应用链球菌菌壁多糖抗体诊断不典型风湿热

The application of serum antibody to group A streptococcal polysaccharide in the diagnosis of atypical rheumatic fever

目的近年研究发现不典型风湿热病例日渐增多,本研究旨在探讨A组链球菌菌壁多糖抗体(antibodytogroupAstreptococcalpolysaccharide,ASP)对诊断不典型风湿热的价值。方法不典型风湿热组57例,对照组为其他病种患者57例。以亚硝酸法提取A组链球菌菌壁粗多糖,分子筛凝胶层析法分离和纯化,经抗原性检测得到具有抗原活性的相关抗原,并通过酶联免疫吸附试验(ELISA)法检测血清中抗多糖抗体。同时检测血沉(ESR)、抗DNA酶-B(anti-deoxyribonucleaseB)、抗链球菌溶血素O(ASO)。比较各种检测方法的诊断价值。结果ASP诊断风湿热的敏感性73.7%,特异性76.6%;ESR敏感性47.4%,特异性46.4%;ASO敏感性15.6%,特异性94.6%;抗DNA酶-B敏感性65.4%,特异性44.6%。进一步作ROC曲线分析及判别分析,结果ASP曲线下面积最大,判别系数亦最大。结论ASP对不典型风湿热及风湿活动有较好的诊断价值,其敏感性和特异性优于ESR,在判断链球菌感染方面亦优于ASO和抗DNA酶-B等传统的检测指标。

Objective To investigate the diagnostic value of antibody to group A streptococcal polysaccharide （ASP） in diagnosing atypical rheumatic fever （RF）. Methods Fifty-seven cases including 33 atypical RF and 24 recurrent attack of RF with chronic rheumatic heart disease were included, and 57 patients suffered from other diseases were used as control. Nitrous acid extraction and molecular sieve chromatography was adopted to extract and purify the polysaccharide. The isolated portion of polysaccharide which possessed strongest antigenity was used to detect the level of serum ASP by enzyme-linked immunosorbent assay （ELISA）. Erythrocyte sedimentation rate （ESR）, antistreptolysin-O （ASO） and anti-deoxyribonuclease B （anti-DNase B） were tested with the same samples. Results The sensitivity and specificity of ASP in the diagnosis of atypical RF was 73.7% and 76.6%; while 47.4% and 46.4% for ESR respectively. As for the evaluation of streptococcal infection, the sensitivity and specificity of ASP, ASO and anti-Dnase B were 73.7%, 15.6%, 65.4% and 76.6%, 94.6%, 44.6%, respectively. ROC curve analysis and discriminant analysis were adopted to compare these laboratory measurements. The results demonstrated that ASP was superior to other methods. Conclusion ASP has a higher sensitivity together with a higher specificity than the other three methods for diagnosing the activity of RF and the infection of streptoccus. It should be a promising diagnostic test for atypical RF.