T细胞酶联免疫斑点法对风湿病患者潜伏性结核感染筛查诊断价值的再研究

目的 比较T细胞酶联免疫斑点法(TSPOT)与结核菌素纯蛋白衍生物(TB-PPD)试验对风湿病患者潜伏结核感染(LTBI)的诊断价值.方法 对260例明确诊断的风湿病患者进行LTBI的筛查.包括询问病史、胸部X线片、PPD试验及应用TSPOT-TB试剂盒对血液标本进行结核分枝杆菌(Mtb)特异性T细胞应答的检测,同时对所有病例进行联合分析.结果 TSPOT检测阳性率24.1%,PPD试验阳性率为39.4%,两者一致率为61.0%.其中PPD阴性/TSPOT阳性29例,PPD阳性/TSPOT阴性67例.卡介苗(BCG)接种史/既往结核病史的患者PPD试验的阳性率显著增高(P<0.05/P<0.01),但两者在TSPOT检测的阳性率上差异无统计学意义(P>0.05.其中127例患者使用生物制剂,9例使用异烟肼预防抗结核治疗,27例因PPD或TSPOT阳性放弃生物制剂治疗.TSPOT(-)PPD(++)的23例患者均在未预防抗结核下按计划接受了生物制剂治疗,上述患者在随访6～18个月期间尚无活动性结核发生.结论 TSPOT技术可能对风湿病(尤其拟接受生物制剂)患者LTBI的诊断提供帮助.

Use of an enzyme-linked immunospot assay for diagnosing latent tuberculosis infection in rheumatic diseases

Objective To compare the efficacy of the conventional PPD skin test and a new enzymelinked immunospot assay(TSPOT-TB)for diagnosing latent tuberculosis infection(LTBI)in patients with rheumatic diseases.Methods Two hundred and sixty rheumatic patients were enrolled,and all were screened for LTBI based on clinical history,chest X-ray,PPD skin test or TSPOT.Results The positive rate of TSPOT assay was 24.1%and that of PPD skin test was 39.4%.The overall concordance rate between the 2tests was 61.0%.Among PPD negative patients (n=149).29 were TSPOT(+)(19.5%).Among PPD(+)patients(n=98),69 were TSPOT(-)(70.0%).The patients who got BCG vaccination or had history of tuberculosis infection showed a significantly higher rate of positive result of PPD skin test than those who did not (P<0.05 or P<0.01).While in TSPOT assay,the BCG vaccination or history of tuberculosis infection did not show influence on TSPOT results(P>0.05).Of the 127 patients who received biological agents after screening for LTBI,9 patients were pretreated with isoniazide.Twenty-seven patients stopped biological agent treatment because of the positive results of PPD or TSPOT.Twenty three patients who had positive PPD but negative TSPOT results received biological agent treatment without isoniazide,and none of them developed active tubereulosis after 6 to 18 months of follow-up.Conclusion BCG vaccination affects the result of PPD test in rheumatic patients,but has no influence on TSPOT results.The infection rate of latent tuberculosis of rheumatic patients in our research is 23.8%detected by TSPOT.