title: Patients suffering from non-IgE-mediated cow's milk protein intolerance cannot be diagnosed based on IgG subclass or IgA responses to milk allergens.
abstract: BACKGROUND
  Cow's milk is one of the most common causes of food allergy. In two-thirds of patients, adverse symptoms following milk ingestion are caused by IgE-mediated allergic reactions, whereas for one-third, the mechanisms are unknown. Aim of this study was to investigate whether patients suffering from non-IgE-mediated cow's milk protein intolerance can be distinguished from persons without cow's milk protein intolerance based on serological measurement of IgG and IgA specific for purified cow's milk antigens.
  
  
  METHODS
  We determined IgG(1-4) subclass and IgA antibody levels to purified recombinant αS1-casein, αS2-casein, β-casein, κ-casein, α-lactalbumin, and β-lactoglobulin in four patient groups by ELISA: Patients with IgE-mediated cow's milk allergy (CMA, n=25), patients with non-IgE-mediated cow's milk protein intolerance (CMPI, n=19), patients with gastrointestinal symptoms not associated with cow's milk ingestion (GI, n=15) and control persons without gastrointestinal problems (C, n=26). Cow's milk-specific IgE levels were determined by ImmunoCAP.
  
  
  RESULTS
  Only CMA patients had IgE antibodies to cow's milk. Cow's milk allergic patients mounted the highest IgG(1) and IgG(4) antibody levels to αS1-casein, αS2-casein, β-casein, κ-casein, and α-lactalbumin. No elevated levels of IgG(4) , IgA, and complement-binding IgG subclasses (IgG(1) , IgG(2) , IgG(3) ) to purified cow's milk allergens were found within the CMPI patients compared to persons without cow's milk protein intolerance (GI and C groups).
  
  
  CONCLUSIONS
  Cow's milk protein intolerant patients cannot be distinguished from persons without cow's milk protein intolerance on the basis of IgG subclass or IgA reactivity to cow's milk allergens.
authors.affiliation: Department of Medical and Chemical Laboratory Diagnostics, Medical University of Vienna, Vienna, Austria.
authors.forename: H
authors.initials: H
authors.lastname: Hochwallner
authors.forename: U
authors.initials: U
authors.lastname: Schulmeister
authors.forename: I
authors.initials: I
authors.lastname: Swoboda
authors.forename: T E
authors.initials: TE
authors.lastname: Twaroch
authors.forename: H
authors.initials: H
authors.lastname: Vogelsang
authors.forename: L
authors.initials: L
authors.lastname: Kazemi-Shirazi
authors.forename: M
authors.initials: M
authors.lastname: Kundi
authors.forename: N
authors.initials: N
authors.lastname: Balic
authors.forename: S
authors.initials: S
authors.lastname: Quirce
authors.forename: H
authors.initials: H
authors.lastname: Rumpold
authors.forename: R
authors.initials: R
authors.lastname: Fröschl
authors.forename: F
authors.initials: F
authors.lastname: Horak
authors.forename: B
authors.initials: B
authors.lastname: Tichatschek
authors.forename: C L
authors.initials: CL
authors.lastname: Stefanescu
authors.forename: Z
authors.initials: Z
authors.lastname: Szépfalusi
authors.forename: N G
authors.initials: NG
authors.lastname: Papadopoulos
authors.forename: A
authors.initials: A
authors.lastname: Mari
authors.forename: C
authors.initials: C
authors.lastname: Ebner
authors.forename: G
authors.initials: G
authors.lastname: Pauli
authors.forename: R
authors.initials: R
authors.lastname: Valenta
authors.forename: S
authors.initials: S
authors.lastname: Spitzauer
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens / Q000276:immunology*; D000818:Animals; D002648:Child; D002675:Child, Preschool; D003165:Complement System Proteins / Q000276:immunology / Q000378:metabolism; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood*; D007073:Immunoglobulin E / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood*; D007223:Infant; D008297:Male; D008875:Middle Aged; D016269:Milk Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D008894:Milk Proteins / Q000276:immunology*; D011485:Protein Binding / Q000276:immunology; D055815:Young Adult
chemical_list: D000485:Allergens; D000939:Epitopes; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D008894:Milk Proteins; D007073:Immunoglobulin E; D003165:Complement System Proteins