高水平血清HCMV IgM在低龄儿童原发性HCMV感染诊断中的作用

Diagnostic role of high HCMV IgM level in serum for HCMV primary infection

目的：探讨血清人巨细胞病毒（HCMV）IgM水平在低龄儿童中诊断原发性HCMV感染的意义。方法收集临床诊断为HCMV感染的患儿血标本56例，年龄为0.5-1岁，采用全自动化学发光法分别定量检测血清HCMV IgG、IgM抗体水平，以及IgG亲和力指数。结果 HCMV IgG＋患儿亲和力检测结果发现，其中IgM-/IgG＋的5例患者都为高亲和力IgG，而IgM＋/IgG＋的42例患者中25例是低亲和力IgG，占59.5%。根据IgM定量检测结果进一步将此47例HCMV IgG＋患儿由低至高分成5组，分别为IgM阴性组（〈30 AU/mL），30-100 AU/mL组，100-170 AU/mL组，170-240 AU/mL组以及大于240 AU/mL组。随着IgM抗体水平的增加，低亲和力样本所占比例呈增高趋势，经卡方检验，差异有统计学意义（χ2=12.72，P〈0.05）。结论在0.5-1岁婴儿中，HCMV IgM水平与HCMV原发感染呈正相关，临床同时参考IgM定量检测和HCMV IgG亲合力检测结果，将对0.5-1岁以内婴幼儿近期HCMV感染发生时间的判定起到有益的互补作用。先进行HCMV IgM定量检测，再进行阳性病例的IgG亲和力检测是低龄儿童原发HCMV感染实验室诊断的可行方案。

Objective To study the diagnostic role of human cytomegalovirus （HCMV） IgM level for HCMV primary infection in lower aged children. Methods 56 serum samples were collected from 0.5~1 years old new borns, who were clinically diagnosed as HCMV infection. HCMV IgM/IgG and IgG avidity were quantitatively detected by automatic CLIA. Results Among the HCMV IgG positive samples, 5 samples, which were IgM-/IgG＋, showed high HCMV IgG avidities. In the remaining 42 samples, which were IgM＋/IgG＋, 25 samples （about 59.5%） showed low IgG avidities. Based on the HCMV IgM level, the samples were further divided into 5 groups：IgM negative group （240 AU/mL group. It was found that the percentage of HCMV IgG low avidity samples were increased with increases of IgM levels. The difference was statistically significant （χ2=12.72, P〈0.05）. Conclusion High HCMV IgM level in serum are positively correlated to HCMV primary infection among newborns of 0.5~1 age. Quantitative IgM assay could be complimentary to diagnosis of primary HCMV infection in paralle with IgG avidity test. This data imply that quantitatively detection of HCMV IgM antibody followed by IgG avidity detection is practical proposal for laboratory diagnosis of HCMV primary infection in lower aged children.