Chronic Lymphocytic Leukemia (CLL)

Chronic lymphocytic leukemia (CLL) is a slow-growing type of blood cancer that primarily affects blood-forming tissues in the bone marrow. B lymphocytes, also called B cells, are a type of white blood cell that normally helps the immune system fight off infection. CLL occurs when the body produces too many abnormal (cancerous) B cells that crowd out the healthy white blood cells, causing bone marrow failure.