Ishii K, Koyama A, Kobayashi M, Kashiwagi H, Narita M
Nihon Jinzo Gakkai Shi. 1989 Aug;31(8):827-37.
To examine the subclinical renal damage in collagen disease, we analyzed the excretion pattern of microproteinuria. We studied 58 collagen disease patients including 25 RA (rheumatoid arthritis) patients, 15 SLE (systemic lupus erythematosus), 5 PSS (progressive systemic sclerosis), 4 MCTD (mixed connective tissue disease), and 9 others. Urinary protein was not detected by urine dipsticks in all patients. Urinary proteins, which were concentrated to 5 mg/ml, were subjected to linear gradient (4-30%) SDS-PAGE and then transferred to nitrocellulose membrane by electrophoretic blotting method. The membrane was stained with Auro Dye and the blotted proteins were identified by enzyme immunoassay using specific antibodies. The percentages of albumin of whole urinary proteins were 27.2 +/- 13.7% in RA and 25.8 +/- 12.6% in PSS, which were significantly lower than that of controls (42.1 +/- 15.3%). However no significant difference in the percentage of urinary albumin was noted between SLE and controls. The percentages of low molecular weight (MW) proteins (proteins having smaller MW than albumin) were higher in RA and PSS. Especially the bands with MW of 25,200 were prominent and these percentages were 11.3 +/- 6.1% in RA and 14.6 +/- 9.1% in PSS, which were significantly higher than controls (5.1 +/- 3.5%). These bands with MW of 25,200 were demonstrated to be free light chains of immunoglobulins by western blotting method. From the above observations, protein excretion patterns in RA or PSS patients were so-called tubular proteinuria, and especially free light chain excretion was increased. We proposed that tubular dysfunction and abnormal production of free light chain might exist frequently in collagen diseases, especially RA and PSS.
为了研究胶原病中的亚临床肾损害，我们分析了微量蛋白尿的排泄模式。我们研究了58例胶原病患者，其中包括25例类风湿关节炎（RA）患者、15例系统性红斑狼疮（SLE）患者、5例进行性系统性硬化症（PSS）患者、4例混合性结缔组织病（MCTD）患者以及9例其他患者。所有患者的尿试纸条检测均未发现尿蛋白。将浓缩至5mg/ml的尿蛋白进行线性梯度（4 - 30%）SDS - PAGE，然后通过电泳印迹法转移至硝酸纤维素膜上。用金染法对膜进行染色，并使用特异性抗体通过酶免疫测定法鉴定印迹蛋白。RA患者全尿蛋白中白蛋白的百分比为27.2±13.7%，PSS患者为25.8±12.6%，均显著低于对照组（42.1±15.3%）。然而，SLE患者与对照组之间尿白蛋白百分比无显著差异。RA和PSS患者中低分子量（MW）蛋白（分子量小于白蛋白的蛋白）的百分比更高。特别是分子量为25200的条带很突出，RA患者中这些条带的百分比为11.3±6.1%，PSS患者为14.6±9.1%，均显著高于对照组（5.1±3.5%）。通过蛋白质印迹法证实，这些分子量为25200的条带为免疫球蛋白的游离轻链。根据上述观察结果，RA或PSS患者的蛋白排泄模式为所谓的肾小管性蛋白尿，尤其是游离轻链排泄增加。我们提出，在胶原病，尤其是RA和PSS中，可能经常存在肾小管功能障碍和游离轻链的异常产生。
