Clinical significance of decline in serum IgE levels in allergic bronchopulmonary aspergillosis

Summary 

Background and Aims

The total serum IgE level is a marker of immunological activity in allergic bronchopulmonary aspergillosis (ABPA), and a 35% decline beyond six weeks is traditionally taken as criteria for remission. The aim of this study was to evaluate the magnitude and clinical significance of decline in serum IgE levels at six weeks in patients with ABPA.

Methods

All consecutive patients with ABPA presenting to the Chest Clinic were followed up with clinical evaluation, total IgE levels and chest x-ray every six weeks for three months. We analyzed the percentage decline in IgE levels and correlated it with clinical outcomes of relapse and complete remission.

Results

Of the 242 asthmatics, 54 were diagnosed with ABPA (29 males, 25 females; mean age-34 years). There was clinical and radiological improvement at six weeks in all patients receiving glucocorticoid therapy. The IgE levels fell by a mean of 38.8%, and the decline was significantly higher in patients with baseline IgE levels >2500IU/mL than with levels ≤2500IU/mL (44% vs. 26%). Twenty-two patients did not attain a 35% decline in IgE levels, and this number was significantly higher in patients with IgE levels <2500IU/mL. On multivariate analysis, the decline in IgE levels at six weeks did not predict clinical outcomes.

Conclusions

A 35% decline in serum IgE levels at six weeks is not seen in all patients with ABPA, and the decline is slower in patients with baseline IgE levels <2500IU/mL. The quantum decline in serum IgE levels does not predict clinical outcomes.

Keywords: ABPA, Allergic bronchopulmonary aspergillosis, High-attenuation mucus, Hyperdense mucus, Computed tomography, Remission, Relapse, IgE