uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Publications (10 of 171) Show all publications
Frodlund, M., Wetterö, J., Dahle, C., Dahlström, Ö., Skogh, T., Rönnelid, J. & Sjöwall, C. (2020). Longitudinal anti-nuclear antibody (ANA) seroconversion in systemic lupus erythematosus: a prospective study of Swedish cases with recent-onset disease. Clinical and Experimental Immunology, 199(3), 245-254
Open this publication in new window or tab >>Longitudinal anti-nuclear antibody (ANA) seroconversion in systemic lupus erythematosus: a prospective study of Swedish cases with recent-onset disease
Show others...
2020 (English)In: Clinical and Experimental Immunology, ISSN 0009-9104, E-ISSN 1365-2249, Vol. 199, no 3, p. 245-254Article in journal (Refereed) Published
Abstract [en]

Serum immunoglobulin (Ig)G anti-nuclear antibodies (ANA) detected by indirect immunofluorescence (IF) microscopy remains a hallmark of systemic lupus erythematosus (SLE). Whether or not IF-ANA status varies over time is controversial. We therefore designed a prospective study with longitudinal follow-up of patients with recent-onset SLE. The study population consisted of 54 recently diagnosed SLE cases, all meeting the 1982 American College of Rheumatology (ACR) and/or the 2012 Systemic Lupus International Collaborating Clinics (SLICC) criteria. Clinical follow-up data, including disease activity, organ damage and sera, were collected from clinical onset of SLE and onwards, in most cases yearly (0-96 months). IF-ANA was analysed on human epithelial cells-2 (HEp-2) cells and categorized regarding staining patterns. Using an addressable laser bead assay (FIDIS (TM) Connective profile), we measured IgG-ANA fine specificities against Ro52/SSA, Ro60/SSA, Sjogren's syndrome type B antigen (La/SSB), Smith antigen (Sm), Smith antigen/ribonucleoprotein (Sm/RNP), U1 RNP (U1RNP), dsDNA, ribosomal-P protein and histone. At baseline, all patients were judged ANA-positive at an abnormal titre corresponding to the 95th percentile of healthy blood donors, but seven of 54 patients (13%) lost ANA-positivity over time. Homogeneous (AC-1; 46%) and speckled (AC-4 or 5; 31%) were the most frequently observed patterns at inclusion, whereas 7% switched pattern at least once during follow-up. Established associations between ANA fine specificities and clinical data were confirmed. Levels of anti-Sm/RNP, but not of anti-dsDNA, correlated with clinical disease activity [modified SLE disease activity 2000 (mSLEDAI-2K)]. Our data indicate that a considerable proportion of Swedish patients with SLE lose ANA-positivity over time, whereas consistent staining patterns were frequent. The clinical and mechanistic relevance of ANA seroconversion remains uncertain. Further prospective evaluations in larger SLE populations with more diverse ethnicities are warranted.

Place, publisher, year, edition, pages
WILEY, 2020
Keywords
autoantibodies, autoimmunity, complement, human, systemic lupus erythematosus
National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-407629 (URN)10.1111/cei.13402 (DOI)000513952100007 ()31778219 (PubMedID)
Available from: 2020-03-31 Created: 2020-03-31 Last updated: 2020-03-31Bibliographically approved
Fox, B. J., Hockley, J., Rigsby, P., Dolman, C., Meroni, P. L. & Rönnelid, J. (2019). A WHO Reference Reagent for lupus (anti-dsDNA) antibodies: international collaborative study to evaluate a candidate preparation. Annals of the Rheumatic Diseases, 78(12), 1677-1680
Open this publication in new window or tab >>A WHO Reference Reagent for lupus (anti-dsDNA) antibodies: international collaborative study to evaluate a candidate preparation
Show others...
2019 (English)In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 78, no 12, p. 1677-1680Article in journal (Refereed) Published
Abstract [en]

Introduction

Antibodies against double-stranded DNA (anti-dsDNA) are a specific biomarker for systemic lupus erythematosus (SLE). The first WHO International Standard (IS) for anti-dsDNA (established in 1985), which was used to assign units to diagnostic tests, was exhausted over a decade ago.

Methods

Plasma from a patient with SLE was first evaluated in 42 European laboratories. The plasma was thereafter used by the National Institute for Biological Standards and Control to prepare a candidate WHO reference preparation for lupus (anti-dsDNA) antibodies. That preparation, coded 15/174, was subjected to an international collaborative study, including 36 laboratories from 17 countries.

Results

The plasma mainly contained anti-dsDNA, other anti-chromatin antibodies and anti-Ku. The international collaborative study showed that the field would benefit from 15/174 as a common reference reagent improving differences in performance between different assays. However, no statistically meaningful overall potency or assay parallelism and commutability could be shown.

Conclusion

15/174 cannot be considered equivalent to the first IS for anti-dsDNA (Wo/80) and was established as a WHO Reference Reagent for lupus (oligo-specific) anti-dsDNA antibodies with a nominal value of 100 units/ampoule. This preparation is intended to be used to align test methods quantifying levels of anti-dsDNA antibodies.

National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-400760 (URN)10.1136/annrheumdis-2019-215845 (DOI)000500726200023 ()31488407 (PubMedID)
Available from: 2020-01-03 Created: 2020-01-03 Last updated: 2020-01-03Bibliographically approved
Boman, A., Brink, M., Lundquist, A., Hansson, M., Mathsson Alm, L., Rönnelid, J., . . . Rantapää-Dahlqvist, S. (2019). Antibodies against citrullinated peptides are associated with clinical and radiological outcomes in patients with early rheumatoid arthritis: a prospective longitudinal inception cohort study. RMD Open, 5(2), Article ID e000946.
Open this publication in new window or tab >>Antibodies against citrullinated peptides are associated with clinical and radiological outcomes in patients with early rheumatoid arthritis: a prospective longitudinal inception cohort study
Show others...
2019 (English)In: RMD Open, E-ISSN 2056-5933, Vol. 5, no 2, article id e000946Article in journal (Refereed) Published
Abstract [en]

Introduction: Anticitrullinated peptide antibody (ACPA) responses for 22 citrullinated peptides in patients with early rheumatoid arthritis (RA) were analysed and related to radiological and clinical outcome during the first 2 years in a prospective inception cohort.

Methods: The ACPA reactivities were assessed in 1022 patients with early RA (symptoms <12 months) using the custom-made microarray chip (Thermo Fisher Scientific, Uppsala, Sweden) in a prospective longitudinal study of observational assessments of Disease Activity Score (DAS28 and its components) and radiology during the first 24 months, accounting for the treatment.

Results: Frequency of ACPA reactivities varied between 13.3% and 63.1%. Of the anticyclic citrullinated peptide-2 (anti-CCP2) antibody-negative patients, ACPA reactivities were positive in 32.6%. Smoking, human leucocyte antigen-shared epitope ( HLA-SE), anti-CCP2/rheumatoid factor, protein tyrosine phosphatase nonreceptor type 22 (1858C/ T) and DAS28 were significantly associated with number of ACPA reactivities. The ACPA reactivities modified differently the development of DAS28 over 24 months (identified using trajectories). Anti-Filaggrin307-324, anti-hnRNP (Peptide)-Z1 and anti-F4-CIT-R antibodies anticipated lower DAS28 values (p<0.01-0.05), while positivity for anti-Fibrinogen(Fib) beta 62-78(74), and anti-Fiba563-583 predicted higher DAS28 (p<0.01 both). Interaction between anti-Fib beta 36-52, anti-Pept-5 and anti-Bla-26 antibodies, respectively, and DAS28 during 24 months decreased significantly the DAS28 values (p<0.01-0.05). Corticosteroids and biologicals were related to DAS28-area under the curve and Larsen score 24 months. Anti-vimentin2-17 antibodies remained significantly associated with Larsen score at baseline and 24 months, respectively, and radiological progression, besides biologicals at 24 months adjusted for sex and age.

Conclusions: Several ACPA reactivities modified significantly the DAS28 development during the first 24 months and were significantly associated with Larsen score at baseline, 24 months and radiological progression.

Place, publisher, year, edition, pages
BMJ PUBLISHING GROUP, 2019
National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-398011 (URN)10.1136/rmdopen-2019-000946 (DOI)000496133800042 ()31565241 (PubMedID)
Funder
Swedish Research Council, K2013-52X-2030707-3Swedish Research Council, Dnr:2018-02551Swedish Rheumatism Association
Available from: 2019-12-04 Created: 2019-12-04 Last updated: 2019-12-04Bibliographically approved
Idborg, H., Zandian, A., Ossipova, E., Wigren, E., Preger, C., Mobarrez, F., . . . Jakobsson, P.-J. (2019). Circulating Levels of Interferon Regulatory Factor-5 Associates With Subgroups of Systemic Lupus Erythematosus Patients.. Frontiers in Immunology, 10, Article ID 1029.
Open this publication in new window or tab >>Circulating Levels of Interferon Regulatory Factor-5 Associates With Subgroups of Systemic Lupus Erythematosus Patients.
Show others...
2019 (English)In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 10, article id 1029Article in journal (Refereed) Published
Abstract [en]

Systemic Lupus Erythematosus (SLE) is a heterogeneous autoimmune disease, which currently lacks specific diagnostic biomarkers. The diversity within the patients obstructs clinical trials but may also reflect differences in underlying pathogenesis. Our objective was to obtain protein profiles to identify potential general biomarkers of SLE and to determine molecular subgroups within SLE for patient stratification. Plasma samples from a cross-sectional study of well-characterized SLE patients (n = 379) and matched population controls (n = 316) were analyzed by antibody suspension bead array targeting 281 proteins. To investigate the differences between SLE and controls, Mann-Whitney U-test with Bonferroni correction, generalized linear modeling and receiver operating characteristics (ROC) analysis were performed. K-means clustering was used to identify molecular SLE subgroups. We identified Interferon regulating factor 5 (IRF5), solute carrier family 22 member 2 (SLC22A2) and S100 calcium binding protein A12 (S100A12) as the three proteins with the largest fold change between SLE patients and controls (SLE/Control = 1.4, 1.4, and 1.2 respectively). The lowest p-values comparing SLE patients and controls were obtained for S100A12, Matrix metalloproteinase-1 (MMP1) and SLC22A2 (padjusted = 3 × 10-9, 3 × 10-6, and 5 × 10-6 respectively). In a set of 15 potential biomarkers differentiating SLE patients and controls, two of the proteins were transcription factors, i.e., IRF5 and SAM pointed domain containing ETS transcription factor (SPDEF). IRF5 was up-regulated while SPDEF was found to be down-regulated in SLE patients. Unsupervised clustering of all investigated proteins identified three molecular subgroups among SLE patients, characterized by (1) high levels of rheumatoid factor-IgM, (2) low IRF5, and (3) high IRF5. IRF5 expressing microparticles were analyzed by flow cytometry in a subset of patients to confirm the presence of IRF5 in plasma and detection of extracellular IRF5 was further confirmed by immunoprecipitation-mass spectrometry (IP-MS). Interestingly IRF5, a known genetic risk factor for SLE, was detected extracellularly and suggested by unsupervised clustering analysis to differentiate between SLE subgroups. Our results imply a set of circulating molecules as markers of possible pathogenic importance in SLE. We believe that these findings could be of relevance for understanding the pathogenesis and diversity of SLE, as well as for selection of patients in clinical trials.

Keywords
Interferon regulating factor 5 (IRF5), SLE - Systemic Lupus Erythematous, antibody suspension bead arrays, biomarker discovery, hierarchical clustering, plasma proteomics, subgroups, unsupervised clustering
National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-385062 (URN)10.3389/fimmu.2019.01029 (DOI)000468162000001 ()31156624 (PubMedID)
Funder
Swedish Research Council, 2017-02577Swedish Research Council, 2018-02399Swedish Research Council, 2018-02535Swedish Research Council, 2018-02000Stockholm County Council, 20160378Stockholm County Council, 20170038Swedish Rheumatism Association, R-748261Swedish Rheumatism Association, R-755861Swedish Rheumatism Association, R-753741Swedish Rheumatism Association, R-850611Swedish Rheumatism Association, R-739631Swedish Society of Medicine
Available from: 2019-06-10 Created: 2019-06-10 Last updated: 2019-06-11Bibliographically approved
Phuong, T. N., Ngoc, L. N., Xuan, H. N., Rönnelid, J., Padyukov, L. & Lundberg, I. E. (2019). Clinical phenotype, autoantibody profile and HLA-DR-type in Vietnamese patients with idiopathic inflammatory myopathies [Letter to the editor]. Rheumatology, 58(2), 361-363
Open this publication in new window or tab >>Clinical phenotype, autoantibody profile and HLA-DR-type in Vietnamese patients with idiopathic inflammatory myopathies
Show others...
2019 (English)In: Rheumatology, ISSN 1462-0324, E-ISSN 1462-0332, Vol. 58, no 2, p. 361-363Article in journal, Letter (Other academic) Published
Place, publisher, year, edition, pages
Oxford University Press, 2019
National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-379424 (URN)10.1093/rheumatology/key313 (DOI)000459631600027 ()30371850 (PubMedID)
Funder
Swedish Research Council, K2014-52X-14045-14
Available from: 2019-03-19 Created: 2019-03-19 Last updated: 2019-03-19Bibliographically approved
Espinosa-Ortega, F., Holmqvist, M., Alexanderson, H., Storfors, H., Mimori, T., Lundberg, I. E. & Rönnelid, J. (2019). Comparison of autoantibody specificities tested by a line blot assay and immunoprecipitation-based algorithm in patients with idiopathic inflammatory myopathies [Letter to the editor]. Annals of the Rheumatic Diseases, 78(6), 858-860
Open this publication in new window or tab >>Comparison of autoantibody specificities tested by a line blot assay and immunoprecipitation-based algorithm in patients with idiopathic inflammatory myopathies
Show others...
2019 (English)In: Annals of the Rheumatic Diseases, ISSN 0003-4967, E-ISSN 1468-2060, Vol. 78, no 6, p. 858-860Article in journal, Letter (Refereed) Published
Place, publisher, year, edition, pages
BMJ Publishing Group Ltd, 2019
National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-389919 (URN)10.1136/annrheumdis-2018-214690 (DOI)000471072800041 ()30760469 (PubMedID)
Funder
Swedish Research CouncilKing Gustaf V Jubilee Fund
Available from: 2019-08-02 Created: 2019-08-02 Last updated: 2019-08-02Bibliographically approved
Hedström, A. K., Rönnelid, J., Klareskog, L. & Alfredsson, L. (2019). Complex Relationships of Smoking, HLA-DRB1 Genes, and Serologic Profiles in Patients With Early Rheumatoid Arthritis: Update From a Swedish Population-Based Case-Control Study. Arthritis & Rheumatology, 71(9), 1504-1511
Open this publication in new window or tab >>Complex Relationships of Smoking, HLA-DRB1 Genes, and Serologic Profiles in Patients With Early Rheumatoid Arthritis: Update From a Swedish Population-Based Case-Control Study
2019 (English)In: Arthritis & Rheumatology, ISSN 2326-5191, E-ISSN 2326-5205, Vol. 71, no 9, p. 1504-1511Article in journal (Refereed) Published
Abstract [en]

Objective Smoking is associated with an increased risk of rheumatoid arthritis (RA) in subsets of patients defined according to the presence or absence of anti-citrullinated protein antibodies (ACPAs) and rheumatoid factors (RFs). Moreover, an interaction between smoking and the HLA-DRB1 shared epitope (SE) has been demonstrated to be a risk factor for seropositive RA. The aim of this study was to investigate the interplay between smoking and the HLA-DRB1 SE with regard to risk of RA in different patient subsets based on ACPA and RF status. Methods Incident cases of RA (3,645 cases, 5,883 matched controls) were divided into 4 subgroups based on the presence or absence of RF and anti-cyclic citrullinated peptide 2 (anti-CCP2) antibodies. The influence of smoking on the risk of disease was determined in each RA subgroup, using logistic regression models with calculation of odds ratios and 95% confidence intervals (95% CIs). The potential interaction between smoking and HLA-DRB1 SE genes was evaluated by calculating the attributable proportion due to interaction (AP). Results In the RF+/anti-CCP2+ subset of RA patients, both smoking and the presence of the HLA-DRB1 SE conferred independent disease risks, and there was a strong interaction between the 2 risk factors (AP 0.4, 95% CI 0.3, 0.5). In the RF-/anti-CCP2+ patient subset, the HLA-DRB1 SE conferred an increased risk of RA, whereas the independent influence of smoking was limited. However, there was a significant interaction between the HLA-DRB1 SE and smoking (AP 0.2, 95% CI 0.02, 0.5). In the RF+/anti-CCP2- patient subset, there was an increased risk of disease among smokers, which was only marginally affected by the presence of the HLA-DRB1 SE, and no interaction between the 2 factors was observed (AP 0.002, 95% CI -0.3, 0.3). In the RF-/anti-CCP2- patient subset, neither smoking nor the presence of the HLA-DRB1 SE conferred an increased risk of RA. Conclusion These findings demonstrate different effects of smoking and HLA-DRB1 in the 4 serologically defined RA subsets.

Place, publisher, year, edition, pages
WILEY, 2019
National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-395557 (URN)10.1002/art.40852 (DOI)000480453400001 ()30742363 (PubMedID)
Funder
Forte, Swedish Research Council for Health, Working Life and Welfare
Available from: 2019-10-21 Created: 2019-10-21 Last updated: 2019-11-08Bibliographically approved
Lloyd, K. A., Wigerblad, G., Sahlstrom, P., Garimella, M. G., Chemin, K., Steen, J., . . . Gronwall, C. (2019). Differential ACPA Binding to Nuclear Antigens Reveals a PAD-Independent Pathway and a Distinct Subset of Acetylation Cross-Reactive Autoantibodies in Rheumatoid Arthritis. Frontiers in Immunology, 9, 1-22, Article ID 3033.
Open this publication in new window or tab >>Differential ACPA Binding to Nuclear Antigens Reveals a PAD-Independent Pathway and a Distinct Subset of Acetylation Cross-Reactive Autoantibodies in Rheumatoid Arthritis
Show others...
2019 (English)In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 9, p. 1-22, article id 3033Article in journal (Refereed) Published
Abstract [en]

Rheumatoid arthritis (RA) associated anti-citrullinated protein autoantibodies (ACPA) target a wide range of modified proteins. Citrullination occurs during physiological processes such as apoptosis, yet little is known about the interaction of ACPA with nuclear antigens or apoptotic cells. Since uncleared apoptotic cells and neutrophil extracellular trap (NET) products have been postulated to be central sources of autoantigen and immunostimulation in autoimmune disease, we sought to characterize the anti-nuclear and anti-neutrophil reactivities of ACFA. Serology showed that a subset of anti-CCP2 seropositive RA patients had high reactivity to full-length citrullinated histones. In contrast, seronegative RA patients displayed elevated IgG reactivity to native histone compared to controls, but no citrulline-specific reactivity. Screening of 10 single B-cell derived monoclonal AGFA from RA patients revealed that four ACPA exhibited strong binding to apoptotic cells and three of these had anti-nuclear (ANA) autoantibody reactivity. Modified histones were confirmed to be the primary targets of this anti-nuclear ACPA subset following immunoprecipitation from apoptotic cell lysates. Monoclonal ACPA were also screened for reactivities against stimulated murine and human neutrophils, and all the nuclear-reactive monoclonal ACPA bound to NETs. Intriguingly, one ACPA mAb displayed a contrasting cytoplasmic perinuclear neutrophil binding and may represent a different NET-reactive ACPA subset. Notably, studies of CRISPR-Cas9 PAD4 KO cells and cells from PAD KO mice showed that the cytoplasmic NET-binding was fully dependent on PAD4, whilst nuclear- and histone-mediated NEI reactivity was largely PAD-independent. Our further analysis revealed that the nuclear binding could be explained by consensus-motif driven ACPA cross-reactivity to acetylated histones. Specific acetylated histone peptides targeted by the monoclonal antibodies were identified and the anti-modified protein autoantibody (AMPA) profile of the ACPA was found to correlate with the functional activity of the antibodies. In conclusion, when investigating monoclonal ACPA, we could group ACPA into distinct subsets based on their nuclear binding-patterns and acetylation-mediated binding to apoptotic cells, neutrophils, and NETs. Differential anti-modified protein reactivities of RA-autoantibody subsets could have an important functional impact and provide insights in RA pathogenesis.

Keywords
anti-citrullinated protein autoantibodies, acetylation, rheumatoid arthritis, anti-CCP, PAD4, apoptosis, neutrophil extracellular traps (NETs), ANA
National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-374429 (URN)10.3389/fimmu.2018.03033 (DOI)000454910500001 ()30662440 (PubMedID)
Funder
Swedish Research CouncilSwedish Rheumatism Association
Available from: 2019-01-28 Created: 2019-01-28 Last updated: 2019-01-28Bibliographically approved
Terao, C., Brynedal, B., Chen, Z., Jiang, X., Westerlind, H., Hansson, M., . . . Raychaudhuri, S. (2019). Distinct HLA Associations with Rheumatoid Arthritis Subsets Defined by Serological Subphenotype. American Journal of Human Genetics, 105(3), 616-624
Open this publication in new window or tab >>Distinct HLA Associations with Rheumatoid Arthritis Subsets Defined by Serological Subphenotype
Show others...
2019 (English)In: American Journal of Human Genetics, ISSN 0002-9297, E-ISSN 1537-6605, Vol. 105, no 3, p. 616-624Article in journal (Refereed) Published
Abstract [en]

Rheumatoid arthritis (RA) is the most common immune-mediated arthritis. Anti-citrullinated peptide antibodies (ACPA) are highly specific to RA and assayed with the commercial CCP2 assay. Genetic drivers of RA within the MHC are different for CCP2-positive and -negative subsets of RA, particularly at HLA-DRB1. However, aspartic acid at amino acid position 9 in HLA-B (BPpos-9) increases risk to both RA subsets. Here we explore how individual serologies associated with RA drive associations within the MHC. To define MHC differences for specific ACPA serologies, we quantified a total of 19 separate ACPAs in RA-affected case subjects from four cohorts (n = 6,805). We found a cluster of tightly co-occurring antibodies (canonical serologies, containing CCP2), along with several independently expressed antibodies (non-canonical serologies). After imputing HLA variants into 6,805 case subjects and 13,467 control subjects, we tested associations between the HLA region and RA subgroups based on the presence of canonical and/or non-canonical serologies. We examined CCP2(+) and CCP2(-) RA-affected case subjects separately. In CCP2(-) RA, we observed that the association between CCP2(-) RA and BPpos-9 was derived from individuals who were positive for non-canonical serologies (omnibus_p = 9.2 x 10(-17)). Similarly, we observed in CCP2(+) RA that associations between subsets of CCP2(+) RA and BPpos-9 were negatively correlated with the number of positive canonical serologies (p = 0.0096). These findings suggest unique genetic characteristics underlying fine-specific ACPAs, suggesting that RA may be further subdivided beyond simply seropositive and seronegative.

Place, publisher, year, edition, pages
CELL PRESS, 2019
National Category
Rheumatology and Autoimmunity
Identifiers
urn:nbn:se:uu:diva-394686 (URN)10.1016/j.ajhg.2019.08.002 (DOI)000484435700014 ()31474319 (PubMedID)
Funder
Swedish Research CouncilForte, Swedish Research Council for Health, Working Life and Welfare
Available from: 2019-10-30 Created: 2019-10-30 Last updated: 2019-10-30Bibliographically approved
Dellavance, A., Baldo, D. C., Zheng, B., Mora, R. A., Fritzler, M. J., Hiepe, F., . . . Andrade, L. E. C. (2019). Establishment of an international autoantibody reference standard for human anti-DFS70 antibodies: proof-of-concept study for a novel Megapool strategy by pooling individual specific sera. Clinical Chemistry and Laboratory Medicine, 57(11), 1754-1763
Open this publication in new window or tab >>Establishment of an international autoantibody reference standard for human anti-DFS70 antibodies: proof-of-concept study for a novel Megapool strategy by pooling individual specific sera
Show others...
2019 (English)In: Clinical Chemistry and Laboratory Medicine, ISSN 1434-6621, E-ISSN 1437-4331, Vol. 57, no 11, p. 1754-1763Article in journal (Refereed) Published
Abstract [en]

Background: International autoantibody standards, traditionally based on material obtained from plasmapheresis of single subjects, represent individual immune response and may not comprehend the heterogeneity of the general population. The anti-DFS70 autoantibody yields a characteristic dense fine speckled (DFS) nuclear pattern on indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) and speaks against autoimmunity. We propose a novel strategy for developing autoantibody reference standards, based on stepwise pooling of serum samples from hundreds of individuals with anti-DFS70 antibodies.

Methods: Within a 2-year period, serum samples were selected from routine HEp-2 IFA according to the following criteria: DFS HEp-2 IFA pattern at titer >= 1:640; anti-DFS70 reactivity in three analyte-specific tests (Western blot [WB], enzyme-linked immunosorbent assay [ELISA] and chemiluminescent immunoassay [CLIA]). Aliquots of individual samples were combined into progressively larger pools with stepwise validation of intermediary pools as for individual samples. Validated intermediary pools were merged into a final pool for lyophilization.

Results: A total of 741 validated samples yielded a 750 mL final pool that was lyophilized into thousands of 200 mu L-aliquots. Reconstituted aliquots yielded the expected anti-DFS70 reactivity in ELISA, CLIA and WB, as well as high-titer DFS HEp-2 IFA pattern. The appropriate antiDFS70 reactivity of the lyophilized pool was confirmed by seven international expert centers, using HEp-2 IFA, ELISA, WB and immunoprecipitation.

Conclusions: This proof-of-concept study provides an innovative and efficient strategy to build serum reference standards for autoantibody testing. The anti-DFS70 standard will integrate the panel of standards of Autoantibody Standardization Committee (ASC, www.autoab.org ), contributing to education for proper assay validation and interpretation of the DFS pattern and other HEp-2 IFA patterns.

Place, publisher, year, edition, pages
WALTER DE GRUYTER GMBH, 2019
Keywords
antinuclear antibodies, autoantibodies, autoimmunity testing, DFS70, HEp-2 cells, reference standards
National Category
Immunology in the medical area
Identifiers
urn:nbn:se:uu:diva-396699 (URN)10.1515/cclm-2019-0087 (DOI)000489114100021 ()31005948 (PubMedID)
Available from: 2019-11-08 Created: 2019-11-08 Last updated: 2019-11-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1186-3226

Search in DiVA

Show all publications