Abstract: Objective To explore the significance of plasma levels of mannan-binding lectin (MBL)-associated serine protease 2
(MASP2) in children with upper respiratory tract infection (URTI). Methods A total of 103 children with URTI and 35 healthy
children were examined for plasma levels of MASP2 and C-reactive protein (CRP). According to CRP levels, white blood cell
count (WBC), stage of infection, and administration of treatments, the children with URTI were divided into the elevated CRP
group (n=48) and the normal CRP group (n=54), elevated WBC group (n=61) and normal WBC group (n=40), the early stage of
infection without treatment group (n=68) and mid-late stage of infection with treatment group (n=35). Results Plasma MASP2
levels was significantly higher in URTI group than in the healthy control group (P<0.001) and showed a close correlation with
age (r=0.302, P<0.01). Plasma MASP2 level was significantly correlated with CRP level in elevated CRP group (r=0.310, P<0.05)
but not in normal CRP group (P>0.05), correlated with WBC in elevated WBC group (r=0.392, P<0.01) but not in normal WBC
group (P>0.05), and was significantly higher in early stage infection without treatment group than in mid-late stage of infection
with treatment group (P<0.01). MASP2, MBL2 and CRP genes had a common binding site for the transcription factor HNF-4α.
Conclusion MASP2 may be an acute-phase protein, and its plasma level might serve as a new reference index in the diagnosis
of URTI in children.