Figure 1. Relative abundance of BALF ALX ligands and ALX receptor expression differs in asthma.

BALF was obtained from subjects with asthma (n = 120) and healthy donors (n = 47, gray circles). Asthmatic subjects were assigned to NSA (n = 51, blue squares) and SA (n = 69, red triangles) cohorts by SARP criteria. (A) LXA₄ and (B) 15-epi-LXA₄ were extracted from BALF and quantified by ELISA (see Methods). (C) ANXA1 and (D) SAA levels were determined by ELISA. Scatter plots show individual data points for each subject normalized to protein levels with the median value noted by the horizontal line. (E) Flow cytometry was performed on viable BAL macrophages in n = 32 HD, n = 33 NSA, and n = 38 SA subjects to measure surface ALX expression. Data are expressed as the ALX index (MFI ALX divided by MFI isotype control). *P < 0.05, **P < 0.01, ***P < 0.005, ****P < 0.001 by Kruskal-Wallis test, followed by Dunn’s test for multiple comparisons. BALF, bronchoalveolar lavage fluid; ALX, airway lipoxin A₄ receptor; HD, healthy donors; NSA, nonsevere asthma; SA, severe asthma; SARP, Severe Asthma Research Program; LXA₄, lipoxin A₄; 15-epi-LXA₄, 15-epimer lipoxin A₄; ELISA, enzyme-linked immunosorbent assay; ANXA1, annexin A1; SAA, serum amyloid A; MFI, median fluorescence intensity.