Specific IgE against Staphylococcus aureus enterotoxins: an independent risk factor for asthma.
BACKGROUND
The role of IgE in patients with severe asthma is not fully understood.


OBJECTIVE
We sought to investigate whether IgE to Staphylococcus aureus enterotoxins might be relevant to disease severity in adult asthmatic patients.


METHODS
Specific IgE antibody concentrations in serum against enterotoxins, grass pollen (GP), and house dust mite allergens and total IgE levels were measured in adult cohorts of 69 control subjects, 152 patients with nonsevere 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.


RESULTS
Enterotoxin IgE positivity was significantly greater in patients with severe asthma (59.6%) than in healthy control subjects (13%, P< .001). Twenty-one percent of patients with severe asthma with enterotoxin IgE were considered nonatopic. Logistic regression analyses demonstrated significantly increased risks for enterotoxin IgE-positive subjects to have any asthma (OR, 7.25; 95% CI, 2.7-19.1) or severe asthma (OR, 11.09; 95% CI, 4.1-29.6) versus enterotoxin IgE-negative subjects. The presence of GP or house dust mite 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 enterotoxin IgE and nonatopic asthma. GP IgE was associated with a higher FEV(1) percent predicted value, and enterotoxin IgE was associated with a lower FEV(1) percent predicted value.


CONCLUSIONS
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 asthma.
Upper Airway Research Laboratory (URL), Ghent University Hospital, Ghent, Belgium. claus.bachert@ugent.be
Claus
C
Bachert
Kristel
K
van Steen
Nan
N
Zhang
Gabriele
G
Holtappels
Tom
T
Cattaert
Bärbel
B
Maus
Roland
R
Buhl
Christian
C
Taube
Stephanie
S
Korn
Marek
M
Kowalski
Jean
J
Bousquet
Peter
P
Howarth
D000305:Adrenal Cortex Hormones / Q000008:administration & dosage / Q000627:therapeutic use; D000328:Adult; D000485:Allergens / Q000276:immunology; D000818:Animals; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use; D000907:Antibodies, Bacterial / Q000097:blood / Q000276:immunology*; D001249:Asthma / Q000150:complications / Q000188:drug therapy / Q000276:immunology* / Q000821:virology; D016022:Case-Control Studies; D004768:Enterotoxins / Q000276:immunology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011058:Pollen / Q000276:immunology; D039981:Pyroglyphidae / Q000276:immunology; D012307:Risk Factors; D012720:Severity of Illness Index; D013203:Staphylococcal Infections / Q000150:complications / Q000188:drug therapy / Q000276:immunology* / Q000382:microbiology; D013211:Staphylococcus aureus / Q000276:immunology*; D018089:Superantigens / Q000097:blood / Q000276:immunology
D000305:Adrenal Cortex Hormones; D000485:Allergens; D018927:Anti-Asthmatic Agents; D000907:Antibodies, Bacterial; D004768:Enterotoxins; D018089:Superantigens; D007073:Immunoglobulin E