Background:Chronic hepatitis C is known to be a general systemic disorder.Few studies focus on periodontium diseases in the course of chronic viral inflammations of the liver. Aim:To analyse the relationship between the stage of periodontium disease and a number of selected lymphocytic phenotypes in blood serum of patients infected with chronic hepatitis C and advanced fibrosis. Material/Methods:The study included 28 patients (mean age of 57.3 years),whose blood serum revealed the presence of HCV-RNA,demonstrated with RT-PCR method,while biopsies helped reveal chronic hepatitis with bridge fibrosis or cirrhosis.Fibrosis was evaluated in Azan-stained preparations. Periodontal inflammation was assessed according to the following criteria:inflammation limbus, swelling, gingival pocket depth, presence of supragingival and subgingival calculus and gomphiasis. Each criterion was assigned 0 or 1 point,cumulatively from 0 to 4 points.Flow cytometry analysis included monoclonal antibodies:CD3,CD4,CD8, CD3/CD16/CD56,CD19 provided by Becton-Dickinson. Analysis of morphological parameters and fluorescence was performed with CellQuest computer software. Results:All patients with advanced liver fibrosis were found to show signs of advanced periodontium diseases (mean cumulative value of 3.25 points).The diseases most frequently encountered included:bleeding and calculus (N=28),deep gingival pockets (N=20)and gomphiasis (N=18).The grade of periodontal disease depended on the total number of T lymphocytes (p