Detection of Immunoglobulin Heavy Chain Gene Rearrangements in Classic Hodgkin Lymphoma Using Commercially Available BIOMED-2 Primers

Abstract

Classic Hodgkin lymphoma (cHL) is regarded as a clonal B-cell neoplasm. The BIOMED-2 group recently validated a set of immunoglobulin heavy chain (IGH) multiplex primers with high sensitivity in B-cell non-Hodgkin lymphomas. We postulated that after using these primers, a higher proportion of the cHLs would have detectable rearrangements without microdissection. Forty-two patients with cHL were selected. The densities of Reed-Sternberg cells/10 high-power field and CD30+ cells/10 high-power field were classified as low, intermediate, or high. The quantities of background CD20+ B cells were classified as low or high. DNA from formalin-fixed, paraffin-embedded sections was used to perform polymerase chain reactions with the InVivoScribe IGH Gene Clonality Assay for ABI detection. Dominant peaks were considered to be monoclonal if they were >3x the height of the polyclonal background, and borderline monoclonal if between 2 and 3x. Overall, 10/42 (24%) of the cHL samples were monoclonal, and 7/42 (17%) were borderline monoclonal. Higher densities of CD30+ cells and lower background B cells were statistically correlated with clonality. The BIOMED-2 primers demonstrate IGH gene clonality in 24% to 40% of cHLs without microdissection. In a subset of the cHL, the IGH gene rearrangement analysis might be useful for diagnosis, but can lead to confusion between cHLs and non-Hodgkin lymphomas if used as a discriminative criterion.