IgG subclass antibodies to dietary antigens in atopic dermatitis.

The role of IgG subclasses and IgG subclass antibodies in atopic disease is controversial. Serum IgG and IgG subclass (IgG1-4) antibodies to the two dietary antigens ovalbumin (OA) and beta-lactoglobulin (BLG) were measured with ELISA-methods in 16 patients with mild or moderate atopic dermatitis (AD) and healthy controls. The IgG antibodies were measured in 31 patients with previous AD and controls. The IgG subclass antibodies to OA and BLG showed predominance of IgG4 and IgG1 for both patients and controls. The levels of IgG and IgG subclass antibodies to OA did not differ between the groups, but the levels of IgG and IgG4 anti-BLG antibody were higher in patients with active AD than in controls. The antibody levels did not correlate with severity of disease or with a history of food allergy/intolerance. IgG4 antibodies to dietary antigens may be elevated in AD, but the diagnostic significance of IgG subclass antibody measurement is limited.