Monoclonal B lymphocytosis
From haematologyetc.co.uk
Monoclonal B-lymphocytosis (MBL) as a distinct entity recognised in the WHO Classification and used to denote the presence of abnormal conal B-cells that do not meet the diagnostic criteria for CLL or other LPD based. It is an important distinction since affected individaual are not regarded as having a lymphoproliferative disorder, although they may experience some symptoms, and the disease may progress.
The diagnosis is suggested from flow cytometry of blood, but always requires clinical confirmation - it is important that reports reflect the need for additional clinical conformation.
Diagnosis is made from blood assessment and is based on the following criteria:
'1. Flow cytometry defined features:
- Evidence that there is a monoclonal population of B lymphocytes (this can be based on their light chain retriction or abnormal phenotype features)
- A profile of flow cytometric profile that suggests either CLL or other LPD
- A count of abnormal cells that is <1x109 for the abnormal poulation (ideally inferred from flow cytometry and absolute lymphocyte count
2. Clinical evidence that there is no significant tissue disease:
- No evidence of lymph node enlargment or other significant tissue involvements by the abnormal cells
- No other features suggesting an active B-lymphoproliferative disease or lymphoma