Treatment for chronic hepatitis B infection (HBV) is targeted at suppressing viral replication and inflammation as well as promoting immune control of viremia. Successful treatment of chronic viral hepatitis relies on the understanding of intrahepatic immune components. Previous studies have shown that intrahepatic immune responses are predictive of natural history and treatment outcomes. Liver-specific immune responses (intra-hepatic immunity) do not correspond to the peripheral components of the immune system (peripheral blood immunity) in chronic hepatitis and likely are more relevant to liver pathology. Thus, peripheral blood mononuclear cells (PBMCs) are insufficient to characterize the intrahepatic and overall relevant immune responses. Currently, liver biopsies are the only means for acquiring liver tissue samples for monitoring intrahepatic conditions. Standard liver biopsies are painful, invasive, and cannot be repeated at frequencies that are necessary for direct observation of liver conditions. We are proposing to use fine needle aspiration biopsy (FNAB) as a minimally invasive procedure for regular monitoring of intrahepatic conditions throughout different disease and treatment stages of chronic HBV infection. A fine needle aspiration biopsy (FNAB) is a simple and quick procedure that is regularly used for sampling superficial solid tumors or cysts. FNAB is also routinely applied for following up the conditions of transplanted organs or tissues (liver, kidney). FNAB has been successfully used for studying the intrahepatic components of anti-HCV and anti-HBV immune responses. The advantages of FNAB that make it a suitable procedure for studying intrahepatic environment are: 1) Minimal invasiveness; 2) Minimum risk; 3) Can be applied multiple times; 4) Good sample quality. Hypothesis: FNAB can be used regularly as a non-invasive procedure to directly investigate and monitor the intrahepatic immune components during different stages of chronic HBV infection and treatment. Study Aims: This study aims at achieving these objectives: - Evaluating the immune profile of the liver- Comparing the intrahepatic immune profile to peripheral blood - Determining the association of intrahepatic immunocyte profiles with different stages of the disease and treatment. These data will be used to develop diagnostic and predictive criteria for different stages of the diseases and treatments. Study design: Patients between the ages of 18 and 70 that were screened and enrolled in at least one of HBRN studies that agree and consent to the FNAB procedure will be considered for the study. Patients with low levels of platelet count, or hemoglobulin, and patients under anticoagulation treatment or end- stage renal diseases will be excluded.