Biological and Clinical Efficacy of Shingrix in Patients With CLL

Inclusion Criteria: * Diagnosis of CLL or small lymphocytic lymphoma (SLL) or CLL-like MBL according to IWCLL guidelines. Patients must belong to one of the following subgroups: * Group A: Patients with MBL or previously untreated early-phase CLL/SLL (Binet stage A or RAI stage 0), with no clear signs of disease progression; * Group B: Patients with active or symptomatic disease according to IWCLL guidelines or with advanced Binet or Rai stages receiving both the first and second vaccine doses before treatment initiation; * Group C: Patients with CLL/SLL receiving targeted drugs (i.e. ibrutinib/acalabrutinib-based treatment or venetoclax-based treatment) for at least 6 months prior to the administration of the first vaccine dose. * Age 18 years or older * Eligible to receive Shingrix according to clinical indication and free of charge through the Italian National Health System * Life expectancy \>6 months * No active, symptomatic herpes zoster infection or varicella-zoster virus reactivation within 12 months prior to vaccination * No prior exposure to Shingrix * Able and willing to provide written informed consent and to comply with the study protocol procedures Exclusion Criteria: * Female patients who are currently in pregnancy or are willing to be pregnant * Any uncontrolled active systemic infection * Intravenous immunoglobulin (IVIG) administration within 3 months prior to vaccination * Concomitant use of radiotherapy or chemotherapy * Hereditary or acquired immunodeficiency syndrome unrelated to CLL * Chronic use of immunosuppressive medications given for indications that are not CLL-related