Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
J Clin Pathol. 2012 Sep;65(9):823-9. doi: 10.1136/jclinpath-2012-200881. Epub 2012 Jun 8.
Plasma cell myeloma (PCM) exhibits immunophenotypic aberrancies that can be used for minimal residual disease (MRD) detection after therapy. The authors sought to determine whether non-neoplastic plasma cells, especially in the bone marrow (BM) post various therapies, would exhibit immunophenotypic variations interfering PCM MRD detection. The authors studied the flow cytometric immunophenotypes of non-neoplastic plasma cells from 50 BM specimens, including 12 untreated BM and 38 BM specimens from patients with non-plasmacytic haematological malignancies undergoing various therapies, and compared with 59 BM specimens positive for PCM MRD. Non-neoplastic plasma cells showed heterogeneous expressions of CD45 (78% (41-100)) and CD19 (80% (52-97)), and were negative for CD20 and CD117. CD56 was observed in a small subset (6% (0-37)) and CD28 in a larger subset (15% (0-59)) of non-neoplastic plasma cells, with the latter more frequently expressed in post-treatment BMs (p=0.01). However, despite a partial immunophenotypic overlap, PCM cells could be reliably discriminated from non-neoplastic plasma cells by the presence of a higher number of aberrancies (3 (1-6) vs 0 (0-2)) and stronger intensity and uniformity of aberrant expression (p<0.001 in each marker using a cut-off value). In addition, simultaneous assessment of cytoplasmic κ/λ with surface markers detected light chain restriction in all 59 PCM cases. In conclusion, non-neoplastic plasma cells in BM are more immunophenotypically heterogeneous than previously understood; however, these immunophenotypic variations differ from those of PCM. With advances in multicolour flow cytometry and application of recently validated markers, PCM MRD may still be reliably distinguished from non-neoplastic plasma cells.
浆细胞骨髓瘤（PCM）表现出免疫表型异常，可用于治疗后微小残留病（MRD）的检测。作者试图确定非肿瘤性浆细胞，特别是在各种治疗后的骨髓（BM）中，是否会表现出干扰 PCM MRD 检测的免疫表型变化。作者研究了 50 个 BM 标本中非肿瘤性浆细胞的流式细胞免疫表型，包括 12 个未经治疗的 BM 标本和 38 个接受各种治疗的非浆细胞性血液恶性肿瘤患者的 BM 标本，并与 59 个 PCM MRD 阳性的 BM 标本进行了比较。非肿瘤性浆细胞表现出 CD45（78%（41-100））和 CD19（80%（52-97））的异质性表达，并且为阴性 CD20 和 CD117。在一小部分（6%（0-37））非肿瘤性浆细胞中观察到 CD56，在更大一部分（15%（0-59））非肿瘤性浆细胞中观察到 CD28，后者在治疗后的 BM 中更频繁表达（p=0.01）。然而，尽管存在部分免疫表型重叠，但 PCM 细胞仍可通过存在更多的异常（3（1-6）与 0（0-2））和更强的异常表达强度和均匀性来可靠地区分非肿瘤性浆细胞（在每个标记物中，使用截止值，p<0.001）。此外，同时评估表面标志物与细胞质κ/λ，在所有 59 例 PCM 病例中均检测到轻链限制。总之，BM 中的非肿瘤性浆细胞比以前理解的具有更多的免疫表型异质性；然而，这些免疫表型变化与 PCM 的不同。随着多色流式细胞术的进步和最近验证的标记物的应用，PCM MRD 可能仍然可以与非肿瘤性浆细胞可靠地区分。
