AB0601 RAPID AND SUSTAINED EFFICACY OF AN INDUCTION TREATMENT WITH A TRIPLE THERAPY INCLUDING HIGH-DOSE INTRAVENOUS IMMUNOGLOBULINS, METHOTREXATE AND GLUCOCORTICOIDS IN ANTI-3-HYDROXY-3-METHYLGLUTARYL-COENZYME A REDUCTASE MYOPATHY

Background:

Anti-3-hydroxy-3-methylglutaryl-coenzime A reductase (HMGCR) myopathy is a new entity, which has been clearly associated to statin use, even if it can be diagnosed in patients without a history of exposure to statin or even in the childhood (1).

Objectives:

The aim of the study is to describe the efficacy of a triple therapy regimen consisting in high-doses of intravenous immunoglobulins (IVIG), methotrexate (MTX), and glucocorticoids (GC) in 16 patients with Anti-HMGCR myopathy enrolled in 6 specialized centres.

Methods:

A total of 16 patients with anti-HMGCR myopathy (7 females; 9 males) were collected. Mean (±standard deviation) age at the onset of disease was 72.4±10.3 years old. All patients were diagnosed having anti-HMGCR myopathy [anti-HMGCR antibodies were measured by chemiluminescence assay (BioFlash, Inova, CA)] (2). Median follow-up was 29.5 months (interquartile range: 15.75-60 months). Anti-HMGCR antibodies were available in the follow-up in 8/16 patients.

Results:

Thirteen out of 16 patients (81.3%) had been exposed to statin (1/13 to red rice), 3/16 (18.7%) were not exposed. As induction therapy, 11/16 patients have been treated with triple therapy (high-dose IVIG, MTX and GC), 2/16 with double therapy (high-dose IVIG and GC), 2/16 have been treated with GC alone, the patient exposed to red rice resolved only with red rice suspension. Clinical remission and normalization of CPK values within month +24 were obtained in all the patients. All the patients were in remission at the last follow-up. Gradual improvement started soon from the first month, and among the 13 patients treated with an aggressive immunosuppresssive therapy including IVIG (13/13), GC (13/13) and methotrexate (11/13), 9/13 normalized the CPK value within 6 months. Clinical and laboratory response was accompanied by significant decrease or normalization of the anti-HMGCR antibody titer. All the patients were either not taking GC (56.3%), or were taking low doses of GC (43.7%) at the last follow-up. Four patients had stopped GC within 6 months. No serious side effects were recorded. After persistent remission, a maintenance immunosuppressive therapy was then administered. Only 3 relapses in 3 different cases were recorded, all of them during drug-free remission in long-term follow-up. Reinduction was again effective in all.

Conclusion:

Anti-HMGCR myopathy is a rare and serious myopathy which usually affects older people during statin treatment. After statin suspension, a rapid and sustained remission can be achieved by induction with a triple aggressive therapy consisting in medium-to high doses of GC, high-dose IVIG, and MTX (3). GC should be tapered as soon as possible. Relapse appears infrequent during maintenance treatment. Monitoring anti-HMGCR antibody titer may be clinically relevant.

References:

[1]AL Mammen et al. N Engl J Med. 2016;374:664-9

[2]Musset L et al. Autoimmun Rev. 2016;15:983-93.

[3]Aggarwal A et al. Scand J Rheumatol. 2019; 1-7.

Acknowledgments:

We thank MD Francesca Grosso and MD Valentina Mecheri from the University of Florence, MD Angela Zuppa and MD Chiara De Michelis, from San Martino Hospital, Genova, for their valued collaboration in data collection

Disclosure of Interests:

Elena Treppo: None declared, Maria Infantino: None declared, Maurizio Benucci: None declared, Viviana Ravagnani: None declared, Boaz Palterer: None declared, Marina Grandis: None declared, Martina Fabris: None declared, Paola Tomietto: None declared, Mariangela Manfredi: None declared, Arianna Sonaglia: None declared, Maria Grazia Giudizi: None declared, Francesca Ligobbi: None declared, Daniele Cammelli: None declared, Paola Parronchi: None declared, Salvatore De Vita Consultant of: Roche, GSK, Speakers bureau: Roche, GSK, Novartis, Luca Quartuccio Consultant of: Abbvie, Bristol, Speakers bureau: Abbvie, Pfizer

FRI0239 ANTI-NXP2 ANTIBODIES: CLINICAL AND SEROLOGICAL ASSOCIATIONS IN A MULTICENTRIC ITALIAN STUDY

Background:

anti-NXP2 antibodies is considered a serological marker of dermatomyositis (DM), with calcinosis, severe myositis and, in some series, cancer. Historically, these associations have been detected with immunoprecipitation (IP), but in the last few years commercial lineblot (LB) assay have been released.

Objectives:

to analyze the clinical features associated to anti-NXP2 antibodies, including the onset of concomitant cancers, both with LB and homemade IP

Methods:

clinical and serological data from medical charts of 213 patients with a diagnosis of inflammatory miosidites without anti-NXP2 (NXP2-), followed-up by two third-level Centers, and 61 anti-NXP2+ patients from 10 Rheumatological centers were analyzed. Anti-myositis specific (MSA) and anti-myositis associated antibodies (MAA) were detected in single centers by LB (Euroimmun Autoimmune Inflammatory Myopathies 16 antigens). Anti-NXP2 was confirmed by protein and RNA IP, as previously described (1)

Results:

clinical diagnosis of anti-NXP2+ positive with LB were 42 DM, 11 PM, inclusion body myositis (IBM) 4, necrotizing myositis and overlap (OM) 1 each. Anti-NXP2+ showed a lower age at onset (p<0.0001) more frequent diagnosis of DM (68.8%vs30%,OR5.2) and IBM (6.5%vs0.49%,OR14.8), typical skin manifestations, myositis (93%vs79% OR3.3), concomitant presence of another MSA (12.7%vs2%, OR6.41) and lower rate of features associated with OM or anti-synthetase syndrome. Serum from 49 NXP2+ was available and IP analysis was made with the confirmation of NXP2 in 31 sera (63.2%) with the following diagnosis: DM 27 cases, PM 3, IBM 1. Whilst the majority of the associations were confirmed comparing NXP2LB+/IP+ with the IIM NXP2-, some peculiar associations were found significant only for the double positive patients: dysphagia (53%vs 30%,OR 2.56) and calcinosis (22%vs6.5% OR4) whereas IBM diagnosis and the presence of concomitant MSA antibodies were lost. Survival time from cancer onset is shown in figure.

IP did not confirmed anti-NXP2 antibodies in 18 sera: in 4 cases at least one MSA/MAA was identified by IP; these 18 patients did not show differences when compared with 213 anti-NXP2-.

Conclusion:

Protein IP confirmed anti-NXP2 antibodies in 63% of LB+ sera. Double positive cases showed more typical DM features and rarely occurred in IIM not DM. Anti-NXP2 positivity by LB should be confirmed by other methods in order to correctly diagnose and characterize IIM patients.

References:

[1]Arthritis Res Ther 2012,30;14:R97

Acknowledgments:

Forum Italiano per la Ricerca Malattie Autoimmuni (FIRMA)

Disclosure of Interests:

Micaela Fredi: None declared, Ilaria Cavazzana: None declared, Angela Ceribelli: None declared, Maria Grazia Lazzaroni: None declared, Simone Barsotti: None declared, Maurizio Benucci: None declared, Lorenzo Cavagna: None declared, Ludovico De Stefano: None declared, Andrea Doria Consultant of: GSK, Pfizer, Abbvie, Novartis, Ely Lilly, Speakers bureau: UCB pharma, GSK, Pfizer, Janssen, Abbvie, Novartis, Ely Lilly, BMS, Giacomo Emmi: None declared, Marco Fornaro: None declared, Federica Furini: None declared, Roberto Gerli: None declared, Maria Grazia Giudizi: None declared, Marcello Govoni: None declared, Anna Ghirardello: None declared, Luca Iaccarino Speakers bureau: GSK, Pfizer, Janssen, Novartis, Florenzo Iannone Consultant of: Speaker and consulting fees from AbbVie, Eli Lilly, Novartis, Pfizer, Roche, Sanofi, UCB, MSD, Speakers bureau: Speaker and consulting fees from AbbVie, Eli Lilly, Novartis, Pfizer, Roche, Sanofi, UCB, MSD, Maria Infantino: None declared, Alessandro Mathieu: None declared, Emiliano Marasco: None declared, Paola Migliorini: None declared, Boaz Palterer: None declared, paola parronchi: None declared, Matteo Piga: None declared, Federico Pratesi: None declared, Antonella Radice: None declared, Carlo Selmi: None declared, Valeria Riccieri: None declared, Marilin Tampoia: None declared, Giovanni Zanframundo: None declared, Angela Tincani: None declared, Franco Franceschini: None declared

Immunoglobulin A antibodies to oxidized collagen type II as a potential biomarker for the stratification of spondyloarthritis from rheumatoid arthritis

OBJECTIVES

The discovery of diseased tissue-specific neoantigens offers the opportunity to develop important disease tissue-specific biomarkers that can help in the prediction, diagnosis, and stratification of diseases. This opportunity is specifically significant for autoimmune diseases where diagnostic biomarkers are not available. Inflammatory autoimmune diseases are commonly associated with local generation of large amounts of reactive oxidants. We have previously identified oxidative post-translationally modified (oxPTM) tissue-specific neoantigens in rheumatoid arthritis (RA) and type 1 diabetes that elicit an immune response. In the current study, we studied the presence and clinical significance of antibodies to oxPTM collagen type II (CII) in patients with spondyloarthritis (SpA).

METHOD

Levels of antibodies specific to native CII and oxPTM-CII were assessed by enzyme-linked immunosorbent assay.

RESULTS

Immunoglobulin G (IgG) binding to oxPTM-CII was observed in 52%, 83%, and 28% of serum samples from patients with axial spondyloarthritis (axSpA), RA, and psoriatic arthritis (PsA), respectively. Importantly, while strong IgA anti-oxPTM-CII responses were detected in axSpA and PsA patients, with 47% and 84% respective binders, no IgA anti-oxPTM-CII was detected in RA patients. IgA anti-oxPTM-CII reactivity in axSpA patients treated with biologics was higher and more frequent, with 85% binders compared to 9% binders in patients treated with synthetic disease-modifying anti-rheumatic drugs.

CONCLUSION

Our data imply that SpA and PsA are associated with the presence of antibodies to oxPTM-CII, suggesting that there may be a humoral component that may distinguish patients with SpA from RA. Our approach could be adapted to other diseases, particularly to inflammatory autoimmune diseases.

Autoantibody profile and clinical patterns in 619 Italian patients with cutaneous lupus erythematosus

BACKGROUND

Anti-nuclear antibodies (ANA), anti-extractable nuclear antigens (ENA) and anti-dsDNA antibodies are often associated with cutaneous lupus erythematosus (CLE), with variable frequency depending on skin subtype. However, specific data based on large case-series on the pathogenetic, diagnostic and prognostic meaning of such autoantibodies are still lacking.

OBJECTIVE

To characterize the correlations between CLE subtypes as well as LE-non-specific skin lesions and their autoantibody pattern.

METHODS

Epidemiological, clinical and immunopathological data of 619 Italian patients with CLE and LE-non-specific skin lesions were analysed. Differences in age, sex, clinical features and autoantibody profile were evaluated in each LE subgroup.

RESULTS

Anti-nuclear antibodies (P < 0.0001), anti-dsDNA (P < 0.0001), ENA (P = 0.001), anti-Sm (P = 0.001), anti-RNP (P = 0.004) and anti-histone (P = 0.005) antibodies were associated with SLE. A strong association between ANA (P < 0.0001) and anti-dsDNA (P < 0.0001) and female gender was also found: positive ANA and positive anti-dsDNA had a higher prevalence among females. Chronic CLE resulted to be negatively associated with ENA (OR = 0.51, P < 0.0001), anti-Ro/SSA (OR = 0.49, P < 0.0001) and anti-dsDNA (OR = 0.37, P < 0.0001). Intermittent CLE resulted to be negatively associated with ENA (OR = 0.50, P = 0.007) and ANA (OR = 0.61, P = 0.025). Subacute CLE resulted to be associated with ENA (OR = 5.19, P < 0.0001), anti-Ro/SSA (OR = 3.83, P < 0.0001), anti-Smith (OR = 2.95, P = 0.004) and anti-RNP (OR = 3.18, P = 0.007). Acute CLE resulted to be strongly associated with anti-dsDNA (OR = 6.0, P < 0.0001) and ANA (OR = 18.1, P < 0.0001). LE-non-specific skin lesions resulted to be significantly associated with systemic involvement. Livedo reticularis was significantly associated with ENA (P = 0.007) and anti-Ro/SSA (P = 0.036). Palpable purpura and periungual telangiectasia were significantly associated with ANA.

CONCLUSION

According to our findings, some well-known associations between CLE subtypes and autoantibody profile were confirmed; moreover, specific association between autoantibodies and LE-non-specific skin lesions was highlighted. A strict association between anti-ENA and anti-Ro/SSA antibodies and livedo reticularis, ANA and palpable purpura, and ANA and periungual telangiectasia was evidenced.

The burden of the variability introduced by the HEp-2 assay kit and the CAD system in ANA indirect immunofluorescence test

According to the recent recommendations of the American College of Rheumatology, ANA Task Force, IIF technique should be considered the gold standard in antinuclear antibodies (ANAs) testing. To overcome the lack of standardization, biomedical industries have developed several computer-aided diagnosis (CAD) systems. Two hundred and sixty-one consecutive samples with suspected autoimmune diseases were tested for ANA by means of IIF on routinely HEp-2 assay kit (Euroimmun AG). Assignment of result was made if consensus for positive/negative was reached by at least 2 out of 3 expert physicians. ANA-IIF was also carried out using 3 CAD systems: Zenit G-Sight (n = 84), Helios (n = 85) and NOVA View (n = 92); human evaluation was repeated on the same substrate of each CAD system (Immco, Aesku and Inova HEp-2 cells, respectively). To anonymize the results, we randomly named these three systems as A, B and C. We ran a statistical analysis computing several measures of agreement between the ratings, and we also improved the evaluation by using the Wilcoxon's test for nonparametric data. Agreement between the human readings on routinely HEp-2 assay kit and human readings on CAD HEp-2 assay was substantial for A (k = 0.82) and B (k = 0.72), and almost perfect for C (k = 0.89). Such readings were statistically different only in case A. Comparing experts' readings with the readings of CAD systems, when the samples were prepared using CAD HEp-2 assay kits, we found almost perfect agreement for B and C (k = 0.86; k = 0.82) and substantial agreement for A (k = 0.73). Again, human and CAD readings were statistically different only in A. When we compared the readings of medical experts on routinely HEp-2 assay kit with the output of the CAD systems that worked using their own slides, we found substantial agreement for all the systems (A: k = 0.62; B: k = 0.65; C: k = 0.71). Such readings were not statistically different. The change of the assay kit and/or the introduction of a CAD system affect the laboratory reporting, with an evident impact on the autoimmune laboratory workflow. The CAD systems may represent one of the most important novel elements of harmonization in the autoimmunity field, reducing intra- and inter-laboratory variability in a new vision of the diagnostic autoimmune platform.

The role of klotho in systemic sclerosis

The aim was to evaluate the role of klotho in the pathogenesis of systemic sclerosis (SSc), through the measurement of its serum concentration in SSc patients compared to healthy controls, and to assess the association with cutaneous and visceral involvement. Blood samples obtained from both SSc patients and healthy controls were analysed by an ELISA assay for the detection of human klotho. SSc patients were globally evaluated for disease activity and assessed through the modified Rodnan's Skin Score, Medsger's scale, pulmonary function tests, 2D-echocardiography, nailfold capillaroscopy and laboratory tests. Our cohort consisted of 69 SSc patients (61 females, mean age 64.5±12.5 years, median disease duration 9.0 (IQR 8) years) and 77 healthy controls (28 females, mean age 49.7±10.2 years). In the group of SSc patients, 19 (27.5%) suffered from a diffuse form of SSc. All patients were receiving IV prostanoids, and some of them were concomitantly treated with immunosuppressive drugs (prednisone, hydroxychloroquine, mofetil mycophenolate, methotrexate, cyclosporin A and azathioprine). The median serum concentration of klotho was significantly lower in patients compared to controls (0.23 ng/mL vs 0.60 ng/mL; p<0.001). However, Spearman's test showed no significant association between klotho serum levels and disease activity, concerning either clinical, laboratory or instrumental findings. Our data show a significant deficit of klotho in SSc patients although any significant association was detected between klotho serum concentration and the clinical, laboratory or instrumental features of the disease. However, due to the limits of the study, further investigations are required.

Jaccoud's arthropathy, an unusual manifestation of idiopathic retroperitoneal fibrosis: rapid improvement of symptoms after tocilizumab treatment

Jaccoud's arthropathy (JA) is a chronic, non erosive, rheumatoid-like deformity associated with rheumatic fever (RF) and systemic lupus erythematosus and with other diseases such as psoriatic arthritis, connective tissue diseases, hypocomplementemic urticarial vasculitis, infections, sarcoidosis and neoplasia. We described a case of JA in a patient with cutaneous psoriasis but with a particular disease evolution associated with idiopathic retropritoneal fibrosis (IRF), evaluated with computed tomography, magnetic resonance and 18F-FDG PET/ CT. The patient, following failure with steroids, methotrexate and etanercept, was treated with tocilizumab (8 mg/kg) once every 4 weeks for 6 months. A rapid improvement of symptoms and disappearance of 18F-FDG uptake was shown. We describe a review of literature of rheumatic manifestations of IRF and the possible role of interleukin-6 in the pathway of JA and IRF.

The impact of biological treatments on the anti-dsDNA and anti-nucleosome tests

Background Anti-double stranded DNA antibodies are a very heterogeneous group of antibodies, quite specific for systemic lupus erythematosus. Newer technologies, such as addressable laser bead immunoassays (ALBIA), show great potential as a diagnostic application. The production of anti-double stranded DNA antibodies is often encountered in inflammatory arthritis; however, literature reports that the actual onset of drug induced lupus in patients treated with biological drugs is a rare event. False positive results for anti-double stranded DNA and anti-nucleosome antibodies detected in patients with inflammatory arthritis treated with different biologics prompted the investigation of full autoantibody profiles to evaluate each biomarker's diagnostic performance in systemic lupus erythematosus. The aim of the study was to compare the diagnostic performance of anti-double stranded DNA antibody and anti-nucleosome antibody methods and to evaluate the value of simultaneously measuring anti-double stranded DNA and anti-nucleosome antibodies, along with other anti-nuclear antibody analytes, as biomarkers for systemic lupus erythematosus, using a more appropriate control cohort including inflammatory arthritis patients with a non-clinical drug induced lupus. Methods Anti-double stranded DNA and anti-nucleosome antibody levels were evaluated in 247 patient samples: 70 systemic lupus erythematosus, 177 disease controls (including 97 inflammatory arthritis during treatment with different biologics) using the Bio-Rad BioPlex® 2200. Results Anti-nucleosome antibodies demonstrated greater clinical sensitivity and specificity than anti-double stranded DNA antibodies. At the manufacturers' cut-off range, considering the two markers as a single or combined test, the "anti-double stranded DNA test or anti-nucleosome antibodies" was the most sensitive combination (0.400) with the best negative likelihood ratio (0.62) and negative predictive value (0.803). Conclusion Anti-nucleosome antibodies are a more sensitive and specific biomarker of systemic lupus erythematosus than anti-double stranded DNA antibodies. Anti-nucleosome antibodies and anti-double stranded DNA antibodies are independent and complementary markers of systemic lupus erythematosus diagnosis and, therefore, are strongly suggested as combined tests (positive predictive value = 0.938). Moreover, the combined use of the two tests may help to overcome the decreased specificity percentage of the anti-double stranded DNA test, when considering an inflammatory arthritis cohort under biological therapies. The ALBIA method for anti-nuclear specificity detection allows a full autoantibody assessment, resulting in a much higher clinical specificity for systemic lupus erythematosus in the presence of ≥3 positive markers and significantly more positive likelihood ratio when ≥2 positive markers are present.

Aseptic HLA B27-positive spondylodiscitis: decreased 18F-FDG uptake after etanercept treatment

We observed a 69-year old man suffering from HLA B27 ankylosing spondylitis with persistent night back pain. 18F-FDG-PET/CT showed an increased metabolism at the level of the spinal space of L2-L3, L3-L4 with increased uptake compatible with spondylodiscitis. He started therapy with etanercept 50 mg/week. After six months of treatment repeated testing showed no uptake of the discs and vertebral bodies.

Trial-based cost-effectiveness of abatacept for rheumatoid arthritis patients in Italy

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic, inflammatory disorder leading to disability and reduced quality of life. Effective treatment is a significant economic burden on the Italian healthcare system. Economic models in RA are commonly based on indirect treatment comparisons.

METHODS

This study assessed the cost-effectiveness of abatacept relative to adalimumab for RA in Italy based on a head-to-head trial by means of a cost-consequence analysis.

RESULTS

Health benefits based on the most stringent efficacy criteria were in favor of abatacept compared to adalimumab. Rates for more costly adverse events were higher for adalimumab compared to abatacept, which was reflected in the lower costs for abatacept (-€237,246 or -€237per patient).

CONCLUSION

The health economic value of abatacept compared with adalimumab from the perspective of the Italian NHS depends on the choice of health outcome. Health gains with abatacept were generally based on more stringent criteria and lower total costs.

Polymyalgia rheumatica: inflammation suppression with low dose of methylprednisolone or modified-release prednisone

OBJECTIVE

Polymyalgia rheumatica (PMR) is an inflammatory disease that affects people aged > 50 years, and is characterised by pain and morning stiffness in the shoulder and pelvic girdle with synovitis of the proximal joints and extra-articular synovial structures. It is currently mainly treated with glucocorticoids (GCs). The aim of the study was to evaluate changes in inflammatory markers and their correlations with cortisol levels after treatment with 6-methylprednisolone (6-MP) or modified-release prednisone (MR-P) in patients with "early" PMR.

PATIENTS AND METHODS

The study involved 81 GC-naïve with "early" PMR diagnosed on the basis of the 2012 EULAR/ACR criteria: 38 treated with 6-MP at a starting dose of 12 mg at 8.00 a.m, gradually tapered to 8, 4 and 2 mg/day, and 43 treated with MR-P at a starting dose of 10 mg at 10 p.m, tapered to 7, 5, 3, 2 and 1 mg. The markers of inflammation (ESR mm/h, CRP mg/dL and fibrinogen mg/dL), the circulating serum levels of cytokines (TNFa and IL-6), and morning serum cortisol levels were evaluated at baseline and during GC treatment.

RESULTS

There were significant differences between baseline and the end of treatment in the serum levels of IL-6 (5.3 ± 9.3 vs 2.8 ± 3.3 pg/mL; p < 0.05) and CRP (2.1 ± 3.3 vs 0.9 ± 1.7 mg/dL; p < 0.01) in the patients treated with MR-P, and in serum cortisol levels (15.8±6.4 vs 13.6+5.6 µg/dL; p < 0.01) in the patients treated with 6-MP. After the first month of treatment, 76.7% of the patients treated with MR-P had IL6 levels at or below the upper normal limit, whereas 52.6% of those treated with 6-MP had normal IL6 levels (p < 0.05). There was also a significant difference in the percentage of patients in whom the daily GC dose was tapered within eight months (6.7% in the MR-P group vs 25% in the 6-MP group; p < 0.001) and, by the end of the study, respectively 59.5% vs 35.1% patients were receiving a low GC dose or had discontinued treatment altogether (OR 2.7, 95% CI 1.0-6.77; p < 0.001). After six and 12 months, respectively 10.3% and 14.3% of the patients had discontinued MR-P, as against none of the patients treated with 6-MP (p < 0.05).

CONCLUSIONS

In this prospective observational study of PMR patients receiving low-dose GCs, the changes in inflammatory markers were similar in those treated with 6-MP or MR-P, whereas morning cortisol levels remained unchanged only in the MR-P group. During the first month of treatment, MR-P chronotherapy given at bedtime significantly decreased IL-6 levels. The percentage of patients stopping GC treatment was higher in the MR-P group than in the 6-MP group.

Pain in systemic sclerosis

Chronic pain is a healthcare problem that significantly affects the mental health, and the professional and private life of patients. It can complicate many disorders and represents a common symptom of rheumatologic diseases, but the data on its prevalence is still limited. Pain is a ubiquitous problem in systemic sclerosis (SSc). SSc-related pain has been studied on the basis of biomedical models and is considered a symptom caused by the disease activity or previous tissue damage. Effective pain management is a primary goal of the treatment strategy, although this symptom in SSc has not yet been investigated in detail. However, these patients do not all respond adequately to pharmacological pain therapies, therefore in these cases a multimodal approach needs to be adopted. This paper must be considered as retracted due to a plagiarism misconduct. See the Retraction note at: https://doi.org/10.4081/reumatismo.2018.1171

Highlights on novel technologies for the detection of antibodies to Ro60, Ro52, and SS-B

OBJECTIVE

We aimed to compare a chemiluminescent immunoassay (CIA, QUANTA Flash) on BIO-FLASH with a multiplex flow immunoassay (MFI) on BioPlex 2200 for the detection of antibodies to Ro60, Ro52, and SS-B.

METHODS

The study included 241 samples, from patients suffering from systemic autoimmune diseases (n = 108) as well as disease controls (n = 133). All samples were tested for anti-Ro52, anti-Ro60, and anti-SS-B (La) antibodies on QUANTA Flash (INOVA Diagnostics, San Diego, USA) and BioPlex 2200 (Bio-Rad Laboratories Inc., Hercules, USA). Discrepant samples were tested by two independent methods: BlueDot/ANA and QUANTRIX Microarray (both D-tek, Belgium).

RESULTS

The overall qualitative agreements were 95.4% (95% confidence interval, CI 92.0-97.7%) for anti-Ro52, 98.8% (95% CI 96.4-99.7%) for anti-Ro60, and 91.7% (95% CI 87.5-94.9%) for anti-SS-B antibodies. There were 34 discrepant samples among all assays (20 anti-SS-B, 11 anti-Ro52, 3 anti-Ro60). 30/33 of retested samples (by D-tek dot blot) agreed with the QUANTA Flash results. Similar findings were obtained with QUANTRIX Microarray kit.

CONCLUSION

QUANTA Flash and BioPlex 2200 show good qualitative agreement. The clinical performances were similar for anti-Ro52 and anti-Ro60 autoantibodies while differences were observed for anti-SS-B (La) antibodies.