The role of immune system in the pathogenesis of infections with hepatotropic viruses is still obscure. The aim of this work was to evaluate individual subpopulations of peripheral blood lymphocytes in children with chronic hepatitis. The study was conducted on 102 children (69 boys, 33 girls) aged 2-17 years with chronic virus hepatitis B (52 patients) and chronic virus hepatitis C (50 children), confirmed by serological and histopathological investigations. The subpopulations of peripheral blood lymphocytes were evaluated with standard techniques for immunofluorescent labelling of whole blood with flow cytometer Coulter EPICS XL 3C with the use of three sets of labelled antibodies (CD 3 / CD 19, CD 8 / CD 56, CD 3 / CD 4 / CD 8). 98% patients displayed anomalies within peripheral blood lymphocytes. The greatest disturbances were observed for NK cells and CD 4 lymphocytes Ð their levels decreased in 79.5% and 60.8% patients, respectively as well as CD 19 lymphocytes, whose percentage levels elevated in 61.5% patients. The level of lymphocytes with CD 3 phenotype was normal in the majority of children (81.4%), just as it was the case with the percentage of CD 8 lymphocytes and CD4:CD8 proportion which remained normal in nearly 54% patients. No significant differences were observed in mean levels of particular subpopulations of peripheral blood lymphocytes between children infected with various types of hepatotropic virus and with various intensification of histopathologic changes in the liver. Our findings confirm the involvement of non-specific defence mechanisms in the pathogenesis of chronic hepatitis.
key words: subpopulations of peripheral blood lymphocytes, chronic virus hepatitis C, chronic virus hepatitis B, children

Keywords: subpopulations of peripheral blood lymphocytes, chronic virus hepatitis C, chronic virus hepatitis B, children