Figure 4.

Mepolizumab decreases expression of the IL-3 receptor on circulating eosinophils but has no effect on IL-5 family cytokine receptor expression on BAL eosinophils. Forty-eight hours after segmental bronchoprovocation with allergen (SBP-Ag), the cytokine receptor expression pattern was assessed on blood eosinophils and on airway eosinophils obtained from the segment challenged with 20% of the participant’s AgPD₂₀ (allergen provocation dose resulting in a 20% reduction in FEV₁) (P values indicated above the solid lines). After mepolizumab administration, IL-3 receptor α chain (IL-3Rα/CD123/IL3RA) and β chain (βc/CD131/CSF2RB) were significantly diminished on blood eosinophils. Overall, however, mepolizumab did not alter the pattern of receptor expression on blood versus BAL eosinophils (P values indicated above the dashed lines). (A) Cell surface protein. Data represent medians with first and third quartiles (n = 9). (B) mRNA fold change normalized to each individual’s premepolizumab circulating eosinophils. Symbols represent values for individual subjects (n = 6 for blood eosinophils; n = 3 for BAL eosinophils). BAL = bronchoalveolar lavage; D2 = Day 2; EOS = eosinophils; GM-CSFRα = granulocyte–macrophage colony–stimulating factor receptor α chain; IL-5Rα = IL-5 receptor α chain; LAD = below the level of accurate detection; ns = not significant.