Bernard A M, Thielemans N O, Lauwerys R R
Unit of Industrial Toxicology and Occupational Medicine, Faculty of Medicine, Catholic University of Louvain, Brussels, Belgium.
Kidney Int Suppl. 1994 Nov;47:S34-7.
Protein 1 or Clara cell protein (CC16) is a 16 kD protein secreted predominantly by Clara cells in terminal bronchioles and from puberty on in the male urogenital tract. The sensitivity of CC16 in urine as an index of proximal tubule dysfunction was compared to that of retinol-binding protein, beta 2-microglobulin and alpha 1-microglobulin. These microproteins were measured by latex immunoassay in the urine from 114 pregnant women, 126 diabetics (65 men and 61 women), 80 workers exposed to cadmium (36 men and 44 women), and from healthy subjects matched for age and sex. In women, CC16 appeared consistently as a much more sensitive index of tubular dysfunction than other microproteins. In female diabetics, for instance, the prevalence of elevated values of CC16 in urine (53%) largely exceeded that of other microproteins (< 30%) and even of albumin (35%). In men, however, the existence of a post-renal secretion contaminating the urine limits the sensitivity of CC16 which was revealed to be higher than that of other microproteins, in diabetics only. The assay of urinary CC16 has the potential, especially in women, to detect very subtle defects of the proximal tubule which pass completely unseen with other microproteins. We postulate that this unique sensitivity of CC16 is due to its very low concentration in tubular fluid which, combined with its anionic character, strongly hinders its access to brush border binding sites.
蛋白1即克拉拉细胞蛋白（CC16）是一种16kD的蛋白质，主要由终末细支气管中的克拉拉细胞分泌，从青春期开始也在男性泌尿生殖道分泌。将尿中CC16作为近端肾小管功能障碍指标的敏感性与视黄醇结合蛋白、β2微球蛋白和α1微球蛋白的敏感性进行了比较。通过乳胶免疫测定法对114名孕妇、126名糖尿病患者（65名男性和61名女性）、80名接触镉的工人（36名男性和44名女性）以及年龄和性别匹配的健康受试者的尿液中的这些微蛋白进行了测量。在女性中，CC16始终显示出比其他微蛋白更敏感的肾小管功能障碍指标。例如，在女性糖尿病患者中，尿中CC16值升高的患病率（53%）大大超过其他微蛋白（<30%）甚至白蛋白（35%）的患病率。然而，在男性中，肾后分泌对尿液的污染限制了CC16的敏感性，仅在糖尿病患者中显示出CC16的敏感性高于其他微蛋白。尿CC16检测有潜力，特别是在女性中，能够检测到近端肾小管非常细微的缺陷，而这些缺陷用其他微蛋白完全检测不到。我们推测CC16这种独特的敏感性是由于其在肾小管液中的浓度非常低，再加上其阴离子特性，强烈阻碍了它与刷状缘结合位点的结合。
