marker. PCR tests give more accurate results by detecting viral DNA. However, in latent hepatitis, antigen is not detected and the viral load may be so low (less than 50 IU/mL) that standard PCR tests cannot detect viral DNA. At the same time, the virus remains active and continues to participate in the destruction of the patient’s liver – the risk of developing cirrhosis of the liver and other lesions in these patients increases by 8-12 times.

“The latent or latent or HBsAg-negative form of hepatitis B is a form characterized by the absence of HBsAg in the blood and the presence of RNA of the virus in liver tissues,” explains Ostankova. “There is virus DNA in the blood plasma, but at such a low level, such a low viral load that it cannot be detected by the standard methods currently used. This is a diagnostic issue. Latent hepatitis B is not routinely detected in Russia.”

In addition, hepatitis B virus can be transmitted from mothers to children, from donors to recipients, even with a latent form of the disease and a low viral load, but timely treatment prevents transmission or at least reduces the risks.

“In Russia, the number of hepatitis B patients registered in medical care records is 3 times less than patients with hepatitis C, but the presence of latent forms of infection may not give a true picture of the prevalence of the disease. The number of such patients today is unpredictable,” adds Irina Pirogova, a gastroenterologist and hepatologist with the highest category at SM-Clinic.

However, it is these patients who represent both a social and medical problem, as they do not receive the necessary treatment in a timely manner and can come into the field of view of the doctor at the stage of cirrhosis and liver cancer, and they are also an unwitting source of disease. hepatitis B infection, the chronic forms of which are far from being cured. everybody has it”.

At the same time, Ostankova notes that, according to the WHO, the prevalence of chronic viral hepatitis B in the world (estimated by the prevalence of HBsAg) is about 296 million people, the prevalence of chronic viral hepatitis C is 58 million people.

“Actually, the prevalence of chronic hepatitis B in the world in general is much higher than the prevalence of chronic hepatitis C, but the fact that registered chronic hepatitis B patients are three times less than the hepatitis C prevalence is indicative of how this is going. Bad things happen in the Russian Federation with timely diagnosis of viral hepatitis B, awareness of the population and the provision of medical care in this area (depending, among other things, on timely diagnosis), ”Ostankova emphasizes.

The method developed for the diagnosis of HBsAg-negative hepatitis B, St. It was the result of extensive research work carried out by the staff of the Pasteur Research Institute of Epidemiology and Microbiology in St. Petersburg. The test was based on fragments of Yulia Ostankova’s doctoral thesis and Alexander Semenov’s doctoral thesis (Head of the Laboratory of HIV Infection Immunology and Virology, Deputy Director of the Institute for Innovative Work; now – Head of the Yekaterinburg Research Institute). Viral Infections of the State Virology and Biotechnology Research Center “Vector”). Therefore, research on blood donors from different countries has shown that up to 30% of donors, including those who donate blood regularly, may suffer from latent hepatitis B. In some donor centers in Russia, this figure was about 4%, in Kazakhstan – more than 9%. The worst case is in African countries, for example the Republic of Guinea. The data were obtained as part of the evaluation of the effectiveness of a new testing system – according to the usual testing, these individuals did not have hepatitis B.

“The highly sensitive PCR test is an important and timely scientific development that will help in the fight against viral hepatitis, whose mortality rate exceeds that from HIV infection and is comparable to mortality from tuberculosis,” Pirogova said. –

PCR diagnosis of hepatitis B is important for the initial diagnosis and identification of patients who are indicated for antiviral therapy based on the amount of a given virus in the blood, otherwise cirrhosis and liver cancer may develop. The advent of a highly sensitive PCR test will solve these problems.”

Modern tests quite successfully cope with the detection of latent hepatitis B, says Vera Belyakova, head of the laboratory at the Blood Center. OK Gavrilova. And even if new, more advanced ones appear, their use in donor blood tests will require full automation – the volumes of incoming material are too large to work with it manually.

Ostankova explains that at the moment the new method is primarily suitable for clinical application and will be useful where a patient has suspected hepatitis B but has not been detected by standard methods.

Every year the number of mutations of the virus increases, new varieties appear that do not cause the production of HBsAg or can infect the body even after vaccination, and it is extremely important to find a way to diagnose the disease in these conditions. on time.