Application of autoantibody markers based on phage display immunoprecipitation sequencing technology in the diagnosis of periprosthetic joint infections.

BACKGROUND

Accurate diagnosis of periprosthetic joint infection (PJI) is critical yet challenging. The role of autoantibodies in PJI remains largely unexplored. In this study, we employed phage display immunoprecipitation sequencing (PhIP-Seq) to profile PJI-associated autoantibodies and assess their diagnostic utility in PJI.

METHODS

We collected plasma samples from a cohort of 45 patients, including 25 with PJI, 9 with aseptic loosening, and 11 post-primary arthroplasty without complications. Initially, PhIP-Seq screening was performed on 10 samples (five PJI and five post-primary arthroplasty) to identify significantly differentially expressed autoantibodies. Subsequently, the immunoglobulin G (IgG) levels of these specific autoantibodies were quantified in the plasma of all participants via ELISA, and statistical analysis was performed to evaluate their diagnostic performance in PJI.

RESULTS

PhIP-Seq identified IFT80 and VPS54 as PJI-associated autoantigens. ELISA confirmed significantly elevated levels of corresponding IgG antibodies in PJI patients compared to those with aseptic loosening or post-primary arthroplasty (p < 0.01). Both autoantibodies demonstrated preliminary diagnostic performance: IFT80 achieved an area under the curve (AUC) of 0.797 (sensitivity = 56.0%, specificity = 95.0%), while VPS54 yielded an AUC of 0.776 (sensitivity = 72.0%, specificity = 75.0%). A combined diagnostic model integrating both biomarkers further enhanced the diagnostic performance (AUC = 0.810, sensitivity = 68.0%, specificity = 80.0%).

CONCLUSION

This study establishes IFT80 and VPS54 as novel autoantibodies in PJI. Their corresponding autoantibodies exhibit robust diagnostic potential, offering support for the development of serological assays to improve PJI diagnosis.