| Autor: |
Frasca L; Istituto Superiore di Sanità, National Center for Drug Research and Evaluation, Rome, Italy., Palazzo R; Istituto Superiore di Sanità, National Center for Drug Research and Evaluation, Rome, Italy., Chimenti MS; Rheumatology, Allergology and Clinical Immunology, University of Rome Tor Vergata, Rome, Italy., Alivernini S; Division of Rheumatology, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy.; Division of Rheumatology, Università Cattolica del Sacro Cuore, Rome, Italy., Tolusso B; Division of Rheumatology, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy., Bui L; Institute of Pathology, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy., Botti E; Dermatology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy., Giunta A; Dermatology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy., Bianchi L; Dermatology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy., Petricca L; Division of Rheumatology, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy., Auteri SE; Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy., Spadaro F; Confocal Microscopy Unit, Core Facilities, Istituto Superiore di Sanità, Rome, Italy., Fonti GL; Rheumatology, Allergology and Clinical Immunology, University of Rome Tor Vergata, Rome, Italy., Falchi M; National AIDS Center, Istituto Superiore di Sanità, Rome, Italy., Evangelista A; Institute of Pathology, Fondazione Policlinico Universitario A. Gemelli, Rome, Italy., Marinari B; Dermatology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Rome, Italy., Pietraforte I; Department of Oncology and Molecular Medicine, Istituto Superiore di Sanità, Rome, Italy., Spinelli FR; Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy., Colasanti T; Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy., Alessandri C; Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy., Conti F; Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy., Gremese E; Division of Rheumatology, Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy.; Division of Rheumatology, Università Cattolica del Sacro Cuore, Rome, Italy., Costanzo A; Skin Pathology Lab, Humanitas Clinical and Research Center, Milan, Italy., Valesini G; Rheumatology Unit, Department of Internal Medicine and Medical Specialties, Sapienza University of Rome, Rome, Italy., Perricone R; Rheumatology, Allergology and Clinical Immunology, University of Rome Tor Vergata, Rome, Italy., Lande R; Istituto Superiore di Sanità, National Center for Drug Research and Evaluation, Rome, Italy. |
| Abstrakt: |
Psoriatic arthritis (PsA) is a chronic inflammatory arthritis associated with psoriasis. A third of psoriatic patients develop PsA via unknown mechanisms. No reliable diagnostic markers are available for PsA, or prognostic biomarkers for PsA development in psoriasis. We previously uncovered a pro-inflammatory role for cathelicidin LL37 in lesional psoriasis skin. LL37 binds nucleic acids and stimulates plasmacytoid/myeloid dendritic cells (pDC, mDCs) to secrete type I interferon (IFN-I) and pro-inflammatory factors. LL37 becomes an autoantigen for psoriatic Th1-Th17/CD8 T cells. Anti-LL37 antibodies were detected in systemic lupus erythematosus, an autoimmune disease characterized by neutrophil-extracellular-traps release (NETosis) in target organs. LL37 can be substrate of irreversible post-translational modifications, citrullination or carbamylation, linked to neutrophil activity. Here we analyzed inflammatory factors, included LL37, in PsA and psoriasis plasma and PsA synovial fluids (SF)/biopsies. We show that LL37 (as a product of infiltrating neutrophils) and autoantibodies to LL37 are elevated in PsA, but not OA SF. Anti-LL37 antibodies correlate with clinical inflammatory markers. Anti-carbamylated/citrullinated-LL37 antibodies are present in PsA SF/plasma and, at lower extent, in psoriasis plasma, but not in controls. Plasma anti-carbamylated-LL37 antibodies correlate with PsA (DAS44) but not psoriasis (PASI) disease activity. Ectopic lymphoid structures, and deposition of immunoglobulin-(Ig)G-complexes (IC) co-localizing with infiltrating neutrophils, are observed in PsA and not OA synovial tissues (ST). Activated complement (C5a, C9), GM-CSF and IFN-I are up-regulated in PsA and not OA synovia and in PsA and psoriasis plasma but not in HD. C9 and GM-CSF levels in PsA SF correlate with clinical inflammatory markers and DAS44 (C9) and with anti-carbamylated/citrullinated-LL37 antibodies (GM-CSF and IFN-I). Thus, we uncover a role for LL37 as a novel PsA autoantibody target and correlation studies suggest participation of anti-LL37 antibodies to PsA pathogenesis. Notably, plasma antibodies to carbamylated-LL37, which correlate with DAS44, suggest their use as new disease activity markers. GM-CSF and complement C5a and C9 elevation may be responsible for autoantigens release by neutrophils and their modification, fueling inflammation and autoreactivity establishment. Finally, targeting GM-CSF, C5a, C9 can be beneficial in PsA. |
