Analysis of negatively charged dye-binding antibodies reactive with double-stranded DNA and heparan sulfate in serum from patients with rheumatic diseases.

Antibodies to double-stranded (ds) DNA are characteristically present in serum from patients with systemic lupus erythematosus (SLE). Recently, anti-dsDNA antibodies have been shown to have the capacity to react with a diversity of molecules with repeating negative charges. Using the anionic dye Cibacron blue F3GA, bound to crosslinked agarose, we analysed the nature of antibodies capable of reacting with this dye in serum samples from patients with various rheumatic diseases. The dye-antibody complex could easily be split by eluting with solutions of increasing ionic strength, suggesting that the interaction is ionic in nature. Pepsin-digested F(ab')2 antibodies retained the capacity to bind Cibacron blue, confirming that the binding occurred via antigen-binding sites on the antibody molecule. The eluates obtained from dye-ligand chromatography of active SLE sera contained antibodies to both dsDNA and heparan sulfate, while those of sera from patients with other non-SLE rheumatic diseases contained antibodies only against heparan sulfate. Furthermore, the dye-ligand eluates of sera from patients with active SLE and other non-SLE rheumatic diseases were found to contain increased amounts of IgG. In one patient with SLE, levels of antibodies to dsDNA and heparan sulfate, and the amounts of total IgG in dye-ligand eluates, were shown to be correlated with disease activity.     

Antibodies against sulphatide in sera from patients with autoimmune rheumatic diseases.

We tested sera of patients with various autoimmune rheumatic diseases for the presence of antibodies against sulphatide (an acidic glycosphingolipid), identified as a target antigen for antibodies against the liver cell membrane. Thirty-five percent (7/20) of patients with lupus in the active stage possessed anti-sulphatide antibodies, whereas 10% (2/20) of those in the inactive stage and 20% (4/20) of those in the stationary stage possessed such antibodies. Moreover, 10% (3/29) of patients with other autoimmune rheumatic diseases also possessed anti-sulphatide antibodies. The level of anti-sulphatide antibodies was significantly correlated with the levels of anti-double-stranded (ds) DNA antibodies (r = 0.634, P less than 0.001) and dextran sulphate-binding IgG (r = 0.407, P less than 0.001). The serum levels of antibodies against sulphatide were correlated with a history of seizures or psychosis in patients with autoimmune rheumatic diseases. Gels coupled with polyanionic dextran sulphate, monoanionic sulphanilic acid and DNA were shown effectively to adsorb anti-sulphatide antibodies in the sera of patients with active systemic lupus erythematosus (SLE) and autoimmune chronic active hepatitis (AI-CAH). These results suggest that the observed reactivity with sulphatide is due to the presence of antibodies capable of reacting with various anionic molecules in the sera of patients with autoimmune rheumatic diseases as well as those with AI-CAH.     

Cross-reactivity of anti-DNA antibodies with proteoglycans.

Ten sera of patients with systemic lupus erythematosus (SLE) were tested in an enzyme linked immunosorbent assay for their ability to react with glycosaminoglycans, constituents of proteoglycans, in relation to their anti-DNA reactivity. The SLE sera reacted with hyaluronic acid and chondroitin sulphate and this reactivity correlated with the anti-DNA activity of these sera. By contrast, sera obtained from patients with other autoimmune diseases or normal sera lacked any of these reactivities. Anti-DNA antibodies purified by affinity chromatography with either oligo dT cellulose or Cibracon blue F3Ga Sepharose reacted with DNA as well as with hyaluronic acid. The cross-reactivity of anti-DNA antibodies could be confirmed by the reaction of a mouse monoclonal anti-DNA antibody with DNA, hyaluronic acid, and chondroitin sulphate. This pattern of cross-reactivities of anti-DNA antibodies suggests that several compounds can function as antigenic targets for these antibodies provided that their structures contain repeating negatively charged groups.     

Preferential recognition of specific DNA motifs by anti-double-stranded DNA autoantibodies

Although antibodies (Ab) specific for double-stranded (ds) DNA are thought to be involved in the etiopathogenesis of systemic lupus erythematosus (SLE), the fine structure of their DNA targets remains elusive. We have adapted a polymerase chain reaction (PCR)-assisted immunoprecipitation method to define the binding sites in DNA sequences recognized by high affinity anti-dsDNA Ab of SLE patients. SLE sera were used to bind templates from a pool of double-stranded oligonucleotides (ON). A central part of 20 base-pair random sequence was flanked by restriction endonuclease recognition sites and sequences complementary to predefined PCR primers. Immunoselected ON were precipitated, isolated from the immune complexes and then subjected to a further immunoprecipitation step after amplification by PCR. After five cycles of immunoprecipitation and PCR, the resulting ON were cloned. Sequence analysis revealed that sera from SLE patients and two human monoclonal anti-dsDNA Ab obtained from SLE patients preferentially select sequences expected to form non-B-DNA structures. Inhibition studies of the Farr assay confirmed the increased affinity of the selected epitopes for anti-DNA Ab as compared to random B-DNA.     

A peptide DNA surrogate that binds and inhibits anti-dsDNA antibodies

Autoantibodies to dsDNA are an important diagnostic marker and pathogenic factor for systemic lupus erythematosus (SLE). Although the anti-dsDNA antibodies present in SLE are indicative of an antigen-driven response, the antigen has not been conclusively identified. The specific SLE anti-dsDNA antibodies were obtained by affinity purification using a dsDNA-coupled Sepharose column. Using the anti-dsDNA antibodies to screen a phage peptide display library, we demonstrated that purified polyclonal anti-dsDNA antibodies and a monoclonal anti-dsDNA antibody specifically bind a 15 mer peptide ASPVTARVLWKASHV. This chemically synthesized peptide could be recognized by anti-dsDNA antibodies in ELISA and Dot blot. This 15 mer peptide can inhibit anti-dsDNA antibodies binding to dsDNA antigen in immunoassays and in the Crithidia luciliae assay while a control peptide did not inhibit anti-dsDNA antibodies. This study demonstrates the potential usefulness of the peptide DNA surrogate in diagnostic tests of SLE and in the investigation of the origin of anti-dsDNA antibodies. It may also be used in studies of the DNA-anti-DNA antibody interaction.     

自身抗体联合检测对系统性红斑狼疮诊断的意义

为了评价抗核小体抗体(anti-nucleosome antibody,AnuA)、抗Sm抗体、抗双链DNA(double stranded-DNA,dsDNA)抗体、抗核糖体P蛋白(ribosomal P protein,rRNP)抗体联合检测对系统性红斑狼疮(SLE)诊断的价值,采用酶联免疫吸附法(ELISA)测定123例SLE患者、61例其他结缔组织病患者和30名健康对照者血清中An.uA、抗dsDNA抗体、抗Sm抗体、抗rRNP抗体含量.结果显示,AnuA、抗dsDNA抗体、抗Sm抗体和抗rRNP抗体在SLE患者中的阳性率明显高于疾病对照组和正常对照组;AnuA与抗dsDNA抗体的敏感性显著高于其他两种自身抗体;抗dsDNA抗体、抗sm抗体和抗rRNP抗体阴性的SLE患者中,AnuA阳性率为52.6%～68.0%;SLE活动期患者与非活动期患者AnuA、抗dsDNA抗体阳性率有显著性差别.四种自身抗体在SLE的诊断中有明显的互补作用,特别是AnuA和抗dsDNA抗体可以弥补其他抗体的不足;AnuA、抗dsDNA抗体与疾病活动性密切相关.AnuA与抗sm抗体或AnuA与抗dsDNA抗体的二联检测可明显提高其对SLE诊断的敏感性.AnuA、抗dsDNA抗体、抗Sm抗体三联检测的阳性率可达87%.自身抗体联合检测提高了诊断的敏感性,对SLE的诊断和治疗有重要意义.     

Reactive oxygen species modify human DNA, eliciting a more discriminating antigen for the diagnosis of systemic lupus erythematosus.

During the development of an ELISA to measure anti-DNA antibodies in systemic lupus erythematosus (SLE) sera, native dsDNA was found not to be the most appropriate antigen to use in ELISA assays for differentiating between SLE patients and those with rheumatoid arthritis (RA), a disease also associated with circulating serum anti-DNA antibodies. By modifying the ELISA technique to incorporate human DNA, denatured by reactive oxygen species, to detect anti-DNA antibodies in SLE sera, results consistently showed an increase in antibody binding when compared with the native antigen; no such trend was observed in the comparable group of RA patients. Using this assay serum anti-dsDNA antibody levels were measured in a group of 20 controls, 20 RA patients (10 seropositive and 10 seronegative) and 30 SLE patients (15 with clinically active disease, 15 with inactive disease). A comparison with the standard radioimmunoassay used to measure anti-DNA antibodies for the diagnosis of SLE showed that the ELISA assay using modified DNA performed better than the standard radioimmunoassay offering an improvement in both clinical specificity and sensitivity. The improved method particularly reduced the problem of false-negative results for SLE patients shown clinically to be either mildly active or inactive.     

Development of anti-dsDNA autoantibodies prior to clinical diagnosis of systemic lupus erythematosus.

Anti-double stranded (dsDNA) antibodies are of considerable diagnostic value and are thought to be involved in the pathogenesis of systemic lupus erythematosus (SLE). Fluctuations in anti-dsDNA antibody levels are also used as markers for disease activity and exacerbations. In this study we sought to evaluate the anti-dsDNA antibody level in serum samples collected before the onset of SLE diagnosis. A total of 130 SLE patients were identified with stored serum samples available prior to diagnosis within the US Department of Defense serum repository. All 633 sera available from these patients were screened for anti-dsDNA antibodies using an enzyme linked immunosorbant assay (ELISA). Within this cohort 55% of cases had detectable anti-dsDNA antibodies prior to SLE diagnosis. The onset of anti-dsDNA antibodies ranged from 9.3 years before to within the same month as diagnosis (with a mean onset 2.7 years before diagnosis). In order to assess for fluctuations in anti-dsDNA levels relative to diagnosis, cases were selected with at least two positive samples, one within 6 months and a second greater than 6 months prior to diagnosis (n = 26). Seven of these cases also had samples available shortly after diagnosis (< or = 6 months) for comparison. Fifty-eight percent of the 26 cases developed a significant rise in anti-dsDNA antibody levels within 6 months of diagnosis. A significant decline in anti-dsDNA levels ensued after diagnosis (and following treatment with corticosteroids) in all seven cases with samples available. Patients with a significant rise in anti-dsDNA antibodies at diagnosis were more likely to have renal disease than those who did not (66.7% compared to 27.3%, chi2 =3.94, P<0.05). These data suggest that anti-dsDNA antibodies are present in SLE patient sera much earlier than previously suspected. In addition, the data are consistent with increases in anti-dsDNA levels contributing to the onset of clinical illness in some patients with SLE.     

Exposure of chromatin and not high affinity for dsDNA determines the nephritogenic impact of anti-dsDNA antibodies in (NZB×NZW)F1 mice

Recent studies have demonstrated that the nephritogenicity of antibodies to dsDNA and nucleosomes confers to binding of glomerular membrane-associated nucleosomes, and not to cross-reacting glomerular antigens. There is no known parameter that determines antibody pathogenicity aside from specificity for dsDNA/nucleosomes, and systemic lupus erytheomatosus (SLE) patients may have high titer anti-dsDNA antibodies irrespective whether they have lupus nephritis or not. One parameter may be antibody affinity, as theoretically only high affinity antibodies may bind in vivo in a stable way. This was analyzed in (NZB × NZW)F1 mice with full-blown lupus nephritis. These mice had serum antibodies to dsDNA, and IgG autoantibodies bound in situ in glomerular membrane-associated electron dense structures as determined by immune electron microscopy (IEM). Intrinsic affinity of purified circulating and glomerular IgG anti-dsDNA antibodies was determined by surface plasmon resonance. The results demonstrate that affinity of glomerular-bound anti-dsDNA antibodies was higher than for those in circulation. However, affinity of glomerular in situ-bound antibodies from different mice varied considerably, from K_D in the range from 10^{? 8} to 10^{? 13}. These results indicate that antibody affinity is not a decisive pathogenic factor, but rather that availability of chromatin fragments may be the factor that determines whether an anti-dsDNA antibody binds in glomeruli or not.     

Specific cross-reaction of anti-dsDNA antibody with platelet integrin GPIIIa49-66

Anti-platelet autoantibodies are frequently found in systemic lupus erythematosus (SLE) patients and contribute to the development of SLE-associated immunologic thrombocytopenia (SLE-ITP). Although the correlation of anti-dsDNA autoantibody with platelet-associated antibody has been reported, the potential mechanism underlying such a correlation is incompletely understood. We have reported that anti-platelet integrin GPIIIa49-66 (CAPESIEFPVSEARVLED) autoantibodies play a major role in the development of HIV-1-related thrombocytopenia (HIV-1-ITP). The strong negative charge of GPIIIa49-66 prompts us to investigate whether GPIIIa49-66 can be an epitope mimicking dsDNA. We report here that anti-GPIIIa49-66 antibodies are found in three out of nine SLE-ITP patients. Double-stranded (ds) DNA competitively inhibited the binding of purified patient anti-dsDNA antibodies to GPIIIa49-66 peptide. Both polyclonal and monoclonal anti-GPIIIa49-66 antibodies are able to cross-react with dsDNA. Consistent with previous reports, the DNA binding activities of anti-GPIIIa49-66 antibodies are mainly dependent on the positively charged amino acid in the heavy-chain complementarity-determining region 3 (HCDR3). The HCDR3 of human SLE anti-dsDNA monoclonal antibody (mAb) 412.67 demonstrates a similar positively charged amino acid chain orientation compared with that of anti-GPIIIa49-66 mAb A11, and it cross-reacts with GPIIIa49-66 peptide. Purified anti-GPIIIa49-66 antibodies from SLE-ITP patients are able to induce platelet fragmentation in vitro and to induce thrombocytopenia in vivo. Thus, our data suggest that specific epitope cross-reaction between GPIIIa49-66 and dsDNA could be a mechanism involved in the development of SLE-associated thrombocytopenia.     

Antinucleosome antibodies in SLE: a two-year follow-up study of 101 patients

We prospectively analyzed the diagnostic sensitivity and specificity as well as the clinical relevance of antinucleosome antibodies in SLE. One hundred and one consecutive SLE patients were followed for 3 years. Three serial serum samples from each patient were tested for antinucleosome antibodies by ELISA (optimum cut-off value 10 U/ml), and for anti-dsDNA antibody (by ELISA and IIF on Crithidia luciliae), and anti-dsDNA avidity (by Scatchard plot analysis). Sera from 100 healthy individuals (HI), 35 patients with systemic sclerosis (SSc), 30 with primary Sj?gren's syndrome (SS), 20 with rheumatoid arthritis (RA) and 48 with infectious diseases (ID), were assayed as controls. SLE activity and damage were evaluated using the ECLAM score and the SLICC/ACR index. At baseline, antinucleosome antibodies were found in 87 patients with SLE (86.1%), in 8 patients with SSc (22.8%), in 2 HI (2%), and in 1 ID (2.1%). The sensitivity and specificity of antinucleosome testing for SLE were 86.1% and 95.3%, respectively. The prevalence of antinucleosome antibodies in SLE was significantly higher than that of anti-dsDNA antibodies, with a correlation between them. No relevant relationship was found between antinucleosome antibodies and disease features, including renal involvement, disease activity, and disease damage. During follow-up, no significant variation was observed in antinucleosome level, nor in anti-dsDNA antibody level or avidity. We conclude that antinucleosome antibodies are commonly found in SLE. Low antibody levels can be detected in SSc, whereas medium/high levels are highly specific for SLE. Their clinical relevance during the disease course and utility for monitoring the individual patient seem to be poor.     

Hidden anti-double stranded DNA antibodies in autoimmune mice

When MRL/l mouse spleen cell culture supernatants were incubated with normal mouse spleen cells, a two-50-fold increase in anti-dsDNA activity was noted. A smaller increase in anti-ssDNA and no change in anti-TNP antibody activity were observed. This 'hidden' antibody in the MRL/l supernatants could not be revealed by DNAse digestion and could not be absorbed by a DNA cellulose column. Hidden antibody was removed from supernatants by sepharose-anti Ig. After DNAase digestion of the MRL/l supernatants, hidden anti-dsDNA could not be revealed by incubation with spleen cells. All the hidden activity was excluded by gel filtration on Sephacryl S-300 (mol. wt greater than 300,000) but was banded in the low density protein area of caesium chloride equilibrium density gradients. It was also noted that MRL/l mouse sera had hidden anti-dsDNA antibodies. Hidden antibodies were present in both the IgG and IgM classes. The revealed antibodies demonstrated impaired ability to bind Fc specific anti-Ig reagents suggesting that they were partially degraded during the incubation with mouse spleen cells. The hidden anti-dsDNA thus appears to represent a DNA-anti-dsDNA complex, perhaps of very high affinity. It may explain why anti-dsDNA but not anti-ssDNA antibodies are of pathological importance in SLE.     

Anti-DNA antibody subpopulations and lupus nephritis

As a consequence of increased insight into the cellular and molecular mechanisms responsible for induction of B cell and T cell autoimmunity to DNA and nucleosomes, there is an obvious need to reconsider the dogma stating that anti-dsDNA antibodies serve as marker antibodies for SLE and also that anti-dsDNA antibodies per se are responsible for the initiation of lupus nephritis. Given that the potential to produce anti-dsDNA antibodies is an inherent property of the normal immune system and that few anti-DNA antibodies have nephritogenic potential, we must try to solve the problem whether it is avidity for DNA, specificity for unique DNA structures or cross-reactivity with non-DNA molecules, that make such antibodies pathogenic and thus potential markers for SLE and lupus nephritis. In this review, we will summarize contemporary problems related to these questions; (1) try to focus on phenotypic differences with respect to the ability to produce anti-dsDNA antibodies between individuals suffering from SLE and those not belonging to this diagnostic group, and (2) to describe differences between pathogenic and non-pathogenic anti-dsDNA antibodies.     

IgG human monoclonal anti-DNA autoantibodies from patients with systemic lupus erythematosus

We describe the production of six mouse-human heterohybridomas secreting human IgG anti-dsDNA antibodies derived from patients with systemic lupus erythematosus (SLE). Peripheral blood cells used for fusion experiments were from patients who were shown to have high numbers of anti-DNA secreting B cells in the peripheral blood. All monoclonal antibodies bind to dsDNA in ELISA systems, five are reactive with Crithidia lucilae kinetoplasts and three precipitate dsDNA in the Farr assay. Inhibition studies revealed a remarkable specificity for certain polynucleotide structures. To our knowledge these are the first hybridomas described in the human system that secrete anti-dsDNA antibodies of the IgG class.     

Monoclonal anti-double-stranded DNA antibodies cross-react with phosphoglycerate kinase 1 and inhibit the expression and production of IL-2 in activated Jurkat T cell line

Anti-double strand DNA antibodies (anti-dsDNA) involve in lupus nephritis. However, their role in tissue damage mechanism remains unclear. In this study, a 45-kDa cognate antigen of anti-dsDNA monoclonal antibodies 9D7 was identified by two-dimensional gel electrophoresis and determined to be human phosphoglycerate kinase 1 (PGK-1) by MALDI-TOF analysis. The binding of 9D7 to PGK-1 was not affected by DNase I but was inhibited by thymus dsDNA. Human SLE sera with high anti-dsDNA titers had a high affinity with PGK. In activated Jurkat T cells, 9D7 decreased the PGK-1 mRNA production and IL-2 promoter activity. Reduction in IL-2 gene expression and protein production were observed in the 9D7-treated cells. Because PGK-1 deficiency may cause mental tardy and hemolytic anemia, interaction between anti-dsDNA and PGK-1 may be important in lupus pathogenesis. Moreover, reduction in IL-2 production by anti-dsDNA suggests their role in increasing infection rate and decreasing proper generation of activation-induced cell death.     

Pathogenic Anti-DNA Antibodies in SLE: Idiotypic Families and Genetic Origins

We have adopted an idiotypic approach to study the double stranded DNA (dsDNA) binding antibodies of systemic lupus erythematosus (SLE). Three anti-idiotypic reagents, 8.12, 31, and F4, identify cross reactive idiotypes that are each expressed on anti-dsDNA antibodies in the sera of many patients with SLE. These idiotypic antibodies are implicated in the pathogenesis of SLE as they are present in immune complex deposits in the kidneys of patients with SLE glomerulonephritis. The autoantibody associated idiotypes are also expressed on antibodies that do not bind DNA. We are investigating the origin of the pathogenic anti-dsDNA antibodies of SLE by comparing the autoantibodies, the antibodies to foreign antigens, and the myeloma proteins that express each SLE associated idiotype. In conjunction with serological analysis of these idiotypic systems, molecular genetic studies indicate that both the 8.12 and the 31 autoantibody associated idiotypes may be germline encoded, while the F4 idiotype is generated by somatic mutation. The data further suggest that the antigenic specificity of the pathogenic anti-DNA antibodies of SLE is acquired through somatic mutation of germline immunoglobulin genes. By studying the regulation of genes capable of encoding pathogenic autoantibodies, in both SLE patients and non-autoimmune individuals, we may be able to elucidate the pathogenesis of autoimmune disease and begin to design more effective therapeutic interventions.     

The specificity of the anti-dsDNA ELISA. A closer look

The anti-dsDNA ELISA is probably one of the most popular techniques for determining antibody reactivity towards dsDNA, since this assay system has proven high sensitivity and is easy to perform. An important difference from other ELISA systems is the use of an intermediate layer (e.g., protamine sulphate or poly-L-lysine) which has been found to be necessary in order to obtain sufficient coating of dsDNA to the plates. When a panel of monoclonal antibodies to DNA (n = 56), all reactive in this anti-dsDNA ELISA were tested on plates coated only with protamine sulphate (PS) a large number were positive, although with a lower reactivity than with DNA. Binding to protamine sulphate occurred via two mechanisms: (1) DNA/anti-DNA immune complexes, present in hybridoma culture supernatants and adherent to protamine sulphate and (2) some IgM antibodies appear to possess an intrinsic affinity for PS. The latter mechanism gives rise to a false positive reaction in the anti-dsDNA ELISA. It was found that 18% of the clones that were unreactive in any anti-dsDNA assay other than the anti-dsDNA ELISA were labelled 'anti-dsDNA' incorrectly. We therefore propose that antibody reactivity towards dsDNA in an ELISA system must be confirmed in other anti-dsDNA assays before such antibodies can be termed 'anti-dsDNA'.     

SLE患者血清抗F(ab′)_2片段抗体的测定及其临床意义

用酶解法制备正常人 IgG-F(ab')_2片段及 SLE 患者血清抗 ds-DNA-F(ab')_2片段,ELISA 法检测同一组(46例)SLE 患者血清中抗 F(ab')_2片段抗体,两者检测结果呈高度相关性.同时发现,缓解期 SLE 患者血清中抗 F(ab')_2片段抗体水平明显高于活动期 SLE 患者,而抗 ds-DNA 抗体水平与之相反.提示,正常人 IgG-F(ab')_2片段与 SLE 患者血清抗 ds-DNA-F(ab')_2片段可能有共同的结构表位,其抗 F(ab')_2片段抗体测定可作为临床观察 SLE 活动性的一个指标.     

Monoclonal human anti-DNA antibodies from EB virus-transformed lymphocytes of systemic lupus erythematosus (SLE) patients

Sixteen monoclonal human anti-DNA antibodies were obtained from Epstein-Barr virus-transformed lymphoblastoid cells of patients with systemic lupus erythematosus (SLE) and were studied in terms of antigenic specificity. All of the antibodies showed polyspecificity to polynucleotides. Among them, some antibodies had a specificity to single-stranded (ss) DNA. Especially, O-8 antibodies showed a preference for polynucleotides with pyrimidine bases. The binding specificity of the antibody was also studied using different sizes of dT oligomers in order to assess the size of the epitope. It was revealed that oligonucleotides with a size of more than 25–30 nucleotides are required for inhibition of the antibody to ss-DNA. Other studies also demonstrated that anti-ss-DNA (O-8) antibody and anti-double-stranded (ds) DNA (NE-28) antibody bound to different combining sites in the same polynucleotides, poly(dT). These results suggest that some anti-ss-DNA antibodies are directed to the conformational structure related to the base sequence and that nucleic acids, therefore, might be responsible for the possible immunogenic stimulus causing the anti-DNA immune response. We also indicate that this type of antibody would be popular among serum anti-DNA antibodies in SLE.     

The autoantibody profile and its association with clinical manifestations in Malay SLE patients

A cross sectional study was conducted to determine the auto-antibody profile of Malay SLE patients in Kelantan, North East Malaysia and to correlate them with clinical presentations. Eighty-two Malay SLE patients who fulfilled the ARA criteria underwent the following tests: ANA, anti-dsDNA antibody, anti-ENA antibody and RF. The results revealed that ANA was positive in 91.5% of the patients, anti-dsDNA antibody in 53.7%, however, anti-ENA antibodies were positive in only 9.8% of the cases at the time of the study and none had a positive RF. The profile of autoantibodies was similar to other studies except for a lower incidence of anti-ENA antibodies. Sixty three percent of patients had lupus nephritis. The pattern of clinical presentations were noted to be more similar to those found among Chinese and Indian SLE populations than compared to the Caucasians. There was a significant association between anti-dsDNA antibody and lupus nephritis and between anti-ENA antibody and thrombocytopenia.