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BACKGROUND: Systemic-lupus-nephritis is a chronic autoimmune disease characterized by immune complex deposition and a flare of autoantibodies and leading to renal injury. OBJECTIVES: To expose anti-Dense-Fine-Speckled-70 (DFS70)-antibodies to genetically-prone-lupus-mice. METHODS: NZBXW/F1 female mice were monitored for the onset of glomerulonephritis by proteinuria upon infusion of anti-DFS70 (40 µg/mouse), commercial-human-IgG (cIgG) or phosphate-buffered-saline (PBS) as controls. The survival time was detected by mice death. Circulating anti-dsDNA were tested by ELISA. Proteinuria, was defined by a standard semi-quantitative-Bayer-Multistix-dipstick. Kidney histology was analyzed by periodic-acid-Schiff-PAS staining. RESULTS: A significantly higher percentage of anti-DFS70-infused mice exhibited prolonged survival time as compared with cIgG and PBS-subjected mice (p < 0.022). One mouse out of 10 mice injected with anti-DFS70-antibodies died at week 36, whereas, 6 out of 10 mice subjected with PBS found dead at this time. Eighty percent of anti-DFS70 injected mice did not show severe glomerulonephritis by histology. CONCLUSIONS: anti-DFS70 attenuated the progression of glomerulonephritis and prolonged the survival time. Circulating anti-DFS70-autoantibodies may confer a protective role against renal injury in murine-lupus-nephritis. Our data may propose a novel therapy approach for lupus patients.
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Anticuerpos Antinucleares/inmunología , Glomerulonefritis/inmunología , Glomerulonefritis/patología , Nefritis Lúpica/inmunología , Nefritis Lúpica/patología , Proteínas Adaptadoras Transductoras de Señales/inmunología , Animales , Anticuerpos Antinucleares/farmacología , Modelos Animales de Enfermedad , Femenino , Riñón/patología , Ratones , Ratones Endogámicos NZB , Proteinuria/inmunología , Proteinuria/patología , Tasa de Supervivencia , Factores de Transcripción/inmunologíaRESUMEN
OBJECTIVE: To determine the frequency of immunodeficiency-like states in SLE and related clinical features. METHODS: Three hundred and fifteen SLE patients and 301 controls were evaluated for C4A and C4B gene copy number, immunoglobulin isotypes, IgG subclasses, total haemolytic complement (CH50), C2, C3 and neutrophil oxidative burst. C2 and C3 genes were sequenced in cases of low C2 or C3 levels. Those presenting abnormal CH50 with normal C2 and C3 underwent C1q-C9 determination. Patients with active SLE and abnormal results were re-tested after the flare or were excluded if no remission was attained. Fifteen patients were excluded on this basis. Persistent abnormal results characterized an immunodeficiency-like state. RESULTS: A significantly higher percentage of SLE patients presented an immunodeficiency-like state compared with controls (28.7% vs 3.3%; P < 0.001), especially low immunoglobulin serum levels. Rigorous testing confirmed only two cases of C2 deficiency carriers among the SLE patients. There were significantly more SLE patients with less than two C4A copies compared with controls. SLE patients had higher frequency of low IgG2, IgG3, IgG4 and IgM levels compared with controls. Patients with low IgG3 or IgG4 presented higher frequency of lupus nephropathy. Patients with low IgM had longer disease duration, older age at SLE onset and lower frequency of oral ulcers. CONCLUSION: An immunodeficiency-like state is present in a sizable fraction of SLE patients. Further studies are warranted to determine the impact of these immunodeficiency states and whether they are a primary condition or are secondary to confounding factors, including SLE itself.
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Síndromes de Inmunodeficiencia/etiología , Lupus Eritematoso Sistémico/inmunología , Adulto , Estudios de Casos y Controles , Complemento C3/genética , Complemento C4a/genética , Complemento C4b/genética , Estudios Transversales , Femenino , Dosificación de Gen/genética , Humanos , Deficiencia de IgG , Nefritis Lúpica/inmunología , Masculino , Fagocitos/metabolismo , Estallido Respiratorio/fisiologíaRESUMEN
OBJECTIVES: High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released into the extracellular milieu. HMGB1 is a biomarker of active disease in several systemic autoimmune diseases. Behçet's disease (BD) is a systemic inflammatory disorder with a waxing/waning course. The objective of this study is to evaluate serum HMGB1 levels as a possible biomarker for disease activity in BD. METHODS: A cross-sectional study measuring serum HMGB1 levels was performed in 26 BD patients and 20 healthy controls. The Brazilian version of the simplified BD Current Activity Form (BR-BDCAFs) was used to measure disease activity. RESULTS: Serum HMGB1 levels were higher in patients with active disease [3.82 (2.54-6.11) ng/ml], in patients with BD without active disease but still on therapy [2.76 (1.89-5.78) ng/ml] and in patients in remission without treatment [2.66 (1.86-4.70) ng/ml] than in healthy controls [0.96 (0.59-1.39) ng/ml], P < 0.001. Levels were comparable between BD patients with active disease, BD without active disease but still on therapy and those in remission without treatment (P = 0.432). There was no correlation between serum HMGB1 levels and BR-BDCAF(s) (ρ = 0.195; P = 0.339). No association could be found between serum HMGB1 levels and specific disease involvement or therapy. So serum HMGB1 levels cannot be used as a biomarker in BD. CONCLUSION: Serum HMGB1 levels are increased in patients with BD as compared with healthy controls. However, no association was found with disease activity, specific organ involvement or therapy in BD.
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Síndrome de Behçet/sangre , Proteína HMGB1/sangre , Adulto , Azatioprina/uso terapéutico , Síndrome de Behçet/tratamiento farmacológico , Biomarcadores/sangre , Estudios de Casos y Controles , Estudios Transversales , Femenino , Glucocorticoides/uso terapéutico , Humanos , Inmunosupresores/uso terapéutico , Masculino , Persona de Mediana Edad , Prednisona/uso terapéutico , Índice de Severidad de la EnfermedadRESUMEN
OBJECTIVES: To test the hypothesis that classical phagocytic functions are constitutively stimulated in patients with Behçet's disease (BD). METHODS: Four study groups were analysed: active BD (aBD; n=30), inactive BD (iBD; n=31); septic patients (SP; n=25); healthy controls (HC; n=30). Microbicide activity against Streptococcus pneumoniae, Streptococcus sanguinis and Candida albicans was determined by means of 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction and absorbance read by ELISA. Flow cytometry analysis evaluated phagocytosis (zymosan particles and microrganisms) and oxidative burst by dihidrorhodamine oxidation before and after stimulation with phorbol myristate acetate (PMA). The supernatant of PBMC cultures under TLR or microbial stimuli and of neutrophil cultures under PMA, LPS or microbial stimuli were used for determination of cytokine production by ELISA. RESULTS: We found no significant differences between the BD patient groups and control groups with regard to oxidative burst, phagocytic activity, microbicide activity or cytokine production. However, the cells from patients with severe BD (based on clinical manifestation) exhibit significantly higher oxidative burst activity, both before and after PMA stimulation, compared to cells from patients with mild BD. Furthermore, we found significant correlations between the BD patients' scores on the simplified Behçet's Disease Current Activity Form adapted for Portuguese (BR-BDCAFs) and Streptococcus sanguinis-stimulated production of IL23 by PBMC and IL8 by neutrophils, and between BR-BDCAFs score and constitutive production of TNF-α, IFNγ, IL6 and IL23 by PBMC. CONCLUSIONS: Patients with severe active BD do exhibit phagocytic dysfunction and some evidence of constitutive activation regarding oxidative burst and cytokine production.
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Síndrome de Behçet/metabolismo , Citocinas/metabolismo , Mediadores de Inflamación/metabolismo , Leucocitos Mononucleares/metabolismo , Activación Neutrófila , Neutrófilos/metabolismo , Fagocitosis , Estallido Respiratorio , Adulto , Síndrome de Behçet/diagnóstico , Síndrome de Behçet/inmunología , Candida albicans/inmunología , Estudios de Casos y Controles , Células Cultivadas , Citocinas/inmunología , Femenino , Humanos , Mediadores de Inflamación/inmunología , Leucocitos Mononucleares/efectos de los fármacos , Leucocitos Mononucleares/inmunología , Leucocitos Mononucleares/microbiología , Masculino , Persona de Mediana Edad , Activación Neutrófila/efectos de los fármacos , Neutrófilos/efectos de los fármacos , Neutrófilos/inmunología , Neutrófilos/microbiología , Fagocitosis/efectos de los fármacos , Fenotipo , Estallido Respiratorio/efectos de los fármacos , Índice de Severidad de la Enfermedad , Streptococcus pneumoniae/inmunología , Streptococcus sanguis/inmunología , Acetato de Tetradecanoilforbol/farmacología , Adulto JovenRESUMEN
Background/Objective: Myasthenia Gravis (MG) is an autoimmune disorder characterized by pathogenic autoantibodies (AAbs) targeting nicotinic acetylcholine receptors (AChR), disrupting neuromuscular communication. RadioImmunoPrecipitation Assay (RIPA) is recommended to detect AChR AAbs, but its complexity and radioactive requirements limit widespread use. We compare non-RIPA anti-AChR immunoassays, including Cell-Based Assay (CBA) and two ELISA kits, against the gold standard RIPA. Methods/Results: 145 samples were included with medical indication for anti-AChR testing. By the RIPA method, 63 were negative (RIPA-Neg <â0.02 nmol/L), 18 were classified as Borderline (≥0.02 -1 nmol/L), and 64 were positive (RIPA-Posâ>â1 nmol/L). The competitive ELISA showed poor agreement with RIPA (Kappaâ=â0.216). The indirect ELISA demonstrated substantial agreement with RIPA (Kappaâ=â0.652), with â¼76% sensitivity and â¼94% specificity for MG diagnostic. The CBA, where fixed cells expressing clustered AChR were used as substrate, exhibited almost perfect agreement with RIPA (Kappaâ=â0.984), yielding â¼98% sensitivity and 96% specificity for MG. In addition, a semiquantitative analysis showed a strong correlation between CBA titration, indirect ELISA, and RIPA levels (râ=â0.793 and râ=â0.789, respectively). Conclusions: The CBA displayed excellent analytical performance for MG diagnostic when compared to RIPA, making it a potential replacement for RIPA in clinical laboratories. Some solid-phase assays (such as the indirect ELISA applied here), as well as CBA titration, offer reliable options to estimate anti-AChR AAb levels after confirming positivity by the CBA.â¥.
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Autoanticuerpos , Ensayo de Inmunoadsorción Enzimática , Miastenia Gravis , Ensayo de Radioinmunoprecipitación , Humanos , Ensayo de Inmunoadsorción Enzimática/métodos , Miastenia Gravis/inmunología , Miastenia Gravis/diagnóstico , Sensibilidad y Especificidad , Receptores Colinérgicos/inmunología , Femenino , Masculino , Persona de Mediana Edad , Adulto , Anciano , Adulto JovenRESUMEN
The classification and diagnosis of systemic autoimmune diseases are frequently based on a collection of criteria composed of clinical, laboratory, imaging, and pathology elements that are strongly associated with the respective disease. Autoantibodies are a distinctive hallmark and have a prominent position in the classification criteria of many autoimmune diseases. The indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA), historically known as the antinuclear antibody test, is a method capable of detecting a wide spectrum of autoantibodies. A positive HEp-2 IFA test is part of the classification criteria for systemic lupus erythematosus (SLE) and juvenile idiopathic arthritis (JIA), as well as the diagnostic criteria for autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC). A positive HEp-2 IFA test can appear as different morphological patterns that are indicative of the most probable autoantibody specificities in the sample. Only some of the HEp-2 IFA patterns are associated with the specific autoantibodies relevant to SLE, JIA, AIH, and PBC, whereas some other patterns occur mainly in non-related conditions and even in apparently healthy individuals. This paper provides a critical review on the subject and proposes that the classification and diagnostic criteria for SLE, JIA, AIH, and PBC could be improved by a modification on the HEp-2 IFA (ANA) criterion in that the staining patterns accepted for each of these diseases should be restricted according to the respective relevant autoantibody specificities.
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Personalized medicine (PM) aims individualized approach to prevention, diagnosis, and treatment. Precision Medicine applies the paradigm of PM by defining groups of individuals with akin characteristics. Often the two terms have been used interchangeably. The quest for PM has been advancing for centuries as traditional nosology classification defines groups of clinical conditions with relatively similar prognoses and treatment options. However, any individual is characterized by a unique set of multiple characteristics and therefore the achievement of PM implies the determination of myriad demographic, epidemiological, clinical, laboratory, and imaging parameters. The accelerated identification of numerous biological variables associated with diverse health conditions contributes to the fulfillment of one of the pre-requisites for PM. The advent of multiplex analytical platforms contributes to the determination of thousands of biological parameters using minute amounts of serum or other biological matrixes. Finally, big data analysis and machine learning contribute to the processing and integration of the multiplexed data at the individual level, allowing for the personalized definition of susceptibility, diagnosis, prognosis, prevention, and treatment. Autoantibodies are traditional biomarkers for autoimmune diseases and can contribute to PM in many aspects, including identification of individuals at risk, early diagnosis, disease sub-phenotyping, definition of prognosis, and treatment, as well as monitoring disease activity. Herein we address how autoantibodies can promote PM in autoimmune diseases using the examples of systemic lupus erythematosus, antiphospholipid syndrome, rheumatoid arthritis, Sjögren syndrome, systemic sclerosis, idiopathic inflammatory myopathies, autoimmune hepatitis, primary biliary cholangitis, and autoimmune neurologic diseases.
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Enfermedades Autoinmunes , Lupus Eritematoso Sistémico , Síndrome de Sjögren , Autoanticuerpos , Humanos , Medicina de Precisión , Síndrome de Sjögren/complicacionesRESUMEN
Ribavirin (RBV) is a guanosine analogue triazole most commonly used in the treatment of chronic hepatitis C (HCV) infection. Although its mechanism of action is a matter of debate, several possibilities have been proposed, including depletion of guanine nucleotides through inhibition of inosine monophosphate dehydrogenase (IMPDH). IMPDH has been shown to assemble into micron-scale rod- and ring-shaped structures (rods/rings or RR), also called "IMPDH filaments," both in vitro and in vivo. Formation of RR structures can occur naturally, potentially to influence IMPDH activity, or when de novo guanosine monophosphate biosynthesis or IMPDH itself are inhibited by nutrient deprivation or drugs like RBV. Numerous studies have also reported the occurrence of autoantibodies targeting RR structures (anti-RR) in HCV patients previously treated or under treatment with interferon-α and ribavirin (IFN/RBV) combination therapy. For this brief study, we considered the strong association between RR autoantibodies and IFN/RBV treatment, and the lack of data assessing how RBV affects RR formation in a variety of tissues in vivo. First, RR structures formed in the spleen and pancreas of normal mice without any treatment. Then, in RBV-treated mice, we detected RR structures in a number of tissues, including stomach, liver, spleen, kidney, brain, skin, and cardiac and skeletal muscle. We made several intriguing observations: predominance of RR structures in the mucosa and submucosa layers of the stomach wall; a high proportion of RR-positive cells in the cerebral cortex, suggesting that RBV actually crosses the blood-brain barrier; and a higher ratio of rings to rods in the epidermis compared to the dermis layer of the skin. Screening for RR structures appears to be a useful method to track tissue penetration of RBV and the many RR-inducing drugs previously identified.
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Antivirales/farmacocinética , IMP Deshidrogenasa/química , Ribavirina/farmacocinética , Animales , Barrera Hematoencefálica , Corteza Cerebral/química , Hepacivirus/efectos de los fármacos , Riñón/química , Masculino , Ratones , Ratones Endogámicos BALB C , Páncreas/química , Bazo/químicaRESUMEN
BACKGROUND: Anti-mitochondria autoantibodies (AMA) occur in > 95% primary biliary cholangitis (PBC) patients. Biochemically normal AMA-positive (BN/AMA+) individuals, occasionally noticed by indirect immunofluorescence (IIF) on HEp-2 cells and confirmed in AMA-specific assays, may represent early stages of PBC. The Enhanced Liver Fibrosis (ELF) score is a surrogate marker for liver fibrosis. This prospective study investigated the ELF score in BN/AMA+ individuals and PBC patients, considering autoantibody avidity and serum levels along the years. METHODS: 327 samples from 35 PBC and 59 BN/AMA+ were prospectively obtained in average 3.83 (range 0.50-7.40) years apart. Samples were tested by IIF on rat-kidney (IIF-AMA), western-blot for AMA (WB-AMA), and ELISA for antibodies against pyruvate-dehydrogenase (PDC-E2), gp210, sp100 and CENP-A/B. Anti-PDC-E2 avidity was determined by 6 M urea-elution ELISA. Alkaline phosphatase (ALP), gamma glutamyl transferase (ɣGT) and ELF score were measured by automated methods. RESULTS: Along the follow-up period BN/AMA+ subjects and PBC patients presented significant increase in serum anti-PDC-E2 (mean 10.45% and 8.86% per year; respectively), anti-PDC-E2 avidity (3.02% and 4.94%/year) and ELF score (3.24% and 2.71%/year). IIF-AMA and ɣGT increased in BN/AMA+ (6.59% and 2.36%) and decreased in PBC (- 4.89%/year and - 3.88%/year). In BN/AMA+ individuals there was positive correlation of ELF with IIF-AMA titer (r = 0.465; p < 0.001) and with anti-PDC-E2 levels (r = 0.239; p < 0.001). Expansion of autoantibody targets along time occurred in 39% BN/AMA+ and 49% PBC patients. The frequency of BN/AMA+ with high probability of having established PBC increased from 7 to 14%. CONCLUSIONS: BN/AMA+ individuals present an orchestrated increase in ELF score and humoral autoimmune response over time, indicating an opportunity for early therapeutic intervention and prevention in autoimmunity.
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The objective of this study was to demonstrate the presence of mycobacterial nucleic acid sequences in peripheral blood and arteries from patients with Takayasu arteritis (TA). Polymerase chain reaction was performed to detect mycobacterial DNA from three different nucleic acid sequences including the insertion sequence (IS) 6110, the 65-kDa heat shock protein gene (HSP65), and the 16S ribosomal RNA (rRNA) gene in peripheral blood from 32 TA patients and in arterial specimens from 10 TA patients. Twenty-eight HIV-negative patients with pulmonary tuberculosis prior to therapy were tested for IS6110 in peripheral blood as positive controls, and 24 blood donors were evaluated as healthy controls (HC). All TA patients were negative for the insertion sequence IS6110 and for HSP65 and 16S rRNA genes in blood samples and in arterial specimens. IS6110 sequence was found in peripheral blood from 22 (78.5 %) patients with pulmonary tuberculosis but not in HC. In conclusion, the strategy of mycobacterial-specific nucleic acid amplification in the peripheral blood and arterial specimens of TA patients was unable to lend support to the association between TA and tuberculosis long suggested in the literature.
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Arterias/microbiología , ADN Bacteriano/sangre , Arteritis de Takayasu/microbiología , Adolescente , Adulto , Proteínas Bacterianas/genética , Estudios de Casos y Controles , Chaperonina 60/genética , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mycobacterium tuberculosis , Reacción en Cadena de la Polimerasa , ARN Ribosómico 16S/genética , Arteritis de Takayasu/sangre , Tuberculosis Pulmonar/sangre , Tuberculosis Pulmonar/epidemiologíaRESUMEN
Chronic inflammation associated with hepatitis C virus (HCV) infection can lead to disabling liver diseases with progression to liver cirrhosis and hepatocellular carcinoma. Despite the recent availability of more effective and less toxic therapeutic options, in most parts of the world the standard treatment consists of a weekly injection of pegylated interferon α (IFN-α) together with a daily dose of ribavirin. HCV patients frequently present circulating non-organ-specific autoantibodies demonstrating a variety of staining patterns in the indirect immunofluorescence assay for antinuclear antibodies (ANA). Between 20% to 40% of HCV patients treated with IFN-α and ribavirin develop autoantibodies showing a peculiar ANA pattern characterized as rods and rings (RR) structures. The aim of this article is to review the recent reports regarding RR structures and anti-rods/rings (anti-RR) autoantibody production by HCV patients after IFN-α/ribavirin treatment. Anti-RR autoantibodies first appear around the sixth month of treatment and reach a plateau around the twelfth month. After treatment completion, anti-RR titers decrease/disappear in half the patients and remain steady in the other half. Some studies have observed a higher frequency of anti-RR antibodies in relapsers, i.e., patients in which circulating virus reappears after initially successful therapy. The main target of anti-RR autoantibodies in HCV patients is inosine-5'-monophosphate dehydrogenase 2 (IMPDH2), the rate-limiting enzyme involved in the guanosine triphosphate biosynthesis pathway. Ribavirin is a direct IMPDH2 inhibitor and is able to induce the formation of RR structures in vitro and in vivo. In conclusion, these observations led to the hypothesis that anti-RR autoantibody production is a human model of immunologic tolerance breakdown that allows us to explore the humoral autoimmune response from the beginning of the putative triggering event: exposure to ribavirin and interferon.
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Anticuerpos Antinucleares/inmunología , Antivirales/efectos adversos , Autoinmunidad/efectos de los fármacos , Hepatitis C Crónica/tratamiento farmacológico , IMP Deshidrogenasa/inmunología , Interferón-alfa/efectos adversos , Ribavirina/efectos adversos , Quimioterapia Combinada , Hepatitis C Crónica/diagnóstico , Hepatitis C Crónica/inmunología , Humanos , IMP Deshidrogenasa/antagonistas & inhibidores , IMP Deshidrogenasa/química , Inmunidad Humoral/efectos de los fármacos , Conformación Proteica , Autotolerancia/efectos de los fármacos , Factores de Tiempo , Resultado del TratamientoRESUMEN
Inhibition of guanosine triphosphate (GTP) and cytidine triphosphate (CTP) biosynthetic pathways induces cells to assemble rod/ring (RR) structures, also named cytoophidia, which consist of the enzymes cytidine triphosphate synthase (CTPS) and inosine-5'-monophosphate dehydrogenase 2 (IMPDH2). We aim to explore the interaction of CTPS and IMPDH2 in the generation of RR structures. HeLa and COS-7 cells were cultured in normal conditions or in the presence of 6-diazo-5-oxo-L-norleucine (DON), ribavirin, or mycophenolic acid (MPA). Over 90% of DON-treated cells presented RR structures. In HeLa cells, 35% of the RR structures were positive for IMPDH2 alone, 26% were CTPS alone, and 31% were IMPDH2/CTPS mixed, while in COS-7 cells, 42% of RR were IMPDH2 alone, 41% were CTPS alone, and 10% were IMPDH2/CTPS mixed. Ribavirin and MPA treatments induced only IMPDH2-based RR. Cells were also transfected with an N-terminal hemagglutinin (NHA)-tagged CTPS1 construct. Over 95% of NHA-CTPS1 transfected cells with DON treatment presented IMPDH2-based RR and almost 100% presented CTPS1-based RR; when treated with ribavirin, over 94% of transfected cells presented IMPDH2-based RR and 37% presented CTPS1-based RR, whereas 2% of untreated transfected cells presented IMPDH2-based RR and 28% presented CTPS1-based RR. These results may help in understanding the relationship between CTP and GTP biosynthetic pathways, especially concerning the formation of filamentous RR structures.
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Ligasas de Carbono-Nitrógeno/metabolismo , Citidina Trifosfato/metabolismo , Guanosina Trifosfato/metabolismo , IMP Deshidrogenasa/metabolismo , Animales , Vías Biosintéticas , Células COS , Chlorocebus aethiops , Células HeLa , Humanos , Unión ProteicaRESUMEN
BACKGROUND: Our laboratory previously reported interesting rods 3-10 µm long and rings 2-5 µm diameter (RR) in the cytoplasm of mammalian cells. Experimental evidence show that both inosine-5'-monophosphate dehydrogenase 2 (IMPDH2) and cytidine triphosphate synthetase (CTPS) are components of RR structures. Several cell types, including mouse embryonic stem cells, and cell lines, such as mouse 3 T3 and rat NRK, naturally present RR structures, while other cells can present RR when treated with compounds interfering with GTP/CTP biosynthetic pathways. In this study, we aimed to investigate the dynamic behavior of these RR in live cells. RESULTS: RR were detected in >90% of COS-7 and HeLa cells treated with 1 mM ribavirin or 6-Diazo-5-oxo-L-norleucine (DON) for 24 h, and in 75% of COS-7 cells treated with 1 mM mycophenolic acid (MPA) for the same period of time. Microinjection of affinity-purified anti-IMPDH2 antibodies in live COS-7 cells treated with ribavirin, DON, or MPA showed mature forms of RR presented as stable and stationary structures in 71% of cells. In the remaining 29% of cells, RR acquired erratic movement and progressively disassembled into fragments and disappeared within 10 min. The specific stationary state and antibody-dependent disassembling of RR structures was independently confirmed in COS-7 and HeLa cells transfected with GFP-tagged IMPDH2. CONCLUSIONS: This is the first demonstration of disassembly of RR structures upon microinjection of anti-IMPDH2 antibodies that led to the disappearance of the molecular aggregates. The disassembly of RR after microinjection of anti-IMPDH2 antibody further strengthens the notion that IMPDH2 are major building blocks of RR. Using two independent methods, this study demonstrated that the induced RR are primarily stationary structures in live cells and that IMPDH2 is a key component of RR.
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INTRODUCTION: Takayasu arteritis (TA) and giant cell arteritis (GCA) are large vessel vasculitides (LVV) that usually present as granulomatous inflammation in arterial walls. High mobility group box 1 (HMGB1) is a nuclear protein that acts as an alarmin when released by dying or activated cells. This study aims to evaluate whether serum HMGB1 can be used as a biomarker in LVV. METHODS: Twenty-nine consecutive TA patients with 29 healthy controls (HC) were evaluated in a cross-sectional study. Eighteen consecutive GCA patients with 16 HC were evaluated at the onset of disease and some of them during follow-up. Serum HMGB1 levels were measured by enzyme-linked immunosorbent assay. RESULTS: In GCA patients at disease onset mean serum HMGB1 levels did not differ from HC (5.74 ± 4.19 ng/ml vs. 4.17 ± 3.14 ng/ml; p = 0.230). No differences in HMGB1 levels were found between GCA patients with and without polymyalgia rheumatica (p = 0.167), ischemic manifestations (p = 0.873), systemic manifestations (p = 0.474) or relapsing disease (p = 0.608). During follow-up, no significant fluctuations on serum HMGB1 levels were observed from baseline to 3 months (n = 13) (p = 0.075), 12 months (n = 6) (p = 0.093) and at the first relapse (n = 4) (p = 0.202). Serum HMGB1 levels did not differ between TA patients and HC [1.19 (0.45-2.10) ng/ml vs. 1.46 (0.89-3.34) ng/ml; p = 0.181] and no difference was found between TA patients with active disease and in remission [1.31 (0.63-2.16) ng/ml vs. 0.75 (0.39-2.05) ng/ml; p = 0.281]. HMGB1 levels were significantly lower in 16 TA patients on statins compared with 13 patients without statins [0.59 (0.29-1.46) ng/ml vs. 1.93 (0.88-3.34) ng/ml; p = 0.019]. Age was independently associated with higher HMGB1 levels regardless of LVV or control status. CONCLUSIONS: Patients with TA and GCA present similar serum HMGB1 levels compared with HC. Serum HMGB1 is not useful to discriminate between active disease and remission. In TA, use of statins was associated with lower HMGB1 levels. HMGB1 is not a biomarker for LVV.
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Biomarcadores/sangre , Arteritis de Células Gigantes/sangre , Proteína HMGB1/sangre , Arteritis de Takayasu/sangre , Factores de Edad , Anciano , Área Bajo la Curva , Estudios Transversales , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Masculino , Persona de Mediana Edad , Curva ROC , Sensibilidad y EspecificidadRESUMEN
The correct identification of all human genes, and their derived transcripts, has not yet been achieved, and it remains one of the major aims of the worldwide genomics community. Computational programs suggest the existence of 30,000 to 40,000 human genes. However, definitive gene identification can only be achieved by experimental approaches. We used two distinct methodologies, one based on the alignment of mouse orthologous sequences to the human genome, and another based on the construction of a high-quality human testis cDNA library, in an attempt to identify new human transcripts within the human genome sequence. We generated 47 complete human transcript sequences, comprising 27 unannotated and 20 annotated sequences. Eight of these transcripts are variants of previously known genes. These transcripts were characterized according to size, number of exons, and chromosomal localization, and a search for protein domains was undertaken based on their putative open reading frames. In silico expression analysis suggests that some of these transcripts are expressed at low levels and in a restricted set of tissues.
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ADN Complementario/genética , Genoma Humano , Análisis de Secuencia de ADN/métodos , Testículo/química , Transcripción Genética/genética , Secuencia de Aminoácidos , Animales , Mapeo Cromosómico , Biblioteca de Genes , Humanos , Masculino , Ratones , Datos de Secuencia MolecularRESUMEN
Autoantibodies to inosine monophosphate dehydrogenase-2 (IMPDH2), an enzyme involved in de novo biosynthesis of guanine nucleotides, are observed in a subset of hepatitis C virus (HCV) patients receiving interferon alpha (IFN-α) plus ribavirin. Anti-IMPDH2 antibodies display a peculiar cytoplasmic "rod/ring" (RR) pattern in IIF-HEp-2. We examined the dynamics of anti-RR autoimmune response with respect to immunoglobulin isotypes, titer, avidity, and protein targets in 80 sequential samples from 15 HCV patients (plus 12 randomly selected anti-RR-positive, totalizing 92 samples) collected over an 18-month period, including samples collected before, during, and after IFN-α + ribavirin treatment. Immunoprecipitation showed reactivity with the 55 kDa IMPDH2 protein in 12/15 patients (80 %) and 11/15 (73 %) reacted with IMPDH2 in a sandwich ELISA. During treatment, anti-IMPDH2 autoantibodies hit their highest levels after 6-12 months of treatment and decreased post-treatment, while anti-HCV antibodies levels were stable over time. Anti-IMPDH2 IgM levels increased up until the sixth month of treatment and remained stable thereafter, while IgG levels increased steadily up to the twelfth month. Both IgG and IgM decreased during the post-treatment period. IgG avidity increased steadily up to the twelfth month of treatment. In conclusion, this study showed that the temporal kinetics of IFN-α + ribavirin-induced humoral autoimmune response to IMPDH2 exhibited a considerably delayed pace of increase in antibody levels and avidity as well as in isotype class switch in comparison with a conventional humoral response to infectious agents. These unique findings uncover intriguing differences between the autoimmune response and the immune response to exogenous agents in humans.
Asunto(s)
Antivirales/uso terapéutico , Autoanticuerpos/inmunología , Hepatitis C/inmunología , IMP Deshidrogenasa/inmunología , Interferón-alfa/uso terapéutico , Ribavirina/uso terapéutico , Hepatitis C/tratamiento farmacológico , Humanos , Inmunoglobulina G/inmunología , Orgánulos/inmunologíaRESUMEN
OBJECTIVE: To compare autoantibody features in patients with primary biliary cirrhosis (PBC) and individuals presenting antimitochondria antibodies (AMAs) but no clinical or biochemical evidence of disease. METHODS: A total of 212 AMA-positive serum samples were classified into four groups: PBC (definite PBC, n = 93); PBC/autoimmune disease (AID; PBC plus other AID, n = 37); biochemically normal (BN) individuals (n = 61); and BN/AID (BN plus other AID, n = 21). Samples were tested by indirect immunofluorescence (IIF) on rat kidney (IIF-AMA) and ELISA [antibodies to pyruvate dehydrogenase E2-complex (PDC-E2), gp-210, Sp-100, and CENP-A/B]. AMA isotype was determined by IIF-AMA. Affinity of anti-PDC-E2 IgG was determined by 8 M urea-modified ELISA. RESULTS: High-titer IIF-AMA was more frequent in PBC and PBC/AID (57 and 70 %) than in BN and BN/AID samples (23 and 19 %) (p < 0.001). Triple isotype IIF-AMA (IgA/IgM/IgG) was more frequent in PBC and PBC/AID samples (35 and 43 %) than in BN sample (18 %; p = 0.008; p = 0.013, respectively). Anti-PDC-E2 levels were higher in PBC (mean 3.82; 95 % CI 3.36-4.29) and PBC/AID samples (3.89; 3.15-4.63) than in BN (2.43; 1.92-2.94) and BN/AID samples (2.52; 1.54-3.50) (p < 0.001). Anti-PDC-E2 avidity was higher in PBC (mean 64.5 %; 95 % CI 57.5-71.5 %) and PBC/AID samples (66.1 %; 54.4-77.8 %) than in BN samples (39.2 %; 30.9-37.5 %) (p < 0.001). PBC and PBC/AID recognized more cell domains (mitochondria, nuclear envelope, PML/sp-100 bodies, centromere) than BN (p = 0.008) and BN/AID samples (p = 0.002). Three variables were independently associated with established PBC: high-avidity anti-PDC-E2 (OR 4.121; 95 % CI 2.118-8.019); high-titer IIF-AMA (OR 4.890; 2.319-10.314); antibodies to three or more antigenic cell domains (OR 9.414; 1.924-46.060). CONCLUSION: The autoantibody profile was quantitatively and qualitatively more robust in definite PBC as compared with AMA-positive biochemically normal individuals.
Asunto(s)
Capilares/efectos de los fármacos , Dermatomiositis/tratamiento farmacológico , Inmunosupresores/uso terapéutico , Capilares/diagnóstico por imagen , Capilares/patología , Preescolar , Dermatomiositis/diagnóstico por imagen , Dermatomiositis/patología , Quimioterapia Combinada , Femenino , Humanos , Inmunosupresores/farmacología , Angioscopía Microscópica , Uñas/irrigación sanguíneaRESUMEN
ABSTRACT Introduction: The detection of autoantibodies in HEp-2 cells represents a relevant tool for the diagnosis of autoimmune diseases, especially rheumatic autoimmune diseases. As a result of the methodological advances, the technique gradually increased the sensitivity, as well as the need for standardization. Objective: To evaluate the implementation of the Brazilian Consensus recommendations for autoantibody determination in HEp-2 cells. Methods: A structured form in a virtual platform was filled in by experts in clinical laboratories that carry out the methodology across the country. The questionnaire addressed the adoption of the Brazilian Consensus guidelines, detailing the technical aspects, quality control, the strategy for reading slides and the release of reports. Results: The study included 53 laboratories responsible for more than 300,000 antinuclear antibody (ANA) tests/month; more than half (58.5%) reported fully adopting the recommendations of the Brazilian Consensus. The majority (83.1%) used the 1:80 for screening dilution, and 75.5% of laboratories, perform education and quality control programs. Only 39.6% reported using more than one kit brand to perform the test, and 32.1% did not report observing all phases of the cell cycle during slide reading. The study also detected some heterogeneity among participants in the identification of patterns. Conclusion: The results confirm the adoption of the Brazilian Consensus recommendations by most of participating laboratories, although with variable extent. There is need for improvement in some aspects, especially those related to the quality control.
RESUMO Introdução: A pesquisa de autoanticorpos em células HEp-2 representa uma relevante ferramenta no auxílio diagnóstico de doenças autoimunes, especialmente as reumáticas. Em virtude dos avanços metodológicos, a técnica aumentou gradativamente a sensibilidade, bem como a necessidade de padronização. Objetivo: Avaliar a implantação das recomendações dos consensos brasileiros de pesquisa de autoanticorpos em células HEp-2. Métodos: Preenchimento de formulário em plataforma virtual direcionada aos laboratórios clínicos que realizam a metodologia. Os participantes responderam a um questionário sobre a adoção das diretrizes dos consensos brasileiros, detalhando os aspectos técnicos, o controle de qualidade, a leitura de lâminas e a emissão de laudos. Resultados: Participaram do estudo 53 laboratórios responsáveis por mais de 300 mil testes de fator antinuclear (FAN)/mês; mais da metade (58,5%) informou adotar integralmente as recomendações dos consensos. A maioria (83,1%) utiliza a diluição 1:80 para triagem, e 75,5% dos laboratórios, programas de educação e controle de qualidade. Apenas 39,6% utilizam mais de uma marca de kit para a realização do teste, e 32,1% não relataram observar todas as fases do ciclo celular na leitura da lâmina. O estudo detectou ainda discreta heterogeneidade entre participantes na identificação de padrões. Conclusão: Os resultados evidenciam a adoção das recomendações dos consensos de forma absoluta pela maioria dos laboratórios participantes, bem como a necessidade de aperfeiçoamento em alguns aspectos relevantes para a qualidade do ensaio.