Interferon-γ release assay as an emergent powerful biomarker in systemic lupus erythematosus
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Updated: Jun 17, 2026
Development and Validation of an Ultrasensitive Single Molecule Array Digital Enzyme-linked Immunosorbent Assay for Human Interferon-α
Published on: June 14, 2018
Yves Renaudineau1,2, Emmanuel Treiner1,2, Fabrice Herin2,3
1Immunology Department Laboratory, Referral Medical Biology Laboratory, Institut Fédératif de Biologie, Toulouse University Hospital, Toulouse, France.
Objectives:
To investigate the ex vivo IFN-γ release assay (IGRA) as a biomarker of systemic lupus erythematosus (SLE) activity and disease outcome.
Methods:
This retrospective study, conducted between 2008 and 2024 at a single tertiary care centre, included 145 SLE patients at various disease stages. Data were collected on spontaneous IFN-γ levels (IGRA-nil) and on phytohemagglutinin-induced IFN-γ levels (IGRA-PHA, after subtracting the IGRA-nil result).
Results:
The ex vivo spontaneous IFN-γ release was increased (IGRA-nil; P = 0.0004) and the PHA-induced IFN-γ release was decreased in active SLE patients (IGRA-PHA; P < 10-4), regardless of treatment, including glucocorticoids. Nephritis, serositis, constitutional symptoms, mucocutaneous and musculoskeletal manifestations were associated with impaired IGRA-PHA release (P < 0.05 for each association). An IGRA-PHA ≥ 8.0 IU/ml, corresponding to the optimal Youden index, predicted clinically inactive SLE better than IGRA-nil (area under the curve = 0.853 vs 0.722) and IGRA-PHA <1.6 IU/ml indicated 100% specificity for active disease. Moreover, IGRA-PHA ≥ 8.0 IU/ml was an independent predictor of clinically inactive SLE in multivariate regression analysis (OR: 10.6 [95% CI: 3.72-30.17]; P = 9.7 × 10-6), and IGRA-PHA ≤1.6 IU/ml was associated with a longer time to achieve remission in a log-rank test (P = 2.4 × 10-6).
Conclusion:
The IGRA-PHA assay appears to be a powerful and independent biomarker for clinically active SLE, when performed at the initiation or intensification of therapy, and as a predictor of treatment-induced remission at therapy evaluation.
