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Casein‐specific immunoglobulins in cow's milk allergic patient subgroups reveal a shift to IgA dominance in tolerant patients
Author(s) -
Sletten Gaynour B. G.,
Halvorsen Ragnhild,
Egaas Eliann,
Halstensen Trond S.
Publication year - 2007
Publication title -
pediatric allergy and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.269
H-Index - 89
eISSN - 1399-3038
pISSN - 0905-6157
DOI - 10.1111/j.1399-3038.2006.00489.x
Subject(s) - immunoglobulin e , casein , immunology , milk allergy , medicine , antibody , allergy , immunoglobulin g , epitope , biology , biochemistry
Differences in casein‐specific immunoglobulin (Ig) G‐subclass and IgA serum levels between reactive and tolerant patients may hint at the immunopathogenesis during tolerance development in cow's milk allergy (CMA). α ‐, β‐ and κ ‐casein‐specific IgG 1 , IgG 4 , IgE and IgA serum levels were compared in clinically reactive and tolerized IgE‐mediated (n = 15) and non‐IgE‐mediated (n = 14) CMA with delayed gastrointestinal symptoms, using enzyme‐linked immunosorbent assay (ELISA) and immunoblot techniques. The median anti‐casein IgE levels in clinically reactive IgE‐mediated CMA patients (n = 9) were 140‐ to 180‐fold higher than in tolerized patients (n = 6) and 160‐ to 200‐fold higher than in controls (n = 10). Median α ‐, β‐ and κ ‐casein‐specific IgG 1 and IgG 4 levels were nine‐ to 60‐fold higher in reactive patients and five‐ to 60‐fold in tolerized patients. Clinical tolerance in IgE‐mediated CMA was thus associated with decreased casein‐specific IgE, IgG 4 and IgG 1 , whereas serum IgA anti‐ α ‐, β ‐ and κ ‐casein remained practically unaltered. Tolerized cow's milk protein (CMP)‐sensitive atopic dermatitis had, in particular, decreased κ ‐casein‐specific IgG 1 levels, compared with clinically reactive patients. The ELISA levels to immunoblot correlation profile for the α ‐, β ‐ and κ ‐casein‐specific IgE suggested that the IgE‐mediated CMA patients predominantly reacted to tertiary α ‐ and β ‐casein epitopes whereas the IgE in non‐IgE‐mediated patients reacted to linearized α ‐, β ‐ and κ ‐casein epitopes. Clinical tolerance in non‐IgE‐mediated CMA patients (n = 9) was associated with a four‐ to 10‐fold decrease in casein‐specific IgE levels, accompanied by a five‐ to eightfold decrease in IgG 1 and five‐ to 60‐fold decrease in IgG 4 levels, whereas casein‐specific IgA levels remained unaltered. Thus, tolerance in both patient groups was characterized by a generalized decreased humoral immune response to caseins, which induced a functional shift to IgA dominance.