Abe M
1st Department of Pathology, School of Medicine, Fukushima Medical University, Fukushima 960-1295.
Rinsho Byori. 2001 Aug;49(8):779-87.
In response to antigen stimulation, B cells undergo a germinal center(GC) reaction such as somatic hypermutations of the immunoglobulin variable region genes, which results in the production and selection of antigen-specific antibodies with increased affinity. Therefore, somatic hypermutations are considered to be a hallmark of GC B cells and their descendants. Pre-GC B cells(precursor B cells, immature B cells, naive B cells and CD5+ B cells) carry no somatic hypermutations, whereas GC B cells and post-GC B cells(memory B cells and plasma cells) express somatic hypermutations. This phenomenon is useful in identifying the cellular origin of various B-cell neoplasms. Precursor B-lymphoblastic leukemia/lymphoma, mantle cell lymphoma, and most B-CLL originate from pre-GC B cells, and follicular lymphoma, Burkitt's lymphoma, marginal zone B-cell lymphoma, diffuse large B-cell lymphoma and myeloma from GC B cells or post-GC B cells. Nodular lymphocyte-predominant Hodgkin's disease and most classical types of Hodgkin's disease are derived from GC B cells. Most human-B cell neoplasms including Hodgkin's disease are derived from GC B cells or their descendants. Molecular processes that modify the DNA of GC B cells, such as somatic hypermutation, class switching and receptor editing occur in the environment of the GCs, and increase the risk of malignant transformation.
针对抗原刺激，B细胞会经历生发中心（GC）反应，如免疫球蛋白可变区基因的体细胞超突变，这会导致产生并选择亲和力增加的抗原特异性抗体。因此，体细胞超突变被认为是GC B细胞及其后代的一个标志。前GC B细胞（前体B细胞、未成熟B细胞、初始B细胞和CD5+B细胞）不携带体细胞超突变，而GC B细胞和后GC B细胞（记忆B细胞和浆细胞）表达体细胞超突变。这种现象有助于识别各种B细胞肿瘤的细胞起源。前体B淋巴细胞白血病/淋巴瘤、套细胞淋巴瘤和大多数B细胞慢性淋巴细胞白血病起源于前GC B细胞，而滤泡性淋巴瘤、伯基特淋巴瘤、边缘区B细胞淋巴瘤、弥漫性大B细胞淋巴瘤和骨髓瘤起源于GC B细胞或后GC B细胞。结节性淋巴细胞为主型霍奇金病和大多数经典型霍奇金病源自GC B细胞。包括霍奇金病在内的大多数人类B细胞肿瘤源自GC B细胞或其后代。在生发中心环境中发生的改变GC B细胞DNA的分子过程，如体细胞超突变、类别转换和受体编辑，会增加恶性转化的风险。
