The diagnosis of leukemic T-cell malignancies is often challenging, due to overlapping features with reactive T-cells and limitations of currently available T-cell clonality assays. Recently developed therapeutic antibodies specific for the mutually exclusive T-cell receptor constant β chain (TRBC)1 and TRBC2 isoforms provide a unique opportunity to assess for TRBC-restriction as a surrogate of clonality in the flow cytometric analysis of T-cell neoplasms. To demonstrate the diagnostic utility of this approach, we studied 164 clinical specimens with (60) or without (104) T-cell neoplasia, in addition to 39 blood samples from healthy donors. Dual TRBC1 and TRBC2 expression was studied within a comprehensive T-cell panel, in a fashion similar to the routine evaluation of kappa and lambda immunoglobulin light chains for the detection of clonal B-cells. Polytypic TRBC expression was demonstrated on total, CD4⁺ and CD8⁺ T-cells from all healthy donors; and by intracellular staining on benign T-cell precursors. All neoplastic T-cells were TRBC-restricted, except for 8 cases (13%) lacking TRBC expression. T-cell clones of uncertain significance were identified in 17 samples without T-cell malignancy (13%) and accounted for smaller subsets than neoplastic clones (median: 4.7 vs. 69% of lymphocytes, p < 0.0001). Single staining for TRBC1 produced spurious TRBC1-dim subsets in 24 clinical specimens (15%), all of which resolved with dual TRBC1/2 staining. Assessment of TRBC restriction by flow cytometry provides a rapid diagnostic method to detect clonal T-cells, and to accurately determine the targetable TRBC isoform expressed by T-cell malignancies.

由于与反应性 T 细胞的重叠特征以及当前可用的 T 细胞克隆性测定的局限性，白血病 T 细胞恶性肿瘤的诊断通常具有挑战性。最近开发的针对相互排斥的 T 细胞受体恒定 β 链 (TRBC)1 和 TRBC2 亚型的特异性治疗抗体，为评估 TRBC 限制性作为 T 细胞肿瘤流式细胞术分析中克隆性的替代物提供了独特的机会。为了证明这种方法的诊断效用，除了来自健康捐献者的 39 份血液样本外，我们还研究了 164 份含有 (60) 份或不含有 (104) T 细胞肿瘤的临床样本。在综合 T 细胞组中研究了 TRBC1 和 TRBC2 双重表达，其方式类似于用于检测克隆 B 细胞的 kappa 和 lambda 免疫球蛋白轻链的常规评估。^{所有健康捐献者的总 T 细胞、CD4 +}和 CD8 ⁺ T 细胞均表现出多型 TRBC 表达；以及对良性 T 细胞前体进行细胞内染色。除 8 例 (13%) 缺乏 TRBC 表达外，所有肿瘤 T 细胞均受 TRBC 限制。在 17 个无 T 细胞恶性肿瘤的样本 (13%) 中鉴定出意义不确定的 T 细胞克隆，其亚群比肿瘤性克隆更小（中位值：淋巴细胞的 4.7% vs. 69%，p  < 0.0001）。TRBC1 的单一染色在 24 个临床样本 (15%) 中产生了虚假的 TRBC1-dim 子集，所有这些子集均通过双重 TRBC1/2 染色得到解决。通过流式细胞术评估 TRBC 限制提供了一种快速诊断方法来检测克隆 T 细胞，并准确确定 T 细胞恶性肿瘤表达的可靶向 TRBC 亚型。