Sensitization to staphylococcus aureus enterotoxins A (SEA) and B (SEB) has been associated with asthma severity, exacerbations and disease control. We aimed to elucidate if there are differences in serum SEA-IgE and SEA-IgE between patients with COPD, asthma and controls and to associate SE sensitization with clinically relevant COPD outcomes.
A derivation cohort [73 COPD patients, 19 asthma patients and 27 sex-matched blood donors, smokers without asthma or COPD (control group)] and a confirmation cohort [342 well-characterized COPD patients] were included in this study. Total IgE levels (tIgE) were determined in serum using the ALEX2 Allergy Explorer. Serum specific SEA-IgE and SEB-IgE were measured using the monoplex ImmnoCAP assay.
In the derivation cohort, neither the percentage nor the concentrations of SEA and SEB differ significantly across the groups. In the confirmation cohort, there were 28 (8.2%) SEA-IgE positive and 40 (11.7%) SEB-IgE positive COPD patients. SEB-IgE positivity was associated to a lower incidence of severe exacerbation as compared to SEB-IgE negativity (80% versus 72.8%, p<0.001). Allergy both in the skin prick test and a rhinitis history were more common among SEA-IgE and SEB-IgE positive patients. SEA-IgE and SEB-IgE positivity was also associated with atopy.
There is a similar prevalence of SEA and SEB sensitization among asthma, COPD and controls.
Although COPD patients do not appear to have higher SEA and SEB sensitization than asthma patients and controls, atopy and allergy are both associated with SEA-IgE and SEB-IgE positivity in COPD patients.Thus, these allergens might help identifying atopic or allergic COPD subgroups.