Anti-C1q como Marcador de Nefritis Lúpica / Anti-C1q as Lupus Nephritis Marker

Introducción: Los autoanticuerpos anti-C1q han sido propuestos como un marcador útil en el lupus eritematoso sistémico por su asociación con la nefritis lúpica. Objetivo: Determinar la prevalencia de anti-C1q en pacientes con lupus eritematoso sistémico y otras enfermedades reumáticas para la evaluar la asociación con la nefropatía lúpica. Métodos: Se incluyeron 179 pacientes con lupus eritematoso sistémico y 82 con otras enfermedades reumáticas. La nefritis lúpica fue diagnosticada en 70 (39 por ciento) de los pacientes con lupus eritematoso sistémico. Los anticuerpos anti-C1q IgG se determinaron por ELISA. Las asociaciones se evaluaron por análisis de regresión logística. Resultados: La prevalencia de anti-C1q fue de 37 poe ciento (66/179) en los pacientes con lupus eritematoso sistémico y de 9 por ciento (7/82) en controles (OR = 6,3; IC 95 por ciento 2,8-14,1; p < 0,001). El anti-C1q fue asociado con proteinuria (OR = 2,6; IC 95 por ciento 1,2-6,0; p < 0,022); eritrosedimentación elevada (OR = 3,2; IC 95 por ciento 1,5-6,7; p < 0,003) y anti-DNAdc (OR = 3,9; IC 95 por ciento 1,7-9,1; p < 0,002). En el modelo de regresión logística ajustado para demografía y anti-DNAdc, aunque la OR del anti-C1q para la nefritis fue 2 veces más alta que en ausencia del anti-C1q, solo se aproximó a la significación estadística. La positividad simultánea de anti-C1q y anti-DNAdc estuvo asociada a la nefritis lúpica (OR = 4,3; IC 95 por ciento 1,9-9,5; p < 0,001). Conclusiones: El anti-C1q se presentó con mayor frecuencia en pacientes con lupus eritematoso sistémico que en los controles. El anti-C1q combinado con anti-DNAdc resultó fuertemente asociado a la nefritis lúpica(AU)

Introducción: Anti-C1q autoantibodies have been proposed as useful marker in systemic lupus erythematosus due to their association with lupus nephritis. Objective: To determine the prevalence of anti-C1q in patients with systemic lupus erythematosus and other rheumatic diseases to evaluate the association with lupus nephropathy. Methods: One hundred seventy-nine patients with systemic lupus erythematosus and 82 with other rheumatic diseases were included. Lupus nephritis was diagnosed in 70 (39percent) of patients with systemic lupus erythematosus. Anti-C1q IgG antibodies were determined by ELISA. Associations were evaluated by logistic regression analysis. Results: The prevalence of anti-C1q was 37percent (66/179) in patients with systemic lupus erythematosus and 9percent (7/82) in controls (OR = 6.3; 95percent CI 2.8-14). .1; p < 0.001). Anti-C1q was associated with proteinuria (OR = 2.6; 95percent CI 1.2-6.0; p < 0.022); elevated erythrocyte sedimentation rate (OR = 3.2; 95percent CI 1.5-6.7; p < 0.003) and anti-dsDNA (OR = 3.9; 95percent CI 1.7-9.1; p < 0.002). In the logistic regression model adjusted for demographics and anti-dsDNA, although the OR of anti-C1q for nephritis was 2-fold higher than in the absence of anti-C1q, it only approached statistical significance. Simultaneous positivity of anti-C1q and anti-dsDNA was associated with lupus nephritis (OR = 4.3; 95percent CI 1.9-9.5; p < 0.001). Conclusions: Anti-C1q occurred more frequently in patients with systemic lupus erythematosus than in controls. Anti-C1q combined with anti-dsDNA was strongly associated with lupus nephritis(AU)

Determinación de anticuerpos anti-dsDNA: evaluación del desempeño de un inmunoensayo quimioluminiscente y correlación con el método de inmunofluorescencia indirecta / Detection of anti-dsDNA antibodies: evaluation of performance of a chemiluminescent immunoassay and correlation to the indirect immunofluorescence assay / Determinação de anticorpos anti-dsDNA: avaliação do desempenho de um imunoensaio quimioluminiscente e correlação com o método de imunoflourescência indireta

Resumen La determinación de anticuerpos anti-dsDNA es de utilidad para el diagnóstico y seguimiento clínico de pacientes con lupus eritematoso sistémico (LES) y es uno de los criterios de clasificación del SLICC-2012. El objetivo del estudio fue verificar el desempeño del inmunoensayo quimioluminiscente (CLIA) QUANTA Flash dsDNA y compararlo con el método en uso de inmunofluorescencia indirecta en Crithidia luciliae (CLIFT). Se analizaron con ambos métodos 195 pacientes con diagnóstico de enfermedades del tejido conectivo y solicitud de anticuerpos anti-dsDNA. Se obtuvieron 38 sueros positivos, 133 negativos y 24 (12,3%) discordantes. Entre estos resultados discordantes, hubo 17 que correspondieron a pacientes con LES y se agruparon en 16 CLIA+/CLIFT- y 1 CLIA-/CLIFT+. Se verificó el desempeño para precisión siguiendo el protocolo EP15-A2 y la linealidad. Se estudió la concordancia mediante el coeficiente Kappa y la correlación con el coeficiente Rho de Spearman. Se observó mayor sensibilidad diagnóstica para CLIA. El grado de acuerdo fue moderado y se obtuvo buena correlación entre los valores cuantitativos de CLIA y los títulos de CLIFT. De acuerdo al buen desempeño encontrado y a los resultados discordantes analizados, la mejor estrategia para la implementación de CLIA sería utilizarla en combinación con CLIFT, lo que aumentaría la sensibilidad diagnóstica sin perder especificidad.

Abstract The detection of anti-dsDNA antibodies is useful for diagnosis and clinical monitoring of patients with systemic lupus erythematosus (SLE) and it is part of the classification criteria according to SLICC 2012. The purpose of this study was to verify the performance of the chemiluminescent immunoassay (CLIA) QUANTA Flash dsDNA and to compare it with the method currently in use, i.e the indirect immunofluorescence in Crithidia luciliae (CLIFT). One hundred and ninety five patients, who presented connective tissue diseases and required the study of anti-dsDNA antibodies, were analyzed. Thirty eight positive serum samples were obtained, 133 were negative and 24 (12.3%) in disagreement. Within the discordant results, there were 17 that corresponded to patients with SLE and they were grouped in 16 CLIA+/CLIFT- and 1 CLIA-/CLIFT+. The accuracy performance was assessed according to the EP15-A2 protocol and linearity. Concordance and correlation were calculated with the Kappa and Spearman's Rho coefficient, respectively. Based on the good performance observed and the discordant results analyzed, the best strategy for CLIA implementation would be to combine it with CLIFT, which would increase the diagnostic sensitivity without losing specificity.

Resumo A determinação dos anticorpos anti-dsDNA é de utilidade para o diagnóstico e seguimento clinico de pacientes com lúpus eritematoso sistêmico (LES) e é um dos critérios de classificação do SLICC 2012. O objetivo do estudo foi verificar o desempenho do imunoensaio quimioluminescente (CLIA) QUANTA Flash dsDNA e compará-lo com o método em uso imunofluorescência indireta em Crithidia luciliae (CLIFT). Foram analisados com os dois métodos, 195 pacientes com diagnóstico de doenças do tecido conjuntivo e solicitude de anticorpos anti-dsDNA. Os resultados foram agrupados em 38 soros positivos, 133 negativos e 24 (12,3%) discordantes. Entre esses resultados discordantes, 17 corresponderam a pacientes com LES e se agruparam em 16 CLIA+/CLIFT- e 1 CLIA-/CLIFT+. Foi verificado o desempenho para precisão seguindo o protocolo EP15-A2 e a linearidade. Foi estudada a concordância mediante o coeficiente Kappa e correlação com o coeficiente Rho de Spearman. Observou-se maior sensibilidade diagnóstica para CLIA. O grau de acordo foi moderado e boa correlação foi observada entre os valores quantitativos de CLIA e os títulos de CLIFT. Com base no bom desempenho encontrado e nos resultados discordantes analisados, a melhor estratégia para implementar o CLIA seria utilizá-lo em combinação com o CLIFT, o que aumentaria a sensibilidade do diagnóstico sem perder a especificidade.

Electrochemical, spectroscopic, and molecular docking studies of the interaction between the anti-retroviral drug indinavir and dsDNA / 药物分析学报

In this study, an electrochemical DNA biosensor was developed using a straightforward methodology to investigate the interaction of indinavir with calf thymus double-stranded deoxyribonucleic acid (ct-dsDNA) for the first time. The decrease in the oxidation signals of deoxyguanosine (dGuo) and deoxy-adenosine (dAdo), measured by differential pulse voltammetry, upon incubation with different con-centrations of indinavir can be attributed to the binding mode of indinavir to ct-dsDNA. The currents of the dGuo and dAdo peaks decreased linearly with the concentration of indinavir in the range of 1.0-10.0μg/mL. The limit of detection and limit of quantification for indinavir were 0.29 and 0.98μg/mL, respectively, based on the dGuo signal, and 0.23 and 0.78μg/mL, respectively, based on the dAdo signal. To gain further insights into the interaction mechanism between indinavir and ct-dsDNA, spectroscopic measurements and molecular docking simulations were performed. The binding constant (Kb) between indinavir and ct-dsDNA was calculated to be 1.64 × 108 M-1, based on spectrofluorometric measure-ments. The obtained results can offer insights into the inhibitory activity of indinavir, which could help to broaden its applications. That is, indinavir can be used to inhibit other mechanisms and/or hallmarks of viral diseases.

Architecture of the herpesvirus genome-packaging complex and implications for DNA translocation

Genome packaging is a fundamental process in a viral life cycle and a prime target of antiviral drugs. Herpesviruses use an ATP-driven packaging motor/terminase complex to translocate and cleave concatemeric dsDNA into procapsids but its molecular architecture and mechanism are unknown. We report atomic structures of a herpesvirus hexameric terminase complex in both the apo and ADP•BeF3-bound states. Each subunit of the hexameric ring comprises three components-the ATPase/terminase pUL15 and two regulator/fixer proteins, pUL28 and pUL33-unlike bacteriophage terminases. Distal to the nuclease domains, six ATPase domains form a central channel with conserved basic-patches conducive to DNA binding and trans-acting arginine fingers are essential to ATP hydrolysis and sequential DNA translocation. Rearrangement of the nuclease domains mediated by regulatory domains converts DNA translocation mode to cleavage mode. Our structures favor a sequential revolution model for DNA translocation and suggest mechanisms for concerted domain rearrangements leading to DNA cleavage.

Architecture of the herpesvirus genome-packaging complex and implications for DNA translocation

Genome packaging is a fundamental process in a viral life cycle and a prime target of antiviral drugs. Herpesviruses use an ATP-driven packaging motor/terminase complex to translocate and cleave concatemeric dsDNA into procapsids but its molecular architecture and mechanism are unknown. We report atomic structures of a herpesvirus hexameric terminase complex in both the apo and ADP•BeF3-bound states. Each subunit of the hexameric ring comprises three components-the ATPase/terminase pUL15 and two regulator/fixer proteins, pUL28 and pUL33-unlike bacteriophage terminases. Distal to the nuclease domains, six ATPase domains form a central channel with conserved basic-patches conducive to DNA binding and trans-acting arginine fingers are essential to ATP hydrolysis and sequential DNA translocation. Rearrangement of the nuclease domains mediated by regulatory domains converts DNA translocation mode to cleavage mode. Our structures favor a sequential revolution model for DNA translocation and suggest mechanisms for concerted domain rearrangements leading to DNA cleavage.

Comparison of urinary parameters, biomarkers, and outcome of childhood systemic lupus erythematosus early onsetlupus nephritis

Abstract Background: Urinary parameters, anti-dsDNA antibodies and complement tests were explored in patients with childhood-Systemic Lupus Erythematosus (cSLE) early-onset lupus nephritis (ELN) from a large multicenter cohort study. Methods: Clinical and laboratory features of cSLE cases with kidney involvement at presentation, were reviewed. Disease activity parameters including SLEDAI-2 K scores and major organ involvement at onset and follow up, with accrued damage scored by SLICC-DI, during last follow up, were compared with those without kidney involvement. Autoantibodies, renal function and complement tests were determined by standard methods. Subjects were grouped by presence or absence of ELN. Results: Out of the 846 subjects enrolled, mean age 11.6 (SD 3.6) years; 427 (50.5%) had ELN. There was no significant difference in the ELN proportion, according to onset age, but ELN frequency was significantly higher in non-Caucasians (p = 0.03). Hematuria, pyuria, urine casts, 24-h proteinuria and arterial hypertension at baseline, all had significant association with ELN outcome (p < 0.001). With a similar follow up time, there were significantly higher SLICC-DI damage scores during last follow up visit (p = 0.004) and also higher death rates (p < 0.0001) in those with ELN. Low C3 (chi-square test, p = 0.01), but not C3 levels associated significantly with ELN. High anti-dsDNA antibody levels were associated with ELN (p < 0.0001), but anti-Sm, anti-RNP, anti-Ro, anti-La antibodies were not associated. Low C4, C4 levels, low CH50 and CH50 values had no significant association. High erythrocyte sedimentation rate (ESR) was associated with the absence of ELN (p = 0.02). Conclusion: The frequency of ELN was 50%, resulting in higher morbidity and mortality compared to those without ELN. The urinary parameters, positive anti-dsDNA and low C3 are reliable for discriminating ELN.(AU)

Correlation Of Indirect Immnofluorescence Patterns On Hep2000 With Anti Ds Dna Levels In Patients With Sle

Background: Antinuclear antibody (ANA) detection is very useful in the diagnosis of systemic lupus erythematosus (SLE). Association of specific autoantibodies with the immunofluorescence pattern of ANA in SLE as noted in Western medical literature has been taken as reference all over the world. However, in developing countries like India such research or data correlating the autoantibodies and their ANA Indirect Immunofluorescence patterns is inadequate. Objective: To identify the correlation between Indirect immunofluorescence patterns of antinuclear antibody on HEp–2 cell and serum levels of anti– double stranded DNA (anti–dsDNA) in SLE patients. Material and Methods: Serum samples of 108 SLE patients who were diagnosed by ACR (American College of Rheumatology) classification criteria, attending Rheumatology OPD of a tertiary care hospital during the study period of six months were subjected for ANA testing by Indirect Immunofluorescence (IIF) on HEp–2 cell and anti–dsDNA levels by ELISA. Results: Out of 108 SLE patients who were all positive by ANA in IIF on HEp–2 cell – exhibited predominantly two fluorescent patterns such as homogeneous in 80 (74%) and speckled 28 (26%) and in those with suspected flare–up homogeneous pattern was strongly associated with anti–dsDNA (p<0.05) and speckled pattern was also predominantly associated with anti–dsDNA (p<0.05). Conclusion: In SLE patients showing either homogeneous or speckled pattern in ANA IIF with suspected flare–up had elevated anti–dsDNA levels

A study to evaluate the correlation between serological profile and histopathology of lupus nephritis

Background: Systemic lupus erythematosus is an autoimmune disease of unknown etiology, characterized by the involvement of multiple organ systems. Organ damage is mediated by tissue binding autoantibodies and immune complexes. High anti-dsDNA titer and low serum complement levels (C3, C4) correlate with disease activity of SLE, especially with lupus nephritis (LN). Aim of the study: To evaluate the correlation between a serological profile (anti-dsDNA, serum C3, and C4) and histopathology of lupus nephritis and to find out the class of LN which has a significant correlation with the serological profile. Materials and methods: This retrospective study was conducted in the Department of Nephrology, Kilpauk Medical College and Hospital, Chennai between 2013-2017 with 50 ANA positive female SLE patients with evidence of lupus nephritis (proteinuria, microscopic hematuria or increased serum creatinine). Serological profile (anti-dsDNA, serum C3, and C4) and renal biopsy were done in all patients. Results: Of 50 patients, 35 (70%) had class IV lupus nephritis, 7 (14%) class II, 4(8%) class V and 4 patients (8%) had class IV and V on renal biopsy. The prevalence of anti dsDNA was 97.1% in LN and 97.4% (38 of 39 pts) in proliferative LN (p<0.001). The C3 level was low in 68% of patients with LN and 84.6% with proliferative LN (p <0.001). C4 level was low in 74% of patients with LN and 87.2% with proliferative LN (p <0.001). In our study, 72% (28 of 39 pts) of the patients with Vasudevan Chelliah, Ramesh Subramanian. A study to evaluate the correlation between serological profile and histopathology of lupus nephritis. IAIM, 2019; 6(4): 36-41. Page 37 proliferative LN (class IV, IV and V) had the combination of anti-dsDNA positivity, low C3,and low C4 levels but none of the patients with class II or class V LN had this combination of serology. Conclusion: In our study, the serological profile of SLE had a significant correlation with histopathology of lupus nephritis. Anti-dsDNA, low C3, and low C4 had a significant independent correlation (p<0.05) with proliferative LN (class IV, IV and V).

Correlation between gut microbiota and anti-dsDNA antibody in the mouse model of systemic lupus erythematosus / 中国实验动物学报

Objective To explore the relationship between gut microbiota and anti-dsDNA antibody in systemic lupus erythematosus(lupus)TC mice. Methods ELISA was performed to detect serum anti-dsDNA antibody in the lupus TC mice. Then,the feces of both dsDNA-positive and -negative mice were collected, and 16S rRNA of the stool sample was sequenced by Illumina HiSeq 2500 high-throughput sequencing,to analyze the relationship between gut microbiota and anti-dsDNA antibody level in the two groups. Results The result of ELISA and mouse fecal high-throughput sequencing showed that the species diversity of gut microbiota in the dsDNA-positive TC mice was significantly lower than that in the dsDNA-negative TC mice. The gut microbiota of TC mice in the two groups showed significant differences at different classification levels: Chloroflexi at phylum level, Betaproteobacteria, Deltaproteobacteria and Ktedonobacteria at class level,Burkholderiales,Desulfovibrionales and Ktedonobacterales at order level,Alcaligenaceae and Desulfovibrionaceae at family level,and Parasutterella and Desulfovibrio at genus level(P<0.05 for all). Conclusions The flora composition of gut microbiota in lupus TC mice is highly correlated with anti-dsDNA antibody. The results of our study provide a basis for further elucidation of the relationship between gut microbiota and the pathogenetic mechanism of systemic lupus erythematosus.

Zika virus NS3 can unwind dsDNA depending on ATP hydrolysis / 基础医学与临床

Objective To investigate whether Zika virus NS3 has ATP hydrolase and DNA helicase activity. Methods Zika NS3 with His tag was expressed in E.coli BL21 and purified by Nicke lagarose beads.ATP hy-drolysis assay was performed to examinethe ATPase activity of NS3.The dsDNA unwinding activity of NS3 was detected according to the principle of fluorescence resonance energy transfer(FRET).NS3 G198A mutant was generated by site-directed mutagenesis and its enzymatic activity was measured subsequently.Results Zika NS3 was capable of hydrolyzing ATP in vitro[Vmax=2.76 μmol/(L· min),Km=0.11 mmol/L].Moreover, Zika NS3 could unwind dsDNA in vitro as that proved by the fluorescence was enhancement in FRET system.G198A mutation impaired NS3 enzymatic activities, including ATP hydrolysis and dsDNA unwinding activities.Conclu-sions Zika NS3 has DNA helicase activity in vitro depending on ATP hydrolysis,and the glycine 198 is impor-tant for its enzymatic activity.

Verification for performance of anti-dsDNA antibody quantitative ELISA kit / 临床检验杂志

Objective To explore the verification methods for the performance of quantitative detection kit of anti-dsDNA antibodiy with enzyme-linked immunosorbent assay (ELISA).Methods The precision was verified according to the EP15-A2 document approved by the American Clinical and Laboratory Standards Institute(CLSI).The accuracy was verified by detecting the samples of previous external quality evaluation(EQA),compared with the comparative kits and recovery test.The lower limit of detection(LLD) was calculated by the results of blank samples.The cut-off value was verified according to the C28-A3C document approved by CLSI and CNAS-CL39:Guidance on the Application of Accreditation Criteria for the Medical Laboratory Quality and Competence in the Field of Clinical Qualitative Immunology respectively.The improved Doumas method was used to verify the range of linearity.Results The measured intra-assay and inter-assay coefficients of variation were lower than those announced by the manufacturer or the calculated values according to the EP15-A2 document.The coincidence rates for negative and positive EQA samples between detected and expected values were 98.4％ (63/64) and 100％ (20/20) respectively.The total coincidence rate was 98.8％ (83/84).The coincidence rate for negative and positive samples between the results from candidate and comparative kits were 91.2％ (52/57) and 87.0％ (40/46) respectively.The total coincidence rate was 89.3％ (92/103) and the Kappa value was 0.783 (P =0.062),which implied excellent consistency between the two kits.The mean recovery rate was 99.65％.The measured LLD was 0.5 IU/mL which was lower than 1 IU/mL as claimed by the manufacturer.The measured cut-off value according to the CNAS-CL39 document was 18.51 IU/mL,which was close to 20 IU/mL announced by the manufacturer.Based on the C28-A3C method,the cut-off value could be approved.The linear regression equation was Y =0.978 8X-3.125 4,r2 =0.996 1.There was no statistical difference between the intercept (-3.125 4) and 0 (t =-0.772,P =0.483).The range of linearity was from 1.6 to 212.5 IU/mL,which was consistent with the values declared by the manufacturer.All the verifications of the five performances above-mentioned could be passed.Conclusion The precision,accuracy,LLD,cut-off value and range of linearity of the candidate quantitative ELISA kit for anti-dsDNA antibody were consistent with the statement of the manufacturer,which indicated the performance of the kits may meet the requirements of clinic diagnosis and treatment.A series of methods used in this study provided a simple protocol for verifying the performance of quantitative ELISA kits.

Diagnostic value of anti-nucleosome antibody for juvenile systemic lupus erythematosus / 临床检验杂志

Objective To evaluate the diagnostic value of anti-nucleosome antibody for juvenile systemic lupus erythematosus (JSLE).Methods Fifty-four patients with JSLE,28 patients with non-JSLE and 26 healthy children were chosen in this study.antinuclear antibody(ANA),anti-nucleosome antibody (AnuA),anti-dsDNA antibody,anti-histone antibody (AHA) and anti-Sm antibody were detected by ELISA or western-blot method.The relevant clinical data were collected and analyzed.Results For diagnosis of JSLE,the sensitivity and specificity of AnuA was 77.78％ and 96.30％.The sensitivity of AnuA combined with ANA,anti-dsDNA and antiSm was higher than that of single detection.AnuA usually associated with fever,oral/nasal pharyngeal ulcer,lung damage,lymphocyte absolute value,urine protein and C3 level.Conclusion AnuA can be used as a serum marker for JSLE diagnosis.The detection of AnuA combined with anti-dsDNA and anti-Sm should be more helpful for diagnosis of JSLE.

Identificación de predictores serológicos de recaída en pacientes con lupus eritematoso sistémico: estudio prospectivo de 12 meses / Identification of relapse aerological predictors in patients with systemic lupus erythematous: a prospective study of 12 months

Introducción: las investigativos efectuadas no han tenido éxito en la búsqueda de biomarcadores serológicos o clínicos suficientemente confiables para predecir las recaídas en el lupus eritematoso sistémico (LES). Objetivo: definir el valor predictivo de las especificidades de anticuerpos antinucleares para la recaída del LES y de la nefritis lúpica. Métodos: estudio analítico, observacional, longitudinal y prospectivo en 120 pacientes adultos con LES inactivo (SLEDAI-2K ≤ 5 puntos). La presencia basal de siete especificidades antinucleares, C3 y C4 bajos se correlacionaron con la ocurrencia de recaída del LES (incrementos en la puntuación de SLEDAI-2K ≥ 4) y de la nefritis lúpica mediante análisis univariado. Las variables más valiosas fueron evaluadas adicionalmente como predictoras con un modelo de regresión logística multivariada para calcular los odds ratio (OR). Resultados: las recaídas del LES y de la nefritis lúpica se observaron en 51 (42,5 por ciento) y 29 (24,2 por ciento) de los pacientes, respectivamente. En el análisis multivariado emergieron como factores de riesgo para la recaída del LES la presencia de los anticuerpos anti-Nu (OR= 1523,0; p < 0,001) y los anti-DNAdc (OR= 12,1; p= 0,044) y de la nefritis lúpica, los anti-Nu (OR= 92,9; p< 0,001) y el C3 bajo (OR= 7,1; p= 0,007), La sub-representación de los anti-RNP resultó un factor de riesgo para la recaída del LES y de la nefritis lúpica (OR= 0,023; p= 0,009 y OR= 0,1; p= 0,025). Conclusiones: los pacientes con LES positivos de anticuerpos anti-Nu, anti-DNAdc o niveles bajos del C3 presentaron un riesgo mayor de recaída del LES y de la nefritis lúpica en los próximos 12 meses, lo que señala la necesidad de estrechar su monitoreo clínico(AU)

Introduction: the research carried out have not been successful in finding serological biomarkers or sufficiently reliable biomarkers for predicting relapse in systemic lupus erythematosus (SLE). Objective: setermine the predictive value of specific antinuclear antibodies for relapse of SLE and lupus nephritis. Methods: an analytical, observational, longitudinal and prospective study was carried out in 120 adult patients with inactive SLE (SLEDAI-2K ≤ 5 points). The baseline presence of seven antinuclear specificities, low C3 and C4 were correlated with the occurrence of SLE relapse (increases in score SLEDAI-2K ≥ 4) and lupus nephritis by univariate analysis. The most valuable variables were further evaluated as predictors a multivariate logistic regression model to calculate the odds ratio (OR). Results: SLE and lupus nephritis relapses were observed in 51 (42.5 percent) and 29 (24.2 percent) patients, respectively. The presence of anti-Nu (OR= 1523.0, P < 0.001) antibodies and anti-dsDNA (OR= 12.1; p = 0.044) and lupus nephritis, anti-Nu (OR= 92.9; p < 0.001) and low C3 (OR= 7.1; p= 0.007) emerged as risk factors for relapse of SLE in multivariate analysis. The underrepresentation of anti-RNP was a risk factor for relapse of SLE and lupus nephritis (OR = 0.023; p= 0.009; OR = 0.1; p= 0.025). Conclusions: SLE patients with positive anti-Nu, anti-dsDNA and low levels of C3 had a higher risk of relapse of SLE and lupus nephritis in the succeeding 12 months, signaling the need for close clinical monitoring(AU)

Anticuerpos antinucleosoma frente a marcadores inmunológicos convencionales en el diagnóstico de la actividad del lupus eritematoso sistémico / Anti-nucleosome antibodies against conventional Immunological markers in the diagnosis of SLE activity

OBJETIVOS: examinar el perfil de anticuerpos en pacientes con lupus eritematoso sistémico y establecer la correlación entre los niveles de anticuerpos y la actividad de la enfermedad y de la nefritis lúpica. MÉTODOS: en 213 pacientes con lupus eritematoso sistémico, atendidos de forma consecutiva, se determinaron los anticuerpos anti-DNA de doble cadena (DNAdc), antinucleosoma (Nu), anti-Sm, anti-RNP, anti-Ro, anti-La y anti-Scl-70 por ensayo inmunoadsorbente ligado a enzima (ELISA), el C3 y el C4. La actividad de la enfermedad fue evaluada por el índice SLEDAI-2K, sin la contribución de anti-DNAdc, C3 ni C4. Los niveles de anticuerpos, el complemento y la actividad del lupus eritematoso sistémico fueron correlacionados. RESULTADOS: los niveles de todos los anticuerpos resultaron superiores significativamente en los pacientes en fase activa de la enfermedad con respecto a los que se hallaban en la fase inactiva. Los coeficientes de correlación de Spearman más altos con la puntuación de SLEDAI-2K correspondieron a los anti-Nu y anti-DNAdc (p= 0,856 y p= 0,616, respectivamente, p < 0,001 para ambos). Las áreas bajo de la curva (AUC) del análisis COR de la actividad del LES fueron en orden decreciente para los anti-Nu= 0,948, anti-DNAdc= 0,810, anti-RNP= 0,705, C4= 0,704, anti-Sm= 0,703, C3= 0,688, anti-Scl-70= 0,611, anti-La= 0,601 y anti-Ro= 0,593; y de la actividad renal para los anti-Nu= 0,845, anti-DNAdc= 0,755, C4= 0,694, C3= 0,670, anti-Sm= 0,641, anti-RNP= 0,630, anti-Scl-70= 0,611, anti-Ro= 0,593 y anti-La= 0,567. CONCLUSIÓN: los anticuerpos anti-Nu mostraron una capacidad discriminatoria excelente para la actividad del LES y de la actividad renal lúpica, superior a la de los anti-DNAdc y el resto de los marcadores.

OBJECTIVES: to examine the profile of antibodies in patients with systemic lupus erythematosus and establish the correlation between antibody levels and disease activity, and lupus nephritis. METHODS: anti-double stranded DNA (dsDNA), antinucleosoma (Nu), anti-Sm, anti-RNP, anti-Ro, anti-La, and anti-Scl-70 antibodies by enzyme-linked immunosorbent assay (ELISA) as well as C3 and C4 were determined in 213 patients with systemic lupus erythematosus who were treated consecutively. Disease activity was assessed by the SLEDAI 2K-index, without the contribution of anti-dsDNA, C3 or C4. The levels of antibodies, complement and activity of systemic lupus erythematosus were correlated. RESULTS: the levels of antibodies turned out to be remarkably higher in patients in the active phase of the disease compared to those who were in the inactive phase. The higher Spearman correlation coefficients with SLEDAI-2K score corresponded to the anti-Nu and anti-dsDNA (p = 0.856 and p = 0.616, respectively, p <0.001 for both). The areas under the ROC curve analysis of the activity of systemic lupus erythematosus were in descending order as follows: anti-Nu = 0.948; anti-dsDNA = 0.810; anti-RNP = 0.705; C4 = 0.704; anti-Sm = 0.703; C3 = 0.688; anti-Scl-70 = 0.611; = 0.601 anti-La. Anti-Ro = 0.593; and renal activity for anti-Nu = 0.845; anti-dsDNA = 0.755; C4= 0.694; C3 = 0.670; anti-Sm = 0.641; anti-RNP = 0.630; anti-Scl-70 = 0.611; anti-Ro = 0.593 and anti-La = 0.567. CONCLUSION: the anti-Un exhibit excellent activity discriminating capacity of SLE lupus and renal activity, higher than the anti-dsDNA and other markers.

Utilidade da triagem dos anticorpos anti-dsDNA por quimioluminescência, seguida de confirmação por imunofluorescência indireta / Usefulness of anti-dsDNA antibody screening with chemiluminescence followed by confirmation by indirect immunofluorescence

OBJETIVO: Avaliar o desempenho de um imunoensaio quimioluminescente (CLIA) para os anticorpos anti-dsDNA, utilizando como referência o teste de imunofluorescência indireta (IFI) sobre Crithidia luciliae. MÉTODOS: O sistema de automação foi previamente aprovado com 81% de eficiência, 100% de sensibilidade e 82% de especificidade, por processo de validação intrínseca em 179 amostras consecutivas de 169 pacientes no início de 2011. A seguir, esses pacientes foram subdivididos em três grupos de acordo com os resultados da pesquisa dos anticorpos anti-dsDNA nas duas metodologias (reagentes, não reagentes e resultados discrepantes). RESULTADOS: Na análise dos dados: 1) 77% (129/169) dos exames haviam sido solicitados por médicos reumatologistas; 2) 57% (97/169) das amostras eram de pacientes lúpicos; 3) Os resultados de CLIA, reagentes e não reagentes, estavam bem definidos e padronizados; 4) A automação reduziu em 70% as passagens pela técnica manual com segurança e qualidade; 5) A alta prevalência de pacientes lúpicos e com nefrite entre os resultados de CLIA falso-positivos corrobora a hipótese de que o índice real de falsa positividade do CLIA seja menor que o encontrado inicialmente neste estudo.

OBJECTIVE: The purpose of this study was to evaluate the performance of a chemiluminescent immunoassay (CLIA) to detect anti-dsDNA antibodies, using the indirect immunofluorescence test (IIF) on Crithidia luciliae as a reference. METHODS: The automation system demonstrated 81% efficiency, 100% sensitivity and 82% specificity according to the intrinsic validation process performed using 179 consecutive samples from 169 patients in the beginning of 2011. These patients were subsequently divided into 3 groups according to the co-reactivity of anti-dsDNA results using the 2 methods (reactive, non-reactive and discrepant results). RESULTS: Upon data analysis, 77% (129/169) of the tests were requested by rheumatologists, and 57% (97/169) of the samples were from lupus patients. Both the reactive and non-reactive results of the CLIA were well defined and standardised, and automation reduced the manual labor required by 70% in a safe and high-quality manner. Furthermore, the high prevalence of patients with lupus and nephritis among the CLIA false-positive results corroborates the hypothesis that the actual index of CLIA false positivity is lower than that initially found in this study.

A Case of ANA-negative, Anti-dsDNA Negative, and Anti-Ro/SSA Positive Membranous Lupus Nephropathy

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of diverse autoantibodies with various systemic organ involvements. In patients with SLE, autoantibodies, such as antinuclear antibody (ANA) and anti-dsDNA antibody, play an important role not only in diagnosing the disease, but also representing the pathogenesis of the disease. ANA is the main screening tool in diagnosis and serum complement levels and anti-dsDNA antibody level are closely related to the disease activities. Nevertheless, exceptionally, some patients represent with negative ANA and/or anti-dsDNA antibody leading to difficulties in diagnosing the disease. Here, we report a case of 37-year old female SLE patient with negative ANA, negative anti-dsDNA antibody, and positive anti-Ro/SSA antibody, which manifested with nephrotic syndrome.

Effects of arsenic trioxide on anti-dsDNA antibody and the expression of DNA methyltransferase 1 and CD11a genes in lupus MRL/lpr mice / 中华风湿病学杂志

ObjectiveTo investigate the effect of arsenic trioxide (ATO) on anti-dsDNA antibody and the expression of DNA methyltransferase 1-mRNA and CD11a-mRNA in lupus MRL/lpr mice.Methods MRL/lpr mice were divided into three groups:the ATO group,the sodium chloride(NS) group,and the cyclophosphamide(CTX) group.The control group consisted of 20 syngeneic normal C57/BL mice,which were subdivided into the ATO group and the NS group.After two-month treatment,all mice were sacrificed.Blood routine test was conducted by SYSMEX KX21.The anti-dsDNA antibody in the serum were detected by ELISA.The expression of DNMT1 and CD11a was determined by RT-PCR.ANOVA and paired t test were used for statistical analysis.Results① The serum level of anti-dsDNA antibody(0.89±0.07) and the gray scale value of CD11a-mRNA(0.43±0.25) in the ATO group were much lower than those in the NS group of MRL/lpr mice(1.77±0.28,P＜0.01; 0.99±0.31,P＜0.05),while the gray scale value of DNMTI-mRNA (0.32±0.30) was significantly higher than that in the NS group(0.16±0.26,P＜0.05 ).② The serum levels of anti-dsDNA antibody was low in both the ATO group and the CTX group (0.90±0.07,0.66±0.22),and it was higher in the ATO group than that in the CTX group (P＜0.05).The gray scale value of DNMT1 mRNA in the ATO group (0.32±0.30) was higher than that in the CTX group (0.16±0.18,P＜0.05) in MRL/lpr mice,and the gray scale value of CD11a mRNA in the ATO group(0.43±0.25) was lower than that in the CTX group (0.86±0.31,P＜0.05) in MRL/lpr mice.③ There was no difference in above parameters between the ATO-group and NS group in C57/BL mice(P＞0.05).ConclusionArsenic trioxide can reduce the serum level of auto-antibody and reverse low methylation.But it has no effect on normal mice.

The cut-off point of Anti-dsDNA test by EliA dsDNA

Objective: To determine the cut-off point of anti-dsDNA for screening by EliA dsDNA. Methods: Serum specimens requested for anti-dsDNA between October and December 2007 were recruited and tested by the Crithidia luciliae immunofluorescence test (CLIFT) and automated fluorescence immunoassay (EliA dsDNA). The CLIFT was considered as the gold standard method. Different levels of sensitivity and specificity were determined and the cut-off point was selected from among them. Results: Of the 133 specimens collected, 35 were positive whereas 98 were negative with the CLIFT. Of those 35 positive specimens, 2, 0, 2, 2 and 29 were, respectively, in ranges of < 5, 5 to 9.9, 10 to 14.9, 15 to 19.9 and > 20 IU/ml by EliA dsDNA. Also, of the 98 negative specimens, 73, 7, 4, 4 and 10 were, respectively, in ranges of < 5, 5 to 9.9, 10 to 14.9, 15 to 19.9 and > 20 IU/ml by EliA dsDNA. The sensitivity and specificity for each level were determined and the value of 11 IU/ml was selected as the cut-off point. Additionally, when clinical diagnosis was used in specimens with discrepant results, the sensitivity of EliA dsDNA was far better than the CLIFT, whereas the specificity of both methods was comparable. Conclusion: The appropriate cut-off point of EliA dsDNA for screening was 11 IU/ml. Furtermore, the diagnostic value of EliA dsDNA was better than the CLIFT when clinical diagnosis was included in the gold standard criteria.

A cross-sectional hospital-based study of autoantibody profile and clinical manifestations of systemic lupus erythematosus in south Indian patients.

Our study was aimed to analyze clinical manifestations, autoantibodies and other serological abnormalities in South Indian patients with systemic lupus erythematosus. Clinical history and findings on systemic examination were noted. Antinuclear antibodies (ANA), antibodies to double-stranded DNA (dsDNA) were detected by immunofluorescence and ANA profile by Immunoblotting. Arthritis was most common followed by fever and skin rash. Clinical manifestations vary according to geographical location of the patient. ANA was positive in 64.28% and anti-dsDNA in 89.36% of patients. All patients with lupus nephritis were positive for dsDNA. Detection of antibodies to dsDNA, RNP and anti-Smith (Sm) are of diagnostic and prognostic importance.

Evaluation of Anti-dsDNA Antibody Tests: Crithidia luciliae Immunofluorescence Test, Immunoblot, Enzyme-linked Immunosorbent Assay, Chemiluminescence Immunoassay / 대한진단검사의학회지

BACKGROUND: Anti-double stranded DNA antibody (anti-dsDNA) test is useful for the diagnosis and monitoring of systemic lupus erythematosus (SLE). Although several methods are available, none of them is completely satisfactory and differences among them have been reported. We evaluated the diagnostic performance of 6 commercial kits for anti-dsDNA detection. METHODS: A total of 142 sera (SLE [N=74], other systemic rheumatic diseases [N=50], other diseases [N=18]) were tested by 6 different assay kits using different antigenic sources of DNA: Crithidia luciliae immunofluorescence test (CLIFT), salmon testes (immunoblot, IB), human (ELISA I), salmon testes with nucleosome linker (ELISA II), plasmid (ELISA III), and synthetic oligonucleotides (chemiluminescence immunoassay, CLIA). RESULTS: With manufacturers' cut-off values, 6 test kits showed sensitivities of 55.4-91.9%. ELISA I had a greater sensitivity than the other five assays (P0.05). With cut-off values set at 95% of specificity, ELISA II had a higher sensitivity than ELISA III (63.5% vs. 41.9%, P<0.05). IB had poor concordance rates with other assays (42.0-65.0%). Pearson correlation coefficients among 4 quantitative assays were 0.667-0.798. CONCLUSIONS: Six different assays showed various performances depending on the methods and cut-off values used. Except IB, the other five assays can be used for the detection of anti-dsDNA.