Croce A, Firuzi O, Altieri F, Eufemi M, Agostino R, Priori R, Bombardieri M, Alessandri C, Valesini G, Saso L
Department of Human Physiology and Pharmacology Vittorio Erspamer, University of Rome La Sapienza, Rome, Italy.
J Clin Lab Anal. 2007;21(5):303-14. doi: 10.1002/jcla.20191.
In patients with rheumatoid arthritis (RA) a decrease in the terminal galactose content of N-linked glycans of the Fc region of agalactosyl immunoglobulin G (IgG) (G0) occurs. The aim of this study was to evaluate, for the first time, the effect of infliximab, a new monoclonal antibody for the treatment of RA, on this phenomenon. A total of 19 patients with active RA were treated with intravenous infliximab (3 mg/kg) in combination with methotrexate (MTX) (10-20 mg). IgG was purified from their serum by caprylic acid. Analysis of IgG glycosylation was performed by lectin blotting/immunoblotting and enzyme linked lectin assay (ELLA)/enzyme linked immunosorbent assay (ELISA) using the Griffonia (bandeiraea) simplicifolia lectin II and protein-A/alkaline phosphatase. The purity of IgG samples obtained was higher than 90%. The sensitivity of the lectin/immunoblotting method was of about 0.25 microg of IgG. The inter- and intraassay coefficients of variation (CV) were 1.3% and 9.0% for lectin blotting, and 4.6% and 8.3% for immunoblotting, respectively. The sensitivity of the ELLA/ELISA approach was 0.025 microg/microL and the inter- and intraassay CV were 6.2% and 7.7% for ELLA, and 5.1% and 14.1% for ELISA, respectively. A good linear correlation (r2=0.18, P<0.05) was obtained between the two different experimental approaches. A decrease of G0 was observed in patients who clinically improved (according to the American College of Rheumatology criteria) following the pharmacological treatment. Our data indicate that infliximab can reduce the concentration of G0 in patients with active RA.
在类风湿关节炎（RA）患者中，无半乳糖免疫球蛋白G（IgG）（G0）的Fc区域N-连接聚糖的末端半乳糖含量会降低。本研究的目的是首次评估一种用于治疗RA的新型单克隆抗体英夫利昔单抗对这一现象的影响。共有19例活动性RA患者接受了静脉注射英夫利昔单抗（3 mg/kg）联合甲氨蝶呤（MTX）（10 - 20 mg）治疗。通过辛酸从他们的血清中纯化IgG。使用非洲相思子（猴耳环）凝集素II和蛋白A/碱性磷酸酶，通过凝集素印迹/免疫印迹以及酶联凝集素测定（ELLA）/酶联免疫吸附测定（ELISA）对IgG糖基化进行分析。获得的IgG样品纯度高于90%。凝集素/免疫印迹法的灵敏度约为0.25 μg IgG。凝集素印迹的批间和批内变异系数（CV）分别为1.3%和9.0%，免疫印迹的批间和批内CV分别为4.6%和8.3%。ELLA/ELISA方法的灵敏度为0.025 μg/μL，ELLA的批间和批内CV分别为6.2%和7.7%，ELISA的批间和批内CV分别为5.1%和14.1%。两种不同的实验方法之间获得了良好的线性相关性（r2 = 0.18，P < 0.05）。在药物治疗后临床改善（根据美国风湿病学会标准）的患者中观察到G0降低。我们的数据表明，英夫利昔单抗可以降低活动性RA患者中G0的浓度。
