INFECTIONS AND ALLERGIC REACTIONS

Prevention of infection and protection of the organism against environ mental agents are the most important functions of the immune system. T he hypersensitivity reactions type I through IV are essential for deal ing with existing infections succesfully. The elements of innate immun ity are functionally closely interwoven with the effectors of acquired immunity. The clinical picture observed during infection greatly depe nds on which immune mechanisms were activated. A whole network of medi ators and cytokines act to modulate the process of inflammation. Examp les of allergic phenomena occurring with infection: 1) Antigens of inf ectious agents can function as potent allergens (e.g. Candida and Aspe rgillus). 2) Locally, superantigens are believed to act as allergens ( staph. aureus endotoxin). 3) The inflammation caused by infection may lead to a transient type-I-disposition if certain T-cell sub-populatio ns persist (TH2). 4) Desintegration of the epidermis and mucosal barri ers due to atopic dermatitis results in a reduction of local anti-infe ctious resistance. Subsequent infections lead to increased contact wit h allergens. 5) Immunodeficiencies (e.g. lack of secretory IgA) predis poses the body to infections as well as to allergic reactions. New the rapeutic strategies are likely to make use of the increasing availabil ity of recombinant human cytokines by attempting to interfere with the pathogenic mechanisms of infection and allergy in a very selective wa y.