IgG4: characteristics and its role in allergic diseases

We present a review on the knowledge accumulated since Parish described the existence of an anaphylactic antibody with properties different from that of IgE. We analyze its biologic and physicochemical characteristics and state its possible dual action such as anaphylactic and blocking antibody. Likewise we point out its etiologic role in the different allergic diseases stressing its participation in atopic and nonatopic bronchial asthma.