婴幼儿巨细胞病毒感染器官损害与基因型

Organ damage and genotypes of infantile cytomegalovirus infection

目的了解婴幼儿人巨细胞病毒(HCMV)感染时,母婴血清抗体不同表型与其肝损伤和致畸的关系,并检测其糖膜蛋白B基因型。方法选择2009年1月—2010年12月某院收治的337例血清HCMVIgG抗体阳性,尿液HCMVDNA定量>500copies/mL的HCMV感染患儿,同时检测其母亲血清HCMVIgG抗体。采用酶联免疫捕获法检测血清HCMV抗体;荧光定量聚合酶链反应(PCR)检测HCMVDNA;人胚肺成纤维细胞(HEL)进行HCMV病毒分离;巢式PCR、限制性片段长度多态性(RFLP)分析技术进行HCMV临床分离株糖膜蛋白B基因型检测。结果在337例HCMV感染患儿中,124例血清抗体表型为HCMVIgM(+)IgG(+),其母亲血清抗体表型HCMVIgG(-)组患儿肝功能异常与致畸率分别为86.42%和40.74%,显著高于母亲IgG(+)组的65.12%和34.88%(均P<0.01);213例患儿血清抗体表型为HCMVIgM(-)IgG(+),其母亲血清抗体表型HCMVIgG(+)与IgG(-)两组比较,患儿肝功能异常率(53.85%vs66.89%)差异无显著性(P>0.05),而致畸率母亲IgG(-)组(28.38%)显著高于IgG(+)组(23.08%)(P<0.05)。HCMVIgG(+),尿液HCMVDNA≥104copies/mL患儿的尿标本中病毒分离阳性率为50.00%(31/62)。随机抽取8株HCMV临床分离株(来源患儿中7例有肝脑损害),检测糖膜蛋白B基因,均为gB1型,与标准株AD169株、TOWNE株的DNA序列相似性分别达94.8%和97.0%。8株HCMV的DNA序列同源性达98.5%;氨基酸序列同源性高达99.4%。结论母亲为HCMVIgG阳性的患儿肝功能异常和致畸率比母亲为HCMVIgG阴性的患儿低。HCMVDNA≥104copies/mL婴幼儿可预示症状性HCMV感染。gB1型可能是导致婴幼儿肝脑损害的主要基因型。

Objective To investigate the association between serum antibodies or glycoprotein B （gB） genotype of human cytomegalovirus （HCMV） with liver damage or birth defect. Methods From January 2009 to December 2010, 337 hospitalized infants whose serum HCMV IgG antibody was positive and HCMV DNA in urine exceeded 500 copies/mL were included in the study. HCMV antibodies （IgG, IgM） of infants and mothers were detected by capture enzyme-linked immunosorbent assay; HCMV DNA in infants were detected by real-time polymerase chain reaction; HCMV from clinical specimens were cultured in human embryonic lung fibroblasts; HCMV gB was genotyped by nested PCR restriction fragment length polymorphism. Results Of 337 infants infected with HCMV, serum HCMV antibodies of 124 were both IgM（ ＋ ） and IgG（ ＋ ）, liver damage rate and birth defect rate were higher in infants whose mothers＇ HCMV IgG were negative than that were positive（86. 42%vs 65.12% for liver damage,40. 74% vs 34. 88% for birth defect, P〈0. 01）; Serum HCMV antibodies were IgM（ - ） and IgG（ ＋ ） in 213 infants,liver damage rate in infants whose mothers serum antibodies were IgG （ ＋ ） was not significantly different compared with that were IgG（ - ）（53. 85% vs 66. 89%, P）0. 05）, but birth defect rate in IgG（ - ） group was higher than IgG （ ＋ ） group （28. 38% vs 23.08%, P〈0. 05）. Isolation rate of HCMV from urine was 50. 00%（31/ 62） in infants whose HCMV IgG were positive and urine HCMV DNA 〉104 copies/mL, gB genotype of 8 random- ly selected HCMV strains（7 were from infants with liver or brain damage） were all gB1, compared with AD169 or TOWNE strain, DNA sequence homology was 94. 8% and 97. 0% respectively, homology of DNA sequence among 8 strains was 98. 5%,and amino sequence was 99. 4%. Conclusion The liver damage and birth defect are lower in infants whose mothers＇ HCMV IgG were positive than that were negative. Urine HCMV DNA 〉10^4 copies/mL in infants can be a marker for HCMV infection, gB1 may be the main genotype in infants liver and brain damage.