Prevalence and Factors Associated with Positivity of Antinuclear Antibodies (ANA) Patterns, Native Anti-DNA and Extractable Nuclear Antigens (ENA) Antibodies: Experience from a Laboratory in Dakar

Background: Diagnosis of autoimmune diseases (AID) is challenging, due to overlapping features with other non-immune disorders. Anti-nuclear antibodies (ANA) are sensitive screening tests but anti-deoxyribonucleic acid-antibody (anti-DNA), and anti-extractable nuclear antigens (anti-ENA) are specific for AIDs. We aimed to look at ANA patterns in our patients and correlated them with anti-ENA for proper interpretation and better patient management cost-effectively. Methods: A retrospective study was conducted over 1 year from January to December 2022 who were tested for ANA at biology medical laboratory of Pasteur Institute of Dakar. Anti-ENA and anti-DNA results were also analyzed for ANA-positive patients. Statistical analysis was performed using STATA 14.0, p Results: 216 patients were analyzed. Women predominated at 79.2% and mean age was 48 years [CI 95%, 46 - 50], with extremes of 10 and 89. Most represented age group was [41 - 60] with 38%. ANA was positive in 27 (12.5%) of patients, 59.2% of whom were strongly positive (titer of 1/1000, 1/3200 or 1/6400). The most common pattern was nuclear speckled, which was found in 77.8% of samples. Anti-ENA and anti-DNA positivity in ANA-positive patients was found respectively in 63% (17/27) and 1.4% (3/27) of the samples analyzed. Most commonly identified anti-ENA was anti-Sm 29.6%, anti-SSA 29.6%, anti-Ro-52 25.9%, anti-RNP 18.5% and anti-SSB 14.8% which was associated with speckled pattern. Association results indicated a significant relationship between both tests and between ANA titer in the anti-ENA- and ANA-positive patients (p 0.001). Conclusions: ANA, Anti-ENA and anti-DNA antibodies are essential for AIDS diagnosis. However, the testing repertoire should follow an algorithm comprising of clinical features, followed by ANA results with nuclear, mitotic, and cytoplasmic patterns, anti-ENA, and anti-DNA for a more meaningful, and cost-effective diagnostic approach.

Detection of Antinuclear Antibodies in Canine Serum by Immunoperoxidase in MDCK and Indirect Immunofluorescence in HEp2 Cells

Antinuclear antibodies are found in animals suffering from Systemic Lupus Erythematosus (SLE) and some other diseases, their presence in the blood is determined by antinuclear antibody (ANA) test using indirect immunofluorescence (IF) with HEp2 cells as a substrate. In this work, an immunoperoxidase (IP) assay was developed to evaluate the ANAs in canine sera, using canine kidney cell lines (MDCK) and compared with a commercial immunofluorescence test on Hep2 cells for this system, a fluoresceinated anti-canine Ig antibody was standardized. The study was performed on 50 sera from dogs submitted to the laboratory with different clinical diagnoses of autoimmune-associated diseases. The procedures on both cells were unified to perform comparisons of the reactions, direct sera or at different dilutions were added to a monolayer of permeabilized MDCK cells, followed by a peroxidized anti-canine IgG conjugate, and a substrate for the IP reaction. The same sera were tested on the commercial IF assay on Hep2 cell system. In 22/50 cases, the presence of LE cells in peripheral blood was determined. A high correlation was found in the detection of antinuclear antibodies between both cell lines and techniques, however there were differences in the reaction patterns in the nucleus and cytoplasm between cell lines. The diffuse nuclear pattern observed in MDCK cells was more related to the presence of high percentages of LE cells in peripheral blood. The differences found in the results were possibly associated with the presence of homologous antigens between the MDCK cells and the dog. In addition, the methodology and standardization for the use and interpretation of a reference serum was developed to unify the interpretation criteria in the laboratory.

Meta-analysis of anti-ribosomal P antibodies in lupus psychosis

AIM: To perform a meta-analysis of the prevalence of anti-ribosomal P(aRP) antibodies in lupus psychosis, and the odds of psychosis in aR P-positive subjects.METHODS: We identified articles by searching PubM ed, PsychI nfo, and ISI, and the reference lists of identified studies.RESULTS: Twenty-four studies met the inclusion criteria. Positive aR P antibodies were found in 51%(91 of 179 total cases) of cases of lupus psychosis. There was an almost 3.5-fold increased odds of psychosis in aR Ppositive patients(OR = 3.46, 95%CI: 1.97-6.09, P < 0.001). The population attributable risk percentage was 36% for aR P antibodies.CONCLUSION: aRP antibodies are common in lupus psychosis, although the potential mechanism(s) underlying this association remain unclear. Given the overlap between the clinical presentation and risk factors for lupus psychosis and schizophrenia, further investigation of aR P antibodies in schizophrenia is warranted.

Comparing different domains of analysis for the characterisation of N-glycans on monoclonal antibodies

With the size of the biopharmaceutical market exponentially increasing,there is an aligned growth in the importance of data-rich analyses,not only to assess drug product safety but also to assist drug development driven by the deeper understanding of structure/function relationships.In monoclonal antibodies,many functions are regulated by N-glycans present in the constant region of the heavy chains and their mechanisms of action are not completely known.The importance of their function focuses analytical research efforts on the development of robust,accurate and fast methods to support drug development and quality control.Released N-glycan analysis is considered as the gold standard for glycosylation characterisation;however,it is not the only method for quantitative analysis of glycoform heterogeneity.In this study,ten different analytical workflows for N-glycan analysis were compared using four monoclonal antibodies.While observing good comparability between the quantitative results generated,it was possible to appreciate the advantages and disadvantages of each technique and to summarise all the observations to guide the choice of the most appropriate analytical workflow according to application and the desired depth of data generated.

Role of autoantibodies in the clinical management of primary biliary cholangitis

Primary biliary cholangitis(PBC)is a chronic cholestatic liver disease characterized by immune-driven destruction of small intrahepatic bile ducts leading a proportion of patients to hepatic failure over the years.Diagnosis at early stages in concert with ursodeoxycholic acid treatment has been linked with prevention of disease progression in the majority of cases.Diagnosis of PBC in a patient with cholestasis relies on the detection of disease-specific autoantibodies,including anti-mitochondrial antibodies,and disease-specific anti-nuclear antibodies targeting sp100 and gp210.These autoantibodies assist the diagnosis of the disease,and are amongst few autoantibodies the presence of which is included in the diagnostic criteria of the disease.They have also become important tools evaluating disease prognosis.Herein,we summarize existing data on detection of PBC-related autoantibodies and their clinical significance.Moreover,we provide insight on novel autoantibodies and their possible prognostic role in PBC patients.

ANALYSIS ON EPITOPES OF IGM WITH MONOCLONAL ANTI-ISOTYPIC AND ANTI-IDIOTYPIC ANTIBODIES AGAINST IgM FROM B-CLL

A double antibodies additivity ELISA test was employed to identify the epltopes which can be recognized by monoclonal antibodies (McAbs) against IgM from B chronic lymphocyte leukemia (B-CLL). The computer grouping programme analysis showed that 4 and- isotypic MaAbs could be divided into two groups and 10 anti- idiotype McAbs could be divided into four groups. The result was consistent with that of the indirect sandwich ELISA and inhibition ELISA test. It suggested that there were at least 6 distinct IgM epitopes which can react specifically with 14 McAbs. Our study indicated that the combination of the additivity ELISA test and the computer grouping programme analysis is of help in studying the relationship of the structure and function of antigen.

Role of C-Peptide in Relation to Levels of Anti-GAD and Islet Cell Antibodies in Characterizing Types of Diabetes in the Young, in Eastern India

Background: Measuring fasting C-peptide (FCP) and antibodies against Glutamic acid decarboxylase (GADA) and Islet cell antibodies (ICA) are not so commonly explored in children and young adults. Objectives: To assess the levels of FCP, GADA and ICA in subjects below the age of 25 years with DM and compare their levels to differentiate between Autoimmune and Non-Autoimmune Type 1 DM. Methodology: Blood samples of 93 subjects diagnosed with DM, reporting to the tertiary care hospital, were analysed for ICA, GADA and FCP. Receiver operating characteristics (ROC) curves were analysed to check the ability of autoimmune markers, BMI and C-peptide to differentiate between Autoimmune (Ai) and Non-Autoimmune (NonAi) diabetes. Results: 30/93 (32.2%) were positive for anti-GAD ab and/or ICA and categorised as Autoimmune (Ai), the most common antibody being, anti-GAD ab (80%) in them. The level of FCP among Ai compared to NonAi, was significantly low (p 20.75 nmol/l) as a very dependable test for diagnosing Ai, Type 1 DM, in children and young adults. Its sensitivity and specificity are in the range of 86.2% and 96.8% respectively. Low level of C-peptide (Conclusion: This study revealed predominant positivity for anti-GAD ab (80%) among Ai+ patients. ROC analysis shows GADA above 20.75 nmol/l and Fasting C-peptide < 0.36 nmol/l as a good indicator for diagnosing Ai in children and young adults.

Peri-nuclear antibodies correlate with survival in Greek primary biliary cirrhosis patients

AIM:To investigate possible associations of anti-nuclear envelope antibody(ANEA)with disease severity and survival in Greek primary biliary cirrhosis(PBC)patients.METHODS:Serum samples were collected at diagnosis from 147 PBC patients(85%female),who were followed-up for a median 89.5 mo(range 1-240).ANEA were detected with indirect immunofluorescence on 1% formaldehyde fixed Hep2 cells,and anti-gp210 antibodies were detected using an enzyme linked immunosorbent assay.Findings were correlated with clinical data,histology,and survival.RESULTS:ANEA were detected in 69/147(46.9%) patients and 31/147(21%)were also anti-gp210 positive.The ANEA positive patients were at a more advanced histological stage(Ⅰ-Ⅱ/Ⅲ-Ⅳ56.5%/43.5% vs 74.4%/25.6%,P=0.005)compared to the ANEA negative ones.They had a higher antimitochondrial antibodies(AMA)titer(≤1:160/>1:160 50.7%/49.3%vs 71.8%/28.2%,P=0.001)and a lower survival time(91.7 ±50.7 mo vs 101.8±55 mo,P=0.043).Moreover,they had more advanced fibrosis,portal inflammation,interface hepatitis,and proliferation of bile ductules(P =0.008,P=0.008,P=0.019,and P=0.027,respectively).They also died more frequently of hepatic failure and/or hepatocellular carcinoma(P=0.016).ANEA positive,anti-gp210 positive patients had a difference in stage(Ⅰ-Ⅱ/Ⅲ-Ⅳ54.8%/45.2%vs 74.4%/25.6%,P= 0.006),AMA titer(≤1:160/>1:160 51.6%/48.4%vs 71.8%/28.2%,P=0.009),survival(91.1±52.9 mo vs 101.8±55 mo,P=0.009),and Mayo risk score(5.5 ±1.9 vs 5.04±1.3,P=0.04)compared to the ANEA negative patients.ANEA positive,anti-gp210 negative patients had a difference in AMA titer(≤1:160/>1:160 50%/50%vs 71.8%/28.2%,P=0.002),stage(Ⅰ-Ⅱ/Ⅲ -Ⅳ57.9%/42.1%vs 74.4%/25.6%,P=0.033),fibrosis(P=0.009),portal inflammation(P=0.018),interface hepatitis(P=0.032),and proliferation of bile ductules(P=0.031).Anti-gp210 positive patients had a worse Mayo risk score(5.5±1.9 vs 4.9±1.7,P=0.038)than the anti-gp210 negative ones.CONCLUSION:The presence of ANEA and anti-gp210 identifies a subgroup of PBC patients with advanced disease severity and poor prognosis.

Autoantibodies in chronic hepatitis C: A clinical perspective

Non-organ-specific autoantibodies and thyroid autoantibodies have been frequently found in chronic carriers of hepatitis C virus(HCV). With respect to endomysial antibodies and tissue transglutaminase, it is controversial whether the prevalence of glutenrelated seromarkers is higher in patients with HCV. In such cases, in addition to acknowledging any currently existing autoimmune disease, recognizing the risk of the patient developing an autoimmune disease during interferon(IFN)-based treatment must be a principle concern. From a clinical point-of-view, the presence of autoantibodies arouses suspicion that an autoimmunedisease may be present or may be precipitated by IFNbased HCV treatment. In this paper, we review the prevalence of autoantibodies in individuals with hepatitis C, the clinical significance of these autoantibodies, and the approach recommended for such situations.

Positive autoantibodies in living liver donors

BACKGROUND There is a nationwide shortage of organs available for liver transplantation.Living donors help meet this growing demand.Not uncommonly,donors will have positive autoantibodies.However,it is unclear whether donor positive autoantibodies are correlated with worse outcomes following living liver donor transplantations.AIM To analyze the significance of positive autoantibodies in donors on post-transplant outcomes in recipients.METHODS We performed a retrospective review of living liver donors who had undergone liver transplantation between January 1,2012 and August 31,2021.Demographic characteristics and pre-transplant data including antinuclear antibodies(ANA)and anti-smooth muscle antibody titers were collected in donors.Outcomes of interest were post-transplantation complications including mortality,biliary strictures,biliary leaks,infection,and rejection.Pediatric recipients and donors without measured pre-transplant autoantibody serologies were excluded from this study.RESULTS 172 living donor liver transplantations were performed during the study period,of which 115 patients met inclusion criteria.37(32%)living donors were autoantibody-positive with a median ANA titer of 1:160(range 1:80 to 1:1280)and median anti-SMA titer of 1:40(range 1:20 to 1:160).There were no significant differences in baseline demographics between the autoantibody positive and negative donors.Post-transplantation rates of death(P value=1),infections(P value=0.66),and overall rates of complications(P value=0.52)were similar between the autoantibody positive and negative groups.Higher incidences of anastomotic strictures and rejection were observed in the autoantibody positive group;however,these differences were not statistically significant(P value=0.07 and P value=0.30 respectively).CONCLUSION Isolated pre-transplant autoantibody positivity is not correlated to worse post-transplant outcomes in living liver donor transplants.

Preparation of Polyclonal Antibodies against NS3 Protein of Japanese Encephalitis Virus

Japanese encephalitis （JE） is a central nervous system disease caused by Japanese encephalitis virus （JEV）, which can infect human and a variety of animals and cause irreversible nerve damages. NS3 protein plays an important role in the process of JEV polyprotein hydrolysis, which is essential for JEV replication. Therefore, NS3 protein may be used as a potential drug target to treat Japanese encephalitis. In this study, the pET-28a-NS3 plasmid was successfully constructed and expressed in E. coli BL21 （ DE3 ） under IPTG induction. The molecular weight of the expressed recombinant protein was 55 ku, which was consistent with the expected result. The positive serum was prepared by immunizing BALB/c mice with NS3 protein and identified by indirect immunofluorescence （IFA）. The results showed that there was a fluorescence reaction between the prepared positive serum of NS3 protein and cells infected with JEV.

Preparation and antigenic characterization of rat monoclonal antibodies againts Hantavirus

Monoclonal antibodies (McAb) to Hantavirus (HTV)were derived from the hybridoma fused with Lou/c plasmocytoma rat cells (IR983F) and spleen cells from lou/c inbred rat immunized with HTV Chen strain. Eleven cell lines producing monoclonal antibodies direc

Analysis of clinical features and prognosis of anti-glomerular basement membrane antibody positive patients with anti-neutrophil cytoplasmic antibodies

Objective To investigate the characteristics and outcome of glomerulonephritis in patients with both antineutrophil cytoplasmic antibody and anti-glomerular basement membrane antibody.Methods The sera of 23 antiGBM glomerulonephritis patients were collected and were tested for ANCA respectively.Characteristics and outcome of patients with coexisting anti-GBM antibody

Presence of serum antinuclear antibodies correlating unfavorable overall survival in patients with chronic lymphocytic leukemia

Background: Serum antinuclear antibodies (ANAs) are positive in some patients with chronic lymphocytic leukemia (CLL), prognostic value of ANAs remains unknown. The aim of this study was to evaluate the role of ANAs as a prognostic factor in CLL. Methods: This study retrospectively analyzed clinical data from 216 newly diagnosed CLL subjects with ANAs test from 2007 to 2017. Multivariate Cox regression analyses were used to screen the independent prognostic factors related to time to first treatment (TTFT), progression free survival (PFS) and overall survival (OS). Receiver operator characteristic curves and area under the curve (AUC) were utilized to assess the predictive accuracy of ANAs together with other independent factors for OS. Results: The incidence of ANAs abnormality at diagnosis was 13.9%. ANAs positivity and TP53 disruption were independent prognostic indicators for OS. The AUC of positive ANAs together with TP53 disruption was 0.766 (95% confidence interval [CI]: 0.697-0.826), which was significantly larger than that of either TP53 disruption (AUC:0.706, 95% CI:0.634-0.772, P=0.034) or positive ANAs (AUC:0.595, 95% CI:0.520-0.668,P<0.001) in OS prediction. Besides, serum positive ANAs as one additional parameter to CLL-international prognostic index (IPI) obtained superior AUCs in predicting CLL OS than CLL-IPI alone. Conclusion: This study identified ANAs as an independent prognostic factor for CLL, and further investigations are needed to validate this finding.

Methodological aspects of anti-human leukocyte antigen antibody analysis in solid organ transplantation

Donor human leukocyte antigen(HLA)-specific antibodies(DSA) play an important role in solid organ transplantation. Preexisting IgG isotype DSA are considered a risk factor for antibody mediated rejection, graft failure or graft loss. The post-transplant development of DSA depends on multiple factors including immunogenicity of mismatched antigens, HLA class Ⅱ typing of the recipient, cytokine gene polymorphisms, and cellular immunoregulatory mechanisms. De novo developed antibodies require special attention because not all DSA have equal clinical significance. Therefore, it is important for transplant clinicians and transplant immunologists to accurately characterize DSA. In this review, the contemporary immunological techniques for detection and characterization of anti-HLA antibodies and their pitfalls are described.

Detection and Analysis of Blood associated Agent of Canine Rheumatism

[Objective] The paper was to explore the relationship between the occurrence of canine rheumatism and blood-associated agent by detecting blood routine indexes and changes in content of anti streptolysin O( ASO),C-reactive protein( CRP) and antinuclear antibody( ANA). [Method]Totally 13 cases of dogs which had been diagnosed with rheumatism by the reference standard of clinical examinations and laboratory diagnosis were selected for treatment,and their venous blood was collected on the day of diagnosis and at 1,3,5 d after treatment,respectively. Another 13 healthy dogs were selected randomly to collect venous blood as well. The white blood cells( WBC) count,neutrophilic granulocyte( Gran#),lymphocyte count( Lymph#) and blood routine index were determined using automatic animal blood cell analyzer. The content of ASO,CRP and ANA were determined using enzyme-linked immunosorbent assay( ELISA). [Result]Blood routine examination showed that there were significant differences in WBC between untreated rheumatismal dogs and healthy dogs( P < 0. 05),but no significant difference was observed on the day of diagnosis and duration of therepay( P > 0. 05). Detection results of blood-associated agent in rheumatismal dogs showed that there were extremely significant differences in ASO and ANA content between the day of diagnosis and duration of therapy( P < 0. 01); there were significant differences in Lymph# and Gran# content of CRP between the day of diagnosis and duration of therapy( P < 0. 05). The ASO,ANA and CRP content in the serum of untreated rheumatismal dogs were higher than those in healthy dogs,and the content of various indicators decreased significantly after treatment,but were still higher than that in healthy dogs. [Conclusion]The incidence of canine rheumatism is positively correlated with WBC count,ASO content,CRP content and ANA content. The variation of CRP content is the most sensitive indicator of the disease.

Automatic Computer Analysis of Digital Images of Triple-Antibody-Stained Prostate Biopsies

Background: Worldwide, prostatic adenocarcinoma is the most common tumour type among men. Aim: The aim of the present investigation was to develop a computer program to identify normal prostate biopsies and distinguish them from biopsies showing premalignant alterations (LGPIN, HGPIN) and adenocarcinoma. Method: Prostate biopsies (n = 2094) taken from 191 consecutive men during 2016 were stained with triple immunehistochemisty (antibodies to AMACRA, p63 and CK 5). Digital images of the biopsies were obtained with a scanning microscope and used to develop an automatic computer program (CelldaTM), intended to identify the morphological alterations. Visual microscopic finding was used as a reference. Result: Of the 191 men, 121 (63.4%) were diagnosed as having prostate adenocarcinoma and 70 (36.6%) as having no malignancy on the basis of the visual microscopy. In comparison, computer analysis identified 134 (70.2%) men with malignant disease and 57 (29.8%) with non-malignant disease after exclusion of artifacts, which constituted 10.4% of areas (indicated as malignant disease). Discrepant results were recorded in 15 (7.9%) men, and in 14 of these cases, HGPIN and areas suggestive of early invasion were common. Thus, it was uncertain whether these cases should be regarded as malignant or not. The agreement between the visual examination and the computer analysis was 92.1% (kappa value 0.823, sensitivity 99.2 and specificity was 0.80). Conclusion: It seems that computer analysis could serve as an adjunct to simplify and shorten the diagnostic procedure, first of all by ensuring that normal prostate biopsies are sorted out from those sent for visual microscopic evaluation.

Analysis of Antisperm Antibody in Cervix Mucus for Azoospermic Men’s Wives

ELISA method was used to detect antisperm antibodies in cervix mucus. Out of 400 women whose husbands had sperms, 92 were antisperm antibody positive (23% ). 42 of 200 women with azoospermic partners were antisperm antibody positive (21% ). No difference was found between the two groups. Hence, antisperm antibodies in azoospermic men's wives may be caused by sperm'sadhering antigens in semina.

Clinical value of chemiluminescence method for detection of antinuclear antibody profiles

BACKGROUND Antinuclear antibodies(ANAs)are crucial in diagnosing autoimmune diseases,mainly systemic lupus erythematosus(SLE).This study aimed to compare the performance of chemiluminescence assay(CLIA)and line immunoassay(LIA)in detecting ANAs in patients with autoimmune diseases,evaluate their diagnostic accuracy for SLE,and develop a novel diagnostic model using CLIA-detected antibodies for SLE.Specimens from patients with autoimmune diseases and physical examination specimens were collected to parallel detect specific antibodies.Individual antibodies'diagnostic performance and a model combining multiple antibodies were assessed.The findings provide valuable insights into improving the diagnosis of SLE through innovative approaches.AIM To compare the performance of CLIA and LIA in detecting ANAs in patients with autoimmune diseases,assess their accuracy for SLE,and develop a novel diagnostic model using CLIA-detected antibodies for SLE.METHODS Specimens have been obtained from 270 patients with clinically diagnosed autoimmune disorders,as well as 130 physical examination specimens.After that,parallel detection of anti-double-stranded DNA(dsDNA)antibody,anti-histone(Histone)antibody,anti-nucleosome(Nuc)antibody,anti-Smith(Sm)antibody,anti-ribosomal P protein(Rib-P)antibody,anti-sicca syndrome A(Ro60)antibody,anti-sicca syndrome A(Ro52)antibody,anti-sicca syndrome(SSB)antibody,anticentromere protein B(Cenp-B)antibody,anti-DNA topoisomerase 1(Scl-70)antibody,anti-histidyl tRNA synthetase(Jo-1)antibody,and anti-mitochondrial M2(AMA-M2)antibody was performed using CLIA and LIA.The detection rates,compliance rates,and diagnostic performance for SLE were compared between the two methodologies,followed by developing a novel diagnostic model for SLE.RESULTS CLIA and LIA exhibited essentially comparable detection rates for anti-dsDNA antibody,anti-Histone antibody,anti-Nuc antibody,anti-Sm antibody,anti-Rib-P antibody,anti-Ro60 antibody,anti-Ro52 antibody,anti-SSB antibody,anti-Cenp-B antibody,anti-DNAScl-70 antibody,anti-Jo-1 antibody and anti-AMA-M2 antibody(P>0.05).The two methods displayed identical results for the detection of anti-dsDNA antibody,anti-Histone antibody,anti-Nuc antibody,anti-Sm antibody,anti-Ro60 antibody,anti-Ro52 antibody,anti-SSB antibody,anti-Cenp-B antibody,anti-Scl-70 antibody,and anti-AMA-M2 antibody(Kappa>0.7,P<0.05),but showed a moderate agreement for the detection of anti-Rib-P antibody and anti-Jo-1 antibody(Kappa=0.671 and 0.665;P<0.05).In addition,the diagnostic performance of these antibodies detected by both methods was similar for SLE.The diagnostic model's area under the curve values,sensitivity,and specificity,including an anti-dsDNA antibody and an anti-Ro60 antibody detected by CLIA,were 0.997,0.962,and 0.978,respectively.These values were higher than the diagnostic performance of individual antibodies.CONCLUSION CLIA and LIA demonstrated excellent overall consistency in detecting ANA profiles.A diagnostic model based on CLIA-detected antibodies can successfully contribute to developing a novel technique for detecting SLE.