抗瓜氨酸化葡萄糖-6-磷酸异构酶多肽抗体的检测及其在类风湿关节炎中的意义

目的：检测类风湿关节炎（rheumatoid arthritis，RA）患者血清中抗瓜氨酸化葡萄糖-6-磷酸异构酶（citrullinated glucose-6-phosphate isomerase，C-GPI）70~88肽抗体（抗C-GPI70~88抗体）和抗C-GPI 435~453肽抗体（抗C-GPI435~453抗体）的水平，同时检测其原型多肽抗体水平，评价抗C-GPI多肽抗体在RA诊断中的价值。方法： 应用酶联免疫吸附法检测191例RA患者、129例其他风湿免疫疾病患者和74例健康对照组血清中抗C-GPI70~88抗体、抗C-GPI435~453抗体、抗GPI70~88抗体和抗GPI435~453抗体的水平，并收集RA患者临床和实验室检查数据，分析抗C-GPI多肽抗体在RA诊断中的价值以及与临床和实验室指标的相关性。结果： （1）RA组抗C-GPI70~88抗体和抗C-GPI435~453抗体的滴度（68.71±4.20和51.78±3.13）显著高于疾病对照组和健康对照组（P<0.05），而抗GPI70~88抗体和抗GPI435~453抗体的滴度在各组中差异无统计学意义。（2）抗C-GPI70~88抗体在RA诊断中的敏感性为41.88%，特异性为84.50%；抗C-GPI435~453抗体在RA诊断中的敏感性为46.05%，特异性为86.05%;联合检测两种抗瓜氨酸化多肽抗体的敏感性为50.79%，特异性为86.05%。（3）抗C-GPI70~88抗体和抗C-GPI435~453抗体在类风湿因子、抗角蛋白抗体、抗环瓜氨酸肽抗体均阴性的RA患者中的阳性率分别为35.00%和45.00%。（4）RA患者抗C-GPI70~88抗体和抗C-GPI435~453抗体阳性组和阴性组之间临床和实验室指标差异无统计学意义。结论： RA患者体内可以检测到抗C-GPI多肽抗体，C-GPI可能参与了RA的发病，对于血清阴性的RA患者有较好的诊断价值。

Significance of antibodies to the citrullinated glucose-6-phosphate isomerase peptides in rheumatoid arthritis

Objective： To detect the anti-citrullinated glucose-6-phosphate isomerase (GPI) 70-88 peptide antibody(anti-C-GPI70-88 antibody),anti-citrullinated GPI 435-453 peptide antibody(anti-C-GPI435-453 antibody), anti-GPI 70-88 peptide antibody(anti-GPI70-88 antibody) and anti-GPI 435-453 peptide antibody(anti-GPI435-453 antibody) in the serum of rheumatoid arthritis(RA) patients,and exa-mine the diagnostic values of the anti-C-GPI peptide antibodies in RA. Methods: The anti-C-GPI70-88 antibody, anti-C-GPI435-453 antibody, anti-GPI70-88 antibody and anti-GPI435-453 antibody were detected by enzyme-linked immunosorbent assay(ELISA) in 191 RA patients,129 other rheumatic diseases and 74 healthy controls. The clinical and laboratory data of the patients with RA were collected, and the values of anti-C-GPI peptide antibodies in the diagnosis of RA and the relationships of anti-C-GPI peptide antibodies with the clinical and laboratory parameters analyzed. Results: (1)The mean titers of the anti-C-GPI70-88 antibody and the anti-C-GPI435-453 antibody in the RA patients (respectively, 68.71±4.20 and 51.78±3.13) were significantly higher than those with other rheumatic diseases and healthy individuals(P<0.05). However,the mean titers of the anti-GPI70-88 antibody and anti-GPI435-453 antibody in the RA patients were similar to those with other rheumatic diseases and healthy individuals.(2)The diagnostic sensitivity and specificity of the anti-C-GPI70-88 antibody for RA were 41.88% and 84.50% respectively; and the diagnostic sensitivity and specificity of the anti-C-GPI435-453 antibody for RA were 46.05% and 86.05% respectively.The sensitivity of combined detection of the two anti-C-GPI peptide antibodies was 50.79%, and the specificity was 81.40%. (3) The positive rates of the anti-C-GPI70-88 antibody and the anti-C-GPI435-453 antibody were 35% and 45% respectively in those patients with negative anti cyclic citrullinated peptide antibody, anti keratin antibody, and rheumatoid factor. (4) There was no significant difference in clinical and laboratory indicators between the anti-C-GPI70-88 antibody or anti-C-GPI435-453 antibody positive group and negative group. Conclusion: The anti-C-GPI70-88 antibody and anti-C-GPI435-453 antibody can be detected in the serum of RA patients, and C-GPI may be involved in the pathogenesis of RA. There is a certain diagnostic significance for the sera-negative RA.