Specific immunotherapy (SCIT) with recombinant allergens: a new option to treat allergic rhinitis

Currently there exist native extracts and allergoids (chemically modified extracts) for the treatment with SCIT of patients suffering from allergic rhinitis. Unfortunately, those extracts have several unfavourable properties (such as collection of allergens, standardization, comparison with extracts of other companies,...). In producing novel substances for SCIT, research groups hope to improve those properties: recombinant allergens promise to pen-nit precise definition and evaluation of the specific properties of those molecules. In this way, allergens could be produced in maximal purity and in a standardized, reproducible manner. Beside that the amount of allergens Could be defined easily by mass units. Furthermore, the potency could be increased and the number of adverse events Could be reduced by creating hypoallergenic variants of recombinant allergens. This article describes how those allergens are produced and modified. Consecutively, the first clinical experiences with recombinant allergens, hypoallergenic variants of recombinant allergens and allergens conjugated to substances are presented. Those trials especially use molecules of grass pollen, birch pollen and ragweed pollen. The results showed a significant reduction of "symptom medication score" and immunological parameters (IgG1/IgG4: increase, reduction of IgE). Some of the trials even proved a favorable safety profile. Concluding those perceptions, it seems to be likely that SCIT with recombinant allergens could represent a possible alternative to the common SCIT. But, therefore, clinical trials have to follow in order to strengthen and support those results.