Monoclonal B‐cell lymphocytosis in first‐degree relatives of patients with sporadic (non‐familial) chronic lymphocytic leukaemia

• Published in: British journal of haematology Vol. 147; no. 3; pp. 339 - 346
• Main Authors: Matos, Daniel M., Ismael, Sebastião J., Scrideli, Carlos A., De Oliveira, Fábio M., Rego, Eduardo M., Falcão, Roberto P.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.11.2009; Blackwell
• Subjects: Adult; Age Distribution; Aged; B cells; B-Lymphocytes; Biological and medical sciences; Brazil - epidemiology; Chromosome Aberrations; chronic lymphocytic leukaemia; Female; first‐degree relatives; Flow Cytometry; Follow-Up Studies; Gene Rearrangement, B-Lymphocyte; Hematologic and hematopoietic diseases; Humans; Immunomagnetic Separation - methods; In Situ Hybridization, Fluorescence; Leukemia, Lymphocytic, Chronic, B-Cell - epidemiology; Leukemia, Lymphocytic, Chronic, B-Cell - genetics; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymphocytosis - epidemiology; Lymphocytosis - genetics; Male; Medical sciences; Middle Aged; monoclonal B‐cell lymphocytosis; Prevalence; Sex Distribution; Brazil; Human; Flow cytometry; Hematology; Sporadic; monoclonal B-cell lymphocytosis; Malignant hemopathy; Hemopathy; B-Lymphocyte; B cells; first-degree relatives; Chronic lymphocytic leukemia; chronic lymphocytic leukaemia; Lymphoproliferative syndrome; Lymphocytosis; Cancer; First degree relative
• ISSN: 0007-1048; 1365-2141
• DOI: 10.1111/j.1365-2141.2009.07861.x

Summary Although biological similarities have been described among monoclonal B‐cell lymphocytosis (MBL) and chronic lymphocytic leukaemia (CLL), the relationships between these two conditions are not fully understood, and new epidemiological studies in different populations and different countries continue to be reported. Here, we investigated 167 first‐degree relatives from 42 families of patients with non‐familial (sporadic) CLL, using four‐colour flow cytometry. MBL was found in seven of 167 subjects (4·1%). Monoclonality was detected in all cases either by light‐chain restriction or by polymerase chain reaction. Fluourescence in situ hybridization did not show any chromosomal abnormality. The prevalence of MBL according to age was 0 (0/54) in individuals aged less than 40 years, 2·5% (2/81) between 40 and 60 years, and 15·6% (5/32) in individuals over 60 years. The prevalence of MBL cases in individuals over 60 years was similar to that found in familial CLL relatives at the same age group. This suggests that in older first‐degree relatives of patients with sporadic CLL, the risk of MBL detection is as high as in older first‐degree relatives from CLL families, which could render these individuals belonging to ‘sporadic CLL families’ as susceptible as individuals from ‘familial CLL’ to the development of clinical CLL.