Bora Kaustubh, Das Umesh, Barman Bhupen, Ruram Alice Abraham
ICMR-Regional Medical Research Centre, North East Region, Dibrugarh, Assam; Department of Biochemistry, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong, Meghalaya, India.
Department of Medical Oncology, North Eastern Indira Gandhi Regional Institute of Health and Medical Sciences, Shillong, Meghalaya, India.
Indian J Pathol Microbiol. 2017 Oct-Dec;60(4):590-592. doi: 10.4103/IJPM.IJPM_311_17.
Monoclonal gammopathies, such as multiple myeloma, typically exhibit high levels of a monoclonal immunoglobulin (M-protein), produced by a clone of abnormally proliferating B-lymphocytes and/or plasma cells. The M-protein can be evaluated by serum protein electrophoresis (SPEP), which yields a single discrete band (M-band), usually in the γ-globulin region. Rarely, two M-bands appear simultaneously at different positions during SPEP - a condition known as biclonal gammopathy, which is a result of clonal expansion of two different neoplastic cell lines. Here, we describe an atypical case of IgA-λ multiple myeloma, where double M-bands (one in β- and the other in γ-globulin region) were found during SPEP simulating biclonal gammopathy, although it was monoclonal in nature. This peculiar presentation of double M-bands in monoclonal gammopathy was attributed to polymeric forms of IgA by systematic workup. Further, we discuss how true and apparent biclonality can be distinguished by inexpensive analytical techniques in resource-constrained settings.
单克隆丙种球蛋白病，如多发性骨髓瘤，通常表现为单克隆免疫球蛋白（M蛋白）水平升高，该蛋白由异常增殖的B淋巴细胞和/或浆细胞克隆产生。M蛋白可通过血清蛋白电泳（SPEP）进行评估，其通常在γ球蛋白区域产生一条单一离散带（M带）。在SPEP过程中，很少会同时在不同位置出现两条M带——这种情况称为双克隆丙种球蛋白病，它是两种不同肿瘤细胞系克隆性扩增的结果。在此，我们描述了一例IgA-λ型多发性骨髓瘤的非典型病例，在SPEP过程中发现了双M带（一条在β球蛋白区域，另一条在γ球蛋白区域），模拟双克隆丙种球蛋白病，尽管其本质上是单克隆的。通过系统检查，单克隆丙种球蛋白病中这种双M带的特殊表现归因于IgA的聚合形式。此外，我们讨论了在资源有限的环境中如何通过廉价的分析技术区分真正的双克隆性和表观双克隆性。
