The Incidence of Hepatitis B in Diffuse Large B-Cell Lymphoma/Chronic Lymphoid Leukemia HBsAg-positive Treated With Rituximab, Chemotherapy and Tenofovir Alafenamide

Inclusion Criteria:

* Signed written informed consent according to ICH/EU/GCP and national local laws.
* Male/non-pregnant/non-lactating female subjects \>18 years old with newly diagnosed DLBCL/Chronic Lymphoid Leukemia who are going to receive treatment with rituximab in combination with chemotherapy.
* HBsAg positivity, serum HBV-DNA negative or positive (\<2000/IU), and normal liver function, including alanine aminotransferase(ALT), aspartate aminotransferase(AST) and bilirubin. (inactive carriers).
* No previous treatment with antiviral drugs for HBV infection.
* Patients with satisfactory renal function.

Exclusion Criteria:

* Hepatic insufficiency for any reason
* History of other liver diseases such as hepatitis C, D, autoimmune hepatitis, primary biliary cirrhosis, Wilsons' disease
* Positive viral markers, such as IgM antibody to hepatitis A virus, hepatitis C virus, IgG antibody to hepatitis D virus, IgM antibody to hepatitis E virus, or antibody to HIV
* Pregnant or breastfeeding women
* Other major systemic diseases, such as active infection, significant cardiac disease, neurological deficit or psychiatric disorder, that the investigators consider being a significant risk
* Patients with moderate or severe renal failure.
* Intolerance to any of the components of the therapeutic regimen. Treatment with any investigational medicinal product (unapproved) in the last 30 days.
* Any other disorder that, in the investigator's opinion, makes the patient ineligible for recruitment or that could interfere in his/her participation or in the conclusion of the study.