Whilst very low-depend MBL rarely progresses to CLL, large-depend MBL progresses to CLL requiring therapy in a charge of 1% to 2% annually. Large-depend MBL is distinguished from Rai 0 CLL according to if the B-cell count is over or below 5 × 109/L. Whilst individuals with the two superior-count MBL and CLL Rai stage 0 are at elevated threat of in