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.MethodsSerum 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.ResultsSerum 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 μmol/L vs 1.56±0.12 μmol/L; P<0.05). IgG2 and IgG4 deficiency (27%) was the most common in 22 RRTI children with vitamin A deficiency.ConclusionsSerum 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. ［Chin J Contemp Pediatr, 2007, 9 (6):557-558］
