EBV capsid antigen-immunoglobulin M antibody titer and serum EBV DNA load are associated with severity of patients with infectious mononucleosis: a retrospective analysis of clinical features of 250 cases

Abstract

Objective To explore the possible associations between EBV capsid antigen-immunoglobulin M antibody (EBV-VCA-IgM), serum EBV DNA load and clinical severity, laboratory results in adolescent and adult patients with infectious mononucleosis (IM). Methods Clinical data of 250 adolescent and adult IM patients were retrospectively analyzed. Patients were divided into two groups by EBV-VCA-IgM titer (>160 U/mL or≤160 U/ mL) and serum EBV DNA level (>3.38 lg copies/mL or <3.38 lg copies/mL), respectively. Clinical data were compared between the two groups, respectively. The t test was used for intergroup comparison and the Mann-Whitney U test was used for non-normally distributed data. Results Compared with those with lower VCA-IgM antibody titer (≤160 U/ mL), sore throat (83.0% [122/147] vs 67.2%[43/64], χ2=6.534, P=0.011), pharynx secretion (59.9% [88/147] vs 40.6% [26/64], χ2=6.645, P=0.010), and swollen tonsils (78.9% [116/147] vs 59.4% [38/64], χ2=8.631, P=0.003) were more common in those with higher VCA-IgM antibody titer (>160 U/mL). ALT level was higher as well in those with higher VCA-IgM antibody titer (290.5[168.0, 460.5] U/L vs 221.0[113.0, 440.5] U/L, Z=-2.251, P=0.024). The peak body temperature ([39.2±0.7] °C vs [38.7±0.7] °C, t=-3.150, P=0.002), maximum WBC counts (16.2 [12.2, 20.4]×109/L vs 13.4[11.1, 17.3] ×109/L, Z=-2.098, P=0.036), maximum percentage of lymphocyte ([72.0±7.8]% vs [68.2±7.0]%, t=-2.238, P=0.028), and lymphocyte EBV DNA load ([5.5±0.9] lg copies/mL vs [4.8±1.0] lg copies/mL, t=-2.602, P=0.012) in those with higher serum EBV DNA load >3.38 lg copies/mL were higher than those with serum EBV DNA load <3.38 lg copies/mL. Regression analysis showed that serum EBV DNA load was associated with the peak body temperature (regression coefficient 0.368, P=0.003) and lymphocyte EBV DNA load (regression coefficient 0.389, P=0.002). Conclusions In adolescents and adults, EBV-VCA-IgM antibody titer and serum EBV DNA load are associated with severity of patients with infectious mononucleosis. Key words: Infectious mononucleosis; Virology; Adult; Adolescent; Severity