Background/Purpose: The pathophysiology of axial spondyloarthritis (axSpA) involves the gut-joint axis. Recent studies suggest more active disease in cases of gut involvement.The objective of this study is to evaluate the impact of bacterial translocation levels at baseline in the DESIR cohort on 5-year outcomes in patients.

Methods: We included patients from the DESIR cohort meeting the 2009 ASAS criteria, for whom serum samples at baseline and 5-year follow-up data were available. Gut permeability was assessed by measuring serum zonulin levels using ELISA. Bacterial translocation was evaluated by quantifying serum levels of lipopolysaccharides (LPS) and their esterified free fatty acid components (3OHC10, 12, 14, 16, and 18) using liquid chromatography coupled with mass spectrometry. Phospholipid transfer protein (PLTP) activity, which plays a role in LPS transfer, was also measured. We analyzed these biomarkers concerning the occurrence of extra-articular manifestations (psoriasis, IBD, and uveitis), radiographic spinal progression assessed by mSASS, sacroiliac joint radiographic progression evaluated by the change in sacroiliitis grade (NYm), and the transition from non-radiographic to radiographic axSpA over 5 years.

Results: Out of 708 patients in the DESIR cohort, 319 met the inclusion criteria. The mean age was 31.7 (±7.3) years, with 49.2% male, 82% HLA-B27 positive, 27% with radiographic axial involvement, and symptom duration of 1.6 (±0.9) years. The cohort included 15% with psoriasis, 6% with IBD, 9% with uveitis, 55% with enthesitis, and 12% with dactylitis. Baseline disease activity scores included a BASDAI of 42 (±20), an ASDAS-CRP of 2.6 (±1), and a CRP of 8.4 (±13) mg/L. At baseline, LPS levels (and their fatty acid subgroups), zonulin levels, and PLTP activity were not associated with the presence of extra-musculoskeletal manifestations or disease activity. These levels also did not differ between patients who developed extra-musculoskeletal manifestations at 5 years and those who did not. In patients with sacroiliac progression, lower total LPS levels (716 ± 199 pmol/mL vs. 656 ± 200 pmol/mL; p = 0.036), lower 3OHC18 levels (252.5 ± 116.8 pmol/mL vs. 205.9 ± 119 pmol/mL; p = 0.007), and lower zonulin levels (147 ± 155 ng/mL vs. 104 ± 103 ng/mL; p = 0.01) were observed. PLTP activity was higher in patients with sacroiliac progression (5.2 ± 1.6 nmol/h/mL vs. 5.8 ± 1.7 nmol/h/mL). In multivariate analysis accounting for age, sex, smoking, and ASDAS-CRP, PLTP activity remained significantly associated with sacroiliac progression (p = 0.028). Finally, in patients transitioning from non-radiographic to radiographic axSpA, lower 3OHC16 levels (290 ± 71 pmol/mL vs. 252 ± 48 pmol/mL) and lower zonulin levels (156 ± 157 ng/mL vs. 72 ± 84 ng/mL; p = 0.003) were noted.

Conclusion: In early axial spondyloarthritis, baseline PLTP activity was associated with sacroiliac radiographic progression at 5 years

ACR Meeting Abstracts - https://acrabstracts.org/abstract/initial-phospholipid-transferase-activity-is-predictive-of-five-year-sacroiliac-radiographic-progression-in-axial-spondyloarthritis-findings-from-the-desir-cohort/