Background The possibility of additional strategies to enhance the effectiveness of specific immunotherapy (SIT) is highly attractive.
Aim The aim of our study was to assess the influence of oral corticosteroids and oral corticosteroids combined with vitamin D3 on the early clinical and immunological effects of SIT.
Methods It was a randomized, double-blind, placebo-controlled trial conducted in 54 asthmatic children allergic to house dust mites. Intervention was based on receiving a single dose of oral steroid, with or without vitamin D3, or placebo only on the day of the build-up phase of SIT.
Results After 12 months of SIT, the median daily inhaled corticosteroid (ICS) dose, which controls the symptoms of asthma, was reduced by 25% in the steroid group. However, a 50% reduction of the median daily ICS dose was observed in the control group. The clinical effects of SIT were not affected in the steroid+D3 group. Concomitantly, we found that intervention with prednisone significantly impaired the induction of T regulatory lymphocytes. Importantly, the clinical and immunological effects of SIT were not affected by intervention with steroids administered with vitamin D3.
Conclusions Our study failed to show a beneficial effect of oral corticosteroids on allergen-specific immunotherapy. We observed that the combined administration of a corticosteroid drug and allergen extract suppressed the early clinical and immunological effects of SIT and that vitamin D3 prevented this ‘adverse’ influence of steroids.