Understanding the genetic architecture of complex disorders is important for identifying disease mechanisms and potential molecular targets for therapeutic interventions. Genetic diseases are broadly classified as either Mendelian (monogenic) diseases or complex (polygenic) diseases. Common, polygenic disorders result from inheritance of multiple common variants with low penetrance. In contrast, monogenic, Mendelian disorders are caused by rare variants with high penetrance at a single genetic locus. However, an increasing number of studies support a role for rare variants of moderate effect size in complex diseases. As a result, genetic approaches previously utilized for discovering rare variants in Mendelian diseases, such as next generation sequencing, can now effectively be applied to complex diseases to define the contribution of both rare and common variants to the genetic burden of polygenic traits and diseases. Alopecia Areata (AA) is a complex autoimmune disease characterized by non-scarring hair loss that is due to a combination of both enviornmental and genetic factors. Our previous Genome-wide Association Study (GWAS) identified at least 14 genetic regions contributing to AA disease susceptibility. Although useful in identifying disease-associated loci and surrounding linkage disequilibrium (LD) blocks, GWAS is not sufficiently granular to 1) elucidate causal (association-driving) variants; and 2) discover rare risk variants. This level of resolution can only be achieved by deep sequencing followed by functional validation of variants. The goal of this thesis was to address these challenges in AA using two genetic approaches that have not been previously utilized in the context of this disease. In Chapter 2, I performed a hypothesis-driven analysis of common variants in a GWAS-associated locus using targeted genomic sequencing. In Chapter 3, I utilized whole exome sequencing (WES) in an unbiased approach to assess rare variant contribution in AA disease risk. To conduct these analyses simultaneously, we designed a whole exome sequencing (WES) chip that also included custom capture of 24 Mb of genomic regions covering the 14 genetic loci previously identified using GWAS. I applied these two sequencing approaches in a large AA patient cohort and identified potentially causal variants in several genes. To interrogate the consequences of these variants, I performed functional analyses to determine the effects of disease-causing variants on the target organ of AA attack, the hair follicle (HF). In Chapter 2, I report on the use of targeted genomic sequencing to interrogate the coding and non-coding regions surrounding a previously implicated GWAS locus. This approach provided fine mapping of coding and non-coding common variants in regions that may be contributing to disease risk. In this thesis, I focused on the effect of genetic perturbations on the end-organ HF, and consequentially prioritized my functional analysis using two criteria: 1) genes expressed in the (HF) and; 2) GWAS regions that were not previously implicated in other autoimmune diseases. One of the regions that satisfied these criteria harbored the Syntaxin 17 (STX17) gene, which encodes a SNARE protein involved in autophagy and mitochondrial fission. Targeted genomic sequencing of the STX17 region in 849 AA cases identified 35 non-coding and 0 coding variants in high LD with the GWAS SNP. Thirty-three variants were significantly enriched in cases compared to controls, and the remaining two were nominally significant. Thirty-two of the significantly associated AA variants were confirmed to be AA skin eQTLs that downregulated expression of STX17 in affected scalp skin of AA patients. Downstream analyses incorporated in silico and functional cell assays that uncovered a novel autophagy-independent role for STX17 in melanocyte biology. I discovered that a reduction of STX17 expression was associated with an accumulation of a melanocyte-specific antigen and increased immunogenicity, as seen by CD8+ T cell infiltrates in the skin of AA patients with low levels of STX17 expression. I used a targeted sequencing approach to successfully identify candidate causal variants driving the GWAS association at the STX17 locus, and propose a novel mechanism underlying STX17-dependent melanocyte perturbation and AA disease. In the second section of this thesis, we used the WES feature of the chip to assess the genetic contribution of rare variation in AA, in a genome-wide and unbiased manner. WES data and gene-level burden analyses of 18,653 genes in 849 AA patients was compared to 15,640 controls to identify rare variants associated with AA. Unexpectedly, this analysis identified one gene, encoding a hair-specific keratin, Keratin 82 (KRT82) that harbored significantly more rare damaging mutations in AA cases compared to controls (p=2.68E-06). Eleven rare damaging mutations were found in 51 AA patients in the heterozygous state (6.01%) compared to 2.58% controls. These variants resided in evolutionary conserved amino acid residues, and nine out of the eleven mutations were located in established disease-causing domains in keratin proteins. I determined that KRT82 expression was absent or largely reduced in AA hair follicles, including the bulb region, the site of AA immune attack. Moreover, AA patients with damaging variants and reduced KRT82 expression had increased perifollicular CD8+ T cell infiltrates in comparison to control HFs with intact KRT82 expression remaining. I proposed that damaging mutations in the coding regions of KRT82 resulted in loss of functional protein, thereby weakening the protective HF cuticle and predisposing the HF to immune attack. In summary, I used two genetic approaches (targeted genomic sequencing and WES) to identify common (Chapter 2) and rare variants (Chapter 3) with novel contributions to the complex genetic architecture of AA. I focused my functional studies on genes expressed in the target HF, with the goal of defining the role of unidentified, variant-mediated end-organ disruption in the predisposition of AA patient HFs to aberrant autoimmune attack. Up to now, most efforts in AA mechanistic studies have focused on the aberrant immune response. The work in my thesis uncovered novel roles for perturbations in the HF itself as a participating factor in AA disease risk.

The anticardiolipin antibody syndrome is relatively uncommon. It should be suspected mostly in young people with unexplained embolic or thrombotic events. A young patient with an abnormal prothrombin time, partial thromboplastin time, or venereal disease research lab test with one of the above noted vascular events would be a suspect for this disorder. Though an antibody test that will qualitatively and quantitatively measure antiphospholipid antibodies is available, its clinical application is not entirely clear. The presence of the antibody will support a diagnosis but cannot be used alone for diagnosis or treatment.

京都大学 / 新制・課程博士 / 博士(医学) / 甲第24192号 / 医博第4886号 / 新制||医||1060(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 萩原 正敏, 教授 森信 暁雄, 教授 遊佐 宏介 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

The complement components C3 and C4 are part of the complement system. The complement system has many tasks to perform in the body and consists of several proteins that all have unique tasks. C3 and C4 are examined, for example, if a deficiency is suspected, in the presence of autoimmune diseases or in the case of recurring bacterial infections. When verifying the analysis and after analyzing of external controls, it has been shown that the reference range is falsely high, especially for C3. The study therefore aimed to verify the analysis of C3 and C4 on Atellica NEPH 630 and establish a correct reference range for respective analysis. The method was verified by evaluating the precision of the method and by comparing the concentration of C3 and C4 measured on Cobas 6000 module C500 with the concentration measured on Atellica NEP 630. In addition, the reference intervals provided by Siemens were evaluated using samples from blood donors and from other healthy individuals. The verification began by performing quality controls on three different levels before analysis of samples. The coefficient of variation was less than 5 % for all control levels for both complement analysis. Reference values ​​for C3 were not in alliance with the reference values ​​provided by Siemens. A new proposed range for C3 is 0.48- 1.37 g/L, while the recommended range can be used for C4.

No description available.

Heparan sulfate (HS), an unbranched sulfated carbohydrate chain, and the HS-degrading enzyme heparanase play important roles in physiological and pathological processes during all stages of life, from early embryogenesis to ageing. Accumulated information shows that HS and heparanase are involved in inflammatory processes and associated diseases, e.g. rheumatoid arthritis (RA) and Alzheimer’s disease. In this thesis I have investigated the role of HS and heparanase (Hpa) in inflammatory-related pathologies. In the first project, Hpa overexpressing mice (Hpa-tg) were induced with a murine model of RA. We found a pro-inflammatory role of Hpa through enhancing the activity of T-cells and innate immune cells, which contributed to an augmented severity of clinical symptoms in the Hpa-tg mice. In my second project, we revealed co-current interaction of heparin with both ApoA1 and SAA of HDL isolated from plasma of inflamed mouse. Mass spectrometry analysis indicated close proximity of ApoA1 and SAA on the HDL surface, providing a molecular and structural mechanism for the simultaneous binding of heparin to apoA1 and SAA. In my third project, we investigated the role of Hpa in AA amyloid formation and resolution in mice in a model of AA-amyloidosis. We found a similar degree of amyloid formation in Hpa-KO mice compared to the wildtype control mice, but the resolution process was faster in Hpa-KO mice. The rapid clearance of deposited SAA in Hpa-KO mice was associated with upregulated expression of matrix metalloproteases. The results suggest an associated function of ECM proteases with heparanase in the process of AA amyloid resolution. In my fourth project, we found that overexpression of heparanase impaired inflammation associated beta amyloid (Aβ) clearance in the brain of an Alzheimer’s disease mouse model. Examination of the cytokine profile of brain lysates revealed an overall lower inflammatory reaction in the double transgenic (tgHpa*Swe) mice compared to single APP-tg (tg-Swe) mice in response to LPS-induced inflammation.

O transplante autólogo de células-tronco hematopoéticas é indicado no tratamento de doenças autoimunes graves e refratárias ou que comprometem a qualidade de vida do paciente. Tal tratamento possui sólidas bases experimentais e clínicas e para alguns já apresenta superioridade ao tratamento convencional. No entanto, é um procedimento considerado agressivo, de alto custo financeiro, que pode acarretar eventos adversos, complicações, fatores de tensão física e psíquica para o paciente e sua família. Essa complexidade exige uma assistência de enfermagem especializada, capaz de assistir o paciente em cada uma das fases do tratamento, a fim de identificar os riscos, as intercorrências e propondo intervenções adequadas. Além disso, é fundamental que o paciente adquira conhecimentos e habilidades para se adaptar às condições impostas pela terapêutica, assim reunirá recursos de autonomia para realizar seu autocuidado. Frente ao exposto, as tecnologias podem ajudar e facilitar a aprendizagem, pois abordam o conteúdo por meio de várias formas e formatos. Nesse contexto, a enfermagem depara-se com o desafio de integrar o uso da Internet® no cuidado prestado ao paciente. A utilização dessa rede enfoca, principalmente, a disponibilização de informação de saúde ou estabelecimento de contato virtual para providenciar informação acessada de forma rápida e adequada à demanda da pessoa. Desta forma, o objetivo deste estudo foi desenvolver um ambiente virtual de aprendizagem com orientações sobre transplante autólogo de células-tronco hematopoéticas para doenças autoimunes. Trata-se de um estudo metodológico, com o objetivo de desenvolver o ambiente virtual de aprendizagem, website, com orientações sobre transplante autólogo de células-tronco hematopoéticas para doenças autoimunes. O website foi construído conforme o modelo de design instrucional, o qual percorreu as seguintes etapas: análise, design, desenvolvimento e implementação. Este foi desenvolvido em plataforma web, na linguagem de marcação Hypertext Markup Language, utilizando-se o programa WebAcappella, Responsive Website Creator 5 e disponibilizado no endereço eletrônico: http://www.transplantardai.com.br. O conteúdo do website foi estruturado nos seguintes tópicos: História, Transplante, Doenças Autoimunes, Links Interessantes, Orientações, Fala Equipe e Dúvidas Frequentes. Os ícones e menus foram criados de modo que o conteúdo atraia o usuário, sem cansar ou distraí-lo, a fim de otimizar os recursos disponíveis no ambiente e facilitar o acesso à busca dessas informações. Assim sendo, o presente estudo desenvolveu um ambiente virtual de aprendizagem que pode ser uma ferramenta utilizada para orientar, cuidar e interagir / Autologous hematopoietic stem cell transplantation is indicated for the treatment of severe or refractory autoimmune diseases, or those which compromise patients\' quality of life. This treatment has solid experimental and clinical foundations, and in some cases, it outranks conventional treatments. However, it is considered an aggressive and high-cost procedure that may lead to adverse events, complications, and factors of physical and psychic tension to patients and their families. This complexity requires specialized nursing care, capable of assisting patients in each phase of the treatment, so as to identify risks and propose appropriate interventions. In addition, patients must acquire knowledge and skills to adapt to the conditions imposed by the treatment, thus gathering autonomy resources to perform self-care. In the light of this, technologies can help and facilitate learning, as they approach content in several ways and formats. In this context, nursing faces the challenge of integrating the use of the Internet® in the care provided to patients. The use of this network focuses, mainly, on making health information available or establishing virtual contact to provide information that can be accessed fast and that is suitable to the person\'s demand. This was a methodological study, with the aim of developing a virtual learning environment and a website, with instructions on autologous hematopoietic stem cell transplantation for autoimmune diseases. The website was built according to an instructional design model, through the following steps: analysis, design, development, and implementation. It was developed on a web platform, using the Hypertext Markup Language and the programs WebAcappella and Responsive Website Creator 5, being available at http://www.transplantardai.com.br. The website content was structured in the following topics: History, Transplantation, Autoimmune diseases, Interesting links, Instructions, Talk to the team and Frequently asked questions. The icons and menus were created so that the content would be attractive to users, without making them tired or distracting them, in order to optimize the resources available in the environment and facilitate access to the search for information. Therefore, the present study developed a virtual learning environment that can be used for guidance, caring, and interaction

O presente estudo teve como objetivo avaliar a eficácia do imunossupressor tópico tacrolimus a 0,1%, aplicado de forma oclusiva com o auxílio de moldeiras individualizadas de silicone em pacientes com gengivite descamativa decorrentes do líquen plano oral (LPO) e do penfigóide das membranas mucosas (PMM). Foram selecionados consecutivamente 18 pacientes que preencheram os critérios de inclusão adotados, sendo 17 mulheres (8 LPO / 9 PMM) e 1 homem com LPO. Após o estabelecimento do diagnóstico os pacientes foram avaliados por um mesmo avaliador quanto aos sinais e sintomas, utilizando-se para isso duas escalas visuais analógicas, uma para dor e outra para ardência, além de um periograma especialmente desenhado para avaliação clínica, demarcando as áreas onde haviam a presença de lesões gengivais no dia zero e no dia 90. Após adequação periodontal os pacientes eram moldados para confecção de uma moldeira individual de silicone para servir de suporte oclusivo para a medicação estudada. A terapêutica adotada foi dividida em duas fases de 45 dias totalizando 90 dias. Na primeira fase os pacientes foram orientados a usar de 1 a 2 gramas da medicação em cada moldeira, duas vezes ao dia por 20 minutos e na segunda fase somente uma vez ao dia. Os possíveis efeitos colaterais eram monitorados durante as consultas de retorno a cada 15 dias. Ao final dos 90 dias avaliamos o percentual de remissão dos sinais, classificada como completa (100%), excelente (75% a 99%), boa (50% a 74%), regular (1 a 44%), inalterada ou com piora do quadro. Nos pacientes estudados obtivemos remissão completa em 4 (30,76%), 4 com remissão excelente (30,76%), 4 com remissão boa (30,76%) e um com remissão regular (7,69%). Em relação aos sintomas da dor obtivemos uma redução média de 60% e em relação a ardência uma redução média de 65,5%. Os pacientes com LPO obtiveram uma redução média da dor de 42,5% e da ardência de 58%, nos pacientes com PMM a redução da dor foi de 92,8% e da ardência de 80,7%. A comparação dos escores de dor antes e após o tratamento apresentou valor de p<0,01 quando realizado o teste de Wilcoxon para amostras pareadas. O mesmo resultado (p<0,01) foi encontrado quando comparados os escores de ardência. Os valores obtidos demonstraram que a diminuição dos escores de dor e ardência foi estatisticamente significante. Como efeitos colaterais observamos que todos relataram alteração transitória de paladar e um paciente com LPO desenvolveu candidose. Concluímos que o tacrolimus a 0,1% aplicado topicamente com moldeiras individuais de silicone foi eficaz no tratamento das gengivites descamativas quanto a dor, ardência e remissão clínica das lesões gengivais em pacientes com LPO e PMM. / The objective of this study was to evaluate the efficacy of application of the topical immunosuppressor 0.1 % tacrolimus in patients with desquamative gingivitis (DG) associated with oral lichen planus (OLP) and mucous membrane pemphigoid (MMP). We selected 18 patients that fulfilled the inclusion criteria: 17 females (8 OLP/ 9MMP) and one male (OLP). After diagnosis, all subjects were evaluated by the same researcher, who assessed pain and burning using two visual analogical scales, one for pain and the other for burning, in conjunction with a diagram of the gingival mucosa. Measurements were made on day zero and day 90. After the periodontal assessment, individualized silicone rubber trays were prepared in order to deliver the drug. The therapeutic strategy was divided in two phases of 45 days for a total of 90 days. In the first treatment phase it was recommended that all patients use one or two grams of 0.1 % tacrolimus in his/her tray for twenty minutes, twice daily; in the second phase, the treatment was to be used only once daily. All side effects were monitored during biweekly return visits. At the end of 90 days, the response to therapy was assessed according to the following scale, as a percentage of remission: complete (100 %), excellent (75 % to 99 %), good (50 % to 74 %), poor (1 % to 49 %), no response (0 %) and worsened. We observed complete remission in 4 patients (30.76 % of the experimental group), excellent in 4 patients (30.76 %), good in 4 patients (30.76 %), and poor in one (7.69%). Pain was reported to be reduced by 60 % while burning was reduced by 65.5 %. OLP patients showed an average reduction by 42.5% of pain and 58% of burning. MMP patients showed an average reduction by 92.8% of pain and 80.7% of burning. After treatment, the data were analyzed by Wilcoxons test; significant differences (p < 0.01) were found for both pain and burning. Side effects included transitory alteration of taste, and one patient was diagnosed with candidiasis. From this study, we conclude that topical application of 0.1% tacrolimus using silicone rubber trays is an effective treatment for desquamative gingivitis, decreasing pain, burning and clinical lesions in OLP and MMP patients.

Ces travaux de recherche visent à mettre au point par une nouvelle « Approche Chimique Inverse » des antigènes synthétiques pour le diagnostic de maladies auto-immunes; utilisant les autoanticorps spécifiques de ces pathologies en tant que biomarqueurs.L'efficacité de ces peptides modifiés en tant qu'outils pour le diagnostic est évaluée par un screening au moyen de tests immunoenzymatiques (SP-ELISA), de sérums de patients atteints de pathologies auto-immunes sélectionnées.Trois maladies ont été étudiées en particulier.La cirrhose primitive biliaire est une maladie auto-immune cholestatique affectant le foie, caractérisée par une destruction progressive des canaux intra-hépatiques, pouvant mener à une cirrhose. Il existe des autoanticorps antimitochondriaux spécifiques à cette maladie qui reconnaissent un epitope lipoylé de la PDC-E2, protéine impliquée dans le cycle énergétique mitochondrial. La synthèse de sondes moléculaires lipoylées basées sur la PDC-E2(167-186) a été mise au point et optimisée. Les antigènes synthétiques ont ainsi été testés sur des sérums de patients de PBC. Les résultats montrent que: 1) la séquence a une importance pour la reconnaissance des anticorps; 2) la chiralité du dithiolane de la lipoyl-lysine ne semble pas avoir d'influence majeure sur la reconnaissance des autoanticorps; 3) l'absence de lipoylation sur le mime de la protéine native semble donner de meilleurs résultats que l'antigène synthétique lipoylé.Le diabète est une maladie caractérisée par une hyperglycémie provoquée par l'action réduite ou inexistante de l'insuline. L'excès de sucre dans le sang peut provoquer des modifications de diverses natures sur les protéines circulantes (glycation, O-glycosylation, N-glycosylation).La synthèse de sondes moléculaires portant ces structures en tant que modifications post-traductionnelles a été mise au point. Les antigènes synthétiques ont ainsi été testés sur des sérums de patients atteints de diabète. Les résultats montrent que trois des peptides testés permettent de différencier les patients atteints de diabète de type 1 (forme autoimmune) de ceux de type 2 (forme non autoimmune) ainsi que des controles sains.La sclérose en plaques est une maladie impliquant une démyélinisation des fibres nerveuses du système nerveux central. Le système immunitaire détruit les protéines composante cette gaine de myéline. La kynurénine est un des métabolites principaux du Tryptophane, et il a été montré que dans la sclérose en plaques, la voie métabolique du Tryptophane pourrait être déréglée.Ainsi, la synthèse de peptides modifiés portant une kynurénine comme modification post-traductionnelle aberrante a été menée à bien. Les résultats ne montrent pas de détection particulière d'anticorps dirigés contre cette modification dans le cas de la sclérose en plaques. / This research work aims to apply the novel concept of “Chemical Reverse Approach” to the design, the production, and the immunological screening of synthetic antigens able to specifically detect autoantibodies in sera of patients affected by immune-mediated diseases. Such specific autoantibodies are considered disease biomarkers and can be used to develop novel diagnostic/prognostic tools for the aforementioned pathologies.In particular, three diseases have been investigated.Primary Biliary Cirrhosis is an autoimmune cholestatic disease of the liver, characterized by progressive destruction of intrahepatic bile ducts. Specific antimitochondrial autoantibodies directed against a lipoylated epitope of the PDC-E2 protein, are considered relevant for the disease. The PDC-E2 protein is involved in the energetic cycle of mitochondria. Synthesis of lipoylated molecular probes based on PDC-E2(167-186) was carried out and optimized. These new synthetic antigens were tested on PBC patients' sera. The results showed that: 1) the sequence is fundamental for antibody recognition; 2) dithiolane lipoyl-lysine chirality does not seem to have any significant influence on antibody recognition; 3) the unlipoylated analogue of the native protein appears to detect a more relevant antibody titre than the lipoylated one.Diabetes is a disease characterized by hyperglycaemia. This condition is caused by the reduced or inexistent action of insulin. Hyperglycaemia can cause various modifications on circulating proteins (such as glycation, O-glycosylation, N-glycosylation).The synthesis of post-translationally modified peptides containing such structures was carried out. These new synthetic antigenic probes were tested on sera from patients suffering from diabetes. The results showed that three peptides among those tested can differentiate patients with type-1 diabetes (autoimmune form) from those with type-2 (non-autoimmune form) and healthy patients.Multiple sclerosis is a demyelinating disease of the central nervous system. The immune system destroys proteins components of myelin sheath. Kynurenine is a major metabolite of Tryptophan, and it has been shown that in multiple sclerosis, the metabolic pathway of Tryptophan may be deregulated.Thus, the synthesis of modified peptides incorporating a kynurenine as an aberrant post-translational modification was carried out. The results show no specific antibody detection in multiple sclerosis sera.

Introdução: a síndrome antifosfolípide (SAF) primária é uma vasculopatia autoimune mediada por autoanticorpos com trombose como sua principal manifestação clínica. A presença de anticorpos antifosfolípides (aPL), embora relevante para confirmar o diagnóstico, não parece ser suficiente para explicar completamente a fisiopatologia da doença e um segundo gatilho é usualmente necessário. Além das hipóteses de infecções virais e insulto inflamatório como possíveis desencadeantes, parece que os receptores toll like (TLR) e o Interferon (IFN) tipo I são possíveis protagonistas nesse processo, contribuindo para o início da trombose. Recentemente, dois pequenos estudos demonstraram que uma porcentagem relevante de pacientes com SAF primária tem uma regulação positiva de genes IFN em células mononucleares do sangue periférico (CMSP). Entretanto, 20% e 28% dos pacientes nessas duas coortes tiveram anticorpos anti-dsDNA positivos, um autoanticorpo altamente específico do lúpus eritematoso sistêmico (LES). Objetivo: avaliar se os pacientes com SAF bem caracterizados apresentam assinatura para interferon nas células mononucleares periféricas. Secundariamente foram avaliadas possíveis associações clínico laboratoriais com a assinatura de IFN. Métodos: foram selecionados 53 pacientes do sexo feminino com diagnóstico de SAF primária de acordo com os critérios de Sidney, com idade igual ou maior a 18 anos, selecionados no Ambulatório de SAF da Disciplina de Reumatologia do HCFMUSP, pareados por sexo e idade com 50 controles saudáveis. Um terceiro grupo com 29 paciente com antecedente de trombofilias não imunomediadas também foi incluido. Após a coleta de sangue as CMSPs foram purificadas por metodologia de Ficoll. A expressão gênica das CMSPs foi realizada através do TaqMan® RNA Assay em placas TLDA. Foram pesquisados 41 genes induzidos por IFN (GIIs). Uma análise de componente principal (ACP) foi realizada para determinar quais genes deveriam compor a assinatura de IFN. O teste de z-score foi utilizado para normalizar e calcular a assinatura de IFN para cada paciente. O cutoff da assinatura de IFN foi definido por uma curva ROC, e foi escolhido o ponto que maximizava a sensibilidade e especificidade. Características demográficas, clínicas e laboratoriais foram analisadas buscando por associações com a assinatura de IFN. Resultados: 11 genes estavam superexpressos nos pacientes com SAF em comparação aos controles. Após a análise de ACP foram escolhidos 6 genes que representavam mais de 95% do comportamento da amostra para compor a assinatura de IFN: DNAJA1, IFI27, IFI6, IFIT5, MX1 e TYK2. O cutoff encontrado pela curva ROC foi de 3,9 folds (AUC = 0,706, S = 0,49, E = 0,86, VPP = 0,79, VPN = 0,61). A assinatura de IFN estava presente em 49% dos pacientes com SAF primário vs. 14% dos controles saudáveis e 17% dos controles positivos (p < 0,001). Foi encontrada associação entre a assinatura de IFN e uma ocorrência mais precoce do primeiro evento clínico (p = 0,023), e com ocorrência de eventos obstétricos (em especial pré-eclâmpsia, p = 0,032). Não foi econtrada nenhuma associação entre a assinatura de IFN e número de eventos trombóticos, exames laboratoriais, comorbidades, antecedentes familiares de doenças autoimunes, e escores de risco de retrombose. De todos os tratamentos em uso a única associação encontrada foi entre uma menor assinatura de IFN e o uso de estatinas (p = 0,026). Conclusão: esse estudo indica que pacientes com SAF primária bem caracterizados apresentam uma assinatura de IFN tipo I, não observada em outras trombofilias não imunidade-mediadas ou em controles saudáveis. Também demonstrou-se que essa superexpressão de genes regulados por IFN tipo I está associada a um início mais precoce dos eventos e pré-eclâmpsia. Mais estudos são necessários para determinar se este subgrupo de pacientes se beneficiará de intervenções terapêuticas direcionadas à via de sinalização IFN tipo I / Introduction: primary antiphospholipid syndrome (PAPS) is an autoimmune vasculopathy mediated by autoantibodies with thrombosis as its main clinical manifestation. The presence of antiphospholipid antibodies, while relevant to confirm the diagnosis, does not seem to be sufficient to fully explain the pathophysiology and a second trigger is usually needed. Besides the hypotheses of viral infections and inflammatory insult as possible triggers, type I Interferon (IFN) has been pointed as a possible protagonist. Recently, two studies have demonstrated that a relevant percentage of PAPS patients have an up-regulation of IFN genes in peripheral blood mononuclear cells (PBMC). However, 20% and 28% of patients in these 2 cohorts, had antidsDNA positive antibodies, a highly specific Systemic Lupus Erythematosus (SLE) autoantibody. Objective: The aim of this study is to determine the prevalence of type I IFN signature in PBMC of patients with PAPS without specific SLE autoantibodies and search for it with clinical and laboratorial associations. Methods: 53 PAPS patients (according to Sydney´s criteria) were consecutively selected and age-matched with 50 healthy controls. A third group, with non-immune-mediated thrombophilia patients, was also included. The expression of 41 IFN induced genes was analysed using real time quantitative PCR (TaqMan Low Density Array). A principal component analysis (PCA) was used to determine which genes should compose the IFN signature and z-score was calculated. The IFN signature score cut-off was defined with a ROC curve, as the point that maximized both the specificity and sensitivity. Clinical and laboratorial features were analysed searching for associations with IFN signature. Results: 11 IFN genes were highly expressed in primary APS patients. After PCA, 6 genes remained in the IFN signature: DNAJA1, IFIT5, IFI27, MX1, IFI6, TYK2. The ROC cutoff was 3,9 folds (AUC = 0.706, S = 0.49, E = 0.86, VPP = 0.79, VPN = 0.61). The type I IFN signature was present in 49% of patients with primary APS compared to 14.0% of healthy controls and 17% of non-immune-mediated thrombophilia patients (p < 0.0001). The mean IFN score was significantly higher in PAPS patients (4.0 fold higher, p < 0.0001) than in controls. A higher IFN signature was associated with a younger age at the first APS event (p = 0.023) and with the presence of obstetric events, especially with preeclampsia (p = 0.032). There was no association between IFN signature and number of thrombotic events, laboratory exams, comorbidities, family history of autoimmune diseases, and thrombosis risk scores. Treatment with statins was associated with lower levels of IFN scores (p = 0.026). Conclusion: our result indicates that PAPS patients, without lupus specific antibodies, have an enhanced type I IFN gene signature, not observed in non-immune mediated thrombophilia. We also provide novel data demonstrating that this overexpression of type I IFN-regulated genes is associated with an earlier onset of APS events and preeclampsia. Further studies are necessary to determine if this subgroup of patients will benefit of interventions targeting the type I IFN signalling pathway