The biological and clinical relationship between CD5+23+ monoclonal B-cell lymphocytosis and chronic lymphocytic leukaemia

Br J Haematol. 2007 Dec;139(5):724-9. doi: 10.1111/j.1365-2141.2007.06863.x.


A CD5(+)23(+) monoclonal B-cell population is detectable in approximately 3% of the general adult population. The phenotype of the monoclonal CD5(+)23(+) B cells is identical to chronic lymphocytic leukaemia (CLL) with respect to a large number of proteins in addition to the standard diagnostic markers used to identify CLL. Studies in CLL families and direct assessment of genetic features indicate a close biological association between indolent CLL and the CLL-phenotype cells detected in individuals with a normal blood count. Patients with a CLL-phenotype monoclonal B-cell lymphocytosis (MBL) often have increasing CLL cell counts with time and some progress to a stage requiring treatment. Analysis of intraclonal variation in the immunoglobulin heavy chain gene suggests a process of clonal diversification rather than clonal selection in the early stages of disease progression. CLL-phenotype MBL is detectable in approximately 10% of cases referred for investigation of a lymphocytosis and future studies should be directed towards the detection of factors which identify MBL patients at risk of disease progression.

Publication types

  • Review

MeSH terms

  • Adult
  • B-Lymphocytes / immunology*
  • CD5 Antigens / blood
  • Chromosome Aberrations
  • Disease Progression
  • Gene Expression Profiling
  • Genetic Predisposition to Disease
  • Humans
  • Leukemia, Lymphocytic, Chronic, B-Cell / genetics*
  • Lymphocytosis / genetics*
  • Middle Aged
  • Receptors, IgE / blood


  • CD5 Antigens
  • Receptors, IgE