[Clinical significance of specific IgG4 antibody in serum]

Specific IgG4 antibodies in sera were measured by ELISA in allergic patients who were diagnosed as susceptible to one or more allergens among mite, milk, soybean or egg white, and also in a non-allergic control group, and their diagnostic significance was investigated. The results obtained were as follows. 1. The level of specific IgG4 antibody was significantly higher in each allergic group than in the non-allergic group. 2. The positive rates in the specific IgG4 antibody determination were higher than those in RAST in the milk-, soybean- and egg white-allergic groups. 3. In each allergic group, the causative allergens were detected more accurately by measuring both specific IgG4 antibody and IgE antibody (RAST) than IgE alone. 4. The positive rates in the specific IgG4 antibody determination were higher than those in the skin test in each allergic group. 5. It was demonstrated that the combination of the skin test with specific IgG4 antibody measurement ensured a more accurate detection of causative allergens than the skin test alone. These results indicated that the measurement of the specific IgG4 antibody is a helpful method to detect the causative allergens in allergic patients.