title: Increased serum IgG and IgA in overweight children relate to a less favourable metabolic phenotype.
abstract: BACKGROUND
  The adaptive immune system has emerged as an unexpected modulator of insulin resistance. B lymphocytes accumulate in adipose tissue and produce pathogenic antibodies that cause insulin resistance.
  
  
  OBJECTIVE
  We studied whether circulating immunoglobulins (IgG, IgA and IgM) were related to metabolic risk markers in pre-pubertal children with and without overweight.
  
  
  METHODS
  Subjects were 270 asymptomatic pre-pubertal Caucasian children (145 lean, 125 overweight) recruited in a primary care setting. Assessments included serum IgG, IgA and IgM concentrations (nephelometry), insulin resistance (HOMA-IR) and fasting lipids (triacylglycerol and high-density lipoprotein [HDL]-cholesterol).
  
  
  RESULTS
  Overweight children had higher IgG and IgA serum levels than lean children (P ≤ 0.01). Increasing serum IgG and IgA, but not IgM, were associated with a less favourable metabolic phenotype, consisting of higher HOMA-IR and triacylglycerol and lower HDL-cholesterol, particularly in obese children, in whom serum IgG and IgA were both independently associated with HOMA-IR (β = 0.308, P = 0.017, r2  = 9.5% and β = 0.361, P = 0.005, r2  = 13.0%, respectively) and triacylglycerol (β = 0.343, P = 0.006, r2  = 11.1% and β = 0.354, P = 0.003, r2  = 12.2%, respectively).
  
  
  CONCLUSIONS
  Increased circulating IgG and IgA in overweight children are associated with a less favourable metabolic phenotype, particularly in obese children. These results suggest a relationship between adaptive immunity and insulin resistance in childhood obesity.
authors.affiliation: Pediatrics, Dr. Josep Trueta Hospital, and Girona Institute for Biomedical Research, Girona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Bassols
authors.forename: A
authors.initials: A
authors.lastname: Prats-Puig
authors.forename: M
authors.initials: M
authors.lastname: Gispert-Saüch
authors.forename: M
authors.initials: M
authors.lastname: Crehuet-Almirall
authors.forename: G
authors.initials: G
authors.lastname: Carreras-Badosa
authors.forename: F
authors.initials: F
authors.lastname: Díaz-Roldán
authors.forename: M
authors.initials: M
authors.lastname: Montesinos-Costa
authors.forename: F
authors.initials: F
authors.lastname: de Zegher
authors.forename: L
authors.initials: L
authors.lastname: Ibáñez
authors.forename: A
authors.initials: A
authors.lastname: López-Bermejo
mesh_terms: D056704:Adaptive Immunity / Q000276:immunology*; D015992:Body Mass Index; D002648:Child; D008076:Cholesterol, HDL / Q000097:blood*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007074:Immunoglobulin G / Q000097:blood*; D007333:Insulin Resistance / Q000276:immunology; D008297:Male; D063766:Pediatric Obesity / Q000097:blood* / Q000276:immunology / Q000517:prevention & control; D010641:Phenotype; D012307:Risk Factors; D013030:Spain; D014280:Triglycerides / Q000097:blood*
chemical_list: D008076:Cholesterol, HDL; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D014280:Triglycerides
keywords: IgA; IgG; insulin; triglycerides