Serum β 2-microglobulin may be a viral biomarker by analyzing children with upper respiratory tract infections and exanthem subitum: a retrospective study

Abstract

Background: Due to the lack of effective and feasible viral biomarkers to distinguish viral infection from bacterial infection, children often receive unnecessary antibiotic treatment. To identify serum β2-microglobulin that distinguishes bacterial upper respiratory tract infection from viral upper respiratory tract infection and exanthem subitum in children.

Methods: This retrospective study was conducted from January 1, 2019 to September 30, 2020 in Yancheng Third People's Hospital. Children with upper respiratory tract infection and exanthem subitum were recruited. The concentration of serum β2-microglobulin in the viral and bacterial infection groups were statistically analyzed.

Results: A total of 291 children included 36 with bacterial upper respiratory tract infection (median age, 13 months; 44.4% female), 197 with viral upper respiratory tract infection (median age, 12 months; 43.7% female) and 58 with exanthem subitum (median age, 13 months; 37.9% female). When the concentration of β2-microglobulin was 2.4mg/L, the sensitivity to distinguish viral from bacterial upper respiratory tract infection was 81.2% (95% CI [75.1-86.4%]), and the specificity was 80.6% (95% CI [64.0-91.8]%). When the cutoff was 2.91 mg/L, the sensitivity of β2-microglobulin to distinguish exanthem subitum from bacterial upper respiratory tract infection was 94.8% (95% CI [85.6-98.9]%), and the specificity was 100% (95% CI [90.3-100]%).

Conclusions: Serum β2-microglobulin may be a significant biological indicator in children with upper respiratory tract infection and exanthem subitum.

Keywords: Exanthem subitum; Serum β2-microglobulin; Upper respiratory tract infections; Viral biomarker.

Figure 1. Pathogens of upper respiratory tract infection.

In the cases of upper respiratory tract infection, there are 36 cases of bacterial infection and 197 cases of viral infection. The children’s ages range from 6 months to 24 months. The main pathogen of bacterial URTI is Streptococcus hemolyticus. The main pathogens of viral URTI are influenza A virus and adenovirus.

Figure 2. β2-MG for identification of viral infection by ROC curve evaluation.

(A) The distribution of serum levels of β2-microglobulin in bacterial URTI, viral URTI and exanthem subitem groups are shown by scatter plot. (B) ROC curves of β2-microglobulin levels for differentiating viral from bacterial URTI. The AUC for β2-microglobulin was 0.91 (95% CI [0.86–0.96]). (C) ROC curves of β2-microglobulin levels for distinguishing exanthem subitem from bacterial URTI. The AUC for β2-microglobulin was 0.99 (95% CI [0.98–1.00]). (D) ROC curves of β2-microglobulin levels for distinguishing exanthem subitem from viral URTI. The AUC for β2-microglobulin was 0.90 (95% CI [0.85–0.95]).