广西壮族自治区实验室确诊麻疹病例麻疹病毒IgG抗体亲和力特征

Avidity of IgG antibody against measles virus from laboratory-confirmed measles cases in Guangxi Zhuang Autonomous Region

目的分析麻疹病毒(Measles virus,MV)IgG阳性实验室确诊麻疹病例的IgG亲和力特征。方法选择广西2015-2017年MV IgG阳性实验室确诊麻疹病例,采用基于MV IgG酶联免疫吸附试验的尿素变性亲和力检测方法,检测血清IgG亲和力,分析平均相对亲和力指数(Relative avidity index,RAI)和高/中/低亲和力比例。结果在136例MV IgG阳性麻疹病例中,IgG平均RAI为49.74%,高、中、低亲和力分别占47.79%、28.68%、23.53%。<8月龄、8-35月龄、3-19岁、20-39岁、≥40岁病例IgG平均RAI分别为23.61%、41.60%、60.80%、52.65%、69.49%,高亲和力比例分别为0.00%、30.77%、80.00%、50.00%、84.62%;0剂次、1剂次、≥2剂次、不详含麻疹成分疫苗(Measles containing vaccine,MCV)免疫史病例的平均RAI分别为43.43%、50.34%、65.38%、47.84%,高亲和力比例分别为36.36%、46.94%、87.50%、42.11%。结论麻疹抗体亲和力随麻疹病例年龄或MCV免疫剂次增加而呈升高趋势;<8月龄和20-39岁病例的抗体亲和力较低或下降,有必要对年轻育龄期妇女加强接种1剂MCV。

Objective To analyze avidity of IgG against measles virus(MV)from laboratory-confirmed measles cases that were IgG-positive to MV.Methods We selected IgG-positive MV from laboratoryconfirmed measles cases in Guangxi from 2015 to 2017 and tested sera for IgG avidity using the urea denaturation avidity detection method based on MV IgG enzyme-linked immunosorbent assay.We analyzed average relative avidity indexes(RAI)and proportions of high,medium,and low avidity.Results Among the 136 MV IgG positive measles cases,the average IgG RAI was 49.74%,and high,medium,and low avidity cases accounted for 47.79%,28.68%,and 23.53%of cases,respectively.Average RAIs for cases aged<8 months,8-35 months,3-19 years,20-39 years,and≥40 years were 23.61%,41.60%,60.80%,52.65%,and 69.49%,with proportions for high avidity being 0.00%,30.77%,80.00%,50.00%,and 84.62%.Average RAIs for cases who had received 0,1,≥2,and an unknown number of doses of measles containing vaccine(MCV)were 43.43%,50.34%,65.38%,and 47.84%,with proportions for high avidity being 36.36%,46.94%,87.50%,and 42.11%.Conclusions The avidity of measles antibodies among measles cases increased with increasing age and number of MCV doses administered.Avidities among cases aged<8 months and 20-39 years were low.It is necessary to give a booster dose of MCV for young women of childbearing-age.