Aboudi N El, Ourahma Y, Biaz A, Idrissi S El M, Dami A, Bouhsain S
Clin Lab. 2025 Sep 1;71(9). doi: 10.7754/Clin.Lab.2025.250213.
Light chain multiple myeloma (LCMM) is a malignant hematological disease characterized by bone marrow infiltration by tumor plasma cells and the secretion of monoclonal free light chains (κ or λ). It is often di-agnosed through hypogammaglobulinemia detected by serum protein electrophoresis, followed by immunotyping showing a monoclonal band in free light chains. However, the structure of monoclonal light chains can sometimes complicate laboratory findings.
The case studied involves a 52-year-old female patient hospitalized for diffuse bone pain and hypercalcemia. Capillary serum protein electrophoresis revealed hypogammaglobulinemia, leading to serum immunofixation (IFE).
IFE showed a wide additional band in κ light chains, with no correspondence to the heavy chain antisera (GAM, D, and E), but similar reactivity with the anti-κ light chain, creating an interpretive challenge. The free light chain assay revealed a very high κ/λ ratio (1,068). Bone marrow examination showed 85% plasma cell infiltration, confirming the diagnosis of LCMM.
This case highlights the diagnostic challenges encountered in certain cases of light chain multiple myeloma and underscores the importance of a multimarker approach combining serum protein electrophoresis, serum immunofixation, and free light chain assays.
轻链多发性骨髓瘤（LCMM）是一种恶性血液系统疾病，其特征为肿瘤浆细胞浸润骨髓并分泌单克隆游离轻链（κ或λ）。通常通过血清蛋白电泳检测到的低丙种球蛋白血症进行诊断，随后免疫分型显示游离轻链中有单克隆条带。然而，单克隆轻链的结构有时会使实验室检查结果变得复杂。
所研究的病例为一名52岁女性患者，因弥漫性骨痛和高钙血症住院。毛细管血清蛋白电泳显示低丙种球蛋白血症，进而进行血清免疫固定电泳（IFE）。
IFE显示κ轻链中有一条宽的附加条带，与重链抗血清（GAM、D和E）不对应，但与抗κ轻链有相似的反应性，这带来了解读挑战。游离轻链检测显示κ/λ比值非常高（1068）。骨髓检查显示浆细胞浸润达85%，确诊为LCMM。
该病例突出了某些轻链多发性骨髓瘤病例所面临的诊断挑战，并强调了结合血清蛋白电泳、血清免疫固定电泳和游离轻链检测的多标志物方法的重要性。
