Laboratory of Pathology, Department of Pathology, Molinette Hospital, via Santena 7, Turin, Italy.
Int J Hematol. 2010 Jul;92(1):198-203. doi: 10.1007/s12185-010-0631-8. Epub 2010 Jun 25.
We report two cases of diffuse large B cell lymphoma (DLBCL), both occurring in the small bowel, which coexpress PAX5, weak or no CD20 and the CD4 antigen. The CD4 was initially identified by flow cytometry and then confirmed by immunohistochemistry. CD4 is a representative marker for helper T-lymphocytes and is present on a subset of thymocytes, peripheral T cells and monocytes or macrophages. Unlike CD2 and CD5, no B cell fractions are known to express CD4. It might be hypothesized that the deregulated control of gene expression in malignant B cells, in particular PAX5, leads to the activation of some silent or repressed genes of T cell differentiation. Although lineage infidelity is described in some B lymphomas, it remains as an uncommon phenomenon; to our knowledge, cases reported here are the first two cases of DLBCL of the gastrointestinal tract coexpressing the CD4 antigen to be described to date.
我们报告了两例弥漫性大 B 细胞淋巴瘤（DLBCL），均发生于小肠，这两种肿瘤均同时表达 PAX5、弱阳性或无 CD20 和 CD4 抗原。CD4 最初是通过流式细胞术鉴定的，然后通过免疫组织化学进一步证实。CD4 是辅助性 T 淋巴细胞的代表性标志物，存在于部分胸腺细胞、外周 T 细胞和单核细胞或巨噬细胞中。与 CD2 和 CD5 不同，已知没有 B 细胞亚群表达 CD4。可以假设恶性 B 细胞中基因表达的调控失调，特别是 PAX5 的调控失调，导致一些 T 细胞分化的沉默或抑制基因的激活。尽管在一些 B 淋巴瘤中描述了谱系不忠实，但它仍然是一种罕见的现象；据我们所知，这里报告的病例是迄今为止描述的首例同时表达 CD4 抗原的胃肠道弥漫性大 B 细胞淋巴瘤。
