Imbalanced immunobiological reactivity, infection and mutagenesis factors in the hepatobiliary system affected by a natural focal habitat factor — a trematode invasion by Opisthorchis felineus

An interaction between decreasing host anti-infective defense due to long-term invasion with Opisthorchis felineus in the hepatobiliary system, duct bile colonization by microflora and revealing the endogenous mutagenesis (carcinogenesis) factor in bile — secondary bile acids — is considered in the article. The role of organism genotype in pathogen-related immune response to Opisthorchis felineus trematode and helminth development in the hepatobiliary system has been shown. The role of dysregulated mechanisms of tissue homeostasis in induction of compensatory chronic homeostatic proliferation and somatic cell oncogenesis is discussed. The study results evidence that disturbed functioning of regulatory T cells, inhibition of the NK cell effector function and very high functional activity of memory B cells are of great importance in imbalanced host immunobiological reactivity, caused by chronic opistorchis invasion. Decreased host anti-infective protection causes intrahepatic bile duct infection with different bacterial species. Presence of secondary bile acids in hepatobiliary system was associated with biliary bacterial strains inhabiting intestinal tract: Proteus vulgaris, Proteus mirabilis, Citrobacter freundii, Bacteroides alcaligues faecalis, Clostridium, Streptococcus faecalis, Еscherichia coli — gut microflora agents. Participation of microbiota in bile acid biotransformation immediately in the duct bile has been confirmed in experiments in vitro. Experimental methods on Drosophila melanogaster and Salmonella typhimurium strains: TA100, TA98 allowed to find out that bile from chronic opistorchiasis patients exerts higher mutagenic activity compared to control groups. Mutational events in somatic and bacterial cells depend on the presence of secondary bile acids (deoxycholic, lithocholic) in duct bile, as well as the level of total bile acid concentration. The study data confirm the concept by Professor A.A. Shain about the presence of endogenous risk factor for developing primary cholangiocellular liver cancer such as secondary bile acids in the bile of chronic opistorchiasis patients. A concept of cholangiocarcinogenesis, based on mutational events, is added up with disturbance of generative cycle in tissue cells and their differentiation due to decreased chalone factor activity, as well as sensitivity threshold to it. Level of investigation and understanding of mechanisms underlying cholangiocarcinogenesis during chronic opisthorchis invasion will allow to develop pathogenetic approaches to correct homeostasis regulation and prevention of cholangiocarcinomas.