Neutrophil Extracellular Traps Profiles in Patients with Incident Systemic Lupus Erythematosus and Lupus Nephritis

• Published in: Journal of rheumatology 2020-03, Vol.47 (3), p.377-386
• Main Authors: Bruschi, Maurizio, Bonanni, Alice, Petretto, Andrea, Vaglio, Augusto, Pratesi, Federico, Santucci, Laura, Migliorini, Paola, Bertelli, Roberta, Galetti, Maricla, Belletti, Silvana, Cavagna, Lorenzo, Moroni, Gabriella, Franceschini, Franco, Fredi, Micaela, Pazzola, Giulia, Allegri, Landino, Sinico, Renato Alberto, Pesce, Giampaola, Bagnasco, Marcello, Manfredi, Angelo, Ramirez, Giuseppe A, Ramoino, Paola, Bianchini, Paolo, Puppo, Francesco, Pupo, Francesca, Negrini, Simone, Mattana, Federico, Emmi, Giacomo, Garibotto, Giacomo, Santoro, Domenico, Scolari, Francesco, Ravelli, Angelo, Tincani, Angela, Cravedi, Paolo, Volpi, Stefano, Candiano, Giovanni, Ghiggeri, Gian Marco
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Autoantibodies - blood; Child; Comorbidity; Deoxyribonuclease I - blood; DNA - immunology; Endodeoxyribonucleases - blood; Endodeoxyribonucleases - genetics; Enzyme-Linked Immunosorbent Assay; Extracellular Traps - immunology; Extracellular Traps - metabolism; Female; Humans; Incidence; Lupus Erythematosus, Systemic - blood; Lupus Erythematosus, Systemic - epidemiology; Lupus Erythematosus, Systemic - immunology; Lupus Nephritis - blood; Lupus Nephritis - epidemiology; Lupus Nephritis - immunology; Male; Middle Aged; Mutation; Neutrophils - immunology; Prospective Studies; Severity of Illness Index; Young Adult
• ISSN: 0315-162X; 1499-2752
• DOI: 10.3899/jrheum.181232

Neutrophil extracellular traps (NET) expose modified antigens for autoantibodies in vasculitis. Little is known about levels and removal pathways of NET in systemic lupus erythematosus (SLE), especially in lupus nephritis (LN). We determined circulating levels and defined NET removal in large subsets of patients with incident SLE (iSLE), some of whom had new-onset nephritis. Serum levels of NET (ELISA), DNase1/DNase1L3 (ELISA), and DNase activity (functional assay) were determined in 216 patients with iSLE [103 had incident LN (iLN)], in 50 patients with other primary glomerulonephritis, and in healthy controls. NET production by neutrophils purified from a random selection of patients was quantified as elastase/DNA release and by immunofluorescence techniques. Serum NET levels were very high in iSLE/iLN compared to all groups of controls and correlated with anti-dsDNA, C3-C4, and proteinuria; iLN had the highest levels. DNase activity was decreased in iLN compared to SLE (20% had one-half DNase activity) despite similar serum levels of DNase1/DNase1L3. In these cases, pretreatment of serum with protein A restored DNase efficiency; 1 patient was homozygous for a c.289_290delAC variant of . NET production by neutrophils purified from LN, SLE, and normal controls was similar in all cases. Patients with iLN have increased circulating NET and reduced DNase activity, the latter being explained by the presence of inhibitory substances in circulation and/or by rare mutations. Accumulation of NET derives from a multifactorial mechanism, and is associated and may contribute to disease severity in SLE, in particular to renal lesions. (Clinical trial registration: The Zeus study was registered at ClinicalTrials.gov, study number NCT02403115).