Recombinant allergens and immunotherapy

The development of new immunotherapy techniques using products produced by molecular biology requires that their efficacy be controlled by appropriate clinical trials. An outline of the principal molecules derived through fundamental research during the past few years will include recombinant allergens corresponding to natural allergens that are pertinent because of their high prevalence of sensitivity, hypoallergenic derivatives of recombinant allergens (polymers, fragments, molecules with mutations or amino acid deletions), hybrid molecules, T-cell epitopes, B-cell epitopes, and molecules conjugated with CpG or other co-stimulants. The biological activity of a large number of these molecules has been demonstrated in vivo. The selection of candidate molecules for immunotherapy will depend first of all on the results of preliminary open studies on a limited number of patients. Here, we report the results of five double blind immunotherapy studies, in which the control group received placebo, and in two studies another group was treated with natural extract. The most statistically significant clinical results were observed with unmodified recombinant allergens, without occurrence of severe systemic reactions. In these five studies, there was a significant increase in the level of specific IgG with the natural allergen and with the recombinant allergens. Decrease in skin test responses in the treated groups relative to the placebo group was significant in two of the three studies. Studies including a greater number of patients are now needed to meet the demands of regulatory requirements for clinical development of recombinant allergens. (C) 2007 Elsevier Masson SAS. Tous droits reserves.