Havenaar E C, Dolhain R J, Turner G A, Goodarzi M T, van Ommen E C, Breedveld F C, van Dijk W
Department of Medical Chemistry, Faculty of Medicine, Vrije Universiteit, Amsterdam, The Netherlands.
Glycoconj J. 1997 Jun;14(4):457-65. doi: 10.1023/a:1018547417702.
This study was performed in order to gain insight into the occurrence, glycosylation and the possible origin of the acute-phase proteins alpha1-acid glycoprotein (AGP) and alpha1-protease inhibitor (PI) in sera and synovial fluid from patients with rheumatoid arthritis (RA). Therefore paired sera and synovial fluid samples from patients with RA, and paired synovial fluid samples from right and left knees of patients with varying degrees of arthritis were studied. Crossed affinity immunoelectrophoresis (CAIE) was used with concanavalin A and Aleuria aurantia lectin for the detection of the degree of branching and fucosylation, respectively, and the monoclonal CSLEX-1 for the detection of Sialyl Lewis(X) (SLe(X)) groups on AGP. For PI, not only CAIE, but also high-pressure-anion-exchange chromatography with pulsed amperometric detection was used to study the glycosylation. It was established that the concentrations of AGP and PI were increased in the serum of RA patients compared to normal healthy controls, but that the concentration of both proteins, as well as albumin, was significantly lower in synovial fluid than in serum. Furthermore, the type of glycosylation of both AGP and PI found in RA was significantly different from that found in normals, with increased fucosylation, but there were no major differences in the degree of branching of AGP- or PI-glycans in RA, compared to normals. No differences in glycosylation could be established between serum and synovial fluid in RA. For PI an increased fucosylation was found, both in serum and synovial fluid, using both methods of detection, and it could be established that only the alpha1-->3- and not the alpha1-->6-fucosylation of PI was affected by RA. The increased fucosylation of AGP resulted in an increased expression of SLe(X) on AGP-glycans. Since the alpha1-->3-fucosylation of AGP was significantly increased in both serum and synovial fluid from RA patients, and this correlated with systemic but not with local disease parameters, it can be suggested that acute phase proteins in synovial fluid are most probably of hepatic origin.
进行这项研究是为了深入了解类风湿性关节炎（RA）患者血清和滑液中急性期蛋白α1-酸性糖蛋白（AGP）和α1-蛋白酶抑制剂（PI）的产生、糖基化及可能来源。因此，对RA患者的配对血清和滑液样本，以及不同程度关节炎患者左右膝关节的配对滑液样本进行了研究。采用伴刀豆球蛋白A和橙黄网柄菌凝集素的交叉亲和免疫电泳（CAIE）分别检测分支程度和岩藻糖基化程度，并用单克隆抗体CSLEX-1检测AGP上的唾液酸化路易斯（X）（SLe（X））基团。对于PI，不仅使用CAIE，还使用带脉冲安培检测的高压阴离子交换色谱法研究糖基化。结果表明，与正常健康对照相比，RA患者血清中AGP和PI的浓度升高，但滑液中这两种蛋白以及白蛋白的浓度均显著低于血清。此外，RA中AGP和PI的糖基化类型与正常情况显著不同，岩藻糖基化增加，但与正常情况相比，RA中AGP或PI聚糖的分支程度没有重大差异。RA患者血清和滑液之间未发现糖基化差异。对于PI，使用两种检测方法均发现血清和滑液中的岩藻糖基化增加，并且可以确定只有PI的α1→3-而非α1→6-岩藻糖基化受RA影响。AGP岩藻糖基化增加导致AGP聚糖上SLe（X）表达增加。由于RA患者血清和滑液中AGP的α1→3-岩藻糖基化均显著增加，且这与全身而非局部疾病参数相关，因此可以认为滑液中的急性期蛋白很可能来源于肝脏。
