Publication Date:
2012-11-16
Description:
Abstract 2883 CLL-like monoclonal B-cell lymphocytosis (MBL) shares common immunophenotypic features and cytogenetic abnormalities with CLL and is generally perceived as its premalignant state. The World Health Organization has set a consensus cut-off of 5×109/L circulating B cells to discriminate between what constitutes ‘disease’ and what not. However, the clonal size within MBL is extremely variable. High-count (HC), clinical MBL is associated with absolute lymphocytosis and progresses to CLL requiring treatment at a rate of 1–2% per year, whereas low-count (LC) MBL is found in the general population through high-sensitivity techniques and carries a risk of progression that is limited if any. Given the high frequency of CLL-like MBL in the general population, it is important to understand the underlying mechanisms and also identify biological markers endowing malignant potential that may distinguish between the different forms. To this end, we performed a detailed immunogenetic profiling of 334 CLL-like MBL cases (78 LC and 256 HC) for a total of 355 productive VDJ rearrangements (including double rearrangements), 91 from LC MBL and 264 from HC MBL. We also compared the immunoglobulin (IG) gene repertoires of MBL to 544 CLL Rai Stage 0 (CLL-0) that were part of an IG sequence dataset of 7424 CLL cases previously analyzed by our group. LC and HC MBL had distinct IG gene repertoires, with over-representation of the IGHV1–69 and IGHV4–34 genes in HC and the IGHV4–59/61 genes in LC MBL, respectively (p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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