TY - JOUR TI - Occurrence and Antigenic Specificity of Perinuclear Anti-Neutrophil Cytoplasmic Antibodies (P-ANCA) in Systemic Autoimmune Diseases AU - Argyropoulou, Ourania D. AU - Goules, V, Andreas AU - Boutzios, Georgios AU - and Tsirogianni, Alexandra AU - Sfontouris, Charalampos AU - Manoussakis, AU - Menelaos N. AU - Vlachoyiannopoulos, Panayiotis G. AU - Tzioufas, AU - Athanasios G. AU - Kapsogeorgou, Efstathia K. JO - Cell Stem Cell PY - 2021 VL - 10 TODO - 8 SP - null PB - MDPI SN - 1934-5909 TODO - 10.3390/cells10082128 TODO - P-ANCA autoantibodies; myeloperoxidase; elastase; vasculitis; systemic autoimmune rheumatic diseases TODO - Perinuclear anti-neutrophilic cytoplasmic antibodies (P-ANCA) recognize heterogeneous antigens, including myeloperoxidase (MPO), lactoferrin, elastase, cathepsin-G and bactericidal/permeability-increasing protein. Although P-ANCA have diagnostic utility in vasculitides, they may also be found in patients with various other systemic autoimmune rheumatic diseases (SARDs). Nevertheless, the clinical significance and the targets recognized by P-ANCA in such patients remain unclear. For this purpose, herein we investigated the occurrence of ANCA-related antigenic specificities in 82 P-ANCA-positive sera by multiplex ELISA, as well as their association with other autoantibodies. The P-ANCA-positive sera corresponded to patients with vasculitides (n = 24), systemic lupus erythematosus (n = 28), antiphospholipid syndrome (n = 5), Sjogren’s syndrome (n = 7), rheumatoid arthritis (n = 3), systemic scleroderma (n = 1), sarcoidosis (n = 1) and Hashimoto ‘ s thyroiditis (n = 13). In most P-ANCA-positive patients studied (51/82, 62.3%), these autoantibodies occurred in high titers (>1:160). The analysis of P-ANCA-positive sera revealed reactivity to MPO in only 50% of patients with vasculitides, whereas it was infrequent in the other disease groups studied. Reactivity to other P-ANCA-related autoantigens was also rarely detected. Our findings support that high P-ANCA titers occur in SARD. The P-ANCA-positive staining pattern is associated with MPO specificity in vasculitides, while in other autoimmune diseases, it mostly involves unknown autoantigens. ER -