Antibodies to ribonucleic acid in systemic lupus erythematosus

Visualization of RNA virus infection in a marine protist with a universal biomarker

Half of the marine virosphere is hypothesized to be RNA viruses (kingdom Orthornavirae) that infect abundant micro-eukaryotic hosts (e.g. protists). To test this, quantitative approaches that broadly track infections in situ are needed. Here, we describe a technique-dsRNA-Immunofluorescence (dsRIF)-that uses a double-stranded RNA (dsRNA) targeting monoclonal antibody to assess host infection status based on the presence of dsRNA, a replicative intermediate of all Orthornavirae infections. We show that the dinoflagellate Heterocapsa circularisquama produces dsRIF signal ~ 1000 times above background autofluorescence when infected by the + ssRNA virus HcRNAV. dsRNA-positive virocells were detected across > 50% of the 48-h infection cycle and accumulated to represent at least 63% of the population. Photosynthetic and chromosomal integrity remained intact during peak replication, indicating HcRNAV infection does not interrupt these processes. This work validates the use of dsRIF on marine RNA viruses and their hosts, setting the stage for quantitative environmental applications that will accelerate understanding of virus-driven ecosystem impacts.

Immune Response to Enterococcus gallinarum in Lupus Patients Is Associated With a Subset of Lupus-Associated Autoantibodies

Interactions between gut microbes and the immune system influence autoimmune disorders like systemic lupus erythematosus (SLE). Recently, Enterococcus gallinarum, a gram-positive commensal gut bacterium, was implicated as a candidate pathobiont in SLE. The present study was undertaken to evaluate the influence of E. gallinarum exposure on clinical parameters of SLE. Since circulating IgG antibodies to whole bacteria have been established as a surrogate marker for bacterial exposure, anti-E. gallinarum IgG antibodies were measured in banked serum samples from SLE patients and healthy controls in the Oklahoma Cohort for Rheumatic Diseases. The associations between anti-E. gallinarum antibody titers and clinical indicators of lupus were studied. Antibodies to human RNA were studied in a subset of patients. Our results show that sera from both patients and healthy controls had IgG and IgA antibodies reactive with E. gallinarum. The antibody titers between the two groups were not different. However, SLE patients with Ribosomal P autoantibodies had higher anti-E. gallinarum IgG titers compared to healthy controls. In addition to anti-Ribosomal P, higher anti-E. gallinarum titers were also significantly associated with the presence of anti-dsDNA and anti-Sm autoantibodies. In the subset of patients with anti-Ribosomal P and anti-dsDNA, the anti-E. gallinarum titers correlated significantly with antibodies to human RNA. Our data show that both healthy individuals and SLE patients were sero-reactive to E. gallinarum. In SLE patients, the immune response to E. gallinarum was associated with antibody response to a specific subset of lupus autoantigens. These findings provide additional evidence that E. gallinarum may be a pathobiont for SLE in susceptible individuals.

Mitochondria Autoimmunity and MNRR1 in Breast Carcinogenesis: A Review

We review here the evidence for participation of mitochondrial autoimmunity in BC inception and progression and propose a new paradigm that may challenge the prevailing thinking in oncogenesis by suggesting that mitochondrial autoimmunity is a major contributor to breast carcinogenesis and probably to the inception and progression of other solid tumors. It has been shown that MNRR1 mediated mitochondrial-nuclear function promotes BC cell growth and migration and the development of metastasis and constitutes a proof of concept supporting the participation of mitochondrial autoimmunity in breast carcinogenesis. The resemblance of the autoantibody profile in BC detected by IFA with that in the rheumatic autoimmune diseases suggested that studies on the autoantibody response to tumor associated antigens and the characterization of the mtDNA- and nDNA-encoded antigens may provide functional data on breast carcinogenesis. We also review the studies supporting the view that a panel of autoreactive nDNA-encoded mitochondrial antigens in addition to MNRR1 may be involved in breast carcinogenesis. These include GAPDH, PKM2, GSTP1, SPATA5, MFF, ncRNA PINK1-AS/DDOST as probably contributing to BC progression and metastases and the evidence suggesting that DDX21 orchestrates a complex signaling network with participation of JUND and ATF3 driving chronic inflammation and breast tumorigenesis. We suggest that the widespread autoreactivity of mtDNA- and nDNA-encoded mitochondrial proteins found in BC sera may be the reflection of autoimmunity triggered by mitochondrial and non-mitochondrial tumor associated antigens involved in multiple tumorigenic pathways. Furthermore, we suggest that mitochondrial proteins may contribute to mitochondrial dysfunction in BC even if mitochondrial respiration is found to be within normal limits. However, although the studies show that mitochondrial autoimmunity is a major factor in breast cancer inception and progression, it is not the only factor since there is a multiplex autoantibody profile targeting centrosome and stem cell antigens as well as anti-idiotypic antibodies, revealing the complex signaling network involved in breast carcinogenesis. In summary, the studies reviewed here open new, unexpected therapeutic avenues for cancer prevention and treatment of patients with cancer derived from an entirely new perspective of breast carcinogenesis.

Neuronal BC RNA Transport Impairments Caused by Systemic Lupus Erythematosus Autoantibodies

The etiology of the autoimmune disorder systemic lupus erythematosus (SLE) remains poorly understood. In neuropsychiatric SLE (NPSLE), autoimmune responses against neural self-antigens find expression in neurological and cognitive alterations. SLE autoantibodies often target nucleic acids, including RNAs and specifically RNA domains with higher-order structural content. We report that autoantibodies directed against neuronal regulatory brain cytoplasmic (BC) RNAs were generated in a subset of SLE patients. By contrast, anti-BC RNA autoantibodies (anti-BC abs) were not detected in sera from patients with autoimmune diseases other than SLE (e.g., rheumatoid arthritis or multiple sclerosis) or in sera from healthy subjects with no evidence of disease. SLE anti-BC abs belong to the IgG class of immunoglobulins and target both primate BC200 RNA and rodent BC1 RNA. They are specifically directed at architectural motifs in BC RNA 5' stem-loop domains that serve as dendritic targeting elements (DTEs). SLE anti-BC abs effectively compete with RNA transport factor heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) for DTE access and significantly diminish BC RNA delivery to synapto-dendritic sites of function. In vivo experiments with male BALB/c mice indicate that, upon lipopolysaccharide-induced opening of the blood-brain barrier, SLE anti-BC abs are taken up by CNS neurons where they significantly impede localization of endogenous BC1 RNA to synapto-dendritic domains. Lack of BC1 RNA causes phenotypic abnormalities including epileptogenic responses and cognitive dysfunction. The combined data indicate a role for anti-BC RNA autoimmunity in SLE and its neuropsychiatric manifestations.SIGNIFICANCE STATEMENT Although clinical manifestations of neuropsychiatric lupus are well recognized, the underlying molecular-cellular alterations have been difficult to determine. We report that sera of a subset of lupus patients contain autoantibodies directed at regulatory brain cytoplasmic (BC) RNAs. These antibodies, which we call anti-BC abs, target the BC RNA 5' domain noncanonical motif structures that specify dendritic delivery. Lupus anti-BC abs effectively compete with RNA transport factor heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) for access to BC RNAs. As a result, hnRNP A2 is displaced, and BC RNAs are impaired in their ability to reach synapto-dendritic sites of function. The results reveal an unexpected link between BC RNA autoantibody recognition and dendritic RNA targeting. Cellular RNA dysregulation may thus be a contributing factor in the pathogenesis of neuropsychiatric lupus.

Is Tolerance Broken in Autoimmunity?

Autoimmune diseases are classified into about 80 different types based on their specificity related to system, organ and/or tissue. About 5% of the western population is affected by this anomaly, but its worldwide incidence is unknown. Autoimmune diseases are heterogeneous in nature and clinical manifestations range from benign disorders to life-threatening conditions. Autoimmunity strikes at any stage of life, but age and/or gender also play role in onset of some of these anomalies. The autoimmune pathogenesis is initiated by the origination of autoantigens, which leads to the development of autoantibodies followed by auto-immunogenicity and the ultimate onset of autoimmunity. There is a lack of suitable therapies to treat autoimmune diseases, because mechanisms involved in the onset of these anomalies were poorly understood. Present therapies are limited to symptomatic treatment and come with severe side effects. Here, I described the molecular mechanisms and cellular events involved in the initiation of autoimmunity and proposed better strategies to modulate such molecular and cellular anomalies, which will help in preventing and/or controlling autoimmune pathogenesis and ultimately aid in enhancing the quality of life.

Autoantigens as Partners in Initiation and Propagation of Autoimmune Rheumatic Diseases

Systemic autoimmune diseases are characterized by specific targeting of a limited group of ubiquitously expressed autoantigens by the immune system. This review examines the mechanisms underlying their selection as immune targets. Initiation of autoimmune responses likely reflects the presentation of antigens with a distinct structure not previously encountered by the immune system, in a proimmune context (injury, malignancy, or infection). Causes of modified structure include somatic mutation and posttranslational modifications (including citrullination and proteolysis). Many autoantigens are components of multimolecular complexes, and some of the other components may provide adjuvant activity. Propagation of autoimmune responses appears to reflect a bidirectional interaction between the immune response and the target tissues in a mutually reinforcing cycle: Immune effector pathways generate additional autoantigen, which feeds further immune response. We propose that this resonance may be a critical principle underlying disease propagation, with specific autoantigens functioning as the hubs around which amplification occurs.

In Vitro Stimulation of C1s Proteolytic Activities by C1s-Presenting Autoantibodies from Patients with Systemic Lupus Erythematosus

Anti-C1s autoantibodies (IgG forms), which recognize the conjunction of C1s heavy chain and light chain (C1s-presenting autoantibodies) from patients with systemic lupus erythematosus (SLE), have been found to stimulate C1s enzymatic activities. This is due to acceleration of the proteolytic hydrolysis of the synthetic substrate C1-1 by C1s, enhancement of the complex formation of C1s with its natural pseudosubstrate, C1 inhibitor (C1 inh), and promotion of proteolytic activation of its natural substrate, C4. Seven of fifteen samples from patients with SLE were found to contain such autoantibodies. The hydrolysis of the synthetic substrate C1-1 catalyzed by C1s in 25 to 27 min in the presence of anti-C1s autoantibodies was equivalent to the hydrolysis of C1-1 catalyzed by C1s alone or C1s with control IgG from healthy sera in 110 min, approximately fourfold faster than the reaction in the absence of anti-C1s autoantibodies. Densitometry scanning data showed that the formation of the C1s-C1 inh complex in the presence of anti-C1s autoantibodies was three to four times greater than that with control IgG. It was also noticed that the autoantibodies convert almost all of the latent forms of C1s to an active form that binds to C1 inh. Another group of Western blots showed that C1s cleaved C4 α-chain three times faster in the presence of autoantibodies than of control IgG. It is likely that the overconsumption of complement components is common in the pathogenesis of tissue damage occurring in SLE.

Antiribosomal antibodies in SLE, infection, and following deliberate immunization

ARA occur in approximately 10% of randomly selected SLE patients but in up to 40% of patients with active disease. Anti-P antibodies appear to be a highly specific diagnostic marker for SLE since they are rarely detected in other multisystem autoimmune disorders. ARA are most frequently directed against the P proteins and the shared conserved C-terminus of the P proteins is immunodominant in almost all sera tested. Anti-P antibodies increase in titer in patients with active disease and have been reported to be detected more frequently in patients with severe behavioral disturbances. This may be particularly true of patients with affective disorders. The clinical utility of serological tests for anti-P in central nervous system lupus must await large, prospective studies. Other ARA antibodies have been detected in patients with SLE. These antibodies include anti-28S rRNA, anti-S10, and anti-L12. In all cases, the frequency with which these antibodies are detected is increased in sera containing anti-P. The P proteins and the 28S rRNA epitope play essential, but as yet undefined, roles in GTPase activity on the ribosome. The L12 protein is the mammalian homologue of the E. coli and yeast proteins known to bind to the 28S rRNA epitope. These findings indicate that some SLE patients produce autoantibodies against multiple components of a functionally related domain of the ribosome. This, in turn, supports the notion that the ribosome initiates and/or maintains autoantibody production. Despite the evidence supporting an antigen driven immune response, attempts to induce anti-P antibodies by immunization with autologous ribosomes in the autoimmune strain of mouse, MRL, have been unsuccessful. It therefore seems likely that the ribosomal components must be altered in some way to break tolerance or that other abnormalities of the immune system are necessary for autoantibody production. Immunization with foreign ribosomes induce anti-P autoantibodies in mice and in apparently normal humans infected with the hemoflaggelate, T. cruzi. The ability of the P proteins to break tolerance in these situations is, most likely, explained by the provision of a T cell epitope (the foreign P protein) together with the multivalency of the P proteins on the ribosome (which activate autoreactive B cells). We therefore propose (Fig. 5) a two-signal model for autoantibody production similar to that suggested for T-B collaboration in the normal immune response and also in the GVHD model of lupus.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of antibodies to RNA in patients with systemic lupus erythematosus and other autoimmune rheumatic diseases

The frequency and clinical associations of anti-RNA antibodies measured by ELISA were assessed in 138 patients with systemic lupus erythematosus (SLE). Of the sera from these patients 9.4% had anti-RNA antibodies but no distinguishing features, clinical, serological or immunogenetic, between those with or without these antibodies could be identified. However, investigations of patients with other autoimmune rheumatic diseases did not reveal any anti-RNA positivity, which indicates a marked disease specificity for anti-RNA antibodies in SLE. The initial anti-RNA antibody screen used a soluble yeast extract as test antigen. The positive sera were further tested against a range of RNAs from 10 different types of rat tissue. In essence few differences were observed, suggesting that the anti-RNA response is directed against common, highly conserved epitopes.

Lupus antiribosomal P antisera contain antibodies to a small fragment of 28S rRNA located in the proposed ribosomal GTPase center

The ribosomal P proteins are necessary for GTPase activity during protein synthesis. In addition to antibodies to the P proteins, sera from lupus patients contain anti-rRNA activity. To determine whether lupus antiribosomal sera recognize the region of 28S rRNA recently proposed to form part of the ribosomal GTPase center, an rRNA fragment corresponding to nucleotides (nt) 1922-2020 was transcribed in vitro and tested for antigenicity. 18 of 24 (75%) lupus sera containing anti-P antibodies, but only 2 of 24 (8%) lupus sera without anti-P, immunoprecipitated this rRNA fragment (p less than 0.001). The binding was specific, since no significant differences were observed between anti-P positive and negative lupus sera in binding to the RNA fragment transcribed in the antisense orientation or to a control region of rRNA. The majority of sera tested protected a rRNA fragment of approximately 68 nucleotides. To evaluate the fine specificity of the anti-28S antibodies, deletions and site-directed mutations were made in the RNA fragment. The anti-28S antisera required nt 1944-1955 for recognition and were remarkably sensitive to destabilizing as well as nondestabilizing mutations in the stems of the RNA fragments. Detection of antiprotein and anti-RNA antibodies directed against a functionally related domain in the ribosome, together with the remarkable specificity of anti-28S antibodies, strongly suggests a direct role for this region of the ribosome in initiating and/or maintaining antiribosomal autoantibody production.

Disease activity in systemic lupus erythematosus related to a range of antibodies binding DNA and synthetic polynucleotides

Antibodies to dDNA, nDNA, Z-DNA, poly(dT), poly(I), poly(dG.dC), poly(dA.dT), and total IgG and IgM were measured in five serial bleeds from 39 patients with systemic lupus erythematosus (SLE). The main findings were that those patients with renal disease form a distinct subset whose antibody levels correlate well with disease activity; anti-poly(dT) antibodies showed the best overall correlation with disease activity; and discriminant functional analysis demonstrated a major improvement in correlation of disease activity with combinations of antibodies to dDNA/nDNA/Z-DNA/poly(dT) (generally 50% or more were correctly classified) than with dDNA or nDNA alone (generally less than 25% correct). Serum IgG (but not IgM) correlated significantly (p less than 0.01) with six antibodies, suggesting that polyclonal activation plays a part in the development of these antibodies, though antibody cross reactivity is not excluded.

Origins of anti-DNA autoantibodies

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Antibodies to distinct polypeptides of RNA polymerase I in sera from patients with rheumatic autoimmune disease

Sera from patients with rheumatic autoimmune diseases were screened for antibodies directed against RNA polymerase I by using a solid-phase radioimmunoassay. Significant levels of the antibodies were detected in the sera of all patients with either systemic lupus erythematosus or mixed connective tissue disease and in 78% of the individuals with rheumatoid arthritis. No detectable anti-RNA polymerase I antibodies were found in the sera from healthy subjects. Individuals taking hydralazine, three of whom exhibited symptoms of drug-induced lupus, had barely detectable levels of the antibodies. Immunoglobulins obtained from sera containing anti-RNA polymerase I antibodies, as determined by the radioimmunoassay, could inhibit RNA polymerase I activity in vitro. Sera from patients with systemic lupus erythematosus contained immunoglobulins directed against the polymerase I-associated polypeptide of Mr 65,000 as well as against the polypeptides of Mr 120,000 or Mr 25,000, or both. Sera from individuals with rheumatoid arthritis reacted with the polypeptide of Mr 65,000 only. The antibodies in the sera of patients with mixed connective tissue disease were directed against the Mr 42,000 polypeptide or a combination of the Mr 65,000, 42,000, and 25,000 polypeptides. These data suggest that the production of anti-RNA polymerase I antibodies may be a unique characteristic of individuals with rheumatic autoimmune diseases and that the production of antibodies against specific polypeptides of RNA polymerase I may be indicative of the particular class of disease.

Studies on autoantibodies to poly (adenosine diphosphate-ribose) in SLE and other autoimmune diseases

Sera from 41 patients with systemic lupus erythematosus (SLE), 87 controls with various diseases, and 30 normal subjects were examined for poly (adenosine diphosphate-ribose) and ds DNA binding. Elevated levels of poly (ADP-ribose) binding were found in 73% of the SLE patients compared with 58% who had raised ds DNA binding. In a further study of 160 sera from 27 patients with SLE, levels of antipoly (ADP-ribose) antibodies were shown to correlate with clinical activity better than either anti-ds DNA or ss DNA antibodies.

Antibodies from patients with connective tissue diseases bind specific subsets of cellular RNA-protein particles

We characterized the RNA-containing antigens precipitated by sera from 260 patients with positive antinuclear antibodies. 49 individuals, most of whom had systemic lupus erythematosus or Sjögren's syndrome, possessed antibodies that precipitated the previously identified RNP, Sm, Ro, and La antigens either singly or in combinations. These antigens, which are located on discrete sets of small nuclear or cytoplasmic RNA-protein particles, exhibited a number of antigenic interrelationships. One patient's serum recognized a new particle containing a small RNA which we have called Th; it also precipitated the Ro complexes. Other patients with systemic lupus erythematosus, hepatitis B virus infection, juvenile rheumatoid arthritis, myositis, and rheumatoid arthritis had antibodies that precipitated specific subsets of ribosomal RNA and transfer RNA. One patient's serum contained a monoclonal immunoglobulin G that precipitated ribosomes. Most of these antibodies identified antigenic determinants constituted at least in part of protein. The specificity of the proteins bound to particular cellular RNA, probably explains the exquisite precision with which antibodies from rheumatic disease patients discriminate among RNA subsets. Such sera should be useful probes for investigating specific roles that different RNA and RNA-protein complexes play in cellular metabolism.

Antibodies against double-stranded RNA in patients with rheumatoid arthritis, osteoarthrosis and Paget's disease of bone

Using a liquid phase radioimmunoassay to detect antibodies to 3H-labelled double-stranded RNA the premise that rheumatoid arthritis and Paget's disease of the bone may be associated with a chronic virus disease was examined. About 33% of patients with rheumatoid arthritis had antibody levels above the normal range and 11% had antibody levels below the normal range of controls (blood bank donors). The low binding activities were attributed to the action of a nuclease that degraded the dsRNA. Some patients with Paget's disease of bone had higher binding activities than the normal range and similar binding activity was also found in patients with osteoarthrosis. The increase in antibodies to double-stranded RNA did not correlate with increasing age.

Electron microscopy of the reactions of anti-poly A. poly U and anti-poly I. poly C antibodies with synthetic polynucleotide complexes and natural nucleic acids

The reactions between purified anti-poly A. poly U and-poly I. poly C. antibodies (IgG and IgM), and synthetic and natural polynucleotides were visualized at the molecular level. This was achieved by the use of fine tungsten bidirectional shadowing of molecules adsorbed onto thin carbon films, combined with dark field electron microscopic observation. A progression was observed from monogamous multivalency (binding of a single multifunctional antigen molecule with several combining sites of the same antibody molecule simultaneously) (Crothers and Metzger, 1972, Immunochemistry, 9, 341-357), to aggregation. Different types of figures were observed, among which loops formed by the coiling of the antigen around a single IgM molecule were very frequently seen. The tendency of IgG antibodies to bind cooperatively to certain antigens was also noted. In contrast, cross-links were seldom encountered. The cross-reactivity of different polynucleotides was also assessed by a quantitative analysis. The length of antigen associated to an antibody molecule (either IgG or IgM) was also measured.

Demonstration of antibodies against Yersinia enterocolitica lipopolysaccharide in human sera by enzyme-linked immunosorbent assay

Antibodies against Yersinia enterocolitica serotype O:3 lipopolysaccharide present in sera from patients with Yersinia infection were studied by using an enzyme-linked immunosorbent assay. Of the sera with significant bacterial agglutination titers against Y. enterocolitica type O:3, 86% contained anti-lipopolysaccharide antibodies of the immunoglobulin G class. With the sera of some patients, we demonstrated increasing anti-lipopolysaccharide antibody levels of immunoglobulin G class in spite of decreasing bacterial agglutination titers. The assay was specific for lipopolysaccharide from Y. enterocolitica type O:3, and in inhibition experiments lipopolysaccharide could be detected in amounts of greater than or equal to 0.5 micrograms/ml.

The ribonucleic acid (RNA) skin test in systemic lupus erythematosus and other connective tissue diseases

A series of 65 patients with different autoimmune diseases was examined using different RNA-solutions for intradermal skin tests. Clinically positive results were obtained most often in patients with mixed connective tissue disease but quite often also in patients with systemic lupus erythematosus and progressive systemic sclerosis or with some symptoms of an automimmune nature. The histological examination of the biopsies from the test sites revealed that there was no correlation between the clinically positive tests and the histological criteria usually used as a sign of a positive test.

Circulating immune complexes in systemic lupus erythematosus

Sera from twenty-one patients with systemic lupus erythematosus (SLE) were analysed for the presence of circulating soluble immune complexes by a sensitive and quantitative radioimmunoassay employing radioiodinated human Clq (Clq-deviation test). In twenty-five normal individuals the percentage of Clq inhibition was 2-64 +/- 4-45%. Eleven of the SLE patients had significantly elevated values, and the mean value for the group was 20-38 +/- 20-64%. The seven patients with renal disease had somewhat higher levels (24-14 +/- 18-70%) than those without kidney involvement (19-00 +/- 21-84%), and elevated levels of antibodies to native DNA also were associated with high levels of percentage of Clq inhibition. Both intermediate (7S-19S) and large (greater than 19S) complexes were present in the sera, and digestions with DNase and RNase indicated that antibodies to DNA and RNA accounted for only some of them. Serial studies in individual patients demonstrated the assocation of circulating complexes with, and often preceding, falling complement levels during disease activation.

Comparative study of immunologic methods for demonstration of antibodies to soluble nuclear antigens. Immunofluorescence, hemagglutination, complement fixation, and immunodiffusion

Four methods to detect antibodies reactive with soluble nuclear antigens were compared-the fluorescent antibody technique, hemagglutination, complement fixation, and immunodiffusion. Centain advantages and disadvantages of each method are described. The first three methods have greater sensitivity than immunodiffusion, but immunodiffusion discriminates most reliably between different antibodies.

A soluble acidic protein of the cell nucleus which reacts with serum from patients with systemic lupus erythermatosus and Sjögren's syndrome

A soluble nuclear antigen that reacts with sera obtained from patients with systemic lupus erythematosus and Sjögren's syndrome has been described. The antigen, tentatively named the Ha antigen after the prototype serum, was shown to react with specific antibodies by precipitin, complement fixation, and immunofluorescence techniques. The Ha antigen prepared from isolated nuclei of calf thymus glands, calf liver, and rat liver showed identical immunological reactivities; a wide distribution among different species and tissues is presumed. The Ha antigen was destroyed by trypsin and relatively mild heat or pH variation from neutrality, but was resistant to DNase or RNase. Many of these characteristics are similar to those of the "B" antigen to which antibodies have recently been described in Sjögren's syndrome. The nuclear origin of the Ha antigen was confirmed by the speckled nuclear immunofluorescence staining pattern given by purified antibody to Ha obtained from a specific immune precipitate. Preliminary results showed approximately 13% of patients with systemic lupus erythematosus and 30% of patients with Sjögren's syndrome had precipitating antibodies to the Ha antigen.

Immunologic regulation of spontaneous antibodies to DNA and RNA I. Significance of IgM and IgG antibodies in SLE patients and asymptomatic relatives

Nine individuals from four families of patients with systemic lupus erythematosus (SLE) were studied by sucrose density gradient fractionation and filter radioimmunoassay for the presence of 19S IgM and 7S IgG antibodies to DNA, poly rA, and poly rA-poly rU. One individual in each family was totally asymptomatic, and at least one had actively systemic lupus erythematosus (SLE). The results indicate: (1) a correlation between 7S antibody to DNA and RNA and active SLE, and (2) the presence of 19S antibody to RNA in the asymptomatic relatives. These findings suggest that SLE may be a disorder of immunological regulation. The distribution of antibodies between IgM and IgG is closely related to disease severity. the asymptomatic relatives may have a partial regulatory abnormality resulting in the limited production of IgM antibodies to RNA. SLE patients may have a more complex failure of regulation permitting the additional synthesis of IgG antibodies to DNA and RNA.

Clinical studies of antibodies binding polyriboadenylic acid in systemic lupus erythematosus

Antibodies of polyriboadenylic acid (poly rA) are demonstrated by filter radioimmunoassay in 75% of patients with systemic lupus erythematosus (SLE), in 54% of patients with discoid lupus erythematosus, and in only 0-7% of normal controls and patients with rheumatoid arthritis or Sjögren's syndrome. These antibodies are distinct from antibodies to single- and double-stranded DNA and double-stranded RNA. Poly rA binding is associated with IgM and IgG serum fractions. Because poly rA may have a role in the transcription of mRNA in mammalian cells and viruses, antibodies to poly rA may be important clues to virologic and immunogenetic mechanisms in the pathogenesis of SLE.

Anti-nucleic acid antibodies in systemic lupus erythematosus patients and their families. Incidence and correlation with lymphocytotoxic antibodies

Anti-RNA antibodies were found in 82% of 28 systemic lupus erythematosus (SLE) probands and in 16% of 124 of their family members. The incidence in 76 control family members was only 5%. In the SLE family members, the antibodies were found exclusively in 21% of the 94 close household contacts of the probands. The incidence of anti-native DNA (nDNA) antibodies was 68% for the SLE probands. The incidence of anti-nDNA antibodies in close household contacts of the probands was 6%, which was not significantly different from the 1% incidence found in control families. Lymphocytotoxic antibodies occurred in 57% of the SLE family members as a whole and in 68% of the close household contacts. In the SLE probands, lymphocytotoxic antibodies correlated with anti-single-stranded RNA (poly A) and anti-nDNA but not with anti-double-stranded RNA (poly A-poly U). On the other hand, lymphocytotoxic antibodies in the household contacts correlated with anti-double-stranded RNA (poly A-poly U) but not with anti-poly A or anti-nDNA. The anti-RNA antibodies were present in consanguineous household contacts but not in nonconsanguineous household contacts. These findings strengthen the hypothesis that both an environmental agent, possibly a virus, as well as the genetic response are important in the pathogenesis of SLE. Family members may therefore be a logical population in whom to search for specific antibodies to a viral agent.

Prevention of spontaneous autoimmunity to DNA in NZB/Swiss mice by treatment with natural double-stranded RNA

Data are presented demonstrating the prevention of spontaneous autoimmune disease in NZB/Swiss mice treated natural double-stranded RNA. The successful treatment of animals was followed both by improvement in clinical manifestations and by the migration inhibition test performed with DNA as antigen. The reasons for the successful employment of natural double-stranded RNA are thought to be in its physicochemical properties.

Double-stranded RNA antibodies in systemic lupus erythematosus

Antibodies to viral double-stranded RNA (ds RNA) have been found in 40% of patients with systemic lupus erythematosus (SLE) and 14-5% of patients with rheumatoid arthritis. These antibodies were diagnostically more specific SLE than those directed against artificial polynucleotides, poly I:C and poly A:U. Although not disease specific, high titres of antibody to ds viral RNA were found almost exclusively in SLE. Serial studies failed to show that RNA antibody levels correlated with disease activity. Although of considerable interest in experimental studies on the pathogenesis of SLE, ds viral RNA antibodies are of little clinical significance in the management of SLE.

Uracil-specific anti-R.N.A. antibodies in scleroderma

Antibodies to single-stranded R.N.A. were found by counter immunoelectrophoresis in all of 40 sera from patients with scleroderma. These antibodies were specific to the uracil bases of R.N.A. Antibodies to R.N.A. were also found in 20 of 40 sera from patients with systemic lupus erythematosus (S.L.E.), but in none of forty controls. Antibodies to R.N.A. found in S.L.E. sera could be differentiated immunochemically from those found in scleroderma in that they were more heterogeneous and could react selectively with either uridine or uridine monophosphate. Antibodies ot D.N.A. were more frequent in S.L.E. than in scleroderma. That antibodies to D.N.A. are actually present in scleroderma and precipitin lines are not the result of cross reactivity with anti-R.N.A. antibodies is indicated by the finding that 10 of the 18 scleroderma sera which reacted with D.N.A. also reacted with thymidine, a base present in D.N.A. but not in R.N.A.

Recent advances in the immunopathogenesis of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic multisystem inflammatory disease having definite etiologic associations with ethnic, genetic, viral and immunologic factors. Its pathologic hallmark, vasculitis, is currently felt to be the end result of an immune-complex mechanism. Several clinical and serologic variants of SLE are recognized including discoid lupus erythematosus (DLE), mixed connective tissue disease (MCTD) and drug-induced equivalents-such as procainamide-induced lupus (PIL). The distinguishing features of these variants as well as their prognosis and therapy are discussed in relation to recent developments in the immunopathogenesis of SLE.