Blood Level of Nitric Oxide Metabolites and Expression of Genes Regulating NO Synthesis in Early Forms of Non-Alcoholic Fatty Liver Disease.

The levels of NO metabolites in the plasma and mRNA of the NOS3, ATG9B, and NOS2 genes in peripheral blood leukocytes of healthy people and patients with early forms of non-alcoholic fatty liver disease (steatosis and weak activity non-alcoholic steatohepatitis) were studied. In patients with steatohepatitis, the concentration of NO metabolites in the blood and the level of mRNA of the NOS2 gene were higher than in patients with steatosis and healthy people. These differences can be of diagnostic value for distinguishing between steatosis and weak activity steatohepatitis in non-alcoholic fatty liver disease. A correlation between the levels of NO metabolites and the expression of the NOS2 gene in weak activity steatohepatitis was established, which indicates activation of NO synthesis in non-alcoholic steatohepatitis due to the expression of the inducible NO synthase gene. The level of the NOS2 gene mRNA in peripheral blood leukocytes of patients with weak activity steatohepatitis correlated with the level of TNFα and IL-6 cytokines. An increase in the level of NO in the blood in weak activity steatohepatitis correlated with the level of MDA, an indicator of oxidative stress.

The Role of the Soluble Interleukin-6 Receptor in the Progression of Nonalcoholic Fatty Liver Disease.

The blood level of soluble IL-6 receptor was measured in patients with different clinical and morphological forms of nonalcoholic fatty liver disease and healthy donors. The relationship of the soluble IL-6 receptor with the content of IL-6, the level of the IL6 gene mRNA, and a number of markers of hepatocyte and peripheral blood leukocyte apoptosis was assessed. It has been established for the first time that progression of nonalcoholic fatty liver disease is associated with changes in the level of soluble IL-6 receptor in the blood. In patients with high activity of nonalcoholic steatohepatitis and liver cirrhosis, the blood concentration of soluble IL-6 receptor sharply decreased in comparison with the earlier stages of progression of nonalcoholic fatty liver disease (liver steatosis, nonalcoholic steatohepatitis of weak and moderate activity). This allows considering the decrease in this indicator as a new diagnostic marker for distinguishing nonalcoholic steatohepatitis of high activity from weak and moderate activity. A close correlation between changes in the level of soluble IL-6 receptor and apoptosis of peripheral blood leukocytes and hepatocytes was revealed.

Hepatocytic Apoptosis and Immune Dysfunction in Decompensation of Alcoholic Liver Cirrhosis with Different Grades of Acute-on-Chronic Liver Failure.

Acute-on-chronic liver failure (ACLF) of varying grades was assessed in 110 patients with alcoholic liver cirrhosis using the on-line CLIF-C ACLF Calculator ( www.efclif.com/scientific-activity/score-calculators/clif-c-aclf ); fragments of cytokeratin-18, TNFα, IL-1ß, IL-4, IL-6, and IL-8 were also assayed. As ACLF progressed from grade 0 to grade 3, the levels of cytokeratin-18 fragments, IL-6, and IL-8 significantly increased, while IL-4 decreased. TNFα peaked in ACLF grade 1, but decreased in grades 2 and 3. IL-1ß did not depend on the ACLF grade. Thus, hepatic damage and immune dysfunction are implicated in the progression of ACLF.

Role of Bacterial Infection in the Development of Acute Liver Failure in Patients with Decompensated Alcoholic Liver Cirrhosis.

We examined 74 patients with acute decompensation of alcoholic liver cirrhosis: 34 (45.9%) with bacterial infection (group 1) and 40 (54.1%) without bacterial infection (group 2). The degree and index of acute-on-chronic liver failure (ACLF) were determined using an on-line CLIF-C ACLF Calculator and the levels of cytokeratin-18 fragments, TNFα, IL-1ß, IL-4, IL-6, and IL-8. In group 1, AST, cytokeratin-18, TNFα, IL-1ß, IL-6, degree and score of ACLF were significantly higher than in group 2. ACLF developed in 18 (52.9%) patients in group 1 and in 11 (27.5%) (p<0.05) patients in group 2. Within 1 month, 10 (29.4%) patients of group 1 and 2 (5%) patients of group 2 died (p<0.05). Patients with bacterial infection showed a more severe course of alcoholic liver cirrhosis and ACLF than those without bacterial infection.

[Hepatocellular damage and inflammation in various forms of alcoholic liver disease].

AIM: The aim of the study was to evaluate hepatocellular damage and immune inflammation in various forms of alcoholic liver disease (ALD). MATERIALS AND METHODS: 104 patients with ALD were examined: 15 (14.4%) with liver steatosis (LS), 19 (18.3%) with steatohepatitis and 70 (67.3%) with liver cirrhosis (LC); men 50 (48.1%), women 54 (51.9%); age 45.78.4 years. Traditional clinical, laboratory, instrumental studies were performed, the levels of fragments of cytokeratin-18 (FCK-18), cytokines IL-1, TNF-, IL-4, IL-6, IL-8 were determined by ELISA. The control group consisted of 39 healthy individuals: men 20 (51.2%), women 19 (48.7%), age 48.58.3 years. RESULTS: In LS, an increase in the level of FCK-18 was noted with normal aminotransferase activity, the content of TNF-, IL-6, IL-1, IL-8 increased and the level of IL-4 decreased compared to those in healthy individuals. In steatohepatitis, a triple increase in aminotransferases and FCK-18 was observed compared with LS, as well as an increase in the level of inflammatory mediators, to a greater extent IL-6, to a lesser extent IL-8, TNF-, a decrease in IL-4, IL-1 remained at the same level. In LC, there was a further increase in FCK-18, significantly more pronounced than an increase in AST, and the increase in cytokines continued to the same extent, the levels of IL-6 and IL-8, to a lesser extent IL-1 and TNF-, and the level of IL-4. CONCLUSION: With the progression of ALD from LS to steatohepatitis, hepatic cell damage was carried out by equally pronounced processes of hepatocyte necrosis and apoptosis, with the development of cirrhosis of the liver, parenchyma damage occurred mainly due to hepatocyte apoptosis. The immuno-inflammatory process progressively increased from the stage of LS to LC with IL-6 and IL-8 undergoing the greatest dynamics. FCK-18 can serve as a non-invasive marker of hepatic cell damage, and IL-6 and IL-8 markers of immune inflammation in ALD.

The relationship of the carriership of allelic variations in rs2228145 (A > C) of the IL6R gene with the levels of VCAM1 and ICAM1 gene transcripts in patients with essential hypertension.

The levels of plasma interleukin 6 and its soluble receptors were found to be elevated in subjects with cardiovascular diseases, which points to amplification of the IL-6-mediated trans-signaling pathway in cells and the development of chronic inflammation. The allelic variation in the rs2228145 IL6R gene is associated with a change in the contents of the soluble and membrane-bound receptor forms mediating the biological activity of IL-6. Cytokine IL-6 is involved in the development of endothelial dysfunction by regulating the expression of the VCAM1 and ICAM1 genes, encoding intercellular adhesion molecules. Prior to this work, no data on the association of essential arterial hypertension (EAH) with rs2228145 allelic variations of the IL6R gene have been reported. The aim of our work was to study the relationship of the carriership of rs2228145 (A > C) allelic variations with the development of EAH and the VCAM1 and ICAM1 transcript levels. We analyzed samples of DNA isolated from the whole blood of 148 healthy donors and 152 patients with EAH (stages I-II). The genotyping was performed by PCR-RFLP. The level of transcripts in peripheral blood leukocytes (PBL) was assessed by real-time PCR. Differences in the frequency distributions of rs2228145 (A > C) genotypes between the control group and the group of patients with EAH (χ2 = 9.303) were found. The frequency of the CC genotype in EAH patients was higher than in healthy people (0.191 and 0.095, respectively). The risk of EAH (I-II stages) development was shown to be 2.3 times higher in CC genotype carriers as compared to individuals with other genotypes (OR = 2.257, 95 % confidence interval 1.100-4.468). The levels of VCAM1 and ICAM1 gene transcripts in PBL of patients with EAH were significantly higher than in healthy people. The level of ICAM1 gene transcripts was almost 4 times higher in patients with CC genotype. The Kruskal-Wallis analysis of variance revealed an effect of rs2228145 (A > C) genotype on the transcriptional activity of ICAM1, which argues for its role in the pathogenesis of endothelial dysfunction and essential hypertension.

Biochemical and molecular-genetic indicators of inflammation and apoptosis in liver cirrhosis as an outcome of the progression of non-alcoholic steatohepatitis.

AIM: A comparative analysis of the complex of clinical and laboratory indicators (including the content of cytokines in blood plasma and the level of expression of TNF and IL6 genes in peripheral leukocytes, as well as the level of biochemical and molecular-genetic indicators of apoptosis, such as the content of tissue polypeptide-specific antigen (TPS) in the blood, the activity of caspases 3, 8 and 9 and the expression level of the encoding genes in peripheral blood leukocytes) in patients with non-alcoholic fatty liver disease (NAFLD) with non-alcoholic steatohepatitis (NASH) of different activity, liver cirrhosis (LC) classes A and B and in the donors of control group. MATERIALS AND METHODS: 158 patients with NAFLD were examined: 116 patients with NASH diagnosed for the first time (NASH of weak, moderate and high activity) and 42 patients with the NAFLD at the stage of liver cirrhosis diagnosed for the first time (classes A and B according to the Child-Pugh classification). The control group consisted of 54 healthy donors. The clinical blood biochemistry, cytokine profile, tissue polypeptide-specific antigen content, the level of the TNF, IL6 gene and caspase gene transcription as well as caspase activity in peripheral blood leukocytes (PBL) were evaluated. RESULTS: In the progression of NASH to LC, together with changes in general clinical parameters, the cytokine profile are changed due to an increase in the level of IL-6 and IL-1ß; in peripheral leukocytes, the activity of caspase 9 increases and the activity of caspase 8 decreases compared to NASH, and the level of the TNF gene expression decreases as compared to NASH of high activity. These parameters can be considered as promising minimally invasive markers of progression of NAFLD to LC. CONCLUSION: In nonalcoholic cirrhosis as an outcome of the progression of non-alcoholic steatohepatitis changes in clinical parameters (indicating the development of hepatocellular deficiency, violation of protein and lipid metabolism, progressive inflammation) are accompanied by specific changes in levels of biochemical and molecular-genetic indicators of apoptosis and inflammation. With the progression of NASH to LC, the cytokine profile changes due to an increase in the level of proinflammatory cytokines, the apoptosis processes triggered by the internal pathway increase and the activity of apoptosis activated via the external pathway decreases in PBL.

Analysis of the Association of TNF -238G>A Gene Polymorphism with the Risk of Rheumatoid Arthritis Development in Russian Population in the Republic of Karelia.

We studied association of the TNF gene -238G>A polymorphism (rs361525) with the risk of rheumatoid arthritis development in the Russian population living in the Republic of Karelia. The influence of rs361525 on the development of rheumatoid arthritis was revealed: genetic predisposition to this disease is associated with the presence of GG genotype. The effect of the genotype on the polymorphic locus of -238G>A on TNF mRNA content was revealed. Increased content of transcripts of this gene is associated with the presence of A allele.

IL6R Gene Polymorphic Variant rs2228145(C >A) as a Marker of Genetic Liability to Nonalcoholic Steatohepatitis in the Russian Population of Karelia.

Association of IL6R gene polymorphic variant rs2228145(C>A) with the development of nonalcoholic steatohepatitis in Karelia residents is detected. The risk of nonalcoholic steatohepatitis is more than 2-fold higher in carriers of CC genotype by rs2228145 polymorphic marker than in carriers of other genotypes. Plasma levels of IL-6 and the content of IL6R gene transcripts in the peripheral blood leukocytes are higher in patients with nonalcoholic steatohepatitis than in normal subjects. No relationships between rs2228145 polymorphism and the level of IL-6 and content of IL6 and IL6R mRNA were detected. Gene IL6R polymorphic variant rs2228145(C>A) seems to be involved in genetic predisposition of the population of Karelia to nonalcoholic steatohepatitis. However, biochemical and molecular mechanisms underlying the relationship of rs2228145 with the development of nonalcoholic steatohepatitis are not yet studied.

The clinical significance of insulin resistance in non-diabetic patients with early forms of non-alcoholic fatty liver disease.

AIM: To assess the presence of insulin resistance (IR) in non-diabetic patients with early forms of non-alcoholic fatty liver disease (NAFLD) - liver steatosis (LS) and steatohepatitis (SH) of mild activity and the influence of IR on the clinical course of these diseases. MATERIALS AND METHODS: 134 patients with NAFLD were examined: 54 with LS and 80 with SH. The control group consisted of 37 healthy donors. Anthropometric parameters (body mass index (BMI), waist circumference (WC)), clinical and biochemical blood indices, including the blood level of cytokeratin-18 fragments (CK-18), TNF-α and IL-6 cytokines, insulin were evaluated. The HOMA index and the fibrosis index (NAFLD FS) were calculated. Patients were divided into groups: I - with the absence of IR (HOMA-index <2.7), II - with the presence of IR (HOMA-index> 2.7). RESULTS: Indicators of hepatic injury, inflammation, cholestasis, fibrosis and atherogenic dyslipidemia are higher in patients with LS of group II (with IR) than in group I patients (without IR). BMI, WC, γ-glutamil transpeptidase, CK-18 and fibrosis index are significantly higher in group II patients with SH compared with group I, there is no significant difference in the level of cytolysis, inflammation and dyslipidemia indices. A high incidence of IR in non-diabetic patients with LS (37.0%) and SH (55.0%) was found and the effect of IR on the clinical course of these diseases was revealed. CONCLUSION: Insulin resistance in non-diabetic patients with NAFLD was detected in SH (55.0%) with higher frequency than in LS (37.0%). In LS, IR is associated with impaired hepatic cell damage, intrahepatic cholestasis, atherogenic dyslipidemia and fibrosis. In SH, IR is combined with reliable growth in indicators of hepatocyte apoptosis, cytokine proinflammatory status and fibrosis. IR determines the progressing course of NAFLD, promoting the transformation of steatosis into steatohepatitis and steatohepatitis into fibrosis and liver cirrhosis.

Gene TNF Polymorphism -308G>A (rs1800629) and Its Relationship with the Efficiency of Ursodeoxycholic Acid Therapy in Patients with Nonalcoholic Stetohepatitis.

Association of TNF gene polymorphism -308G>A with the development of nonalcoholic steatohepatitis in the Russian population was revealed. Carriers of allele A of the TNF gene marker -308G>A have significantly higher risk of nonalcoholic steatohepatitis development: OR=1.69 (1.05; 2.71). Allele A carriage by this marker predicts an increase in the basal HDL level and a decrease in LDL and IL-10 levels in the blood of healthy subjects. Patients with nonalcoholic steatohepatitis, differing by the TNF gene -308G>A marker genotype, differ by the time course of the markers of hepatocellular damage (ALT, AST), activity of hepatocyte apoptosis (tissue polypeptide-specific antigen), and activation of specific humoral immunity (γ-globulin) in response to therapy with ursodeoxycholic acid in a dose of 10-15 mg/kg over 4-6 weeks. Carriers of allele A of the TNF gene polymorphic marker -308G>A are more sensitive to ursodeoxycholic acid therapy than carriers of GG genotype.

[Features of a necrotic and inflammatory process in different forms of nonalcoholic fatty liver disease]. / Osobennosti nekroticheski-vospalitel'nogo protsessa pri raznykh formakh nealkogol'noi zhirovoi bolezni pecheni.

AIM: To identify the features of development of a necrotic and inflammatory process in different forms of nonalcoholic fatty liver disease (NAFLD), by comparatively analyzing a full set of clinical and laboratory parameters, including the cytokine status and the expression level of enzyme genes controlling the apoptosis of peripheral leukocytes. SUBJECTS AND METHODS: 86 patients with NAFLD, including 8 (9.3%) with hepatic steatosis (HS), 70 (81.4%) with nonalcoholic steatohepatitis (NASH), 40, 19, and 11 with mild, moderate, and high disease activity, respectively, and 8 (9.3%) with liver cirrhosis (LC), were examined. A control group consisted of 34 healthy donors. Clinical and biochemical blood indices, cytokine profile, and the level of caspase gene transcripts in the peripheral blood leukocytes (PBL) were estimated. RESULTS: As compared to the controls, the patients with HS had higher tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) levels and lower caspase 3, 6, and 8 mRNA in PBL. The concentration of IL-10 in NASH was higher than that in steatosis and positively correlated with the level of proinflammatory cytokines. The levels of TNF-α and IL6 were higher in the patients with NASH than in the controls. Those of C-reactive protein, γ-globulin, IL-6, and cytokeratin-18 fragment increased with the progression of NASH. In the latter, the transcriptional activity of caspase-3 gene decreased relative to the reference value and negatively correlated with the level of proinflammatory cytokines. In the patients with LC, the gene expression profile of caspases in PBL was similar to that in the control group; the level of IL-6 was higher than that in steatosis and NASH, that of IL-1ß was higher than in HS and positively correlated the concentration of IL-6 and the activity of alanine aminotransferase and aspartate aminotransferase. CONCLUSION: The features of a necrotic and inflammatory process were identified in different forms of NAFLD. When the latter progressed, the cytokine profile and gene expression levels of caspases in PBL altered along with a change in the general clinical picture.

Caspase 3, 6, 8, and 9 Gene Expression in Peripheral Blood Leukocytes and Plasma Concentrations of IL-6 and TNF-α in Carriers of Different Polymorphic Marker -174G>C Genotypes of IL6 Gene Associated with the Risk of Nonalcoholic Steatohepatitis.

We revealed an association of IL6 gene -174G>C polymorphism with the development of nonalcoholic steatohepatitis in the Russian population. The risk is significantly higher in carriers of C allele: OR=1.77 (1.04; 3.02). The effects of -174G>C substitution in IL6 gene involving caspase 9 gene transcripts in peripheral blood leukocytes and on blood content of TNF-α in healthy individuals without clinical manifestations of nonalcoholic steatohepatitis were detected. The content of caspase 9 gene transcripts in peripheral blood leukocytes and plasma level of TNF-α were significantly higher in healthy subjects carrying C allele than in carriers of GG genotype. The levels of caspases 3, 6, 8, and 9 gene transcripts in peripheral blood leukocytes and plasma concentrations of TNF-α in patients with nonalcoholic steatohepatitis did not depend on IL6 genotype by -174G

[Association of FOXP3 gene -3279 C>A polymorphism with the risk of pulmonary sarcoidosis]. / Assotsiatsiia polimorfizma -3279 C>A gena FOXP3 s riskom razvitiia sarkoidoza legkikh.

AIM: To investigate the association of the polymorphic marker -3279 C>A of the FOXP3 gene with the risk of pulmonary sarcoidosis (PS) and to estimate the transcription level of this gene in the carriers of different genotypes of this polymorphic marker. SUBJECTS AND METHODS: The investigation included 99 patients of Russian ethnicity (mean age, 45.41±1.31 years) living in the Republic of Karelia, who were diagnosed with persistent PS, and 116 healthy donors (mean age, 42.06±1.30 years) in the control group. The alleles and genotypes of the polymorphic marker -3279 C>A of the FOXP3 gene were identified using polymerase chain reaction (PCR)-restriction fragment length polymorphism. The number of transcripts of the studied gene in the peripheral blood leukocytes of healthy donors and PS patients was determined with real-time PCR. RESULTS: The control group and the PS patient one had no statistically significant differences in the distribution of the frequencies of alleles and genotypes by the polymorphic marker -308G>A of the FOXP3 gene (p > 0.05). The number of FOXP3 gene transcripts was not statistically significantly different in the peripheral blood leukocytes of patients with PS and control individuals. No statistically significant differences were observed in the mRNA expression levels in the above-mentioned gene in the carriers of different genotypes by the polymorphic marker -3279 C>A of the FOXP3 gene in all examined groups. CONCLUSION: The polymorphic marker -3279 C>A of the FOXP3 gene is unassociated with the risk of PS.

The level of cytokines and expression of caspase genes in rheumatoid arthritis.

The level of TNFα and IL6 in the blood plasma of patients with rheumatoid arthritis (RA) who received antiinflammatory therapy with methotrexate (MT) was significantly lower than in the patients without MT treatment. The level of caspase 6 and 9 gene transcripts in peripheral blood lymphocytes in patients with rheumatoid arthritic diagnosed for the first time and in patients with MT treatment were not significantly different. At the same time, the level of caspase 3 mRNA expression was significantly higher in the cells of the RA patients with MT therapy compared to the patients without MT therapy.

[Circadian CLOCK Gene Variants, Parameters of Arterial Stiffness and Blood Pressure Levels in Subjects Without Arterial Hypertension].

CLOCK gene polymorphic variants, parameters of arterial stiffness and blood pressure (BP) variability were studied in 115 normotensive Russian patients without cardiovascular diseases (62 men, 53 women; mean age 36.4+/-1.01 years). Examination included ECG, 24h BP monitoring, duplex scan of carotid arteries, registration of vascular stiffness parameters, and genotyping of the following polymorphic markers of CLOCK: 3111T>C (3-untranslated region), 862T>C (exon 9) and 257T>G (promoter region) by PCR-RFLP method. Pulse wave velocity was not significantly different among carriers of various 257T>G, 862T>C, 3111T>C genotypes. Augmentation index (Aix night, Aix max) values were lower in individuals with genotypes allegedly associated with essential hypertension and ischemic heart disease (257GG, 862CC, 3111CC). Arterial stiffness index (ASI) was significantly higher in men having CC genotype of 862T>C. Polymorphic variants 257T>G and 862T>C SNPs of CLOCK gene were found to be associated with parameters reflecting BP variability (morning rise of diastolic BP and rate of BP rise). These results provide a basis for suggestion that the CLOCK gene polymorphism is one of factors determining elastic properties of vascular wall. The suggestion is supported by discussion of possible molecular mechanisms of circadian genes impact on elasticity and rigidity of vessel.

[EFFICIENCY OF URSODEOXYCHOLIC ACID APPLICATION IN NONALCOCHOLIC STEATOHEPATITIS].

AIM: to estimate the efficiency of ursodeoxycholic acid (UDHC) in nonalcocholic steatohepatitis (NASH) by analysis of conventional clinical datas, apoptosis and liver perfusion parameters. MATERIALS AND METHODS: UDHC was used as monotherapy in treatment of 92 NASH patients in daily dose 10-15 mg/kg. We have observed 44 (47.8%) males, 48 (52.2%) females, age was 56.8 ± 7.2 years, BMI was 28.4 ± 2.3 kg/m2, waist circumference was 93.8 ± 8.3 cm. Functional liver tests (ALAT, ASAT, alcaline phosphatase--APh, gamma-glutamyltranspeptidase--GGTP), abdominal ultrasonography and dopplerography of liver blood flow, kaspase-3, 6, 8, 9 genes expression in blood leucocytes were estimated. Periods of controls research and UDCA treatment were: 4-8 weeks in 92 patients, 20-24 weeks in 18 (19.6%) patients and 40-48 weeks in 13 (14.1%) patients. RESULTS: Significant positive dynamics of liver functional tests and decrease of kaspase-3, 6, 9 genes expression in blood leucocytes were observed over 4-8 weeks, normalization of liver tests--over 20-24 weeks and significant amelioration of venous and arterial liver perfusion parameters--over 40-48 weeks. CONCLUSION: Ursodeoxycholic acid in daily dose of 10-15 mg/kg in nonalcocholic steatohepatitis caused positive dynamics of cytolytic and cholestasis parameters, leucocytic apoptosis and venous and arterial liver blood flow parameters.

Expression of circadian rhythm genes CLOCK, BMAL1, and PER1 in buccal epithelial cells of patients with essential arterial hypertension in dependence on polymorphic variants of CLOCK and BMAL1 genes.

The transcript levels of circadian rhythm genes CLOCK, BMAL1, and PER1 in buccal epithelial cells of the patients with essential arterial hypertension was analyzed in relation to polymorphic variants of CLOCK and BMAL1 genes. These levels were assessed with realtime PCR method at daily hours 9, 13, and 17. The significant differences were revealed in transcript levels of the examined genes in patients with various genotypes at the polymorphic markers 3111TC and 257TG regulatory regions of CLOCK gene. The study detected no significant differences among the carriers of various genotypes at polymorphic markers 862TC and 2121GA of CLOCK gene and 56445TC of BMAL1 gene.

[Tourism, imported parasitic diseases, and their prevention].

The paper gives the results of observations of 1558 patients before and after tourist travels to tropical countries and 368 individuals visiting the north areas of the Russian Federation. Different conditions (malaria, amebiasis, leishmaniasis, intestinal and tissue helminthiasis, insect bites, venomous fish pricks, medusa burn, tick bites, etc.) were found in 402 persons. Prophylactic immunization included vaccination against hepatitis A and B viruses, meningitis, typhus, yellow fever, tick-borne encephalitis in more than 2500 patients (not including influenza vaccination in the epidemic season). The performed observations reinforce the statement that imported pathology is urgent to Russia and suggest that it is necessary to develop this section of medicine and to set up a network of health care facilities with a necessary therapeutic and diagnostic base to render skilled care to tourists. It is essential to improve medical staff training in travel medicine.