(293) Altered Pigr/Iga Mucosal Immunity in Bronchiolitis Obliterans Syndrome

PurposeLong-term survival after lung transplantation (LT) is hampered by the occurrence of chronic allograft dysfunction (CLAD). CLAD may manifest as bronchiolitis obliterans syndrome (BOS) or restrictive (RAS), and triggered several factors, e.g. post-transplant infections. As immunoglobulin (Ig) A crucial to ensure mucosal immunity limit airway microbial load, we explored whether IgA its epithelial receptor, polymeric Ig receptor (pIgR) are impaired in BOS.MethodsBronchoalveolar lavages (BAL, n=120) sera (n=179) from LT recipients included Cohort for Lung Transplantation were collected at defined timepoints LT, prior diagnosis functional stability (BOS-free, n=30) BOS (pre-BOS, n=30). BAL assessed secretory (S)-IgA. Sera IgA, S-IgA component (SC, released pIgR apical cleavage transcytosis). expression was quantified transbronchial biopsies BOS-free (n=20), pre-BOS (n=19) (n=12), well end-stage explants (n=15).ResultsBAL reduced (Fig. 1A, 16.1 vs 33.4 µg/ml, p<0.01). Serum with no difference across groups. In contrast, serum SC increased 1B-C, S-IgA: 40.6 21.2µg/ml, p<0.05; SC: 156.0 97.2ng/ml, p<0.001). bronchiolar 1D-E, p<0.05 pre-BOS), further decrease (p<0.0001 pre-BOS).ConclusionBAL decreased levels suggest that pIgR/IgA system BOS. This alteration present CLAD. reflect a spill-over bronchoalveolar fluids, witnessing an permeability respiratory barrier. These features could play pathogenic role increasing susceptibility local Long-term Bronchoalveolar (n=15). pre-BOS).