Limberková R, Smíšková D, Havlíčková M, Herrmannová K, Lexová P, Malý M
Epidemiol Mikrobiol Imunol. 2015 Mar;64(1):16-9.
Serological diagnosis of epidemic mumps can be difficult in vaccinated persons, particularly due to the absence of specific IgM antibodies. The aim was to find whether adding the detection of IgA antibodies to the currently used routine serological diagnosis of mumps (detection of IgM and IgG antibodies in an acute serum sample) would make the serological diagnosis of mumps more effective in a population with a high vaccination coverage. At the same time, ELISA kits for the detection of early IgA and IgM antibodies against the mumps virus were compared and statistical analysis of the results was performed.
Sixty-four acute sera from patients with laboratory confirmed diagnosis of mumps were included in the study. Clinical specimens were collected at the onset of clinical symptoms. To test the sera, the MASTAZYME ELISA Mumps IgA kit (MAST DIAGNOSTICA, Germany) with the MASTSORB sorbent (RF and IgG) and Enzygnost Anti-Parotitis-Virus/IgM kit (Siemens, Germany) were used. A panel of 121 acute sera with no epidemiological link to mumps virus served as specificity controls for the IgA assay. The epidemiological data were derived from the EPIDAT system. The level of agreement was assessed using the McNemara test and Cohen's coefficient kappa. The Stata 9.2 software (Stata Corp LP, College Station, USA) was used for statistical analysis.
The detection of IgA and IgM antibodies against the mumps virus yielded concordant results in 50/64 acute sera, 32 positive and 18 negative, i.e. an agreement of 78.12 %. Of the remaining 14 samples, 13 were only IgA positive and one was only IgM positive. The controls showed non-specific IgA positivity in 5/121 samples which indicates a 96% specificity.
The absence of specific IgM antibodies against mumps virus is relatively often seen in vaccinated indivi-duals; nevertheless, the test is routinely used in patients with suspected active infection. The test for IgA antibodies, which is not routinely performed, significantly increased the detection rate of the disease. Based on the results of the present study, it can be concluded that the combination of the anti-mumps IgM and IgA assays increased the effectiveness of the serological diagnosis at the onset of clinical symptoms from less than 52% to nearly 72%.
对于接种过疫苗的人群，流行性腮腺炎的血清学诊断可能存在困难，尤其是因为缺乏特异性IgM抗体。本研究旨在探究，在目前常用的腮腺炎常规血清学诊断方法（检测急性血清样本中的IgM和IgG抗体）中加入IgA抗体检测，是否能在疫苗接种覆盖率高的人群中提高腮腺炎血清学诊断的有效性。同时，对检测腮腺炎病毒早期IgA和IgM抗体的ELISA试剂盒进行比较，并对结果进行统计分析。
本研究纳入了64份实验室确诊为腮腺炎患者的急性血清。临床标本在临床症状出现时采集。为检测血清，使用了配有MASTSORB吸附剂（RF和IgG）的MASTAZYME ELISA腮腺炎IgA试剂盒（德国MAST DIAGNOSTICA公司）和Enzygnost抗腮腺炎病毒/IgM试剂盒（德国西门子公司）。一组121份与腮腺炎病毒无流行病学关联的急性血清用作IgA检测的特异性对照。流行病学数据来自EPIDAT系统。使用McNemara检验和Cohen's kappa系数评估一致性水平。使用Stata 9.2软件（美国德克萨斯州大学站Stata公司）进行统计分析。
在64份急性血清中，检测腮腺炎病毒的IgA和IgM抗体结果一致的有50份，其中32份为阳性，18份为阴性，即一致性为78.12%。在其余14份样本中，13份仅IgA呈阳性，1份仅IgM呈阳性。对照样本中有5/121出现非特异性IgA阳性，表明特异性为96%。
在接种过疫苗的个体中，相对常见缺乏针对腮腺炎病毒的特异性IgM抗体，但该检测仍常规用于疑似活动性感染的患者。通常不进行的IgA抗体检测显著提高了疾病的检出率。根据本研究结果，可以得出结论，抗腮腺炎IgM和IgA检测相结合，使临床症状出现时血清学诊断的有效性从不到52%提高到了近72%。
