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Duus K, Draborg AH, Güven E, Moreno YM, Jacobsen S, Nielsen CT, Houen G. A fluorescence sedimentation assay for dsDNA antibodies. Scandinavian Journal of Clinical and Laboratory Investigation 2017; 77:465-471. [DOI: 10.1080/00365513.2017.1339232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- K. Duus
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
| | - A. H. Draborg
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
| | - E. Güven
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
| | - Y. M. Moreno
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
| | - S. Jacobsen
- Copenhagen Lupus and Vasculitis Clinic, Centre for Rheumatology and Spine Disease, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - C. T. Nielsen
- Copenhagen Lupus and Vasculitis Clinic, Centre for Rheumatology and Spine Disease, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - G. Houen
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Copenhagen, Denmark
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3
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Evtugyn G, Porfireva A, Hianik T, Cheburova M, Budnikov H. Potentiometric DNA Sensor Based on Electropolymerized Phenothiazines for Protein Detection. ELECTROANAL 2008. [DOI: 10.1002/elan.200704186] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Haugbro K, Nossent JC, Winkler T, Figenschau Y, Rekvig OP. Anti-dsDNA antibodies and disease classification in antinuclear antibody positive patients: the role of analytical diversity. Ann Rheum Dis 2004; 63:386-94. [PMID: 15020332 PMCID: PMC1754943 DOI: 10.1136/ard.2003.016303] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The presence of "anti-DNA antibodies in abnormal titres" is a well established criterion for SLE classification, but there is no agreement on the performance of this test. OBJECTIVE To study the correlation between clinical findings and five different solid and solution phase anti-DNA antibody assays. METHODS 158 consecutively collected ANA positive sera were studied in a double blind fashion. Anti-DNA antibodies were determined by different solid phase assays (ssDNA-, dsDNA- specific ELISA, EliA anti-dsDNA assay, Crithidia luciliae assay), and by an experimental solution phase anti-DNA assay using biotinylated pUC18 plasmid, human, calf thymus, and E coli DNA. Antibody affinity was determined by surface plasmon resonance. Clinical data were obtained independently of the laboratory analyses and later related to the anti-dsDNA findings. RESULTS Anti-dsDNA antibodies were most frequently detected by ELISA, but were not specific for SLE as they were present in up to 30% of other disease groups. Those detected by the Crithidia luciliae assay were predictive for SLE, while antibodies binding in solution phase ELISA using the pUC18 correlated strongly with the Crithidia luciliae assay. Surface plasmon resonance analysis showed that antibody binding to pUC18 was not due to higher relative affinity for dsDNA in general, but apparently to specificity for that plasmid DNA. Serum samples from three patients with lupus nephritis were positive in both pUC18 solution phase and Crithidia luciliae assays. CONCLUSIONS Assay principle selection is decisive for the detection of clinically significant anti-DNA antibodies. Revision of the anti-DNA antibody criterion in the SLE classification may be needed.
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Affiliation(s)
- K Haugbro
- Department of Biochemistry, Institute of Medical Biology, University of Tromsø, N-9037 Tromsø, Norway
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Förger F, Matthias T, Oppermann M, Becker H, Helmke K. Clinical significance of anti-dsDNA antibody isotypes: IgG/IgM ratio of anti-dsDNA antibodies as a prognostic marker for lupus nephritis. Lupus 2004; 13:36-44. [PMID: 14870916 DOI: 10.1191/0961203304lu485oa] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The objective of this paper is to investigate the association between patterns of anti-dsDNA antibody isotypes and specific clinical manifestations (categorized in renal, musculoskeletal, cutaneous, hematological, pulmonary, neurological and cardiac). Sera of 202 systemic lupus erythematosus (SLE) patients, 33 patients suffering from other autoimmune diseases and 115 healthy blood donors were analysed for anti-dsDNA antibodies by IgG-, IgA- and IgM-specific ELISA, Farr-assay and CLIF. A subset of 24 SLE patients was investigated in a longitudinal study over a period of one to six years. Disease activity of 105 SLE patients was measured according to the ECLAM score. In the cohort of SLE patients 63% were positive for the IgG class, 40% for the IgA and 57% for the IgM class specific anti-dsDNA ELISA. Sensitivity (79%) and specificity (99%) for the diagnosis of SLE appeared to be highest for the ELISA measuring all isotypes of anti-dsDNA antibodies. The concentrations of anti-dsDNA isotypes showed a strong correlation with disease activity. Analysing the relationship between IgG, IgA and IgM anti-dsDNA antibody isotypes and clinical manifestation, we found a significant association of the IgM isotype with cutaneous involvement and of the IgG isotype with lupus nephritis. The IgG/IgM ratio of anti-dsDNA antibodies represented a significant parameter to distinguish patients with lupus nephritis from those without renal involvement. In the longitudinal study, a continuous ratio under 0.8 was associated with absence of renal involvement throughout the investigated period. In conclusion, the evaluation of anti-dsDNA isotypes provides a diagnostic tool to define subsets within SLE patients with different clinical manifestations. In particular, the IgG/IgM ratio of anti-dsDNA antibodies could be used as a prognostic marker for lupus nephritis during the course of the disease.
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Affiliation(s)
- F Förger
- IV Department of Internal Medicine, Clinical Immunology and Rheumatology, Hospital Munich-Bogenhausen, Teaching Hospital of the Technical University of Munich, Germany
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Abstract
ANA IIF is an effective screening assay in patients with clinical features of SLE and will detect most anti-ssDNA, anti-dsDNA, ENAs, and other autoantibodies. False positives are common. The clinical importance cannot be extrapolated from the ANA titre or pattern, although higher titres (> 1/160) are more likely to be important. HEp-2 cells are the most sensitive substrate for ANA detection, but this must be balanced against an increased incidence of insignificant positivity. ANA positive samples should be subjected to more specific assays for the diagnosis of SLE. A combination of ENA (Ro/La/Sm/RNP) and dsDNA assays will detect most patients with SLE as long as the characteristics of the assays used are well understood. ESR and CRP measurements provide useful additional information. Sjogren's syndrome and MCTD will produce overlapping serology with SLE, and anti-dsDNA titres are sometimes seen in autoimmune hepatitis and rheumatoid arthritis. All results should be reported in the light of the clinical details, by an experienced immunologist. A suggested diagnostic protocol is outlined in fig 1. The type of assay used crucially influences the predictive value of the tests. ELISA technology dominates routine laboratory practice, but tends to produce more false positive and true weak positive results, which may reduce the PPV of the test. This can be minimised by using IgG specific conjugates and careful assay validation. The NPV for SLE [figure: see text] is high for most assays but the PPV varies. Where necessary, laboratories should use crithidia or Farr dsDNA assays to confirm dubious ELISA dsDNA results, and ID/IB to confirm dubious ENA results. For monitoring, a precise, quantitative assay is required. It is unclear whether the detection of IgM or low affinity antibodies has a role here. A combination of anti-dsDNA, C3, C4, CRP, and ESR assays provides the most useful clinical information. Anti-ssDNA assays are likely to be useful, and are potentially more robust than anti-dsDNA assays, but require more validation. Local validation of individual assays and EQA participation is essential. Not all assays that apparently measure the same antibody specificities have equal clinical relevance, even within a single technology. Insufficient international or national reference preparations are currently available for many antibody specificities to enable effective standardisation. Quality assurance schemes reveal large differences in units reported by different assays for some analytes, even when calibrated against an IRP or equivalent reference preparation. Serial results can therefore only be compared from the same laboratory at present. Most autoantibodies increase during active disease, but few prospective data are currently available to justify treatment on the basis of rising titres. Further randomised prospective studies are required to examine the importance of antibody isotype and affinity in the monitoring of SLE by individual assay methods. The most important aspect of the appropriate use of laboratory assays is to become familiar with the limitations of the technology currently in use in your local laboratory, and to consult with your clinical immunologist in cases of doubt, preferably before commencing serological screening.
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Affiliation(s)
- W Egner
- Department of Immunology and Protein Reference Unit, Northern General Hospital, Sheffield, UK.
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7
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Gerli R, Paganelli R, Cossarizza A, Muscat C, Piccolo G, Barbieri D, Mariotti S, Monti D, Bistoni O, Raiola E, Venanzi FM, Bertotto A, Franceschi C. Long-term immunologic effects of thymectomy in patients with myasthenia gravis. J Allergy Clin Immunol 1999; 103:865-72. [PMID: 10329821 DOI: 10.1016/s0091-6749(99)70431-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Thymectomy (Tx) is a common therapeutic option to treat myasthenia gravis (MG), but its effects on the immune system are still obscure in humans. OBJECTIVE We sought to evaluate long-term immunologic effects of therapeutic Tx in patients with MG. METHODS T- and B-cell subsets and T-cell repertoire were analyzed in 35 patients with MG, 16 with previous Tx (at least 8 years before), 6 with recent (<1 year) Tx, and 13 without Tx, as well as in 32 healthy subjects used as normal control subjects. Serum immunoglobulins and a variety of autoantibodies were also measured. A subsequent 3-year clinical follow-up was performed to verify the possible appearance of systemic autoimmune diseases. RESULTS The long-term thymectomized (Txd) patients had mild T-cell lymphopenia and an expansion of some Vbeta families among circulating CD4+ and CD8+ T cells. They displayed a normal number of total B and CD5+ B-circulating lymphocytes, but they also displayed a polyclonal increase in serum IgM and IgG associated with the presence of high levels of a variety of organ- and nonorgan-specific autoantibodies, including anti-dsDNA and anticardiolipin, without clinical evidence of autoimmune disease. These serologic abnormalities were not detectable in both non-Txd and recently Txd patients. After 3 years, 2 long-term Txd patients had systemic lupus erythematosus and an undifferentiated connective tissue disease. CONCLUSIONS The association between MG and laboratory findings of systemic autoimmune disease may be in part related to Tx rather than to MG. Tx may represent a risk for the development of systemic autoimmune disorders over years in patients with MG.
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Affiliation(s)
- R Gerli
- Section of Internal Medicine and Oncological Sciences (Center for the Study of Rheumatic Diseases), University of Perugia, Italy
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Bootsma H, Spronk PE, Hummel EJ, de Boer G, ter Borg EJ, Limburg PC, Kallenberg CG. Anti-double stranded DNA antibodies in systemic lupus erythematosus: detection and clinical relevance of IgM-class antibodies. Scand J Rheumatol 1996; 25:352-9. [PMID: 8996469 DOI: 10.3109/03009749609065646] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We determined the discriminative value of the Farr assay in comparison to ELISA and Crithidia luciliae immunofluorescence assay (IFT) for detecting anti-dsDNA antibodies as a diagnostic tool for systemic lupus erythematosus (SLE). Special attention was paid to the diagnostic significance of IgM-class anti-dsDNA. Sera were analyzed from 74 patients with SLE, 257 patients with other auto-immune diseases, and 50 healthy controls. All sera were tested for anti-dsDNA using the IFT (anti-total immunoglobulin conjugate), ELISA (anti-IgG and anti-IgM conjugates), and the 125I Farr assay. Specificity and sensitivity for a diagnosis of SLE appeared to be highest for the Farr. All SLE sera with IgM-class anti-dsDNA without IgG-class anti-dsDNA as detected by ELISA, were positive when tested by the Farr assay. In contrast, most of the sera with IgM-class anti-dsDNA as detected by ELISA from patients with diseases other than SLE were negative when tested by Farr assay.
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Affiliation(s)
- H Bootsma
- Department of Internal Medicine, University Hospital Groningen, The Netherlands
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van Dam AP, Wekking EM, Callewaert JA, Schipperijn AJ, Oomen HA, de Jong J, Swaak AJ, Smeenk RJ, Feltkamp TE. Psychiatric symptoms before systemic lupus erythematosus is diagnosed. Rheumatol Int 1994; 14:57-62. [PMID: 7824836 DOI: 10.1007/bf00300248] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Psychiatric symptoms are rarely reported as an initial feature of systemic lupus erythematosus (SLE). Nevertheless, many patients have the feeling that psychiatric symptoms occurred before they were diagnosed as having SLE. This feeling was confirmed by an enquiry among members of the Dutch Lupus Patients Society: half of them had experienced psychiatric complaints before SLE was diagnosed. Two-thirds of these patients searched for professional help for these complaints. This motivated us to study whether SLE patients were admitted into psychiatric hospitals without being diagnosed as having SLE. Sera from 2121 patients admitted to a psychiatric hospital and from 500 controls matched for sex and age were tested for the presence of antinuclear antibodies (ANA) and antibodies to DNA. ANA were found in 3% of patients, as well as controls. Anti-DNA antibodies were found in 1% of both patients and controls. Two out of 114 patients psychiatric patients with ANA and/or anti-DNA antibodies had SLE and/or Sjögren's syndrome. We concluded that SLE is not an important cause of admission to psychiatric hospitals. Routine tests for the determination of antinuclear and anti-DNA antibodies on admissions in these hospitals thus would not seem useful. To study whether patients with another chronic disease also had psychiatric complaints before being diagnosed, we performed the same enquiry among members of the Dutch Sarcoidosis Patients Society. The results were almost equal to those of the enquiry of the members of the Dutch Lupus Patients Society. Why members of both societies so often report psychiatric symptoms before their disease is diagnosed should be a subject of further studies.
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Affiliation(s)
- A P van Dam
- Department of Autoimmune Diseases, Central Laboratory of the Netherlands Red Cross Blood Transfusion Service, Amsterdam
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Yoshida S, Castles JJ, Gershwin ME. The pathogenesis of autoimmunity in New Zealand mice. Semin Arthritis Rheum 1990; 19:224-42. [PMID: 2181670 DOI: 10.1016/0049-0172(90)90002-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- S Yoshida
- Department of Internal Medicine, School of Medicine, University of California, Davis
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Nossent JC, Huysen V, Smeenk RJ, Swaak AJ. Low avidity antibodies to double stranded DNA in systemic lupus erythematosus: a longitudinal study of their clinical significance. Ann Rheum Dis 1989; 48:677-82. [PMID: 2789501 PMCID: PMC1003846 DOI: 10.1136/ard.48.8.677] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
In a longitudinal study the relevance of the detection of low avidity antibodies to double stranded DNA (dsDNA) as measured by the polyethylene glycol (PEG) assay in patients with systemic lupus erythematosus (SLE) was evaluated. It was found that 35 patients positive in the PEG assay only--that is, having only low avidity anti-dsDNA in their circulation, had a mild course of their SLE with absence of renal involvement. The PEG assay had little predictive value but a high specificity (90.2%) for clinical exacerbations; furthermore, a change in avidity of anti-dsDNA in such patients was seldom observed. In 14 patients positive in both Farr and PEG assays--that is, with a relative preponderance of high avidity anti-dsDNA, there was a clear correlation between rises in Farr assay and major exacerbations, while the PEG assay on its own was not helpful in predicting disease manifestations; disease manifestations were often heralded by a change in the Farr/PEG ratio, with renal and cerebral exacerbations associated with the greatest increase in the Farr/PEG ratio (more than 10 times the previous value).
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Affiliation(s)
- J C Nossent
- Department of Rheumatology, Dr Daniel den Hoed Clinic, Rotterdam, The Netherlands
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Pollard KM, Webb J. Structural requirements of DNA used in the Farr assay to detect antibodies directed against double-stranded DNA. Rheumatol Int 1987; 7:161-8. [PMID: 3313663 DOI: 10.1007/bf00270364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The measurement of antibodies to DNA in SLE requires the use of double-stranded DNA (dsDNA), demonstrably free of single-stranded regions. Such dsDNA preparations can, however, contain other structural components. In this study DNA preparations with defined structure, both secondary (single- and double-stranded and random base-paired) and tertiary (superhelical and open circular), were used in the Farr assay to measure the DNA binding of sera from patients with SLE and related connective-tissue diseases. The presence of true single-stranded DNA regions in denatured DNA, native DNA, and dsDNA containing single-stranded regions increased the DNA binding measured in all sera. DsDNA, whether intact or containing small regions of random base-pairing, was bound by sera from the majority of patients with SLE but not by non-SLE sera. Superhelical dsDNA from bacteriophage PM2 was bound by SLE sera to a greater extent than linear dsDNA was. Inhibition experiments suggested that this difference in binding to DNA according to tertiary, as opposed to secondary, structure is because there are fewer available binding sites on superhelical dsDNA. DNA binding, as measured by the Farr assay, can thus be influenced by both secondary and tertiary DNA structure. Using superhelical DNA, advantage can be taken of the dsDNA form plus tertiary structure to enhance DNA binding of SLE sera beyond the levels achieved using linear dsDNA.
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Affiliation(s)
- K M Pollard
- Department of Rheumatology, University of Sydney, Royal North Shore Hospital, St Leonards, NSW, Australia
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Smeenk RJ, Lucassen WA, Swaak TJ. Is anticardiolipin activity a cross-reaction of anti-DNA or a separate entity? ARTHRITIS AND RHEUMATISM 1987; 30:607-17. [PMID: 3606679 DOI: 10.1002/art.1780300602] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Putative cross-reactions between anti-DNA and anticardiolipin activities were studied using sera of different patients and a panel of monoclonal antibodies to DNA. Sera were obtained from patients with systemic lupus erythematosus, from patients with syphilis, and from heroin addicts who showed a biologic false-positive result on the serologic test for syphilis. While the patients with syphilis and the heroin addicts had elevated levels of anticardiolipin antibodies in their circulation, no reactivity with DNA was observed in these sera. Sera from systemic lupus erythematosus patients often showed both anti-DNA and anticardiolipin activity. Although a correlation between anti-DNA and anticardiolipin titers was found, this did not always result from cross-reactivity of the same population of antibodies. In fact, we observed a relationship between cross-reactivity and antibody avidity. Anti-DNA of high avidity to DNA showed little cross-reactivity with cardiolipin. Anticardiolipin activity in such sera was based on the presence of specific anticardiolipin antibodies. Anti-DNA of low avidity was found to cross-react with cardiolipin. Among monoclonal antibodies to DNA, we found that cross-reactions with cardiolipin were rare: only 6 of 55 anti-DNA clones produced antibodies that also reacted with cardiolipin.
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Pollard KM, Steele R, Hogg S, Webb J. Measurement of serum DNA binding in chronic active hepatitis and systemic lupus erythematosus using the Farr assay. Rheumatol Int 1986; 6:139-44. [PMID: 3529336 DOI: 10.1007/bf00270351] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Antibodies to double-stranded DNA (dsDNA), generally regarded as highly specific for systemic lupus erythematosus (SLE), have also been reported in chronic active hepatitis (CAH). Using the Farr assay and E. coli DNA, fractionated by benzoylated-naphthoylated-DEAE cellulose chromatography into dsDNA and dsDNA containing single-stranded regions, we compared the serum DNA binding of CAH and SLE patients. Although CAH sera were found to have dsDNA binding significantly above the normal control group such binding was of low level and we could find no evidence of markedly elevated dsDNA binding in CAH. However 12 of the 20 CAH sera studied did bind preferentially to dsDNA containing single-stranded regions suggesting the presence of anti-single-stranded DNA antibodies. We conclude that the description of elevated anti-dsDNA antibodies, as measured by the Farr assay, in CAH is due to the interaction of anti-single-stranded DNA antibodies or other serum components with single-stranded DNA contaminating dsDNA preparations.
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Hale GM, Highton J, Kalmakoff J, Palmer DG. Changes in anti-DNA antibody affinity during exacerbations of systemic lupus erythematosus. Scand J Rheumatol 1986; 15:243-50. [PMID: 3492037 DOI: 10.3109/03009748609092586] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The level and average functional affinity of anti-DNA antibody were measured retrospectively in successive serum samples from 5 patients with systemic lupus erythematosus. In 2 patients, severe flares of disease activity were associated with an increase in the level and average functional affinity of anti-DNA antibodies. Three patients who did not experience significant flares in disease activity exhibited more constant levels of antibody of lower average functional affinity. The appearance of antibody of high functional affinity during disease exacerbations suggests that such antibodies may be pathogenic.
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Kumar V, Krasny S, Beutner EH. Specificity of the Crithidia luciliae method for detecting anti-DNA antibodies. Effect of absorption for lipoproteins. Immunol Invest 1985; 14:199-210. [PMID: 2995252 DOI: 10.3109/08820138509076144] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Using the immunofluorescent (IF) assay with Crithidia luciliae smears, anti-native (n) DNA antibodies were detected in the sera of 12 of 20 systemic lupus erythematosus (SLE) patients, in 1 of 6 mixed connective tissue disease cases, in 2 of 38 patients with systemic sclerosis but in none of the sera from 96 normal subjects. All anti-nDNA antibodies were associated with antinuclear antibodies (ANA). However, occasionally sera were encountered in routine screening which appear to be positive for anti-DNA antibodies but negative for ANA. Studies of such sera indicate that this is a nonspecific reaction which can be abolished by treating sera with dextran sulfate or heparin. Treatment of SLE sera with these agents had no effect on their anti-nDNA antibody activity. Absorption of sera with Aerosil eliminated the false positive reactions with C. luciliae; however, this treatment also removed immunoglobulins, ANA and anti-nDNA antibodies. Evidence is reviewed which points to a role of complexes of low density lipoprotein and IgG in the nonspecific binding reactions with C. luciliae which is seen as false positive reactions for anti-nDNA antibodies.
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van Oss CJ, Smeenk RJ, Aarden LA. Inhibition of association vs. dissociation of high-avidity DNA/anti-DNA complexes:possible involvement of secondary hydrogen bonds. Immunol Invest 1985; 14:245-53. [PMID: 4044023 DOI: 10.3109/08820138509076148] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Recent results on the conditions of ionic strength needed to prevent the association of dsDNA with high avidity human anti-dsDNA, were compared with the insufficiency of even the highest practicable ionic strengths to effect the dissociation of such antigen-antibody complexes, once formed (1). Further analysis of these results make us conclude that such high avidity dsDNA-anti-dsDNA complexes, which in the initial stages of their formation are mainly of the Coulombic variety, subsequently evolve, at least in part, into hydrogen bonds.
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Swaak T, Smeenk R. Detection of anti-dsDNA as a diagnostic tool: a prospective study in 441 non-systemic lupus erythematosus patients with anti-dsDNA antibody (anti-dsDNA). Ann Rheum Dis 1985; 44:245-51. [PMID: 3872637 PMCID: PMC1001620 DOI: 10.1136/ard.44.4.245] [Citation(s) in RCA: 70] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The diagnostic significance of anti-double-stranded deoxyribonucleic acid (anti-dsDNA) determination was evaluated in a prospective manner from 1974 to 1982 in a group of 441 patients without systemic lupus erythematosus whose sera were found to contain antibodies to dsDNA on routine screening (Farr assay). Within one year 69% (304) of these patients fulfilled the preliminary American Rheumatism Association (ARA) criteria for systemic lupus erythematosus (SLE). Eighty-two of the remaining 137 patients were followed up for several years. At the end of the study 52% of these patients had also developed systemic lupus erythematosus. Patients who developed systemic lupus erythematosus were characterised by the occurrence of relatively high avidity anti-dsDNA in the circulation compared with patients who did not develop systemic lupus erythematosus. It can be concluded that about 85% of patients without systemic lupus erythematosus with anti-dsDNA in the circulation will develop SLE within a few years. Taking into account the relative avidity of anti-dsDNA, as determined by calculation of Farr/polyethylene glycol (PEG) ratios, we conclude that patients with relatively high avidity anti-dsDNA are more prone to develop systemic lupus erythematosus than patients with relatively low avidity anti-dsDNA.
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Smeenk R, Westgeest T, Swaak T. Antinuclear antibody determination: the present state of diagnostic and clinical relevance. Scand J Rheumatol Suppl 1985; 56:78-92. [PMID: 3890156 DOI: 10.3109/03009748509102067] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Determination of antinuclear antibodies (ANA) will gain in diagnostic significance if a specific type of ANA can be related to a defined clinical disorder. The past decade has brought us quite a lot of papers dedicated to this subject. Yet, with exception of the DNA/anti-DNA system, observed correlations have remained scarce or contradictory. Also, still little is known about the pathogenic role of ANA. Perhaps more recent approaches using biochemical technologies will provide us with highly purified nuclear antigens necessary to study possible correlations at a more sophisticated level.
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Swaak AJ, Statius van Eps LW, Aarden LA, Feltkamp TE. Azathioprine in the treatment of systemic lupus erythematosus. A three-year prospective study. Clin Rheumatol 1984; 3:285-91. [PMID: 6333314 DOI: 10.1007/bf02032333] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In a prospective study, the effect of azathioprine on the clinical course and the anti-dsDNA profile was evaluated in 17 patients with systemic lupus erythematosus (SLE). During this prospective longitudinal study, exacerbations were never observed. Three periods of continuous anti-dsDNA increases with a doubling time (T2) shorter than 10 weeks were noted. Both the clinical symptoms and the anti-dsDNA levels improved after the administration of azathioprine. These results necessitate a careful double-blind trial for the use of this drug to prevent SLE exacerbations.
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Abstract
In systemic lupus erythematosus, some immunologic tests quantify disease activity, enable prediction of higher risk patterns of disease, and serve as therapeutic guides. In rheumatoid arthritis, serologic phenomena are significantly associated with more severe and sustained joint disease and with visceral manifestations (vasculitides and granulomas), but they have not been useful in monitoring the course of disease or response to therapy. In other rheumatic syndromes, a variety of antinuclear specificities show promise as marker antibodies, but their prognostic and therapeutic implications remain largely unexplored.
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Alarcón-Segovia D. Antibodies to Nuclear and Other Intracellular Antigens in the Connective Tissue Diseases. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/s0307-742x(21)00450-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Smeenk RJ, Aarden LA, van Oss CJ. Comparison between dissociation and inhibition of association of DNA/anti-DNA complexes. IMMUNOLOGICAL COMMUNICATIONS 1983; 12:177-88. [PMID: 6874000 DOI: 10.3109/08820138309066867] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
A study was made of the increases in ionic strength (mu) and in pH that would effect: a) the inhibition of association of anti-double stranded (ds) DNA and dsDNA, and b) the dissociation of anti-dsDNA from dsDNA, with respect to high avidity as well as to low avidity human anti-dsDNA antibodies, using Crithidia luciliae kinetoplasts as a source of dsDNA. The results obtained appear to indicate that the electrostatic component of the antigen-antibody bond does not become stronger with time (for times spans less than 1 hr).
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26
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Smeenk R, Duin T, Aarden L. Influence of pH on the detection of low- and high-avidity anti-dsDNA. J Immunol Methods 1982; 55:361-73. [PMID: 6187861 DOI: 10.1016/0022-1759(82)90096-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In 2 radioimmunoassays in use to detect antibodies to dsDNA, the Farr assay and the PEG assay, we observed inhibitory effects of normal human serum (NHS) on the DNA binding by SLE sera. This was found to be due by the fact that, during incubation at 37 degrees C, CO2, introduced in the incubation mixture by the serum, evaporates from the mixture. This results in increase in pH to values well above pH 8.0, which in turn leads to a decreased DNA binding by antibody. When SLE sera are tested at low dilution, this phenomenon may lead to false negative results. Proper pH control, by the use of buffers with a greater buffering capacity than PBS, completely prevented the observed inhibitory effects. However, under these conditions NHS bound significant amounts of DNA in both assays. The non-specific DNA binding by NHS was found to be heat-stable, but could be eliminated either by aerosil treatment of the sera or by addition of dextran sulphate to the incubation mixture. Lipoproteins and, to a lesser extent, the complement component C1q appear responsible for this non-specific binding. To avoid false negative results with SLE sera as well as non-specific binding by NHS, we propose the use of stronger buffers in combination with added dextran sulphate to the incubation mixture in both the Farr assay and the PEG assay.
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