OBJECTIVE: Neutrophil Extracellular Traps (NETs) expose modified antigens for auto-antibodies in vasculitis (SVV). Little is known on levels and removal pathways of NETs in Systemic Lupus Erythematosus (SLE), especially in lupus nephritis (LN). We determined circulating levels and defined NETs removal in large subsets of incident SLE patients, a part with newly onset nephritis. METHODS: Serum levels of NETs (ELISA), DNase1/DNase1L3 (ELISAs) and DNase activity (functional assay) were determined in 216 incident SLE patients, 103 had incident LN, in 50 patients with other primary glomerulonephritis and in healthy controls. Ex vivo NETs production by neutrophils purified from a random selection of patients was quantified as elastase/DNA release and by immunofluorescence techniques. RESULTS: Serum NETs were very high in iSLE/iLN compared to all groups of controls and correlated with anti-dsDNA, C3-C4 and proteinuria; incident LN 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, pre-treatment of serum with Protein A restored DNase efficiency; one patient was homozygous for a c.289_290delAC variant of DNASE1L3. Ex vivo NETs production by neutrophils purified from LN, SLE and normal controls was similar in all cases. CONCLUSION: iLN patients have increased circulating NETs and reduced DNase activity, the later being explained by the presence of inhibitory substances in circulation and/or by rare DNase1L3 mutations. Accumulation of NETs derives from a multi-factorial mechanism, is associated and may contribute to disease severity in SLE, in particular to renal lesions.
Neutrophil Extracellular Traps (NETs) profiles in patients with incident SLE and lupus nephritis.
Pratesi F;Migliorini P;
2019-01-01
Abstract
OBJECTIVE: Neutrophil Extracellular Traps (NETs) expose modified antigens for auto-antibodies in vasculitis (SVV). Little is known on levels and removal pathways of NETs in Systemic Lupus Erythematosus (SLE), especially in lupus nephritis (LN). We determined circulating levels and defined NETs removal in large subsets of incident SLE patients, a part with newly onset nephritis. METHODS: Serum levels of NETs (ELISA), DNase1/DNase1L3 (ELISAs) and DNase activity (functional assay) were determined in 216 incident SLE patients, 103 had incident LN, in 50 patients with other primary glomerulonephritis and in healthy controls. Ex vivo NETs production by neutrophils purified from a random selection of patients was quantified as elastase/DNA release and by immunofluorescence techniques. RESULTS: Serum NETs were very high in iSLE/iLN compared to all groups of controls and correlated with anti-dsDNA, C3-C4 and proteinuria; incident LN 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, pre-treatment of serum with Protein A restored DNase efficiency; one patient was homozygous for a c.289_290delAC variant of DNASE1L3. Ex vivo NETs production by neutrophils purified from LN, SLE and normal controls was similar in all cases. CONCLUSION: iLN patients have increased circulating NETs and reduced DNase activity, the later being explained by the presence of inhibitory substances in circulation and/or by rare DNase1L3 mutations. Accumulation of NETs derives from a multi-factorial mechanism, is associated and may contribute to disease severity in SLE, in particular to renal lesions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
