title: The relationships among immunoglobulin levels, allergic sensitization, and viral respiratory illnesses in early childhood.
abstract: IgE plays an essential role in type I allergy, however, there is less information about the relationship between other immunoglobulins (IgA and IgG) and atopic phenotypes in early childhood. We hypothesized that levels of circulating IgA in early childhood would be inversely related to the number of respiratory infections and the risk of becoming sensitized to allergens. Immunoglobulin levels were analyzed (ELISA) in plasma samples (IgG, IgA), and in nasal secretions (IgA) from children participating in a high-risk birth cohort study. Samples were available from 264 children at age 2 yr and 257 children at age 4 yr, and results were compared to rates of respiratory illnesses, allergic sensitization, atopic dermatitis (AD), and asthma. Children who were sensitized to allergens had higher rather than lower levels of circulating IgA. A subgroup analysis showed that IgA levels were increased in relationship to foods sensitization (58 vs. 50 mg/dl, p = 0.003) but not aeroallergen sensitization (52 vs. 53 mg/dl, p = 0.11). IgA levels in the plasma correlated with levels of IgE levels (r(s) =0.19, p = 0.003). Levels of IgE, but not IgG or IgA, were positively correlated with rates of respiratory illnesses, AD, and the risk of developing asthma. Finally, there were no significant relationships between IgA in nasal secretions and infectious outcomes. In conclusion, low-normal concentrations of plasma IgA are associated with a reduced prevalence of allergic sensitization in infancy. Further, levels of IgA and IgG in plasma within the range of normal, and IgA in nasal secretions, do not appear to influence the risk of subsequent respiratory illnesses. Further studies to define relationships between IgA and allergic sensitization are likely to provide new insights into the pathogenesis of allergic diseases in infancy.
authors.affiliation: Department of Pediatrics, University of Wisconsin, Madison, WI, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Possin
authors.forename: Stephanie
authors.initials: S
authors.lastname: Morgan
authors.forename: Douglas F
authors.initials: DF
authors.lastname: DaSilva
authors.forename: Christopher
authors.initials: C
authors.lastname: Tisler
authors.forename: Tressa E
authors.initials: TE
authors.lastname: Pappas
authors.forename: Kathy A
authors.initials: KA
authors.lastname: Roberg
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Anderson
authors.forename: Michael D
authors.initials: MD
authors.lastname: Evans
authors.forename: Ronald
authors.initials: R
authors.lastname: Gangnon
authors.forename: Robert F
authors.initials: RF
authors.lastname: Lemanske
authors.forename: James E
authors.initials: JE
authors.lastname: Gern
mesh_terms: D017668:Age of Onset; D000485:Allergens / Q000276:immunology; D002675:Child, Preschool; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D007070:Immunoglobulin A / Q000097:blood; D007073:Immunoglobulin E / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D011446:Prospective Studies; D012141:Respiratory Tract Infections / Q000097:blood / Q000453:epidemiology* / Q000276:immunology; D012307:Risk Factors; D014777:Virus Diseases / Q000097:blood / Q000453:epidemiology* / Q000276:immunology
chemical_list: D000485:Allergens; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007073:Immunoglobulin E
references.citation: Am J Respir Crit Care Med. 1996 Jun;153(6 Pt 1):1785-9
references.pmid: 8665035
references.citation: J Pathol. 2006 Jan;208(2):270-82
references.pmid: 16362985
references.citation: Ann Allergy. 1977 Nov;39(5):328-31
references.pmid: 920998
references.citation: Curr Opin Immunol. 2008 Apr;20(2):170-7
references.pmid: 18456485
references.citation: Pediatr Allergy Immunol. 2002 Dec;13(6):386-93
references.pmid: 12485313
references.citation: Lancet. 1974 Aug 31;2(7879):485-8
references.pmid: 4136547
references.citation: Clin Exp Allergy. 2002 Sep;32(9):1293-8
references.pmid: 12220466
references.citation: J Allergy Clin Immunol. 2009 Nov;124(5):1078-87
references.pmid: 19895995
references.citation: Thorax. 2000 Aug;55 Suppl 1:S2-10
references.pmid: 10943631
references.citation: Clin Exp Immunol. 1985 Dec;62(3):753-7
references.pmid: 4085155
references.citation: J Allergy Clin Immunol. 2005 Sep;116(3):571-7
references.pmid: 16159626
references.citation: Am J Respir Crit Care Med. 2008 Oct 1;178(7):667-72
references.pmid: 18565953
references.citation: Scand J Immunol. 2005 May;61(5):466-74
references.pmid: 15882439
references.citation: Pediatr Allergy Immunol. 2002;13(s15):38-43
references.pmid: 12688623
references.citation: J Pediatr. 1992 Jul;121(1):23-7
references.pmid: 1625088
references.citation: Clin Exp Allergy. 2008 Jan;38(1):69-78
references.pmid: 17976218
references.citation: Pediatr Allergy Immunol. 1994 Nov;5(4):202-8
references.pmid: 7894626
references.citation: J Allergy Clin Immunol. 2000 Apr;105(4):803-13
references.pmid: 10756233
references.citation: Lancet. 1999 Jan 16;353(9148):196-200
references.pmid: 9923875