自身抗体对甲苯胺红不加热血清试验检测结果的影响分析

Analysis of the Effects of Autoantibodies on Toluidine Red Unheated Serum Test

目的探讨不同类型的自身抗体对甲苯胺红不加热血清试验(TRUST)检测结果的影响,为梅毒相关临床诊疗实践提供参考依据。方法纳入2020年3月至7月于我院进行抗核抗体(ANA)、抗心磷脂抗体(ACA)、抗可溶性抗原可提取性核抗原(ENA)抗体、狼疮抗凝物(LA)检测且结果阳性的患者140例,以及性别、年龄匹配且上述自身抗体检测阴性的健康对照者107例,收集血清样本进行TRUST和梅毒螺旋体颗粒凝集试验(TPPA)检测,当TRUST阳性而TPPA阴性时认为TRUST为假阳性结果,分析不同类型自身抗体导致TRUST假阳性的情况。结果病例组中TRUST阳性患者有17例(12.14%),阳性率明显高于健康对照组(0.00%)(P<0.05)。17例TRUST阳性患者的ANA均为阳性,其中,ANA单阳性者5例、ANA+ENA双阳性者8例、ANA+ENA+ACA+LA均阳性者4例。17例患者中1例经TPPA和临床确诊为梅毒患者,其TRUST滴度为1∶8;其余16例患者经TPPA验证均为TRUST假阳性,其TRUST滴度分别为1∶1阳性15例和1∶2阳性1例。结论自身抗体如ANA的存在可导致TRUST试验出现低滴度(≤1∶2)假阳性,因此,在诊断梅毒相关疾病时应结合流行病学、临床表现及其他血清学检测结果,降低误诊率,提高诊断水平。

Objective To explore the influence of different autoantibodies on the toluidine red unheated serum test(TRUST),so as to provide reference for clinical practice in diagnosis and treatment of syphilis.Methods From March to July of 2020,140 samples tested positive for any of antinuclear antibody(ANA),anticardiolipin antibody(ACA),extractable nuclear antigen(Extractable nuclear antigen,ENA)antibody or lupus anticoagulant(LA),107 samples from gender and age-matched healthy controls(HCs)were also included.Serum specimens mentioned above were collected for TRUST and treponema pallidum particle assay(TPPA).Result of TRUST was considered as false-positive when TRUST was positive and TPPA was negative.Influence of these autoantibodies on the results of TRUST were analyzed.Results 12.14%(17/140)of all samples in the case group showed positive TRUST results,which were significantly higher than that in healthy control group(0.00%)(P<0.05).Tests of ANA were all positive for those 17 TRUST-positive samples,of which 5 cases were positive only for ANA,8 cases were positive for both ANA and ENA,and 4 cases were positive for all four types of autoantibodies.In addition,among the 17 patients with positive results of TRUST,one was diagnosed as syphilis by positive TPPA and clinical info,with TRUST titer 1∶8.The other 16 samples were confirmed as false-positive TRUST according to the negative TPPA results,among which 15 cases had a 1∶1 TRUST titer and 1 case had a 1∶2 TRUST titer.Conclusion The presence of autoantibodies such as ANA can lead to a low-titer(≤1∶2)false-positive TRUST results.Therefore,in order to reduce the rate of misdiagnosis,all the epidemiology information,clinical manifestations and other serological test results should be considered when making a diagnose of syphilis-related diseases.