The effects of MDR-1 gene polymorphisms on the clinical course of chronic hepatitis B infection

Chronic HBV infection is associated with a high morbidity and mortality rate due to the increased risk of hepatic cirrhosis and hepatocellular cancer. Treatment modalities and resistance are currently being investigated. Several mechanisms underlie drug resistance. P-glycoprotein (P-gp), the product of the multidrug resistance gene (MDR-1), is a well-known mechanism of the MDR phenotype. MDR gene C1236T polymorphism is associated with decreased p-gp function. The mutation of the MDR gene can affect the clinical course of the disease and response rate to treatment. The aim of our study was to investigate the relationship between MDR gene polymorphism and clinical course and treatment responses in chronic HBV infection. Methods: A total of 90 (male∕female: 69/21) patients with chronic HBV infection under Lamivudine treatment were enrolled in this study. Mean ages were 49.8±12.6 (range: 22-75) years. The patients were categorized as: Treatment-respondent (group 1: HBV-DNA is negative at the 24th week) and treatment-refractory (group 2: HBV-DNA is still positive after the 24th week). Group 1 consisted of 51 (M/F: 38/13) and group 2 consisted of 39 (M∕F: 31∕9) patients. There was no significant difference between the ages and genders of the two groups. Histologic activity indexes (HAI), total bilirubin, AST and ALT levels, and HBV-DNA titers were significantly higher in the patients in group 2 than in group 1 (p<0.05).