Detection of anti-eIF2B autoantibodies in systemic sclerosis by immunoprecipitation-mass spectrometry

Dear Editor, Anti-eukaryotic initiation factor 2B (eIF2B) autoantibodies are a recently described autoantibody specificity in SSc associated with diffuse cutaneous involvement, interstitial lung disease (ILD) and a cytoplasmic pattern on HEp-2 indirect immunofluorescence (HEp-2 IIF) [1–3]. Hitherto only 19 patients have been identified, all by radiolabelled protein immunoprecipitation [1–3]. Here we describe immunoprecipitation-mass spectrometry (IP-MS) as a detection method for anti-eIF2B autoantibodies and further characterize the precipitation pattern of the eIF2B complex as precipitated by various anti-eIF2B sera. We also further document the clinical associations of anti-eIF2B autoantibodies. The study was approved by the following Ethical Committees: University Hospitals Leuven (S60347/B32220071204) (Leuven) and Hospices civils de Lyon, Lyon (CT 69HCL21_0501) (Lyon). This was a retrospective study using left-over material of samples submitted to the clinical laboratory (secondary use) for which an informed consent waiver was authorized by the Ethical Committee of the University Hospitals Leuven, Belgium, and Hospices civils de Lyon, France. Patients were notified of the content and aim of the study. The patient data have been anonymized.