Sarcoidosis is characterized by multiorgan involvement and granulomatous inflammation. Its origin is unknown and the potential role of autoimmunity has not been sufficiently determined. We investigated the presence of autoantibodies in sarcoidosis using protein array technology. The derivation cohort consisted of patients with sarcoidosis (n = 25) and controls including autoimmune disease and blood donors (n = 246). In addition, we tested a validation cohort including pulmonary sarcoidosis patients (n = 58) and healthy controls (n = 13). Initially, sera of three patients with sarcoidosis were screened using a protein array with 28.000 proteins against controls. Thereby we identified the Negative Elongation Factor E (NELF-E) as an autoantigen. With confirmatory Enzyme-linked Immunosorbent Assay (ELISA)testing, 29/82 patients (35%) with sarcoidosis had antibodies against NELF-E of the Immunoglobulin (Ig) G type, whereas 18/253 (7%) sera of the controls were positive for NELF-E. Clinically, there was an association of the frequency of NELF-E antibody detection with lung parenchymal involvement and corresponding x-ray types. NELF-E autoantibodies are associated with sarcoidosis and should be further investigated.

Introduction Complex regional pain syndrome (CRPS) is a complication following trauma or surgery and may be difficult to diagnose since biomarkers are lacking. Using protein array technology, we found antibodies binding to p29ING4, which we further characterized using ELISA. Methods Thirty-six sera of early-stage type 1 CRPS, 66 sera of rheumatoid arthritis (RA), 53 sera of axial spondyloarthritis (axSpA), 29 sera of psoriatic arthritis (PsA), 22 sera of patients after radial fractures (trauma control), and 100 sera of blood donors (BD) were analyzed for anti-p29ING4. We established ELISAs with 7 different antigens and using different secondary antibodies binding to IgG, IgG1, IgG2, IgG3, IgG4, IgA, and IgM, and 2 different tests to detect immune complexes (IC) of p29ING4 and IgG or IgG1. Results The highest likelihood ratios versus CRPS and trauma control were observed considering the A1-23 (sensitivity 19%, specificity 100%, LR > 19) using IgG as a secondary antibody, the A120-165 (sensitivity 17%, specificity 100%, LR = 17) using IgG as a secondary antibody and the A120-165 (sensitivity 31%, specificity 95%, LR = 6.2) using IgA as a secondary antibody. IC of p29ING4 and IgG were present in 11/36 (31%) CRPS sera, 17/64 (27%) RA sera, 13/53 (25%) SpA sera, 5/29 (17%) PsA sera, 1/22 (5%) trauma control sera, and 4/100 (4%) sera of BD. IC of p29ING4 and IgG1 were present in 14/36 (39%) CRPS sera, 19/64 (30%) RA sera, 13/53 (25%) SpA, 1/29 (3%) PsA, 2/22 (9%) trauma control, and 4/100 (4%) of the BD sera. Conclusion Due to the lack of other biomarkers of type 1 CRPS, P29ING4 autoantibodies could be helpful in its diagnostic workup.

Bildgebende Verfahren auf der Grundlage der ultraschallgestützten Elastografie ermöglichen eine nichtinvasive Bewertung der elastischen Eigenschaften von Gewebe und verbessern so den diagnostischen Wert der Ultraschalldiagnostik. Unterschieden werden kann zwischen der Shear-Wave-Elastografie, bei der die von einem speziellen Schallkopf erzeugten Scherwellen zur Berechnung der Gewebeelastizität herangezogen werden, und der Strain-Elastografie. Bei der Strain-Elastografie werden durch wiederholte Kompression mit dem Schallkopf Verschiebungen innerhalb des Gewebes erzeugt. Durch Berechnung des Dehnungsverhältnisses zwischen 2 Regionen können Aussagen über die Beschaffenheit und ggf. Dignität getroffen werden [Iro H et al. Atlas of Head and Neck Ultrasound 2013; 205–218]. Exemplarisch stellen wir die Methode der Strain-Elastografie dar.

Background Making the diagnosis of adult-onset Still’s disease (AOSD) is mainly based on the exclusion of inflammatory, infectious and malignant diseases. There are no specific clinical or laboratory findings for AOSD. Elevated ferritin levels, liver enzyme levels, C-reactive protein levels, erythrocyte sedimentation rate and leukocytosis can be found in other inflammatory diseases as well. Objectives We aimed to identify new autoantibodies as diagnostic tools for AOSD. Methods We were studying sera of 3 patients with AOSD using a protein array loaded with more than 27000 human recombinant proteins (imagenes biolifesciences, Berlin). Sera of patients with SpA, RA, eGPA, GPA, HIV infection, B-NHL, CRPS, GCA, PMR, MS, osteoarthritis, TA and sarcoidosis served as controls. In the further process, we established an ELISA against a new autoantigen identified by the array in order to measure the autoantibodies in larger patient numbers. Results Using the protein array, we detected IgG autoantibodies binding to Dihydropyrimidinase-related protein 4 (DRP-4) (collapsin response mediator protein 3) and in 2/3 patients with AOSD IgG autoantibodies binding to proteasome subunit alpha type-1 (EC 3.4.25.1) (proteasome component C2) (macropain subunit C2) (multicatalytic endopeptidase complex subunit C2) in 2/3 AOSD patients, but not in more than 50 controls. Using the ELISA, we detected Auto-Abs binding to Macropain subunit C2 and DRP-4 in 65% of the patients with AOSD, in 0.7 % of blood donors, 9.1% of RA patients with RA, 10% of GPA patients, 22% of the patients with PMR and GCA, 3.4% of the patients with Sjögren’s syndrome, 10.5% of the SLE patients, 21% of the patients with febrile severe infections and in 0.7% of the patients with malignant diseases. Conclusions Autoantibodies against DRP-4 and Macropain C2 are associated with AOSD and may be useful as a diagnostic tool of AOSD. Disclosure of Interest None Declared