Detection of Immunoglobin Heavy Chain Gene Rearrangements in Nodular Lymphocyte Predominant Hodgkin Lymphoma Using Commercially Available BIOMED-2 Primers
WK Brix, GC Bullock, DM Haverstick, RM Seaner, LM Silverman, MS Mahadevan, JC Cousar. University of Virginia, Charlottesville, VA
Background: Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a clonal B-cell neoplasm. The differential diagnosis for NLPHL includes progressive transformation of germinal centers (PTGC), classical Hodgkin lymphoma (cHL) and reactive hyperplasia. As part of the Concerted Action project BIOMED-2 an extensively validated set of IgH and IgK multiplex PCR primers were developed and have high sensitivity for detecting clonality in a variety of B-cell non-Hodgkin lymphomas. Our laboratory previously evaluated the BIOMED-2 IgH assay in detecting clonality in cHL and detected clonality in 24% of cHL cases without prior microdissection. We hypothesize that this approach could be used to determine clonality in NLPHL.
Design: 10 NLPHL and 4 PTGC cases were selected. The densities of LP cells/10 hpf were classified as low (< or = 24/ 10 hpf) or high (>24/ 10 hpf). Background CD 20 positive cells were classified as predominantly B-cells or mixed B and T-cells. DNA from formalin-fixed, paraffin-embedded sections was subjected to PCR with the InVivoScribe IgH Gene Clonality Assay® followed by capillary electrophoresis and ABI Genescan® detection. Dominant peaks were clonal if >3x the height of the polyclonal background, and suspicious for clonality if between 2-3x.
Results: 2 of 10 (20%) of NLPHLs were clonal and in both cases clones were detected by primers that target D-J rearrangements. Clonality was associated with a high density of LP cells (>24/ 10 hpf). All cases of PTGC were negative.
Conclusions: BIOMED-2 IgH assay detected clonality in 20% of NLPHL without microdissection. All clones were detected by the primers that target D-J rearrangements suggesting that somatic hypermutation of IgH V regions may affect the ability to detect clones in NLPHL. Based on this finding we anticipate that the addition of the BIOMED-2 IgK primers may enhance sensitivity of clonality detection in NLPHL. In NLPHL, IGH gene rearrangement analysis may have limited use for diagnosis and discrimination from PTGC, but clonality cannot be used to discriminate between NLPHL, cHL and non-Hodgkin lymphomas.
Wednesday, March 24, 2010 9:30 AM
Poster Session V # 203, Wednesday Morning