Chronic Lymphocytic Leukaemia (CLL)

Chronic lymphocytic leukaemia (CLL) is caused by a monoclonal proliferation of well-differentiated lymphocytes which are almost always B-cells (99%). It is the most common form of leukaemia seen in adults.

Features

• often none: may be picked up by an incidental finding of lymphocytosis
• constitutional: anorexia, weight loss
• bleeding, infections
• lymphadenopathy more marked than chronic myeloid leukaemia

Investigations

• full blood count:
  • lymphocytosis
  • anaemia: may occur either due to bone marrow replacement or autoimmune hemolytic anaemia (AIHA)
  • thrombocytopenia: may occur either due to bone marrow replacement or immune thrombocytopenia (ITP)
• blood film: smudge cells (also known as smear cells)
• immunophenotyping is the key investigation
  • most cases can be identified using a panel of antibodies specific for CD5, CD19, CD20 and CD23

Peripheral blood film showing smudge B cells

Complications

• anaemia
• hypogammaglobulinaemia leading to recurrent infections
• warm autoimmune haemolytic anaemia in 10-15% of patients
• transformation to high-grade lymphoma (Richter's transformation)

Richter's transformation

Richter’s transformation occurs when leukaemia cells enter the lymph node and change into a high-grade, fast-growing non-Hodgkin's lymphoma. Patients often become unwell very suddenly.

Richter’s transformation is indicated by the following symptoms: