retrospective and prospective multicenter observational clinical and biological data collection from all patients with newly diagnosed CLL, SLL or MBL.

retrospective cohort: all cases with a diagnosis between January 1st 2010 and August 31th 2021.

prospective cohort: all patients with a diagnosis between September 1st 2021 and September 1st 2025.

This is a retrospective and prospective multicenter observational study designed by the Gruppo Italiano Malattie EMatologiche dell'Adulto (GIMEMA). The study consists of clinical and biological data collection from all patients with newly diagnosed CLL, SLL or MBL (according to the WHO 2007 and 2018 diagnostic criteria). The retrospective part aims at including all cases followed at participating centers with a diagnosis between January 1st 2010 and August 31th 2021 (planned study initiation), while the prospective part will include all patients with a documented diagnosis of CLL, SLL or MBL between September 1st 2021 and September 1st 2025 by the first immunophenotypic/histological evaluation. The data is collected through electronic case report form accessible by the participating centers on a dedicated platform.

Inclusion Criteria:

1. Age ≥18 years at diagnosis

2. One of the following diagnoses that meet the international diagnostic criteria (iwCLL2018 and WHO2017)

   1. Chronic lymphocytic leukemia (CLL)
   2. Small lymphocytic lymphoma (SLL)
   3. CLL-like monoclonal B-cell lymphocytosis (MBL)

3. Retrospective cohort: CLL/SLL/MBL diagnosis between January 1st 2010 and August 31th 2021.

4. Prospective cohort: CLL/SLL/MBL diagnosis between September 1st 2021 and September 1st, 2025.

5. Signed written informed consent according to ICH/EU/GCP and national local laws (if applicable)

Exclusion Criteria:

• - -

All patients with CLL/SLL or MBL diagnosis followed at participant sites starting from January 1st, 2010 (retrospective cohort) and from September 1st, 2021 (prospective cohort).