12. Chronic lymphocytic leukemia

Definition

• Chronic lymphocytic leukemia is a chronic lymphoproliferative disorder characterized by monoclonal B cell proliferation!
• Characterized by increased production of mature but dysfunctional B lymphocytes

Etiology

• Exact cause is unknown!
• Genetic factors are the most likely cause as opposed to environmental factors
• Risk factors:
• Occupational exposure to chemicals
• Radiation exposure
• Tobacco users

Pathogenesis

• The pathogenesis of CLL is a two-step process:
• The first step is the development of MBL cells secondary to multiple factors such as antigenic stimulation, genetic mutations, and cytogenetic abnormalities
• The second step is the progression of MBL to CLL by the further insult to the B-cell clone
• Either due to additional genetic abnormalities or changes in the bone marrow microenvironment

Symptoms

• Mean age of diagnosis is 72 years!
• 1/3 are asymptomatic!
• Enlargement of LN:
• Cervical
• Axillary
• Inguinal
• Features of anemia
• Fever
• Night sweats
• Weight loss
• Itching
• Patients with thrombocytopenia may show bruising or purpura
• Splenomegaly and hepatomegaly (less common)
• Immunosupression- bacterial infections predominate, viral (herpes) and fungal infections also seen