BACKGROUND T-cell/histiocyte rich large B-cell lymphoma (THRLBCL) is B-cell lymphoma in which rare neoplastic cells are embedded in a reactive infiltrate. We describe the first characterization of the neoplastic cells by flow cytometry (FC). METHODS Using FC, we immunophenotyped the neoplastic cells of 11 cases of THRLBCL and 11 cases of DLBCL, NOS (controls). Neoplastic THRLBCL cells were also purified by flow cytometric cell sorting (FCCS). RESULTS A neoplastic THRLBCL population was detected by FC in 9 of 11 cases (82%). Neoplastic THRLBCL cells demonstrated an aberrant germinal center B-cell immunophenotype (bright CD20, bright CD40; positive for Bcl-6 and CD75; weakly positive for CD32; negative for IgH). With regard to adhesion molecules, CD54 was overexpressed, CD58 expression varied between cases, and CD50 expression was intermediate. Evaluation of immunomodulatory receptors demonstrated that PD-L2 was weakly expressed and PD-L1 was variably expressed. Finally, FCCS of two cases showed large multi-lobated cells with morphology consistent with neoplastic cells of THRLBCL. CONCLUSIONS The immunophenotype identified and the morphology of the FCCS purified cells confirms the FC defined populations are neoplastic cells from THRLBCL. While the cohort is small, neoplastic THRLBCL cells lack surface immunoglobulins. CD40, CD50, and CD54 were overexpressed in THRLBCL relative to DLBCL, NOS, perhaps contributing to the predominance of T cells in THRLBCL. Expression of CD32, PD-L1, and PD-L2 may be useful in distinguishing THRLBCL and NLPHL. Finally, the FC assays will be useful for purifying neoplastic cells of THRLBCL and for diagnostic immunophenotyping of THRLBCL. © 2019 International Clinical Cytometry Society.

中文翻译：

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流式细胞术和流式细胞术分选的肿瘤细胞的免疫表型特征和纯化涉及的淋巴结中的T细胞/富含富集细胞的大B细胞淋巴瘤。

背景技术富含T细胞/组织细胞的大B细胞淋巴瘤（THRLBCL）是B细胞淋巴瘤，其中罕见的赘生性细胞包埋在反应性浸润物中。我们描述了流式细胞仪（FC）的肿瘤细胞的第一个特征。方法我们使用FC对11例THRLBCL和11例DLBCL，NOS（对照）的肿瘤细胞进行免疫表型分析。还通过流式细胞术分选术（FCCS）纯化了肿瘤性THRLBCL细胞。结果11例病例中有9例通过FC检测到了肿瘤性THRLBCL人群（82％）。肿瘤性THRLBCL细胞表现出异常的生发中心B细胞免疫表型（明亮的CD20，明亮的CD40；对Bcl-6和CD75呈阳性；对CD32呈弱阳性；对IgH呈阴性）。关于粘附分子，CD54过表达，CD58表达在不同病例之间变化，并且CD50表达是中等的。免疫调节受体的评估表明PD-L2弱表达，PD-L1可变表达。最后，两个病例的FCCS显示大的多叶细胞，其形态与THRLBCL的赘生性细胞一致。结论鉴定出的免疫表型和FCCS纯化细胞的形态证实了FC定义的群体是来自THRLBCL的赘生性细胞。尽管队列很小，但肿瘤性THRLBCL细胞缺乏表面免疫球蛋白。相对于DLBCL，NOS，THRLBCL中CD40，CD50和CD54的表达过高，这可能是THRLBCL中T细胞占优势的原因。CD32，PD-L1和PD-L2的表达可能有助于区分THRLBCL和NLPHL。最后，FC测定法对于纯化THRLBCL的赘生性细胞和THRLBCL的诊断免疫表型将是有用的。