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BioMed Research International
Volume 2014, Article ID 809103, 6 pages
http://dx.doi.org/10.1155/2014/809103
Research Article

Clonotypic Analysis of Immunoglobulin Heavy Chain Sequences in Patients with Waldenström’s Macroglobulinemia: Correlation with MYD88 L265P Somatic Mutation Status, Clinical Features, and Outcome

Hematology Section of First Department of Propaedeutic Medicine, National and Kapodistrian University of Athens Medical School, Laikon Hospital, Agiou Thoma 17, 11527 Athens, Greece

Received 18 April 2014; Accepted 12 July 2014; Published 14 August 2014

Academic Editor: Gerassimos Pangalis

Copyright © 2014 Loizos Petrikkos et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We performed IGH clonotypic sequence analysis in WM in order to determine whether a preferential IGH gene rearrangement was observed and to assess IGHV mutational status in blood and/or bone marrow samples from 36 WM patients. In addition we investigated the presence of MYD88 L265P somatic mutation. After IGH VDJ locus amplification, monoclonal VDJ rearranged fragments were sequenced and analyzed. MYD88 L265P mutation was detected by AS-PCR. The most frequent family usage was IGHV3 (74%); IGHV3-23 and IGHV3-74 segments were used in 26% and 17%, respectively. Somatic hypermutation was seen in 91% of cases. MYD88 L265P mutation was found in 65,5% of patients and absent in the 3 unmutated. These findings did not correlate with clinical findings and outcome. Conclusion. IGH genes’ repertoire differed in WM from those observed in other B-cell disorders with a recurrent IGHV3-23 and IGHV3-74 usage; monoclonal IGHV was mutated in most cases, and a high but not omnipresent prevalence of MYD88 L265P mutation was observed. In addition, the identification of 3 patients with unmutated IGHV gene segments, negative for the MYD88 L265P mutation, could support the hypothesis that an extra-germinal B-cell may represent the originating malignant cell in this minority of WM patients.