Bulut I, et al. - In this study performed on 36 severe allergic asthmatic subjects and 36 healthy controls, the impacts of omalizumab on serum pregnancy-associated plasma protein-A (PAPP-A), insulin-like growth factor binding protein-4 (IGFBP-4), and insulin-like growth factor (IGF)-1 levels were determined using an ultrasensitive enzyme-linked immunosorbent assay (ELISA) kit and routine commercial ELISA kits. Before therapy (baseline) and after six months of omalizumab therapy, these levels were measured in patients with severe asthma. Remarkably higher serum PAPP-A and IGFB-4 levels were detected among asthmatic subjects vs control subjects. However, compared to control subjects, similar serum IGF-I levels were detected in asthmatic subjects. A significant decrease in the serum PAPP-A, IGF-I, and IGFB4 levels was noted after 6-month omalizumab treatment in asthma subjects. Overall, a possible utility of PAPP-A level as a biomarker for predicting airway remodeling in patients with severe asthma receiving omalizumab was suggested. PAPP-A level may also reflect the response to treatment.