Specific IgE against staphylococcal enterotoxin [superantigens] in allergic rhinitis: an independent risk factor for severe bronchial asthma

The study aimed to investigate whether IgE to Staphylococcus aureus enterotoxins might be relevant to disease severity in adult asthmatic patients. Specific IgE antibody concentrations in serum against enterotoxins, grass pollen [GP], and house dust mite [HDM] allergens and total IgE levels were measured in 69 adult control subjects, 152 patients with non-severe asthma, and 166 patients with severe asthma. Severe asthma was defined as inadequately controlled disease despite high-dose inhaled corticosteroids plus at least 2 other controller therapies, including oral steroids. Statistical analysis demonstrated Enterotoxin IgE positivity which was significantly greater in patients with severe asthma [59.67%] than in healthy control subjects [13% P< .001]. Twenty-one percent of patients with severe asthma showing positive enterotoxin IgE were considered non atopic. Also statistical analyses demonstrated significantly increased risks for enterotoxin IgE-positive subjects to have severe asthma [95%] versus enterotoxin IgE-negative subjects. The presence of GP or house dust IgE antibodies was not associated with either significantly increased risk for asthma or severity. Oral steroid use and hospitalizations were significantly increased in patients with positive enterotoxin IgE and non-atopic asthma. GP IgE was associated with a higher FEV1 percent predicted value and enterotoxin IgE was associated with a lower FEV1 percent predicted value. Staphylococcal enterotoxin IgE antibodies, but not IgE against inhalant allergens, are risk factors for asthma severity. We hypothesize that the presence of enterotoxin IgE in serum indicates the involvement of Staphylococcal superantigens in the pathophysiology of patients with severe bronchial asthma