CLINICAL LIVER MORPHOLOGY: CYTOTOXIC LYMPHOCYTES

Background. The liver is the organ of the immune system, in which various populations of lymphocytes are representatives of congenital and acquired immunity: NK cells, NKT cells, LGL cells, CD8 + (CTL) cells that participate in cytotoxic reactions. The aim of the study is to present the structural and functional characteristics of the main populations of cytotoxic lymphocytes that take an active part in the development of inflammation in viral liver damage. Material and methods. Morphological evaluation of intravital hepatic biopsy specimens of patients with chronic viral hepatitis was performed by light and electron microscopy with the use of classical and original techniques for fixing and staining preparations. Results. A detailed description of the structure of the main populations of lymphocytes in the liver (NK cells, NKT cells, LGL cells, CD8 + cells) and their basic immunomorphological data and cytotoxic characteristics are presented. The main methods used in clinical practice for morphological evaluation of the activity of inflammation in the liver are described. Conclusions. The most studied participants in the development of cytotoxicity in chronic viral hepatitis are lymphocytes, which cause direct and indirect damage to hepatocytes: NK cells, NKT cells, LGL and CTL (CD8+ T cells) cells that differ by their phenotypic as well as structural and functional characteristics. The classical method of light microscopy of liver biopsy samples does not allow to differentiate populations of cytotoxic lymphocytes, in contrast to light microscopy of semi-thin sections and electron microscopy. An additional morphological indicator for the evaluation of activity and monitoring of inflammation in the liver can be a morphological (quantitative) characteristic of the cellular population of lymphocytes of the congenital and adaptive immunity.