Smith G, Spellerberg M, Boulton F, Roelcke D, Stevenson F
Wessex Blood Transfusion Centre, Tenovus Laboratory, Southampton, UK.
Vox Sang. 1995;68(4):231-5. doi: 10.1111/j.1423-0410.1995.tb02578.x.
Most autoanti-red cell antibodies found in patients with cold agglutinin disease are specific for the I or i carbohydrate antigenic determinants. However, antibodies specific for other antigens such as Pr or Sa can also be found, and these are identified by their pattern of reactivity with enzyme-treated red cells. Recently, it has been shown that the vast majority of anti-Ii antibodies react with a monoclonal anti-idiotypic antibody (9G4); this reactivity arises from restriction of the immunoglobulin heavy chains used to encode the antibodies to a single VH4-21 gene, VH4-21. The 9G4 antibody appears specific for this gene product, and we have used it to analyse VH4-21 gene involvement in encoding a spectrum of red cell antibodies of various specificities. The results support the strong association between usage of this gene and anti-Ii specificity and indicate that it is not generally used by other specificities. In particular, it is striking that the unsubstituted type 2 oligosaccharide antigens (I and i) induce a highly restricted autoantibody response very different from that induced by the sialylated type 2 antigens (Sia-b, -1 and 1b). The 9G4 antibody therefore provides a simple tool for discrimination between these autoanti-red cell antibodies, which should be of use in red cell serology.
在冷凝集素病患者中发现的大多数自身抗红细胞抗体对I或i碳水化合物抗原决定簇具有特异性。然而，也能发现对其他抗原如Pr或Sa具有特异性的抗体，这些抗体通过它们与酶处理红细胞的反应模式来鉴定。最近研究表明，绝大多数抗Ii抗体与一种单克隆抗独特型抗体（9G4）发生反应；这种反应性源于用于编码抗体的免疫球蛋白重链被限制在单个VH4 - 21基因，即VH4 - 21。9G4抗体似乎对该基因产物具有特异性，我们已用它来分析VH4 - 21基因在编码一系列不同特异性红细胞抗体中的作用。结果支持该基因的使用与抗Ii特异性之间存在强关联，并表明其他特异性抗体一般不使用该基因。特别值得注意的是，未被取代的2型寡糖抗原（I和i）诱导的自身抗体反应高度受限，与唾液酸化的2型抗原（Sia - b、- 1和1b）诱导的反应非常不同。因此，9G4抗体为区分这些自身抗红细胞抗体提供了一个简单工具，这在红细胞血清学中应会有用。
