Bailey E M, McDermott T J, Bloch K J
Department of Pathology, Harvard Medical School, Boston, Mass.
Arch Pathol Lab Med. 1993 Jul;117(7):707-10.
--To describe the recently reported urinary light-chain "ladder" pattern and to indicate that this phenomenon, which may give rise to confusion with Bence Jones protein (BJP), may be observed during routine examination of 50-fold concentrated urine samples tested by high-resolution agarose gel electrophoresis and immunofixation.
--Urine samples that were usually submitted for examination for the presence of BJP were concentrated 50-fold. Concentrated urine samples were subjected to immunoelectrophoresis and agarose gel electrophoresis. Samples that failed to show a BJP on immunoelectrophoresis but which did show a faint banding pattern in the stained agarose gel were subjected to immunofixation. RESULTS--Samples of urine from 23 patients failed to show a distinct BJP. Nevertheless, these samples did show a kappa, with or without a lambda, light-chain banding pattern. The urine samples came from patients with serum M components associated with neoplasms of either plasma cells (n = 2) or lymphocytes (n = 2) or with M components of undetermined significance (n = 6). The remainder came from patients with infectious (n = 8), inflammatory (n = 4), or neoplastic (n = 1) processes. Some of these patients had no apparent renal disease, while others had variably altered renal function. CONCLUSIONS--The urinary light-chain ladder pattern was found by routine examination of 50-fold concentrated urine samples subjected to agarose gel electrophoresis and immunofixation. The pattern probably reflects the limited heterogeneity of normal human light chains. Detection in the urine samples of some patients may reflect increased synthesis, failure of resorption/degradation in the kidney, or the interference in proximal tubular function by substances producing transient tubular proteinuria. The presence of the light-chain ladder pattern in urine may prevent the detection of small amounts of BJP sharing the electrophoretic mobility of one of the normal light-chain bands.
描述近期报道的尿轻链“阶梯”模式，并指出这种可能与本-周蛋白（BJP）混淆的现象，可在通过高分辨率琼脂糖凝胶电泳和免疫固定检测50倍浓缩尿样的常规检查中观察到。
通常送检以检测BJP的尿样被浓缩50倍。浓缩尿样进行免疫电泳和琼脂糖凝胶电泳。免疫电泳未显示BJP但在染色琼脂糖凝胶中显示微弱条带模式的样品进行免疫固定。结果：23例患者的尿样未显示明显的BJP。然而，这些样品确实显示了κ链，有或没有λ链的轻链条带模式。尿样来自患有与浆细胞瘤（n = 2）或淋巴细胞瘤（n = 2）相关的血清M成分的患者，或来自具有意义未明的M成分的患者（n = 6）。其余来自患有感染性（n = 8）、炎症性（n = 4）或肿瘤性（n = 1）疾病的患者。这些患者中一些没有明显的肾脏疾病，而另一些患者的肾功能有不同程度的改变。结论：通过对50倍浓缩尿样进行琼脂糖凝胶电泳和免疫固定的常规检查发现了尿轻链阶梯模式。这种模式可能反映了正常人轻链有限的异质性。在一些患者的尿样中检测到这种模式可能反映了合成增加、肾脏重吸收/降解失败或产生短暂性肾小管蛋白尿的物质对近端肾小管功能的干扰。尿中轻链阶梯模式的存在可能会妨碍检测到与正常轻链带之一具有相同电泳迁移率的少量BJP。
