Abstract:

Objective To investigate the characteristics of lymphocyte subsets in children with Epstein-Barr virus（EBV） infection,and to study EBV DNA load. Methods A total of 17 infectious mononucleosis（IM）patients,18 chronic active Epstein-Barr virus（CAEBV） infection patients and 15 healthy children were enrolled. Lymphocyte subsets were determined by flow cytometry. EBV DNA load in peripheral blood was determined by fluorescence quantitation polymerase chain reaction（PCR）. The results were analyzed statistically by Kruskal-Wallis H test and Mann-Whitney U test. The correlation analysis was performed by Spearman method. Results The lymphocyte count and proportion and CD4⁺T and CD8⁺T cell counts in IM group were higher than those in healthy control group（P<0.05）,and the proportion and count median of CD8⁺T cell reached up to 61.5% and 5 217/μL. Natural killer（NK） cell and CD19⁺ cell proportions in IM group were lower than those in healthy control group（P<0.05）. The lymphocyte proportion in CAEBV group was higher than that in healthy control group（P<0.05）,and there was no statistical significance in B,NK,CD4⁺T and CD8⁺T cell counts between the 2 groups（P>0.05）. CD4⁺T and CD8⁺T cell counts in CAEBV group were lower than those in IM group（P<0.05）. The medians of EBV DNA load in IM and CAEBV groups were 4.90×10³ and 1.25×10^{4 copies}/mL,respectively. The EBV DNA loads between the 2 groups had statistical significance（P=0.027）. No correlation was found between the number of lymphocyte subsets and EBV DNA load（P>0.05）. Conclusions The characteristics of lymphocyte subsets between the 2 groups are different. The increasing of extensively activated CD8⁺T cells in IM group is a cause for lymphocyte count increasing. The combined determination of lymphocyte subsets and EBV DNA load is helpful for the differential diagnosis of IM infection and CAEBV infection.

Key words: Epstein-Barr virus, T cell, B cell, Natural killer cell, DNA load, Infectious mononucleosis, Chronic active Epstein-Barr virus infection