Billadeau D, Ahmann G, Greipp P, Van Ness B
Department of Biochemistry, University of Minnesota, Minneapolis 55455.
J Exp Med. 1993 Sep 1;178(3):1023-31. doi: 10.1084/jem.178.3.1023.
One of the distinguishing features of multiple myeloma (MM) is the proliferation of a clonal plasma cell population in the bone marrow (BM). It is of particular interest that the tumor plasma cells appear to be restricted to the microenvironment of the BM and are rarely detected in the peripheral system, yet the disease is found widely disseminated throughout the axial skeleton. Furthermore, isolation of MM tumor cell lines has proven to be quite problematic due to their slow growth rate. These observations have instigated the search for earlier cells in the B cell lineage that are clonally related to the plasma cell tumor and that may represent the growth fraction of the tumor. We used allele-specific oligonucleotides (ASO) derived from the third complementarity determining region of the rearranged tumor immunoglobulin heavy chain gene to detect isotypes clonally related to the plasma cell tumor. By reverse transcribing RNA from the BM with a panel of CH primers (mu, delta, alpha, and gamma), followed by ASO-polymerase chain reaction amplification, we demonstrate the existence of preswitch isotype species that are clonally related to the myeloma tumor. Furthermore, we show that separation of the BM cells into CD45+ and CD38+ cell populations results in a lineage-specific expression of the clonally related RNA molecules, with the C mu and C delta in the CD45+, and C gamma in the CD38+ population. Interestingly, clonally related C alpha transcripts are also derived from the CD45+ fraction. These results confirm the presence of B cell populations clonally related to the plasma cell tumor and are consistent with models that propose the existence of myeloma precursors.
多发性骨髓瘤（MM）的一个显著特征是骨髓（BM）中克隆性浆细胞群体的增殖。特别值得关注的是，肿瘤浆细胞似乎局限于骨髓的微环境中，在外周系统中很少被检测到，然而该疾病却广泛分布于整个中轴骨骼。此外，由于MM肿瘤细胞系生长缓慢，其分离已被证明是相当困难的。这些观察结果促使人们寻找B细胞谱系中与浆细胞瘤克隆相关且可能代表肿瘤生长部分的早期细胞。我们使用源自重排的肿瘤免疫球蛋白重链基因第三互补决定区的等位基因特异性寡核苷酸（ASO）来检测与浆细胞瘤克隆相关的同种型。通过用一组CH引物（μ、δ、α和γ）从骨髓中逆转录RNA，然后进行ASO-聚合酶链反应扩增，我们证明了存在与骨髓瘤肿瘤克隆相关的转换前同种型。此外，我们表明将骨髓细胞分离为CD45 +和CD38 +细胞群体导致克隆相关RNA分子的谱系特异性表达，CD45 +群体中为Cμ和Cδ，CD38 +群体中为Cγ。有趣的是，克隆相关的Cα转录本也源自CD45 +部分。这些结果证实了存在与浆细胞瘤克隆相关的B细胞群体，并且与提出骨髓瘤前体存在的模型一致。
