Specific down-regulation of anti-allergen IgE and IgG antibodies in humans associated with injections of allergen-specific antibody complexes.

Several approaches have recently been put forward describing attempts to suppress the IgE immune response towards allergens, which is thought to be the key event in allergic diseases. In a series of clinical trials we have shown that injections of complexes made up from allergen and specific antibodies are an effective treatment for allergic bronchial asthma and atopic dermatitis. In the work presented here we have examined the humoral immunity changes associated with the use of such complexes in a group of 19 adult patients suffering from atopic dermatitis and hypersensitive to Dermatophagoides pteronyssinus (Dp), and in whom a significant clinical improvement was observed. By comparing serum samples taken prior to and after 4 months of therapy, we show that the administration of immune complexes is associated with: (i) a significant and selective reduction of IgG and IgE antibodies specific for Dp allergens; (ii) a down-regulation that affects only the antibodies present in the complexes; (iii) the induction of corresponding anti-idiotypic antibodies. To our knowledge, this is the first demonstration in humans that an anti-allergen antibody response can be down-regulated in a highly selective manner and that this is accompanied by significant clinical improvement. Moreover, the selective reduction of IgG antibodies could be of value in the treatment of some forms of auto-immune diseases.