中文摘要：

目的 检测早期RA患者血清中IgG、IgA和IgM亚型抗肽酰基精氨酸脱亚胺酶4（PAD4）抗体水平,分析3种抗体亚型在早期RA中的临床意义.方法 纳入病程≤2年的RA患者88例,其他风湿病患者62例,健康对照57名.以ELISA检测患者血清中IgG、IgA及IgM型抗PAD4抗体水平.分析各抗体亚型与RA患者临床和实验室指标的关系.采用t检验,U检验和Spearman相关性分析进行统计学分析.结果 ①RA患者IgG、IgA和IgM型抗PAD4抗体的敏感度分别为28.41％、36.36％和9.09％,IgG、IgA和IgM 3种抗体亚型对诊断RA的特异度分别为94.12％、93.28％及95.80％.②IgA亚型抗PAD4抗体与患者的年龄（r=0.234,P=0.028）、DAS28（r=0.309,P=0.007）、ESR（r=0.382,P=0.000）和CRP（r=0.291,P=0.008）呈正相关,与病程（r=-0.295,P=0.006）呈负相关.③IgA亚型与IgG亚型抗PAD4抗体呈正相关（r=0.451,P＜0.01）.在IgG亚型阴性的RA患者中,IgA亚型抗PAD4抗体的阳性率为29％（18/63）,提示IgA亚型对于IgG亚型抗PAD4抗体阴性的RA患者具有补充的诊断价值.结论 早期RA患者血清中可以检测到抗PAD4抗体,主要以IgA亚型和IgG亚型为主,其中IgA亚型与RA患者病程呈负相关,提示其可能在RA的早期阶段发挥作用.

英文摘要：

Objective To evaluate the prevalence and clinical significance of IgG,IgA and IgM isotypes of anti-peptidylarginine deiminase 4 （anti-PAD4） antibodies in early rheumatoid arthritis （RA）.Methods IgG,IgA and IgM isotypes of anti-PAD4 antibodies were measured in the sera of 88 RA patients with disease duration less than 2 years,62 patients with other rheumatic diseases and 57 healthy subjects.The diagnostic performance of IgG,IgA and IgM isotypes of anti-PAD4 antibodies and their relationship with disease duration,DAS28,ESR,CRP,anti-CCP antibodies and rheumatoid factor （RF） were evaluated.Data analysis were performed using t test,U test and Spearman＆#39;s association analysis.Results ① The sensitivities of IgG,IgA,and IgM isotypes for early RA were 28.41%,36.36% and 9.09% respectively.The specificities of IgG,IgA and IgM isotypes were 94.12%,93.28% and 95.80% respectively.② IgA isotype was positively correlated with age （r=0.234,P=0.028）,DAS28 （r=0.309,P=0.007）,ESR （r=0.382,P=0.000） and CRP （r=0.291,P=0.008）,while negatively correlated with disease duration （r=-0.295,P=0.006）.③ IgA isotype was positively correlated with IgG isotype （r=0.451,P〈0.01）.In the IgG negative patients,the positivity of IgA isotype was 29%（18/63）,which indicated that the IgA isotype might be helpful in diagnosing RA in IgG isotype negative patients.Conclusion Anti-PAD4 antibodies can be detected in early RA,primarily with IgA and IgG isotypes.IgA isotype has negative correlation with disease duration,indicating that IgA isotype of anti-PAD4 antibody may play a role in the very early stage RA.