Correlation between presence of clonal rearrangements of immunoglobulin heavy chain genes and B-cell antigen expression in Hodgkin's disease

Southern blot analysis of Hodgkin's disease (HD), although often compromised by the small number of abnormal cells present in the tissue, have tended to favor a B-cell derivation of the Hodgkin's and Reed-Sternberg (HRS) cells in cases of nodular sclerosis (NS) and mixed cellularity (MC) Hodgkin's disease. Eighteen frozen and 29 paraffin-embedded sections of lymph node specimens from 29 patients with pretreatment HD (22 NSHD and 7 MCHD) were studied by molecular analysis and immunohistochemistry to determine the phenotype of HRS cells. All cases were reviewed and showed typical morphology and CD45-, CD30+, CD15+, BLA.36+ HRS cells. In 11 of 29 (38%) cases, HRS cells were reactive with at least one B-cell marker (CD20, CD79a, MB2), 7 of 29 (24%) cases showed reactivity with the T-cell marker CD3, and 11 of 29 (38%) cases displayed a "null" phenotype. By using a polymerase chain reaction (PCR) and consensus primers for the V and J regions of the immunoglobulin heavy chain (IgH) gene, the authors were able to detect B-cell clonality in 9 of 18 (50%) frozen samples of HD analyzed. IgH gene rearrangement was present in 8 of 15 (53%) NSHD and in 1 of 3 (33%) MCHD. In five of nine (56%) of these cases, HRS cells were reactive with at least one B-cell marker, whereas one case expressed the T-cell marker CD3. The other three cases with IgH gene rearrangement showed a "null" immunophenotype. IgH gene analysis was negative in all remaining CD3+ cases and in two other cases that expressed B-cell markers by immunohistology. Southern blotting failed to detect rearrangement of the T-cell receptor beta-chain gene and immunoglobulin heavy and light genes in any of these cases. The results show that PCR represents a specific and sensitive technique for the detection of IgH gene rearrangements in cases of Hodgkin's disease. The results also suggest a lymphoid B-cell derivation of HRS cells in a high proportion of the cases.