Recombinant allergens for diagnosis and immunotherapy of allergic disorders, with emphasis on cockroach allergy.

The prevalence of allergic disorders has increased over the past few decades and the quality of life has been significantly influenced at least for the allergic subjects. Allergen avoidance is thought to be the best way of preventing clinical manifestation of the disease, however, it is not possible for some allergens, and other pharmacological and/or immunological treatment has to be made. Repetitive injection of sensitized allergens to the patients (immunotherapy) is the only known curative approach to the disease even though the exact mechanism is not clear to date. Crude extract of allergens has lots of shortcomings which might arouse unexpected results. Genetic engineering and recombinant allergens are thought to be one of the alternative ways to overcome these limitations. Genetic engineering could facilitate the investigation of immune responses of the subjects especially on B cell and T cell epitopes, and produce the therapeutic allergens which might minimize the possible side effects. Furthermore, conjugation of immuno-modulatory molecules such as CpG-ODN, cytokines, or toxins which could act specifically to the given allergens, and maleylation of the allergens could maximize the prophylactic or therapeutic effect. Immunotherapies for the pollen allergy and insect sting allergy have been thought to be successful. House dust mite allergy and cockroach allergy have been reported less beneficial by immunotherapeutic approaches. Cockroaches are one of the most important causes of asthma, and severe complications are often reported in the children in city dwellers with low-incomes. The studies of the biological functions of cockroach allergens and the use of recombinant allergens should allow understanding of mechanisms of cockroach-elicited allergic disorders and development of allergen-specific and sensitive diagnostics and tailored therapeutic approaches in the future.