Abstract
Long-term variability of serum total IgE (sIgEtot) has been reported in asthmatics. This study evaluates the dynamics and the factors predictive of this variability.
sIgEtot levels were prospectively measured over 1 year in 41 moderate-to-severe asthmatics treated with high-dose of inhaled corticosteroids and long-acting β2 agonists (and untreated with omalizumab). Patients were divided into 3 groups according to their baseline sIgEtot level: low (≤75 IU/mL; n=10), intermediate (76-700 IU/mL; n=20) or high (>700 IU/mL; n=11). The sIgEtot variability and factors predictive of IgEtot variability were studied.
The mean sIgEtot (whole group) fluctuated over 1 year and showed an overall non-significant decrease from baseline (p=0.21). Four to 29% of the sIgEtot variability depended on within-patient variability. No factor predictive of the within-patient variability was identified in the intermediate sIgEtot group. In the low sIgEtot group, however, the level of sIgEtot increased over 1 year in patients exposed to allergens (p<0.001) or who used oral corticosteroids (OCS) (p=0.011), and the odds of having an exacerbation since the previous visit increased by 30% if sIgEtot increased by 100 IU/mL (p<0.0001). Unexpectedly, in the high sIgEtot group, the odds of having an exacerbation since the previous visit decreased by 5% if sIgEtot increased by 100 IU/mL (p=0.005). These trends should be confirmed in a bigger cohort.
In this small cohort of moderate-to-severe asthmatics, a limited within-patient variability of sIgEtot levels was observed over 1 year. This variability depended on allergen exposure, OCS use (probably related to exacerbation management) and exacerbations in patients with low and high baseline sIgEtot.
- Copyright ©the authors 2016
