Background:Paediatric systemic lupus erythematosus (pSLE) is an autoimmune disorder of childhood characterized by the production of autoantibodies against nuclear antigens. In the last decade, several studies showed an up-regu-lation of genes induced by type I interferons (IFN?) in peripheral blood and tissuesof pSLE patients2. It has been reported that the expression of this group of genes,known as the type I IFN signature, correlates with disease activity2. More recently, also the type II interferon (IFN?) has been implicated in pSLE; however, its precise role has not been clarified yet3. Objectives:To investigate the role of IFN?in the pathogenesis of pSLE evaluat-ing: 1) the expression levels of IFN?-related genes in the peripheral blood of pSLEpatients; 2) the possible cross-talk between IFN?and type I IFNs.Methods:Expression levels of IFN?-induced genes (IFI27, IFI44L, IFIT1,RSAD2, ISG15, SIGLEC1), IFN?-induced genes (CXCL9, IDO1) and IFN? itself were analysed by quantitative PCR (qPCR) in whole blood of pSLE patients and healthy donors (HDs). We developed a type II IFN score similarly to the type I IFNscore described by Crow 4. Peripheral blood mononuclear cells (PBMCs) from 6HDs were stimulated in vitro with recombinant human IFN?and IFN?2b; gene expression was evaluated by qPCR. CXCL9 and CXCL10 in sera and superna-tants from stimulated cells were measured by ELISA. Whole blood of pSLEpatients and HD was incubated with an anti-IFN? neutralizing antibody and isotype control, and later type I and type II signatures were assessed. For eachpatient, SLEDAI was calculated.Results:Expression levels of both IFN?-induced genes, IFN?-induced genesand IFN?were upregulated in pSLE patients with active disease (n = 21) com-pared to HDs and pSLE patients with inactive disease (n = 17). The type II IFNscore correlated with the SLEDAI (r= 0.64,P< 0.01). As previously reported, alsothe type I IFN score correlated with SLEDAI (r= 0.67,P< 0.01). We also foundincreased serum levels of CXCL9 and CXCL10 in pSLE patients compared toHDs (P< 0.05).In order to study a possible crass-talk between type I and type II IFNs, we stimulated in vitroHD PBMCs with recombinant IFN?2b and IFN? for 6 hours: we analysed the expression levels of type I and type II IFN signatures and assessed the production of CXCL9 and CXCL10 in the supernatants. IFN?2b strongly up-regulated the expression of IFN?, CXCL9 and IDO1. On the other hand, IFN?induced the expression of the 6 IFN?-related genes. IFN?, but not IFN?2b, induced the release of CXCL9 in supernatants. Both IFN?and IFN?2b induced the production of CXCL10. IFN? also up-regulated the expression levels of both TLR7 and TLR9, two potent inducer of IFN?. Finally, whole blood of pSLE was incubated with anti-IFN? neutralizing antibody for 24 hours: the type II signature was significantly downregulated (P< 0.05), whereas the type I signature was reduced without reaching statistical significance. Conclusion:Our data suggest a potential role of IFN?in the pathogenesis of pSLE. IFN?-induced genes in whole blood and CXCL9 in serum are increased in pSLE patients. Type I and type II signatures are not strictly interferon-specific as IFN? can induce the expression of type I genes. Moreover, blocking of IFN?in the blood of pSLE patients reduces the type II signature confirming the presence of IFN? in the blood of pSLE patients. IFN? also induces the expression of TLR7 andTLR9, and IFN? induces the expression of IFN?, thus establishing a positive crosstalk between IFN? and IFN? that potentiate their reciprocal biological activity in pSLE. REFERENCES[1] Petri M, et al. Lupus. 2009 Oct;18:980-9.[2] Munroe M, et al. Ann Rheum Dis 2016;75:2014-2021.[3] Rice GI, et al. Lancet Neurol 2013;12:1159-69. Disclosure of Interests: Gian Marco Moneta: None declared, Claudia Bracaglia: None declared, Ivan Caiello: None declared, Raffaele Pecoraro: None declared, Chiara Farroni: None declared, Fabio Basta: None declared, Luisa Bracci-Laudiero: None declared, Rita Carsetti: None declared, Fabrizio De Benedetti Grant/research support from: Abbvie, SOBI, Novimmune, Roche, Novartis,Sanofi, Pfizer, Emiliano Marasco: None declared
INTERFERON-g AMPLIFIES IMMUNE RESPONSE MEDIATED BY TYPE I INTERFERONS IN PAEDIATRIC SYSTEMIC LUPUS ERYTHEMATOSUS AND CORRELATES WITH DISEASE ACTIVITY
2019
Abstract
Background:Paediatric systemic lupus erythematosus (pSLE) is an autoimmune disorder of childhood characterized by the production of autoantibodies against nuclear antigens. In the last decade, several studies showed an up-regu-lation of genes induced by type I interferons (IFN?) in peripheral blood and tissuesof pSLE patients2. It has been reported that the expression of this group of genes,known as the type I IFN signature, correlates with disease activity2. More recently, also the type II interferon (IFN?) has been implicated in pSLE; however, its precise role has not been clarified yet3. Objectives:To investigate the role of IFN?in the pathogenesis of pSLE evaluat-ing: 1) the expression levels of IFN?-related genes in the peripheral blood of pSLEpatients; 2) the possible cross-talk between IFN?and type I IFNs.Methods:Expression levels of IFN?-induced genes (IFI27, IFI44L, IFIT1,RSAD2, ISG15, SIGLEC1), IFN?-induced genes (CXCL9, IDO1) and IFN? itself were analysed by quantitative PCR (qPCR) in whole blood of pSLE patients and healthy donors (HDs). We developed a type II IFN score similarly to the type I IFNscore described by Crow 4. Peripheral blood mononuclear cells (PBMCs) from 6HDs were stimulated in vitro with recombinant human IFN?and IFN?2b; gene expression was evaluated by qPCR. CXCL9 and CXCL10 in sera and superna-tants from stimulated cells were measured by ELISA. Whole blood of pSLEpatients and HD was incubated with an anti-IFN? neutralizing antibody and isotype control, and later type I and type II signatures were assessed. For eachpatient, SLEDAI was calculated.Results:Expression levels of both IFN?-induced genes, IFN?-induced genesand IFN?were upregulated in pSLE patients with active disease (n = 21) com-pared to HDs and pSLE patients with inactive disease (n = 17). The type II IFNscore correlated with the SLEDAI (r= 0.64,P< 0.01). As previously reported, alsothe type I IFN score correlated with SLEDAI (r= 0.67,P< 0.01). We also foundincreased serum levels of CXCL9 and CXCL10 in pSLE patients compared toHDs (P< 0.05).In order to study a possible crass-talk between type I and type II IFNs, we stimulated in vitroHD PBMCs with recombinant IFN?2b and IFN? for 6 hours: we analysed the expression levels of type I and type II IFN signatures and assessed the production of CXCL9 and CXCL10 in the supernatants. IFN?2b strongly up-regulated the expression of IFN?, CXCL9 and IDO1. On the other hand, IFN?induced the expression of the 6 IFN?-related genes. IFN?, but not IFN?2b, induced the release of CXCL9 in supernatants. Both IFN?and IFN?2b induced the production of CXCL10. IFN? also up-regulated the expression levels of both TLR7 and TLR9, two potent inducer of IFN?. Finally, whole blood of pSLE was incubated with anti-IFN? neutralizing antibody for 24 hours: the type II signature was significantly downregulated (P< 0.05), whereas the type I signature was reduced without reaching statistical significance. Conclusion:Our data suggest a potential role of IFN?in the pathogenesis of pSLE. IFN?-induced genes in whole blood and CXCL9 in serum are increased in pSLE patients. Type I and type II signatures are not strictly interferon-specific as IFN? can induce the expression of type I genes. Moreover, blocking of IFN?in the blood of pSLE patients reduces the type II signature confirming the presence of IFN? in the blood of pSLE patients. IFN? also induces the expression of TLR7 andTLR9, and IFN? induces the expression of IFN?, thus establishing a positive crosstalk between IFN? and IFN? that potentiate their reciprocal biological activity in pSLE. REFERENCES[1] Petri M, et al. Lupus. 2009 Oct;18:980-9.[2] Munroe M, et al. Ann Rheum Dis 2016;75:2014-2021.[3] Rice GI, et al. Lancet Neurol 2013;12:1159-69. Disclosure of Interests: Gian Marco Moneta: None declared, Claudia Bracaglia: None declared, Ivan Caiello: None declared, Raffaele Pecoraro: None declared, Chiara Farroni: None declared, Fabio Basta: None declared, Luisa Bracci-Laudiero: None declared, Rita Carsetti: None declared, Fabrizio De Benedetti Grant/research support from: Abbvie, SOBI, Novimmune, Roche, Novartis,Sanofi, Pfizer, Emiliano Marasco: None declaredI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
