[Explore the origin of H/RS cells on protein and gene]

To explore the origin and clonality of H/RS cells.Immunohistochemical method was used to detect the expression of B-cell-specific activator protein (BSAP) and CD(20) in 33 paraffin-embedded tissues of classical Hodgkin lymphoma (cHL). IgH gene rearrangement was detected in 33 paraffin-embedded cHL tissue and 6 microsectioned H/RS cell samples. The PCR products of a case of cHL and its microsectioned cells were sequenced.H/RS cells were positive for BSAP in 30 of 33 (90.91%) cHL cases and positive for CD(20) in 10/33 (30.30%) cases. There was a significant difference between the expression of BSAP and CD(20) in H/RS cells (P = 0.000). BSAP and CD(20) were positive in almost all B cells of lymph node reactive hyperplasia and malignant cells in B-cell lymphomas while were negative in all malignant cells of T-cell lymphomas. 16 of 33 cHL were positive for gene rearrangement, and microsectioned H/RS cells in 14 of 19 tubes displayed clonal bands of rearrangement. There was no significant difference among the rearrangement rates in tubes containing different numbers of H/RS cells (P = 0.280). Sequencing analyses of the PCR products from both paraffin-embedded tissue and microsection of the same patient revealed the rearranged V segments, but the sequences were not identical.H/RS cells were originated from B cells of different differentiation stage.