Oritani K, Katagiri S, Tominaga N, Iida M, Amano T, Karasuno T, Matsumura I, Mitsui H, Kanayama Y, Yonezawa T
Second Department of Internal Medicine, Osaka University Medical School, Japan.
Br J Haematol. 1990 May;75(1):10-5. doi: 10.1111/j.1365-2141.1990.tb02610.x.
A study was made of 29 patients with monoclonal gammopathies to detect aberrations in immunoglobulin (Ig) light chain isotype expression in lymphocytes at various levels of B-cell differentiation, namely, circulating surface Ig positive (SIg+) cells, Ig-secreting cells (plaque forming cells, PFC) and mitogen-induced PFC. By using kappa-lambda analysis, two major phenotypes of aberrant Ig light chain isotype expression were found in circulating B cells at these three levels of differentiation: an absolute increase in B cells bearing the same Ig light chain isotype as that of monoclonal protein (clonal B-cell excess), and a relative decrease in those B cells (isotypic discordance). Isotypic discordance (ID) was found to be essentially negative in patients with monoclonal gammopathy of undetermined significance (MGUS) provided that they were in a stable condition. In myeloma patients, ID was found only in stage I, except for a remission case of stage III (4/7 in stage I, 0/8 in stage II, and 1/6 in stage III). ID was not restricted to a circulating SIg+ cell level but was also demonstrable at a spontaneous or pokeweed mitogen-induced PFC level. However, ID was negative at a PFC level induced by Staphylococcus aureus Cowan I. Clonal B-cell excess (CE) was frequently found in patients with active myeloma but not in stable patients (0/8 in MGUS, 1/7 in stage I, 8/8 in stage II, and 4/6 in stage III). CE was positive not only at a circulating SIg+ cell level but also at a circulating PFC level. Furthermore, patients with CE at a PFC level were found to have a higher proliferating capacity, defined as a percentage labelling index of marrow myeloma cells, than those without CE at a PFC level (P less than 0.02). ID and CE can therefore be considered as useful markers for discriminating between MGUS and myeloma, evaluating the clinical stability and predicting the clinical course.
对29例单克隆丙种球蛋白病患者进行了一项研究，以检测不同B细胞分化水平的淋巴细胞中免疫球蛋白（Ig）轻链同种型表达的异常情况，这些水平包括循环表面Ig阳性（SIg+）细胞、Ig分泌细胞（空斑形成细胞，PFC）和丝裂原诱导的PFC。通过κ-λ分析，在这三个分化水平的循环B细胞中发现了两种主要的异常Ig轻链同种型表达表型：携带与单克隆蛋白相同Ig轻链同种型的B细胞绝对增加（克隆性B细胞增多），以及这些B细胞相对减少（同种型不一致）。发现意义未明的单克隆丙种球蛋白病（MGUS）患者在病情稳定时，同种型不一致（ID）基本为阴性。在骨髓瘤患者中，仅在I期发现ID，III期的1例缓解病例除外（I期4/7，II期0/8，III期1/6）。ID不仅限于循环SIg+细胞水平，在自发或商陆丝裂原诱导的PFC水平也可检测到。然而，在金黄色葡萄球菌Cowan I诱导的PFC水平，ID为阴性。活跃骨髓瘤患者中经常发现克隆性B细胞增多（CE），病情稳定的患者则未发现（MGUS中0/8，I期1/7，II期8/8，III期4/6）。CE不仅在循环SIg+细胞水平为阳性，在循环PFC水平也为阳性。此外，PFC水平有CE的患者，其增殖能力（定义为骨髓骨髓瘤细胞的标记指数百分比）高于PFC水平无CE的患者（P<0.02）。因此，ID和CE可被视为区分MGUS和骨髓瘤、评估临床稳定性及预测临床病程的有用标志物。
