Serum Specific IgE to Staphylococcal Superantigens in Sera of ASA-intolerant Asthma

Abstract

Objective : Several studies suggest that serum total IgE (tIgE) level tended to be higher in ASA-intolerant asthma (AIA) than in other types of non-atopic asthma, whether they are atopics or non-atopics. A pathogenic role of superantigens was suggested in inflammatory responses of upper respiratory allergy with increased IgE production. To investigate a role of staphylococcal superantigens in AIA, we measured serum specific IgE level to three staphylococcal superantigens (SEA, SEB, TSST-1) in the sera of ASA-tolerant asthma (AIA), ASA tolerant asthma (ATA) patients, and normal control (NC). METHOD : Fifty-six AIA patients showing positive responses on L-ASA bronchoprovocation test, 40 ATA, and 30 non-atopic healty controls were enrolled. Serum specific IgE to three staphylococcal superantigens were measured by CAP system (Pharmacia, Uppsala, Sweden). RESULT : The prevalences of specific IgE to each superantigens were highest in AIA, followed by ATA and NC. Significanct differences were noted in the prevalence of IgE to TSST-1 and SEB between AIA and NC (P<0.05, respectively). Serum total IgE levels were significantly higher in superantigen-positive AIA patients (P<0.05, respectively). Furthermore, in non-atopic AIA patients, those with TSST-1 specific IgE had significantly higher total IgE levels (P<0.05, respectively). There were no correlations between superantigen-specific IgE level and sex, atopy status or presence of urticaria. Significant correlations were found between specific IgE to SEB or TSST-1 and serum total IgE level (r=0.42, 0.30, P<0.05), and specific IgE to TSST-1 and PC20 methacholine (r=-0.36, P<0.05). No significant correlations were found between superantigen-specific IgE and serum soluble CD30 level or cumulative dose of L-ASA inhaled. CONCLUSION: Superantigen may contribute to increase in serum total IgE level, in particular, significant association with TSST-1 was noted in non-atopic AIA patients. Further studies will be needed to investigate how they contribute to AIA pathophysiology.