Vol 48, No 3 (2003)

Molecular and genetic data are summarized on the origin of influenza A virus pandemic variants. Conceptual modifications of the reassortment theory of the origin of pandemic strains are discussed in connection with the appearance of new H5 and H9 avian influenza viruses, which caused the respiratory infection in man and which are presently in the focus of attention as possible agents of future pandemic.

The purpose of the present study was to investigate the influence produced by viral proteins in the hepatic cells and RNA of hepatitis С virus (HCV) on the indices of T- and B-cell response in 52 patients with chronic hepatitis С (СНС). A relative count of peripheral-blood lymphocytes (PBL), expressing antigens CD3*, CD4*, CD8*, CD16*, CD20* and CD95* was estimated. The repertoire of antibodies to HCV proteins was specified. The thus obtained data were compared with an activity and a disease stage by using the histological diagnosis and alanine-aminotransferase (ALT) level as well as with the presence of HCV RNA in the serum and viral protein of the liver. Such comparison of data and the use of the correlation analysis made it possible to establish that the antibodies to NS5 protein were detected reliably more often in patients with a more pronounced hepatic fibrosis, with a higher ALT activity and with expression of HCV proteins in the liver. At the same time, the presence of proteins in the liver and of RNA in the serum were accompanied by a more active humoral response to the non-structure proteins of NS4 and NS5 as well as by more profound discrepancies of the immunity T-cell chain (a lowered ratio of CD47 CD8* and a smaller content of CD95*). There were no differences between PBL of the studied populations in patients with various activities and an HCV stage. A relatively bigger quantity of CD95* - positive PBL was found to be reliably higher in patients with viremia but lower in those cases, in which HCV proteins were detected in the liver. This confirms the inhibiting ability of HCV proteins to the Fas-mediated apoptose of PBL in CHC patient.

Molecular probes were designed for the purpose of specific determination of flavioviruses transmitted by the ticks of tick-borne encephalitis (TBE) and Omsk hemorrhagic fever (OHV) as well as by mosquitoes of Japanese encephalitis (JE), North Nile (NN), Murrey Valley encephalitis (MVE), Saint-Lois encephalitis (SLE), dengue 1-4 and of yellow fever (YF). The probes are synthetic deoxyoligonucleotides with the 18-20 long basis and complementary for the RNA fragments defined by computer analysis. The thus obtained probes, which specifically hybridize themselves with the sets of the TBE virus or of the OHV virus and do not hybridize themselves with other TBE viruses' sets. Group-specific probes for YE and dengue viruses as well as virus-specific probes, which are able to detect each of the above viruses without any cross effects, were suggested for indexing and identifying the flaviviruses transmitted by mosquitoes.

A multi- enzyme immune-assay test system was designed for seroty ping of genotypes hepatitis С virus (HCV) and a method of such typing of the serum of patients with hepatitis С was worked out. The above test-system was worked out on the basis of a study of 10 type-specific peptides modeling different fragments from NS4-protein variable region of HCV. The designed test system was evaluated by using a set of 42 serum samples obtained at random from patients with chronic hepatitis C, which had been preliminarily genotyped by polymerase chain reaction. The seroty ping makes it possible to identify the type-specific antibodies in the blood sera of patients, including those cases when viremia was absent. Differences in the circulation of HCV in Moscow (Russia) and Vitebsk (Byelorussia) were established by using the designed test-system.

New antiviral drug "Nikavir" was clinically tested in acute hepatitis В (АНВ). A total of 60 AHB patients were followed up; 30 patients were in the main group and 30 persons were in the control group. The treatment with Nikavir of AHB patients was shown to ensure a favorable clinical disease course and it was accompanied by a quicker rate in reduction of the activity of serum enzymes AIAT, AcAT, alkaline phosphatase and of gamma-glutamiltranspeptidase; besides, it was accompanied by an early elimination of such serum markers of AHB like HBeAg, HbsAg and HBV DNA. Wikavir can be used in the treatment of patients with mild and moderate forms of AHB.