Abstract:

Objective To evaluate the role of the avidity of Epstein-Barr virus （EBV）capsid antigen（EBV-CA） -specific IgG antibodies and immunological changes among children with infectious mononucleosis （IM）. Methods A total of 5 882 children （500 cases of IM and 5 382 cases of non-IM） were enrolled for determining the avidities of EBV-CA IgG antibodies and EBV-CA IgM antibodies. The avidities of EBV-CA IgG antibodies and EBV-CA IgM antibodies,EBV DNA load,heterotypic lymphocytes and lymphocyte subsets in peripheral blood were determined. Receiver operating characteristic （ROC） curves were used to evaluate the efficiency of the avidities of EBV-CA IgG antibodies and EBV-CA IgM antibodies,heterotypic lymphocyte percentage and EBV DNA individually and combinedly in the diagnosis of IM. The immunological changes among children with IM were observed. Totally,502 clinically assigned IM child samples conducted EBV DNA and lymphocyte subset determinations were reviewed as well,and the immunological changes were compared between EBV DNA positive and negative samples. Results A total of 1 031 of 5 882 （17.53%） children got any one of the 4 indicators with the avidities of EBV-CA IgG antibodies and EBV-CA IgM antibodies,heterotypic lymphocyte percentage and EBV DNA as a positive control. IM ranked top （38.1%） in the disease panel. Receiver operating characteristic （ROC） curve analysis revealed that the areas under curve （AUC） for the avidities of EBV-CA IgG antibodies and EBV-CA IgM antibodies,heterotypic lymphocyte percentage and EBV DNA reached to 0.883,0.729,0.788 and 0.664,respectively,while the 4 indicators' combined analysis got the AUC of 0.847. The 1 031 children were classified into 4 groups as infant （<1-year-old）,baby （1-3-year-old）,preschool age （4-6-year-old） and school age （7-17-year-old） groups. Except infant group,in the other 3 groups,IM patients had lower proportions of CD3^-CD16⁺CD56⁺ natural killer（NK） cells,CD3^-CD19⁺B cells,CD3⁺CD4⁺ T cells and CD4⁺/CD8⁺ ratio than those of non-IM patients （P<0.01）,and they had higher proportions of CD3⁺ T cells and CD3⁺CD8⁺ T cells than those of non-IM patients （P<0.01）. In infant group,IM patients had lower CD3^-CD19⁺ B cell proportion （P<0.01） and higher CD3⁺ T cell,CD3⁺CD8⁺T cell proportions than non-IM patients （P<0.01）. There was no statistical significance of CD3^-CD16⁺CD56⁺ NK cell proportion,CD3⁺CD4⁺ T cell proportion and CD4⁺/CD8⁺ ratio between IM and non-IM patients （P>0.05）. In IM patients,the alteration of lymphocyte subsets got more significance in EBV DNA positive patients than negative patients. Conclusions For the diagnosis of IM,the avidity of EBV-CA IgG antibody is more efficient than heterotypic lymphocyte percentage,EBV-CA IgM antibody and EBV DNA. Cell immune status is disturbed in IM children,and is even worse for those with positive EBV DNA.

Key words: Avidity of Epstein-Barr virus capsid antigen-specific IgG antibody, Epstein-Barr virus, Infectious mononucleosis