Overexpression of RHAMM^FL and RHAMM⁻⁴⁸ from MM B and plasma cells, B-lymphoma, and B-CLL, as compared with normal B cells and chronically activated B cells from patients with Crohn’s disease. (A) RHAMM^FL and RHAMM⁻⁴⁸ were amplified by RT-PCR from 500 ng of RNA from the B cells of 6 myeloma patients (a, b, c, d, e, f), the BM plasma cells of 5 myeloma patients (g, h, I, j, k), and the pooled B cells from 2 patients with Crohn’s disease (lane l). The same quantity of RNA (500 ng) and cDNA (5 μL) was used in the RT-PCR step for all cell populations analyzed so that the level of RHAMM expression could be compared between the different cell populations in the figure. The quality of RNA isolated from all B-cell populations was comparable as determined by amplification of CD19 transcripts from a separate aliquot of the same cDNA (5 μL) from which RHAMM was amplified (data not shown). A 613-bp fragment was amplified for RHAMM^FL and a 565-bp fragment for RHAMM⁻⁴⁸. (B) RHAMM^FL and RHAMM⁻⁴⁸ were amplified by RT-PCR from 500 ng of RNA from the malignant lymph nodes of 3 patients (m, n, o), the PBMC of 3 CLL patients (p, q, r), the B cells of 3 normal individuals (s, t, u), and the B cells from a patient with Crohn’s disease (v). The same quantity of RNA (500 ng) and cDNA (5 μL) was used in the RT-PCR step for all cell populations analyzed so that the level of RHAMM expression could be compared between the different cell populations in the figure. The quality of RNA isolated from all B-cell populations was comparable as determined by amplification of CD19 transcripts from a separate aliquot of the same cDNA (5 μL) from which RHAMM was amplified (data not shown). (C) Shows that the amplification product in A, from the BM plasma cells of patients g, h, I, j, and k, resolves into RHAMM^FL and RHAMM⁻⁴⁸. The amplification products were analyzed by gel electrophoresis and visualized by ethidium bromide staining.