Autoantibodies Against Nuclear, Nucleolar, and Mitochondrial Antigens in Systemic Sclerosis (Scleroderma)

Toxicity of the spike protein of COVID-19 is a redox shift phenomenon: A novel therapeutic approach

We previously demonstrated that most diseases display a form of anabolism due to mitochondrial impairment: in cancer, a daughter cell is formed; in Alzheimer's disease, amyloid plaques; in inflammation cytokines and lymphokines. The infection by Covid-19 follows a similar pattern. Long-term effects include redox shift and cellular anabolism as a result of the Warburg effect and mitochondrial dysfunction. This unrelenting anabolism leads to the cytokine storm, chronic fatigue, chronic inflammation or neurodegenerative diseases. Drugs such as Lipoic acid and Methylene Blue have been shown to enhance the mitochondrial activity, relieve the Warburg effect and increase catabolism. Similarly, coMeBining Methylene Blue, Chlorine dioxide and Lipoic acid may help reduce long-term Covid-19 effects by stimulating the catabolism.

Messenger RNA turnover and its regulation in herpesviral infection

The ability to regulate cellular gene expression is a key aspect of the lifecycles of a diverse array of viruses. In fact, viral infection often results in a global shutoff of host cellular gene expression; such inhibition serves not only to ensure maximal viral gene expression without competition from the host for essential machinery and substrates but also aids in evasion of immune responses detrimental to successful viral replication and dissemination. Within the herpesvirus family, host shutoff is a prominent feature of both the alpha- and gamma-herpesviruses. Intriguingly, while both classes of herpesviruses block cellular gene expression by inducing decay of messenger RNAs, the viral factors responsible for this phenotype as well as the mechanisms by which it is achieved are quite distinct. However, data suggest that the host shutoff functions of alpha- and gamma-herpesviruses are likely achieved both through the activity of virally encoded nucleases as well as via modulation of cellular RNA degradation pathways. This review highlights the processes governing normal cellular messenger RNA decay and then details the mechanisms by which herpesviruses promote accelerated RNA turnover. Parallels between the viral and cellular degradation systems as well as the known interactions between viral host shutoff factors and the cellular RNA turnover machinery are highlighted.

Idiopathic portal hypertension associated with systemic sclerosis and Sjögren’s syndrome

We report a patient with idiopathic portal hypertension (IPH) associated with systemic sclerosis (SSc) and Sjögren's syndrome. A 72-year-old Japanese woman was admitted to our hospital because of Raynaud's phenomenon, sclerodactyly, and dyspnea. The patient had splenomegaly, esophageal varices in the absence of extrahepatic portal obstruction, and cirrhosis of the liver. Immunological studies revealed positive anti-nuclear antibodies and high titers of anti-Scl-70, anti-SS-A, anti-centromere, and anti-mitochondrial M2 antibodies. Histological examinations of the liver biopsy specimen revealed stenosis and loss of small portal veins without findings of primary biliary cirrhosis. The patient was diagnosed as having IPH associated with SSc and Sjögren's syndrome. These observations suggest an immunological role in the pathogenesis of IPH.

Antinuclear antibody testing

The ANA test is an excellent screening test for patients with SLE and a few other connective tissue diseases. The LE cell preparation is an assay that is subjective and costly. Because of the presence of a superior screening test (the ANA) and superior specific auto-antibody tests, the author recommends that the use of LE cell preparations be discontinued. ANA screening tests may be performed either by indirect microscopic serology (usually IFA) or EIA. The latter technique is readily automated and many new products for this screening test have appeared in the past decade. The products differ, however, and laboratories are cautioned to test each in the context of the clinical needs of their clinicians. Proper use of the ANA test requires each laboratory to determine the cutoff used under their conditions of assay. Although either ANA screening test has a high negative predictive value in numerous studies, proper selection of patients to be tested is key to improving the predictive value of a positive result. The American College of Rheumatism criteria are reviewed and recommended as part of the patient selection process for this testing.

Antinuclear antibody testing in systemic autoimmune disease

This article discusses the use and interpretation of antinuclear antibody (ANA) testing in connective tissue diseases. Methods of ANA detection are discussed and analyzed in detail as is the role of ANAs in systemic lupus, scleroderma, and polymyositis, connective tissue diseases with prominent pulmonary involvement.

Clinical significance of antinuclear antibodies in systemic rheumatic diseases

Autoantibodies directed to intracellular antigens can be detected in many systemic rheumatic diseases. In this review, we discuss the clinical significance of antinuclear antibodies (ANA) associated with systemic lupus erythematosus (SLE), Slögren's syndrome, scleroderma and polymyositis/dermatomyositis, the immunogenetic factors associated with these four autoimmune diseases, and the possible role of autoantibodies in the etiopathogenesis of autoimmune disease. The antibodies associated with systemic rheumatic diseases serve as important tools in the initial diagnosis, and they are also useful in the evaluation of prognosis. However, for correct conclusions, the autoantibody findings should be carefully considered and interpreted in clinical context.

Childhood-onset scleroderma: is it different from adult-onset disease

OBJECTIVE

To distinguish childhood-onset scleroderma from adult-onset disease.

METHODS

The clinical and serologic features of 58 patients with childhood-onset scleroderma (11 patients with diffuse cutaneous systemic sclerosis [SSc], 16 with linear SSc, 14 with linear morphea, and 17 with morphea) were examined in the largest cohort of such patients studied to date. These parameters were compared with data obtained from patients with adult-onset disease.

RESULTS

Childhood-onset scleroderma resembled adult-onset disease with regard to the heterogeneity of clinical expression and subsets of disease, but it also differed from adult-onset disease in a number of clinical and laboratory parameters. The predominant childhood-onset disease presentation was the localized form of the disease, with limited and diffuse SSc being less notable. There was a significant association of trauma with childhood-onset scleroderma (P < 0.0001), which was not noted in adult-onset disease. Furthermore, in contrast to adult disease, patients with childhood-onset disease had normal levels of parameters of vascular activation (von Willebrand factor, angiotensin-converting enzyme, E-selectin, and endothelin-1), T cell activation (soluble interleukin-2 receptors), and collagen synthesis (carboxy-terminal type I and amino-terminal type III), a notable lack of anticentromere antibodies, and abnormal coagulation indices.

CONCLUSION

A number of features distinguish childhood-onset scleroderma from adult-onset disease.

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.

Plasma endothelin correlates with antiendothelial antibodies in patients with mixed connective tissue disease

BACKGROUND

Elevated circulating levels of the vasoactive peptide endothelin-1 have been reported in various cardiovascular disorders. Because these conditions are frequently associated with endothelial dysfunction and damage and the vasoconstrictor effect of endothelin-1 is believed to be produced at the local vascular level, it is uncertain whether circulating endothelin-1 is a causal factor in enhanced vascular tone or instead a marker of endothelial injury.

METHODS AND RESULTS

We tested whether elevated immunoreactive endothelin-1 could be detected by radioimmunoassay in plasma and whether endothelin-1 levels correlated with antiendothelial autoantibodies in patients with mixed connective tissue disease. Venous blood samples were collected from 21 patients in the morning after an overnight fast and before medication. The plasma immunoreactive endothelin-1 level was 2.7 +/- 0.5 pg/mL (range, 1.1 to 5.2 pg/ml; n = 9) and 7.3 +/- 1.5 pg/mL (range, 2.8 to 20.7 pg/mL; n = 12) in patients who had no antiendothelial antibodies and in patients with antiendothelial antibodies, respectively. These latter values were significantly (P < .001) increased compared with 10 age-matched healthy volunteers (2.0 +/- 0.3 pg/mL; range, 0.5 to 3.0 pg/mL). Plasma endothelin-1 level strongly correlated with antiendothelial antibodies (rs = .836, n = 21, P < .001), whereas there was no correlation between age, systolic and diastolic blood pressures, antinuclear antibodies, and duration of the disease and endothelin-1 values. The incidence of Raynaud's phenomenon and angina did not differ significantly in patients with low and high endothelin-1 levels.

CONCLUSIONS

This study showed that mixed connective tissue disease is associated with elevated plasma immunoreactive endothelin-1 and that endothelin-1 levels significantly correlate with antiendothelial autoantibodies. These findings suggest that increases in plasma endothelin-1 concentration may be secondary to vascular injury and do not necessarily represent enhanced susceptibility to vasoconstriction.

Molecular structure and function of autoantigens in systemic sclerosis

Autoantibodies in systemic sclerosis target a limited set of nuclear proteins, principally those of the nucleolus and RNA transcription complexes. These antibodies have proved helpful in diagnosis of this disease, and have been used extensively as probes of nuclear structure and function. Despite these advances, the events that initially trigger autoantibody production in systemic sclerosis are not yet known. While these ANA are not known to disrupt cellular processes by entering living cells, or to cause tissue injury (in contrast to SLE, where autoantibodies may mediate tissue damage), it seems likely that they do not merely represent epiphenomena of the disease. Rather, it is logical to assume that their origin is in some manner tied to etiology of systemic sclerosis, since they segregate by syndrome within the spectrum of this disease (for example, anti-kinetochore antibodies occur in limited cutaneous disease, and anti-topoisomerase I and anti-RNA polymerase antibodies occur in diffuse disease), and since they are distinct from the ANA found in other connective tissue diseases in their selectivity for the nucleolus and RNA polymerases.

Autoantibodies in systemic sclerosis

There are 3 major autoantibodies in sera from patients with scleroderma: 1) anticentromere antibodies (ACA), 2) anti-topoisomerase I (anti-topo I), and 3) anti-RNA polymerases. Each is present in about 25% of patients and are mutually exclusive. ACA are found in patients with primary and secondary Raynaud's disease and in patients with primary biliary cirrhosis. Anti-topo I and anti-RNA polymerases are found exclusively in scleroderma. Each autoantibody is present in specific subsets of scleroderma patients. ACA and anti-topo I have been well studied and their presence and titer are stable over time. The anti-topo I and ACA are of all three isotypes, recognize multiple epitopes on the antigens and have stable cross reactive or private idiotypes. The antigen, topoisomerase I, has domains which have homology to viral proteins. Other autoantibodies predominantly recognize nucleolar antigens, are found in less than 15% of patients, and are not specific for scleroderma.

Analysis of the specificity of anti-PM-Scl autoantibodies

OBJECTIVE

To compare the specificity of anti-PM-Scl autoantibodies in serum samples from 43 patients with myositis, scleroderma, or both.

METHODS

Anti-PM-Scl immunoprecipitates from HeLa cell extract were used as antigen for immunoblot analyses to determine the antigenic components. A series of complementary DNA fragments was expressed in Escherichia coli for immunoblot examination of the reaction with the 100-kd protein.

RESULTS

The immunoblot against immunoprecipitates was sensitive and specific for detecting reactions with components of the PM-Scl antigen: 42 of 43 sera (97.7%) reacted with the 100-kd, 27 of 43 (62.8%) with the 70-kd, and 5 of 43 (11.6%) with the 37-kd protein (not previously recognized as antigenic). Forty-one sera reacted with N-terminal protein S1 (amino acids 11-437), 39 with central protein S2 (amino acids 439-749), and 24 with C-terminal protein S3 (amino acids 750-882). Of 42 sera tested, 28 (66.7%) reacted most strongly with S1, and 6 (14.3%) reacted most strongly with S2. Absorption studies implied additional, conformational epitopes not present on the bacterially expressed antigen.

CONCLUSION

There was an overall similarity in reactivity to the PM-Scl antigen, but there were differences in the reactivity to the 70-kd and 37-kd proteins, as well as in the relative strength of the reactivity to the S2 protein.

Clinical correlation of anticentromere antibodies

A retrospective survey of all patients with a positive anticentromere antibody (ACA) determination was undertaken over a 3-years period of time in a university hospital. Forty-five patients were positive for anticentromere antibodies. The analysis of the clinical characteristics and diagnoses of the patients with anticentromere antibodies were correlated and showed a diverse array of symptoms. Only 4.4% had CREST syndrome, 6.7% had limited scleroderma, 17.8% had diffuse scleroderma, 20% had other connective tissue diseases, 20% had other miscellaneous rheumatic conditions, 11.1% had tumours and 20% other nonrheumatic diseases. The study shows that the presence of ACA, as detected during routine ANA-testing, does not strongly suggest a diagnosis of CREST at that time. The presence of a scleroderma-variant in almost 50% of the patients and the occurrence of Raynaud's phenomenon in 62% underscores, however, an association of ACA with (early) scleroderma-like disorders.

Autoantibodies in scleroderma

Autoantibodies directed against nuclear, nucleolar, and a number of cytoplasmic components are described in the sera of scleroderma patients. Early studies of autoantibodies that relied on cryopreserved sections of rodent organ substrates showed that approximately 50% of scleroderma patients had anti-nuclear antibodies (ANA). More recent studies that have used tissue culture cell substrates have shown that up to 98% of scleroderma patients have a positive ANA. In all of these studies, the presence of different patterns of staining have suggested that scleroderma sera reacted with a variety of intracellular antigens. The use of molecular and immunochemical techniques has now shown that over 20 intracellular autoantigens are targets of autoantibodies in scleroderma sera. Clinical studies have shown that these autoantibodies are important diagnostic and prognostic markers in scleroderma. In the future, autoantibody testing may be used to monitor the patient's response to immunological therapies.

Diagnostic significance of nailfold bleeding in scleroderma spectrum disorders

BACKGROUND

The early detection of scleroderma spectrum disorders (SSD) is important.

OBJECTIVE

Our purpose was to determine the prevalence of nailfold bleeding in SSD.

METHODS

We examined patients for nailfold bleeding in the following three groups: (1) 81 patients with SSD including 50 patients with scleroderma, 10 with mixed connective tissue disease, and 21 with Raynaud's phenomenon having specific antinuclear antibody (ANA); (2) 99 patients with other connective tissue diseases or primary Raynaud's phenomenon; and (3) 200 patients with common skin diseases.

RESULTS

The frequency of nailfold bleeding was significantly higher in SSD (75.3%) than in other connective tissue diseases (12.1%) and in controls (3.0%). The presence of nailfold bleeding in two or more fingers showed a 98.3% specificity for SSD. Among the patients with SSD, the incidence of nailfold bleeding in scleroderma, mixed connective tissue disease, and Raynaud's phenomenon with specific ANA was similar. Nailfold bleeding strongly correlated with the presence of anticentromere antibody.

CONCLUSION

The presence of nailfold bleeding is useful for the early detection of SSD.

Evidence for autoimmunity in the tight skin mouse model of systemic sclerosis

The tight skin mouse strain has been proposed for use as an animal model of systemic sclerosis because this animal exhibits a condition that has biochemical and pathologic similarities to the human disease. To date, however, evidence of inflammatory and immunologic changes in the tight skin mouse has been scarce. We demonstrated the presence of antinuclear antibodies in approximately half of these mice ages 8 months and older. This suggests that there is an autoimmune component in their disease process. The antibodies were identified as anti-topoisomerase I by a characteristic staining pattern on HEp-2 cells and by Western blot analysis. Except for a low incidence of anti-DNA antibodies, none of the other parameters tested, including mitogen responses, lymphokine production, and anti-erythrocyte antibodies, was indicative of immune system dysregulation.