Value of IgG4 antibodies against foods in atopic dermatitis

Various authors have linked IgG4 antibodies to biological activities that are apparently contradictory in different studies. On one hand, it has been confirmed that during immunotherapy with inhalant and Hymenoptera venom antigens, an increase is produced in specific IgG4 levels.

On the other hand, it has been suggested that these antibodies can intervene in hypersensitivity reactions, basically when these are directed against food antigens. We studied IgG4 levels against milk and egg fractions in patients with atopic dermatitis (AD) (n = 23), and in healthy individuals (n = 20). Patients with AD had significantly much higher IgG4 levels against egg white (24.16 micrograms/ml), egg yolk (9.96 micrograms/ml) and beta-lactoglobulin (10 micrograms/ml) than those found in healthy individuals (6.75, 3.12, 3.35 micrograms/ml, respectively), with no significant differences for alpha-lactalbumin and casein.

Patients with AD without hypersensitivity to egg and milk, at the moment of the study, also had significantly higher levels than those of control individuals, against egg white (27.11 micrograms/ml), egg yolk (12 micrograms/ml) and beta-lactoglobulin (11.72 micrograms/ml). There were no differences in IgG4 levels against alpha-lactalbumin, beta-lactoglobulin and casein, when comparing patients with AD and hypersensitivity to milk, and patients with AD without present hypersensitivity to milk.

We concluded that patients with AD presented high IgG4 levels against egg and milk fractions, in relation to the healthy population, and that the fraction of milk with the highest antigenic potency was beta-lactoglobulin.

CITATION  Allergol Immunopathol (Madr). 1990 Jul-Aug;18(4):187-90