The purpose of the present study is to develop a biological prognostic index in patients with Binet stage A Chronic Lymphocytic Leukemia (CLL) who do not necessitate therapy according to NCI guidelines and to prospectively validate the proposed score system based on the absence/presence of 1, 2 or 3 unfavorable prognostic markers such as cluster of differentiation 38 (CD38) expression, Zap-70 expression and immunoglobulin heavy chain variable region (IgVH) configuration.

Clinical data including information on disease localization and laboratory parameters will be collected at study entry, during follow up and at disease progression (or after 36 months after registration) Biological markers will be evaluated at centralized laboratory, at study entry and at time of disease progression (or after 24 months of follow-up for non progressed patients) Using the scoring system, patients can be separated into 3 risk groups: low-risk (score 0), intermediate-risk (score 1) and high-risk (score 2-3), with significantly different clinical courses.

Inclusion Criteria:

• Established diagnosis of B-CLL by NCI criteria, performed by local haematologist. (Diagnosis will be confirmed by the biological review committee according to flow cytometry analysis (positive clusters of differentiation antigen 5 (CD5), 19 (CD19),23 (CD23)).
• Age > 18 years and < 70 years.
• Eastern Cooperative Oncology Group (ECOG)<=2.
• Binet stage A.
• Diagnosis performed within 12 months before inclusion in the study.
• Patients who do not necessitate therapy by NCI guidelines (watch and wait policy).
• Shipment of peripheral blood sample to centralized laboratory for biological assessment.
• Clinical data including baseline information on disease localization and laboratory parameters at staging and assurance of follow up updating for at least 3 years are requested.
• Written informed consent.

Exclusion Criteria:

• Patients with CLL whose diagnosis exceed 12 months before registration.
• Patients with leukemic phase of lymphoproliferative disorders of B origin CD5- and/or CD23- according to flow cytometry analysis.
• Clinical Binet stage B or C.
• Patients who necessitate therapy according to NCI guide-lines (no watch and wait policy).
• Age > 70 years.
• Without a written informed consent.

Previously untreated Binet stage A B-CLL patients, who do not necessitate therapy according to NCI guidelines