288 ADA activity in patients with hepatitis © 2007 Journal of Microbiology, Immunology and Infection Adenosine deaminase activity in serum of patients with hepatitis — a useful tool in monitoring clinical status Selçuk Kaya, Emel Sesli Çetin, Buket Cicio ğ lu Arıdo ğ an, Salih Arıkan, Mustafa Demirci Department of Microbiology and Clinical Microbiology, Faculty of Medicine, Süleyman Demirel University, Isparta, Turkey Received: November 14, 2006 Revised: January 20, 2007 Accepted: February 15, 2007 Corresponding author: Selçuk Kaya, Istanbul Cad. No: 52 Kat: 4/14, Isparta 32100, Turkey. E-mail: selcuk@med.sdu.edu.tr Background and Purpose: The evaluation of adenosine deaminase (ADA) activity in sera of patients with hepatitis should be considered a useful tool in the monitoring of their clinical status. In this study, we aimed to determine the relationship between viral load, transaminase levels, and serum ADA levels in hepatitis B virus (HBV)- and hepatitis C virus (HCV)-infected patients. Methods: Seventy three patients with hepatitis B, 71 patients with hepatitis C and 40 healthy individuals were included. Patients with HBV and HCV infections were classified into 3 groups according to viral load. Serum ADA levels were investigated by colorimetric assays. Results: Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and ADA levels of HBV- and HCV-infected patients were higher than those of the control group. These differences were statistically significant for the levels of all enzymes in HCV-infected patients (p<0.05), and all except AST (p>0.05) in HBV-infected patients. ADA levels of HBV-infected patients with high viral loads were higher than those in HBV-infected patients with intermediate and low viral loads, and the difference was detectably significant between patients with high and intermediate viral loads. Evaluation of HCV-infected patients according to viral load showed no statistically significant relationship between viral load and serum ADA, ALT, and AST levels (p>0.05). HBV- and HCV-infected patients with high ALT and AST levels showed statistically significantly higher levels of ADA than patients with normal ALT and AST levels (p<0.001). Conclusions: We suggest that serum ADA levels are associated more with the level of serum transaminases than viral load in HBV- and HCV-infected patients. In the treatment of patients with hepatitis, serum ADA levels should be considered a useful tool for the monitoring of liver condition. Key words: Adenosine deaminase; Hepacivirus; Hepatitis B virus; Viral load Original Article J Microbiol Immunol Infect. 2007;40:288-292 Introduction Hepatitis B and C are diseases characterized by a high global prevalence, complex clinical course, and limited effectiveness of currently available antiviral therapy. Approximately 350 million people are infected with hepatitis B virus (HBV) worldwide, and the World Health Organization estimates that approximately 170 million people are infected with hepatitis C virus (HCV) [1,2]. HBV and HCV infections account for a substantial proportion of liver diseases worldwide. The most important biological characteristic of HBVs and HCVs is their ability to cause chronic hepatitis [3,4]. The natural course of HBV infection is variable, ranging from an inactive hepatitis B surface antigen (HBsAg) carrier state to the progressive chronic hepatitis that can evolve into liver cirrhosis and hepatocellular carcinoma [5]. HCV infection becomes chronic in 80% of infected individuals resulting in different degrees of chronic hepatitis, with 20-30% of these cases pro- gressing to cirrhosis within a period of 20 years [6]. The mechanisms involved in liver damage induced by viral hepatitis are not fully understood, though both viral and host factors are believed to be implicated. Liver lesions could be the result of immune responses or the cytopathic actions of the virus. Cytotoxic T cells and ·