Differentiation of RNP- and SM-antibody subsets in SLE and MCTD patients by a new ELISA using recombinant antigens.

Connective tissue diseases often have overlapping clinical features and laboratory abnormalities. The distinctiveness of mixed connective tissue disease (MCTD) as an entity is of scientific interest and practical importance. In order to discriminate between MCTD and SLE patients we used a newly developed, commercially not available ELISA with recombinant antigen expressed in Baculovirus infected cells. This ELISA detects antibodies against RNP and Sm in complex as well as the subsets U1-snRNP 68 kDa, RNP-A, RNP-C (RNP), Sm-BB' and SS-D. We analyzed 66 RNP-positive consecutive patients prediagnosed as SLE or MCTD/overlap-syndrome. 45/66 patients were found to be U1-snRNP-68 kDa positive (27 SLE, 18 MCTD), 51/66 RNP-A [36,15] and 44/66 RNP-C [31,13]. 35/66 had antibodies against Sm-BB' (30 SLE, 5 MCTD), 10/66 against Sm-D (all SLE). 28/66 were found to be U1-snRNP-68 kDa and Sm-BB' positive (23 SLE, 5 MCTD), while 8/66 where U1-snRNP-68 kDa and Sm-D positive (all SLE). The combination of antibodies against 68 kDa, Aand C was exclusively observed in 6 MCTD patients, while the combination against 68 kDa, A, C, Sm-BB' and Sm-D was restricted to 8 patients with SLE. The antibody combination to 68 kDa, A, C and Sm-BB' was also found in 11/20 SLE patients with major organ involvement. In SLE and MCTD, determination of subsets of antibodies against Ul-snRNP-68 kDa and Sm-complex allows a differentiation of patient subgroups with more definite diagnoses and potential prognostic impact.     

Antibodies to hnRNP core protein A1 in connective tissue diseases

We investigated the specificity of circulating autoantibodies to a heterogeneous nuclear ribonuclear protein A1 (hnRNP A1), obtained by recombinant DNA technique, in different rheumatic diseases: systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), scleroderma, primary Sjogren's syndrome (SS), idiopathic Raynaud (IR), mixed connective tissue disease (MCTD), and healthy donors. All sera were tested by ELISA on hnRNP A1 protein. Positive values were obtained in 22% SLE, 19% scleroderma, 10% IR, 40% (2/5) MCTD, 5% SS, and 50% RA patients. The majority of patients reacted with the aminoterminal part (UP1) of hnRNP A1; however, some RA patients reacted also with the carboxy-terminal part that shows partial homology with keratin. Therefore, hnRNP A1 (UP1) can be considered a target of antinuclear autoimmunity in various rheumatic disorders.     

Clinical and immunological aspects of autoantibodies to RA33/hnRNP-A/B proteins — A link between RA,SLE and MCTD

Heterogeneous nuclear ribonucleoprotein (hnRNP) complexes are major constituents of the spliceosome. They are composed of approximately 30 different proteins which can bind to nascent pre-mRNA. Among these, the hnRNP-A/B proteins form a subgroup of highly related proteins consisting of two adjacent RNA binding domains (RBD) within the N-terminal parts, whereas the C-terminal halves contain almost 50% glycine residues. These proteins, in particular A2/RA33, are targeted by autoantibodies from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD). In SLE anti-hnRNP antibodies frequently occur together with antibodies to U1 small nuclear RNP (U1-snRNP) and Sm, other proteins of the spliceosome. Preliminary epitope mapping studies have revealed major antibody binding sites in the RNA binding regions for all three diseases. Nevertheless, there is some indication of disease specific epitope recognition. Studies in animal models have demonstrated anti-RA33/hnRNP-A/B antibodies in lupus-prone mouse strains.Thus, autoantibodies to the spliceosomal hnRNP-A/B proteins are a common feature of RA, SLE, and MCTD. However, these diseases differ in their reactivities to other spliceosomal proteins, especially anti-U1 snRNP and Sm. Therefore, anti-RA33/hnRNP-A/B autoantibodies are not only valuable diagnostic markers but may also allow additional insights into the pathogenesis of rheumatic autoimmune diseases.Abbreviations AS ankylosing spondylitis - hnRNP heterogeneous nuclear ribonucleoprotein - MCTD mixed connective tissue disease - PSA psoriatic arthropathy - RA rheumatoid arthritis - RBD RNA binding domain - SLE systemic lupus erythematosus - snRNP small nuclear ribonucleoprotein     

Seroprevalence of Helicobacter pylori Infection in Patients with Connective Tissue Diseases

To assess the possibility that Helicobacter pylori might be an etiologic agent, titers of anti-H. pylori IgG in sera of patients with connective tissue diseases [rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), polymyositis or dermatomyositis (PM/DM), progressive systemic sclerosis (PSS), mixed connective tissue disease (MCTD) and Sjögren's syndrome (SjS)] were compared with those of non-patient (healthy) volunteers and of patients with chronic pulmonary diseases (CPD) by ELISA using an extract of sonicated H. pylori as the antigen. Among patients with connective tissue diseases, those with SLE and RA had anti-H. pylori titers as low as healthy volunteers. Patients with SjS had much higher average titers than patients with CPD (P<0.05). We previously reported that levels of myeloid calcium-binding protein (MRP8 and MRP14) were elevated in the serum of patients with connective tissue diseases. No correlation was found between serum levels of anti-H. pylori IgG and of MRP, a novel marker of inflammation. Furthermore, sera with high IgG titers were selected, and their reactivity with the H. pylori antigen were analyzed by Western blotting. H. pylori antigens with a variety of molecular masses were immunostained with sera from patients and from healthy volunteers, but a 16-kDa antigen was only immunostained by reaction with the sera of patients with MCTD and SjS, although the number of test samples was small.     

Clinical relevance of autoantibodies in systemic rheumatic diseases

Autoantibodies directed to intracellular antigens are serological hallmarks of systemic rheumatic diseases. Identification of circulating autoantibodies is helpful in establishing the correct diagnosis, indicating the prognosis and providing a guide to treatment and follow-up. Some autoantibodies are included in diagnostic and classification criteria for diseases such as anti-Sm antigen and anti-double-stranded DNA antibodies in systemic lupus erythematosus, anti-U1 nuclear ribonucleoprotein antibodies in mixed connective tissue disease, and anti-SS-A/Ro and anti-SS-B/La antibodies in Sjögren's syndrome. Over the past 30 years, the identification of new autoantibody systems was advanced by the initiation or adaptation of novel techniques such as double immunodiffusion to detect antibodies to saline-soluble nuclear antigens, extraction-reconstitution and ELISA techniques to detect histone and chromatin antibodies, immunoblotting and immunoprecipitation to detect a wide range of antibodies directed against naturally occurring and recombinant proteins. These techniques have been made possible by advances in cellular and molecular biology and in turn, the sera from index patients have been important reagents to identify novel intracellular macromolecules. This paper will focus on the clinical relevance of several autoantibody systems described by Tan and his colleagues over the past 30 years.Abbreviations ANA antinuclear antibody - CENPs centromere proteins - CTD connective tissue disease - DIA drug-induced autoimmunity - DIL drug-induced lupus - HIV human immunodeficiency virus - IIF indirect immunofluorescence - JCA juvenile chronic arthritis - MCTD mixed connective tissue disease - MSA mitotic spindle apparatus - NOR nucleolar organizer - NuMA nuclear mitosis antigen - PBC primary biliary cirrhosis - PCNA proliferating cell nuclear antigen - PM polymyositis - RA rheumatoid arthritis - RNP ribonucleoprotein - SLE systemic lupus erythematosus - SS Sjögren's syndrome - SSc systemic sclerosis - UCTD undifferentiated connective tissue disease     

A diepitopic sequential oligopeptide carrier (SOCn) as mimic of the sm autoantigen: synthesis, conformation and biological assays.

Anti-Sm (Sm: U1-U6 RNA-protein complex) antibodies are usually considered highly specific for systemic lupus erythematosus (SLE), while anti-U1RNP (U1RNP: U1RNA-protein complex) are thought of as diagnostic criteria for the mixed connective tissue disease (MCTD). However, both antibody specificities coexist in SLE and MCTD, in varying percentages. Although the anti-Sm/anti-U1RNP immunological cross-reactivity has been initially attributed to a common motif, PPXY(Z)PP (where X, Y, Z are various amino acids), found in the Sm, U1-A and U1-C autoantigens, it appears that the conformational features of the Sm epitopes also play an important role in the immunoreactivity. The PPGMRPP and PPGIRGP main epitopes of the Sm antigen were coupled in duplicate to the tetrameric Ac-(Lys-Aib-Gly)4-OH, SOC4, carrier to form the [(PPGMRPP)2, (PPGIRGP)2]-SOC4 construct as a mimic of the native Sm. It was found that: (i) the 3(10) helical structure of SOC4 allows the epitopes to adopt an exposed orientation, similar to their free forms, that facilitates their recognition from the anti-Sm antibodies, and (ii) the U1-RNP cross-reactivity is minimized.     

Antibodies from patients with mixed connective tissue disease react with heterogeneous nuclear ribonucleoprotein or ribonucleic acid (hnRNP/RNA) of the nuclear matrix

The sera of patients with mixed connective tissue disease (MCTD) have high titers of antibodies directed against nuclear U1-ribonucleoprotein (U1-RNP). This antigen is easily extracted from nuclear preparations with physiologic saline and from tissue sections with 0.1 HCl, leaving the nucleic acids and nuclear matrix behind. When U1-RNP is extracted from HEp-2 cells with 0.1 N HCl, the sera of 32/32 patients with MCTD react with another antigen that is exposed by the extraction procedure. This antigen is not destroyed by trypsin and deoxyribonuclease 1 treatment but is sensitive to both purified ribonuclease A and purified micrococcal nuclease. Absorption studies showed that the antibody reacting with this antigen cannot be absorbed by sheep red blood cells coated with extracts of rabbit thymus that contain U1-RNP. Radioimmunoassay showed that the reaction of the unadsorbed antibody was with heterogeneous nuclear ribonucleoprotein or ribonucleic acid (hnRNP/RNA) and not with transfer RNA or ribosomal RNA. The hnRNP/RNA antigen is demonstrated as discrete particles in the internucleolar chromatin of interphase cells, but in metaphase cells the antigen is diffusely dispersed. The distribution, solubility, and biochemical characteristics suggest that the antigenic moiety is part of the nuclear matrix. Therefore, MCTD sera contain antibodies that react with at least two species of nuclear RNP: small nuclear RNP (snRNP), as described by others, and a high m.w. hnRNP/RNA bound to the nuclear matrix.     

Titer and specificity of autoantibody to beta 2-microglobulin in sera from patients with rheumatic disease.

Sera from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD) possessed higher titer of antibody to human β₂-microglobulin (β₂m) than those from healthy controls and patients with Behçet's disease in the enzyme-linked immunosorbent assay. It was also confirmed by the immunoprecipitation method. Anti-β₂m antibody in sera from those patients immunoprecipitated free β₂m but not β₂m in association with major histocompatibility complex class I antigen heavy chain. It was suggested that anti-β₂m antibody in sera from either patients or healthy controls might be directed mainly against free β₂m. The relationship between the anti-β₂m antibody and anti-lymphocytotoxic antibody found in those patients is discussed.     

Sister-chromatid exchange frequencies in lymphocytes of controls and patients with connective tissue diseases

It has been considered by some workers that sister-chromatid exchange (SCE) frequencies are elevated in patients with scleroderma and systemic lupus erythematosus (SLE). However, these observations were based on limited numbers of patients. Other have postulated the presence of a defect in DNA repair in cells from patients with various connective tissue diseases, including scleroderma and SLE. We report our findings from a large survey of SCE frequencies in patients with connective tissue diseases. Their diagnoses are scleroderma, SLE, rheumatoid arthritis, juvenile chronic arthritis, Behcet's syndrome and polyarteritis nodosa. These patients had never received cytotoxic drugs. Healthy individuals, hospital patients with diagnoses other than connective tissue disease and relatives of patients with scleroderma have been used as controls. The results have been analysed by generalized linear modelling, and we have shown that patients with SLE and Behcet's syndrome and controls with viral infections have elevated SCE frequencies, both before and after adjustments have been made for the effect on SCEs of an individual's age, smoking habits, sex and race. The SCEs of patients with scleroderma and their relatives were normal. SCE frequencies increased with age by 4% per decade and the SCE frequencies of smokers were approximately 12% higher than those of nonsmokers of similar age. The sex of an individual did not significantly affect SCEs but individuals from the Middle East were found to have lower counts than those originating from other parts of the world.     

Defective expression and function of the leukocyte associated Ig-like receptor 1 in B lymphocytes from systemic lupus erythematosus patients

Systemic lupus erythematosus (SLE) is characterized by the production of a wide array of autoantibodies and dysregulation of B cell function. The leukocyte associated Immunoglobulin (Ig)-like receptor (LAIR)1 is a transmembrane molecule belonging to Ig superfamily which binds to different types of collagen. Herein, we have determined the expression and function of LAIR1 on B lymphocyte from SLE patients. LAIR1 expression in peripheral blood B lymphocytes from 54 SLE, 24 mixed connective tissue disease (MCTD), 20 systemic sclerosis (SSc) patients, 14 rheumatoid arthritis (RA) and 40 sex and age matched healthy donors (HD) have been analyzed by immunofluorescence. The effect of LAIR1 ligation by specific monoclonal antibodies, collagen or collagen producing mesenchymal stromal cells from reactive lymph nodes or bone marrow on Ig production by pokeweed mitogen and B cell receptor (BCR)-mediated NF-kB activation was assessed by ELISA and TransAM assay. The percentage of CD20(+) B lymphocytes lacking or showing reduced expression of LAIR1 was markedly increased in SLE and MCTD but not in SSc or RA patients compared to HD. The downregulation of LAIR1 expression was not dependent on corticosteroid therapy. Interestingly, LAIR1 engagement by collagen or collagen-producing mesenchymal stromal cells in SLE patients with low LAIR1 expression on B cells delivered a lower inhibiting signal on Ig production. In addition, NF-kB p65 subunit activation upon BCR and LAIR1 co-engagement was less inhibited in SLE patients than in HD. Our findings indicate defective LAIR1 expression and function in SLE B lymphocytes, possible contributing to an altered control of B lymphocytes behavior.     

Autoantibodies specific for apoptotic U1-70K are superior serological markers for mixed connective tissue disease

Modifications occurring on autoantigens during cell death have been proposed to have a role in the initiation of autoimmune diseases. Patients suffering from mixed connective tissue disease (MCTD) produce autoantibodies directed to U1 small nuclear ribonucleoprotein (snRNP), and antibodies against a 70 kDa protein component, the U1-70K (70K) protein, are the most prominent. During apoptosis, 70K is cleaved by caspase-3 to a 40 kDa product, which remains associated with the complex. Autoantibodies preferentially recognizing the apoptotic form of 70K have been described previously, and an apoptosis-specific epitope on 70K has been identified. This study shows that 29 of 53 (54%) MCTD sera preferentially recognize the apoptotic form of 70K over intact 70K. Moreover, we show that antibodies directed to an apoptosis-specific epitope on 70K are more specifically associated with MCTD than other anti-70K antibodies, suggesting that apoptotic 70K is a better antigen for the detection of these antibodies in MCTD patients. Longitudinal analysis of 12 MCTD patients showed in several patients that early sera are relatively enriched with antibodies recognizing an apoptosis-specific epitope, and that the levels of these apoptosis-specific antibodies decrease in time. These findings indicate that the early detection of apoptotic 70K is of considerable interest for anti-U1 snRNP-positive patients.     

Prevalence of HSP47 antigen and autoantibodies to HSP47 in the sera of patients with mixed connective tissue disease

The 47-kDa heat shock protein (HSP47) is an endoplasmic reticulum molecular chaperone that assists in the maturation of collagen molecules and whose expression is known to be upregulated in lesions of fibrotic diseases. We examined the levels of HSP47 protein and autoantibodies to HSP47 in the sera of patients with rheumatic autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, Sj?gren's syndrome, and mixed connective tissue disease (MCTD) by enzyme-linked immunosorbent assay and immunoblot analysis. Patients with idiopathic pulmonary fibrosis (IPF) were assessed as an example of non-autoimmune fibrotic disease. HSP47 antigen and autoantibody levels are significantly elevated in the sera of the rheumatic autoimmune disease patients, but not in the sera of the IPF patients. The sera of the MCTD patients showed particularly high levels of HSP47 antigen relative to healthy controls (1.99+/-0.22 vs 0.41+/-0.07 ng/ml). Autoantibodies to HSP47 were also in high levels in the sera of MCTD patients. These results suggest that simultaneous occurrence of systemic inflammation and upregulation of HSP47 caused leakage of HSP47 from fibrotic lesions into the peripheral blood, and the leaked antigen induced high titer of autoantibodies to HSP47. The high levels of HSP47 antigen and autoantibody may be useful blood markers of MCTD.     

Study of antibodies to heterologous connective tissue, isolated from sera of patients with rheumatism]

Antibodies against connective tissue elements of various bovine organs were isolated from the sera of rheumatic fever patients with the aid of immunosorbents (bovine connective tissue extract and erythrocyte stroma). The antibody preparations obtained were not identical and contained antibodies against different antigens of bovine connective tissue. The antibody preparations failed to react with human connective tissue components.     

Association of pre-microRNAs genetic variants with susceptibility in systemic lupus erythematosus

MicroRNAs (miRNAs) may play important roles in SLE, but genetic polymorphisms of miRNAs and their relationships with various autoantibodies present in SLE patients remain unclear. Here, we report that 213 SLE patients and 209 healthy individuals of Chinese had been taken into this case–control studies, which had been performed by selecting two miRNAs (hsa-mir-146a rs2910164 G>C, and hsa-mir-499 rs3746444 T>C) to analyze the genetic polymorphisms. The single nucleotide polymorphism (SNP) variants had been analyzed by PCR–RFLP and serum anti-ribonucleoprotein (anti-RNP), anti-Sm nuclear antigen (anti-Sm) antibodies had been determined by an anti-ENA kit and serum anti-double-stranded DNA (anti-dsDNA) antibodies had been assessed by indirect immunofluorescence. We found that hsa-mir-146a rs2910164 and hsa-mir-499 rs3746444 polymorphisms had no significant relationship with SLE susceptibility. The genotype frequencies of rs2910164 (GG, CC, and GC) were 16, 37, and 47% in SLE patients, but 11, 39, and 50% in healthy group (P = 0.397), respectively; The genotype frequencies of rs3746444 (CC, TT, and TC) were 3, 74, and 23% in SLE patients, but 3, 76, and 22% in healthy group (P = 0.892), respectively. The G and C allele frequencies of rs2910164 were 39 and 61% in SLE patients, but 36 and 64% in healthy group (P = 0.990), respectively. The C and T allele frequencies of rs3746444 were 15 and 85% in SLE patients, but 14 and 86% in healthy group (P = 0.702), respectively. In addition, we also showed no significant difference in the distribution of rs2910164 and rs3746444 genotypes in each of the three antibodies (anti-RNP, anti-Sm, and anti-dsDNA).     

Persistence of influenza serum antibodies in humans following immunization with a bivalent A/Victoria and A/New Jersey vaccine.

The persistence of serum antibodies 1 year after immunization with a bivalent vaccine containing recombinant viruses that were antigenically identical with A/Victoria/3/75 (H3N2) and A/New Jersey/8/76 (Hsw1N1) viruses was measured in 128 persons aged 18 to 65 years. Serum samples were tested with the hemagglutination inhibition assay against the two vaccine antigens and against A/Texas/1/77 (H3N2) and A/USSR/90/77 (H1N1) viruses. Prior to vaccination 56% and 79% of the participants had been found to be seronegative to A/Victoria and A/New Jersey antigens respectively; the geometric mean antibody titres were low (1:5 to 1:11) except in persons aged 51 to 65 years, whose mean titre of antibody to the A/New Jersey antigen was 1:23, and persons aged 26 to 35 years, whose mean titre of antibody to the A/USSR antigen was 1:25. By 3 weeks after vaccination 85% of the seronegative persons had a fourfold or greater rise in titres of antibodies to the viruses in the vaccine, and 70% had a fourfold increase in titre of antibody to the A/Texas antigen. Of the persons aged 26 to 35 years (seronegative and seropositive) 68% had a fourfold or greater increase in titre of antibody to the A/USSR antigen. There was no change in the mean titres of 19 unvaccinated control subjects during the observation period. At 6 and 12 months after vaccination the titres of antibodies to the A/Victoria and A/New Jersey antigens had declined moderately in all age groups from those observed 3 weeks after vaccination. The rate of decline was similar for the various antibodies except that to the A/USSR antigen in persons 26 to 35 years of age, in whom the decline was much slower.     

The reaction of SLE antibodies with native, single stranded RNA: radioassay and binding specificities.

Escherichia coli 3H-tRNA and MS2 phage 125I-RNA were prepared and used in a sensitive nitrocellulose filter assay. Antibodies that bound these RNA ligands occurred in the sera of several patients with SLE, but not in sera of patients with other connective tissue diseases. The antibody populations that bound polyribonucleotides (largely IgG) were distinct from antibody populations that bound polydeoxyribonucleotides. Competition experiments showed that the anti-RNA antibodies preferentially bound native ssRNA as compared with synthetic single and double stranded polyribonucleotides. There was increasing affinity with increasing m.w. of the ssRNA. The anti-tRNA population was of restricted heterogeneity (Sips index 0.83) and bound tRNA with an average association constant (Ko) of 9 x 10(6) l/mole at 4 degrees C. The anti-MS2 RNA population was much more heterogeneous (Sips index 0.67) and bound MS2 RNA with a Ko of about 3 x 10(9) l/mole at 4 degrees C. Whereas NZB/NZW mice spontaneously produce RNA reactive antibodies with conformation specificity for native tRNA, human SLE anti-RNA antibodies appear to have very little of this type of conformation specificity.     

Mixed connective tissue disease. A clinico-serological study of 17 cases

Mixed connective tissue disease (MCTD) was described as a distinct clinical syndrome in 1972. Since then many cases have been reported in the literature worldwide. In this study we present our experience with a group of 17 Mexican patients with this syndrome, and we analyze their clinical and serological features, as well as the causes of death in these patients. The patients are Mexican mestizos living in Guadalajara and most of them have been followed-up at Hospital General de Occidente for a period of 1–10 years. The female/male ratio was 16:1, and their age ranged from 14–55 years with a mean of 29 years. The disease duration has ranged from 1–17 years, with a mean of 6 years. Among the clinical manifestations we have found a high frequency of lymphadenopathy when compared with published series (13/17 or 76%), and the laboratory findings in our patients included a very high polyclonal increase of gammaglobulins (93%), lymphopenia (76%), direct immunofluorescence speckled nuclear epidermal deposits in skin biopsies (75%) and positive rheumatoid factor (65%). Other clinical and serological features were similar to those reported in other series of patients with MCTD. Six of the 17 patients have died (35%), and in 3 of them (17.5%) the cause of death was due to an infectious disease that suddenly presented, and apparently was not related to a concomitant high dose of steroids or malnutrition in the patients. It seems that in addition to the already well known autoimmune abnormalities that occur in MCTD, there are other features like the presence of lymphadenopathy, the high polyclonal increase of gammaglobulins, and the lymphopenia, that reflect the profound disturbance of the immune system in this syndrome, possibly contributing to the sudden appearance of a severe infectious disease in some of our patients.Abbreviations ANA antinuclear antibody - CIE counterimmunoelectrophoresis - MCTD mixed connective tissue disease - PHA passive hemagglutination - PM polymyositis - RF rheumatoid factor - SLE systemic lupus erythematosus - SS systemic sclerosis (SS)     

多肽抗体谱免疫印迹法检测ENA抗体的临床应用

本文报道应用多肽抗体谱印迹法检测风湿性疾病患者的ＥＮＡ抗体,该法一次可检测７种抗体。应用本法检测ＳＬＥ８５例,其Ｓｍ抗体阳性率为２０．０％,ｕ１－ＲＮＰ抗体为４１．１％,ＳＳ－Ａ抗体为１０．５％ＳＳ－Ｂ抗体为３．５％,抗核糖体为７．０％。检测ＤＬＥ６例,其山ｕ１－ＲＮＰ抗体阳性率为３３．０％。检测ＰＭ／ＤＭ１５例,其ｕ１－ＲＮＰ抗体阳性率为１３．０％,Ｊｏ－１抗体为１４．０％。检测ＲＡ４８例,其ｕ１－ＲＮＰ抗体的阳性率为３３．３％。检测ＳＳ２１例,其ＳＳ－Ａ抗体阳性率为４３．０％,ＳＳ－Ｂ抗体为３８．０％,检测ＰＳＳ９例,其Ｓｃｌ－７０抗体阳性率为２２．０％。检测ＭＣＴＤ１０例,其ｕ１－ＲＮＰ抗体阳性率为５０．０％。健康人对照１００例,７种抗体均为阴性。显示应用多肽抗体谱印迹法检测结果与国内其它方法所测得结果基本一致,但可检测的抗体种类多于其它方法。     

Characterization of mouse and human monoclonal antibodies cross-reactive with SLE serum antibodies to guanosine

Two new monoclonal antibodies, one a mouse IgM and the other a human IgM that reacted with guanosine, were compared to human serum antibodies from patients with systemic lupus erythematosus (SLE). The human monoclonal antibody was polyspecific in its binding to the nucleoside bases, whereas the mouse monoclonal antibody was relatively specific for guanosine when compared by using an enzyme-linked immunosorbent assay (ELISA). Neither antibody bound polyguanylic acid or denatured single-stranded (ss) DNA, however. Serum IgG antibodies from seven patients with SLE cross-reacted with the mouse monoclonal antibody and showed considerable specificity for guanosine. In contrast, the human serum IgG antiguanosine antibodies also bound ssDNA but not dsDNA or polyguanylic acid. Serum IgG antibodies to guanosine measured by ELISA from the seven SLE patients had a decreased response when compared to the total serum IgG response to ssDNA, and most of the antibodies that bound guanosine also bound ssDNA. These studies provide new evidence that there are specific IgG antibodies to guanosine in SLE sera that are a small fraction of the antibodies to ssDNA. Further efforts to define the role of these guanosine antibodies in SLE may provide a better understanding of the basic mechanisms responsible for the development of SLE in man.     

Anti-RNP monoclonal antibodies derived from a mouse strain with lupus-like autoimmunity

systemic lupus erythematosus (SLE) and related rheumatic and connective-tissue diseases are often associated with the production of antibodies directed against a variety of specific cellular components. Recent evidence indicates that two such autoantigens, the Sm and RNP antigens recognized by SLE sera, exist in small ribonucleoprotein complexes found in the nuclei of higher eukaryotes. Studies of the structure and function of these autoantigenic particles with human sera used as probes have been limited because of the multiplicity of autoantibodies often found in an individual serum. Through this communication, we report that MRL/Mp-+/+ (MRL/n) mice, which spontaneously develop a disease exhibiting many of the characteristics of human SLE, possess anti-RNP antibodies in addition to anti-Sm and anti-DNA as previously reported. Spleen cells from one such autoimmune mouse were used to produce a stable hybridoma secreting antibodies that react simultaneously with a protein of Mr 40,000 and a doublet of approximately 70,000, a pattern of reactivity identical to and characteristic of human SLE anti-RNP autoantibodies.