Occurs where there is chronic proliferation of a single type of well differentiated lymphocyte, usually B-lymphocytes
Aetiology
Usually affects adults over 55 years of age
Clinical features
Often asymptomatic
Can present with infections, anaemia, bleeding, and weight loss
Can cause warm autoimmune haemolytic anaemia
Investigations
Bloods:
Blood count: Hb normal or low; ↑WCC and may be very high; platelets normal or low
Blood film: ↑lymphocytes, i.e. > 5×109/L
May show ‘smear’ or ‘smudge’ cells - occur during the process of preparing the blood film where aged or fragile white blood cells rupture and leave a smudge on the film
Bone marrow:
Similar to peripheral blood; may be heavily infiltrated with lymphocytes
Immunophenotyping - mainly CD19/20 and CD5 B cells which may weakly express surface immunoglobulins
Cytogenetics - e.g. deletion of 13q (most common), trisomy 12
Bone marrow aspiration and biopsy with flow cytometry is not required in all cases of CLL, but may be necessary in some instances to establish a diagnosis and assess other complicating factors such as anaemia and thrombocytopaenia
Others
Coombs’ test - may be positive if there is haemolysis
Immunoglobulins - may be low or normal
Management
Depends on the stage of the disease
Chemotherapeutic interventions in early-stage disease is not usually necessary
Absolute indications for treatment include weight loss of more than 10% over 6 months, night sweats for longer than 1 month, and progressive marrow failure (anaemia or thrombocytopenia)