title: [Serum levels of IgG subclasses and vitamin A in children with recurrent respiratory tract infection].
abstract: OBJECTIVE
  The development of recurrent respiratory tract infection (RRTI) is related to vitamin A deficiency and immune function abnormality in children. This study examined serum levels of IgG subclasses and vitamin A in children with recurrent respiratory tract infection.
  
  
  METHODS
  Serum IgG subclasses levels (IgG1, IgG2, IgG3, IgG4) were detected using ELISA and serum vitamin A levels were detected using high performance liquid chromatography-Miller method in 80 children with RRTI (ranged from 2-10 years old). The values were compared with those from 80 aged-matched healthy children.
  
  
  RESULTS
  Serum levels of IgG2 (1.52 +/- 0.18 g/L) and IgG4 (0.22 +/- 0.12 g/L) in children with RRTI were significantly lower than controls (IgG2: 2.23 +/- 0.08 g/L; IgG4: 0.28 +/- 0.01 g/L) (P < 0.05). Serum vitamin A levels in children with RRTI were also significantly lower than controls (1.16 +/- 0.22 micromol/L vs 1.56 +/- 0.12 micromol/L; P < 0.05). IgG2 and IgG4 deficiency (27%) was the most common in 22 RRTI children with vitamin A deficiency.
  
  
  CONCLUSIONS
  Serum levels of IgG subclasses, IgG2 and IgG4, and vitamin A decrease in children with RRTI. There might be some relationship between the decreased IgG2 and IgG4 levels and vitamin A deficiency.
authors: Nanjing Children's Hospital Affiliated to Nanjing Medical University, Nanjing, China. molisa.student@sina.com
authors: Li
authors: L
authors: Qian
authors: Ji-Rong
authors: JR
authors: Lu
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000145:classification; D008297:Male; D012141:Respiratory Tract Infections / Q000097:blood*; D014801:Vitamin A / Q000097:blood*
chemical_list: D007074:Immunoglobulin G; D014801:Vitamin A