Detection and role of Superantigens as precipitating factor in broncho alveolar lavage (BAL) of asthmatic patients

Abstract

Allergic bronchial asthma, refers to the tendency to develop an exaggerated lgE antibody response. It is well known that IgE dependent activation and cellular recruitment particularly tissue eosinophilia are under the local regulation of distinct cytokines produced by allergen activated T-lymphocytes. Among these allergens are the staphylococcal aureus enterotoxins (SE) known as superantigens (SAg). SAg are potent immunomodulator that stimulate larger subset of T cells than conventional peptide antigen leading to profound proliferative events and massive cytokines production, such as IL I, IL2, IL4 , IL5, IL6 and TNFa followed in vivo by a deletion of reactive T cells. In this study to establish the role of SE namely SEA, SEB , SEC and SED in triggering bronchial asthma, 20 patients with bronchial asthma as well as normal volunteers were investigated as regards their enterotoxins secreting potential of staphylococcus aureus in their liquefied bronchial lavage.. In addition their BAL levels of IL-2 and IL4 were measured as indicators for the state of T helper- I and T helper -2 respectively. Our results showed that staph. aureus with enterotoxins secreting potential was identified in the majority of cases (15 out of the 20 patients i.e 75%) in comprison to 0% in controls and significantly increase in levels of BAL IL2 and BAL IL4 were found in patients compared to controls.