Agreement between local and central anti-synthetase antibodies detection: results from the Classification Criteria of Anti-Synthetase Syndrome project biobank

OBJECTIVES

The CLASS (Classification Criteria of Anti-Synthetase Syndrome) project is a large international multicentre study that aims to create the first data-driven anti-synthetase syndrome (ASSD) classification criteria. Identifying anti-aminoacyl tRNA synthetase antibodies (anti-ARS) is crucial for diagnosis, and several commercial immunoassays are now available for this purpose. However, using these assays risks yielding false-positive or false-negative results, potentially leading to misdiagnosis. The established reference standard for detecting anti-ARS is immunoprecipitation (IP), typically employed in research rather than routine autoantibody testing. We gathered samples from participating centers and results from local anti-ARS testing. As an "ad-interim" study within the CLASS project, we aimed to assess how local immunoassays perform in real-world settings compared to our central definition of anti-ARS positivity.

METHODS

We collected 787 serum samples from participating centres for the CLASS project and their local anti-ARS test results. These samples underwent initial central testing using RNA-IP. Following this, the specificity of ARS was reconfirmed centrally through ELISA, line-blot assay (LIA), and, in cases of conflicting results, protein-IP. The sensitivity, specificity, positive likelihood ratio and positive and negative predictive values were evaluated. We also calculated the inter-rater agreement between central and local results using a weighted κ co-efficient.

RESULTS

Our analysis demonstrates that local, real-world detection of anti-Jo1 is reliable with high sensitivity and specificity with a very good level of agreement with our central definition of anti-Jo1 antibody positivity. However, the agreement between local immunoassay and central determination of anti-non-Jo1 antibodies varied, especially among results obtained using local LIA, ELISA and "other" methods.

CONCLUSIONS

Our study evaluates the performance of real-world identification of anti-synthetase antibodies in a large cohort of multi-national patients with ASSD and controls. Our analysis reinforces the reliability of real-world anti-Jo1 detection methods. In contrast, challenges persist for anti-non-Jo1 identification, particularly anti-PL7 and rarer antibodies such as anti-OJ/KS. Clinicians should exercise caution when interpreting anti-synthetase antibodies, especially when commercial immunoassays test positive for non-anti-Jo1 antibodies.

Relapse after cessation of weekly tocilizumab for giant cell arteritis: a multicentre service evaluation in England

OBJECTIVES

The National Health Service in England funds 12 months of weekly subcutaneous tocilizumab (qwTCZ) for patients with relapsing or refractory giant cell arteritis (GCA). During the COVID-19 pandemic, some patients were allowed longer treatment. We sought to describe what happened to patients after cessation of qwTCZ.

METHODS

Multicentre service evaluation of relapse after stopping qwTCZ for GCA. The log-rank test was used to identify significant differences in time to relapse.

RESULTS

336 GCA patients were analysed from 40 centres, treated with qwTCZ for a median (interquartile range, IQR) of 12 (12-17) months. At time of stopping qwTCZ, median (IQR) prednisolone dose was 2 (0-5) mg/day. By 6, 12 and 24 months after stopping qwTCZ, 21.4%, 35.4% and 48.6% respectively had relapsed, requiring an increase in prednisolone dose to a median (IQR) of 20 (10-40) mg/day. 33.6% of relapsers had a major relapse as defined by EULAR. Time to relapse was shorter in those that had previously also relapsed during qwTCZ treatment (P = 0.0017); in those not in remission at qwTCZ cessation (P = 0.0036); and in those with large vessel involvement on imaging (P = 0.0296). Age ≥65, gender, GCA-related sight loss, qwTCZ treatment duration, TCZ taper, prednisolone dosing, and conventional synthetic DMARD use were not associated with time to relapse.

CONCLUSION

Up to half our patients with GCA relapsed after stopping qwTCZ, often requiring a substantial increase in prednisolone dose. One third of relapsers had a major relapse. Extended use of TCZ or repeat treatment for relapse should be considered for these patients.

Distinct HLA associations with autoantibody-defined subgroups in idiopathic inflammatory myopathies

BACKGROUND

In patients with idiopathic inflammatory myopathies (IIM), autoantibodies are associated with specific clinical phenotypes suggesting a pathogenic role of adaptive immunity. We explored if autoantibody profiles are associated with specific HLA genetic variants and clinical manifestations in IIM.

METHODS

We included 1348 IIM patients and determined the occurrence of 14 myositis-specific or -associated autoantibodies. We used unsupervised cluster analysis to identify autoantibody-defined subgroups and logistic regression to estimate associations with clinical manifestations, HLA-DRB1, HLA-DQA1, HLA-DQB1 alleles, and amino acids imputed from genetic information of HLA class II and I molecules.

FINDINGS

We identified eight subgroups with the following dominant autoantibodies: anti-Ro52, -U1RNP, -PM/Scl, -Mi2, -Jo1, -Jo1/Ro52, -TIF1γ or negative for all analysed autoantibodies. Associations with HLA-DRB1∗11, HLA-DRB1∗15, HLA-DQA1∗03, and HLA-DQB1∗03 were present in the anti-U1RNP-dominated subgroup. HLA-DRB1∗03, HLA-DQA1∗05, and HLA-DQB1∗02 alleles were overrepresented in the anti-PM/Scl and anti-Jo1/Ro52-dominated subgroups. HLA-DRB1∗16, HLA-DRB1∗07 alleles were most frequent in anti-Mi2 and HLA-DRB1∗01 and HLA-DRB1∗07 alleles in the anti-TIF1γ subgroup. The HLA-DRB1∗13, HLA-DQA1∗01 and HLA-DQB1∗06 alleles were overrepresented in the negative subgroup. Significant signals from variations in class I molecules were detected in the subgroups dominated by anti-Mi2, anti-Jo1/Ro52, anti-TIF1γ, and the negative subgroup.

INTERPRETATION

Distinct HLA class II and I associations were observed for almost all autoantibody-defined subgroups. The associations support autoantibody profiles use for classifying IIM which would likely reflect underlying pathogenic mechanisms better than classifications based on clinical symptoms and/or histopathological features.

FUNDING

See a detailed list of funding bodies in the Acknowledgements section at the end of the manuscript.

Incidence of giant cell arteritis is associated with COVID-19 prevalence: A population-level retrospective study

Background

Following the first wave of the COVID-19 pandemic, it was observed that giant cell arteritis (GCA) diagnoses increased at the Royal National Hospital for Rheumatic Diseases (RNHRD) in Bath, UK. This finding may support the viral aetiology hypothesis of GCA. Better understanding of the causes of GCA may help improve diagnostic and treatment strategies leading to better outcomes for patients.

Objectives

The study aims to estimate the local incidence of GCA during the early COVID-19 pandemic (2020-2021) and compare it to pre-pandemic (2015-2019) data. This study will also evaluate the temporal relationship between COVID-19 infections and GCA diagnoses.

Methods

Annual incidence rates of GCA were calculated between 2015 and 2021. Local COVID-19 prevalence was estimated by measuring the number of hospital beds taken up by COVID-19 positive patients. Poisson statistics were used to compare the annual mean incidence of GCA between 2019 and 2020, and Granger causality tested the temporal relationship between COVID-19 prevalence and GCA incidence.

Results

There were 60 (95% confidence interval [CI] 46-77) GCA diagnoses made in 2020 compared to 28 (CI 19-41) in 2019 (P = 0.016). Peaks in the number of COVID-19 inpatients correlated with peaks in GCA diagnoses. Granger causality testing found a statistically significant association between these peaks with a lag period of 40-45 days.

Conclusion

The incidence of GCA in Bath was significantly increased in 2020 and 2021 compared to 2015-2019. The lag period between peaks was 40-45 days, suggesting that the COVID-19 virus may be a precipitating factor for GCA. More work is currently underway to interrogate the causal relationship between these two diseases.

Health outcomes of penicillin allergy testing in children: a systematic review

BACKGROUND

Penicillin allergy labels are commonly acquired in childhood and lead to avoidance of first-line penicillin antibiotics. Understanding the health outcomes of penicillin allergy testing (PAT) can strengthen its place in antimicrobial stewardship efforts.

OBJECTIVES

To identify and summarize the health outcomes of PAT in children.

METHODS

Embase, MEDLINE, Web of Science, Cochrane Library, SCOPUS and CINAHL were searched from inception to 11 Oct 2021 (Embase and MEDLINE updated April 2022). Studies that utilized in vivo PAT in children (≤18 years old) and reported outcomes relevant to the study objectives were included.

RESULTS

Thirty-seven studies were included in the review, with a total of 8411 participants. The most commonly reported outcomes were delabelling, subsequent penicillin courses, and tolerability to penicillin courses. Ten studies had patient-reported tolerability to subsequent penicillin use, with a median 93.6% (IQR 90.3%-97.8%) of children tolerating a subsequent course of penicillins. In eight studies, a median 97.3% (IQR 96.4%-99.0%) of children were reported as 'delabelled' after a negative PAT without further definition. Three separate studies verified delabelling by checking electronic or primary care medical records, where 48.0%-68.3% children were delabelled. No studies reported on outcomes relating to disease burden such as antibiotic resistance, mortality, infection rates or cure rates.

CONCLUSIONS

Safety and efficacy of PAT and subsequent penicillin use was the focus of existing literature. Further research is required to determine the long-term impact of delabelling penicillin allergies on disease burden.

OP0160 HLA-DRB1 ASSOCIATIONS WITH AUTOANTIBODY-DEFINED SUBGROUPS IN IDIOPATHIC INFLAMMATORY MYOPATHIES (IIM)

Background

There is a gap between how IIM patients are classified in practice and current validated classification criteria1. Also, different associations with genetic variations in HLA can inform about different T-cell mechanisms involved in disease pathogenesis.

Objectives

We aimed to systematically study associations between HLA-DRB1 alleles, clinical manifestations, and autoantibody-defined IIM subgroups.

Methods

We included 1348 IIM patients from five European countries. An unsupervised cluster analysis was performed using 14 autoantibodies: anti-Jo1, -PL7, -PL12, -EJ, -OJ, -SRP, -U1RNP, -Ro52, -Mi2, -TIF1γ, -MDA5, -PMScl, -SAE1, and -NXP2 to identify patients’ subgroups. Logistic regressions were used to estimate the associations between HLA-DRB1 alleles, clinical manifestations and the identified subgroups.

Results

Eight subgroups were defined by the autoantibody status (Table 1). Three of the subgroups (1, 2 and 6) have overlapping autoantibodies, while four are almost monospecific (3,4,5 and 7), and one (8) has patients negative for tested autoantibodies. Figure 1 represents the significant associations between HLA-DRB1 alleles and the eight subgroups. Heliotrope rash and Gottron’s sign were significantly more frequent in subgroups 3 (OR:2.2 95%CI:[1.1-4.8], OR:2.6 95%CI:[1.3-5.9], respectively), 4 (OR:12 95%CI:[3.6-75], OR:7.8 95%CI:[2.8-33], respectively) and 7 (OR:22 95%CI:[4.5-385], OR:10 95%CI:[3.1-65], respectively), and Raynaud’s phenomenon was significantly more frequent in subgroup 6 (OR:3.3 95%CI:[1.2-11]).

Table 1.

Autoantibody-defined subgroups using an unsupervised cluster analysis.

Subgroups/ MedoidsVariables1 Ro522 U1RNP3 PMScl4 Mi25 Jo16 Jo1/Ro527 TIF18 None*Alln (%)137 (10)183 (14)107 (8)65 (5)119 (9)140 (10)78 (6)519 (39)1348 (100)Female (%)93 (68)116 (63)79 (74)45 (69)76 (64)96 (69)64 (82)313 (60)882 (65)Age at diagnosis, median (IQR)56 (16)51.5 (23)51 (25)57 (22.5)47.5 (23.25)52 (19.5)53.5 (21.75)58 (22)55 (23)AutoantibodiesAnti-Jo106 (3)01 (2)119 (100)140 (100)00266 (20)Anti-PL77 (5)13 (7)00000020 (1.5)Anti-PL125 (4)3 (2)1 (1)01 (1)00010 (0.7)Anti-EJ2 (2)00000002 (0.1)Anti-OJ07 (4)0000007 (0.5)Anti-TIF110 (7)2 (1)2 (2)00078 (100)092 (7)Anti-Mi21 (1)1 (1)1 (1)65 (100)02 (1)0070 (5)Anti-SAE18 (6)23 (13)00000031 (2)Anti-NXP21 (1)23 (13)1 (1)0000025 (2)Anti-MDA59 (7)10 (6)1 (1)1 (2)01 (1)0022 (2)Anti-SRP8 (6)32 (18)00000040 (3)Anti-Ro52137 (100)16 (9)000140 (100)00293 (22)Anti-PMScl11 (8)1 (1)107 (100)00000119 (9)Anti-U1RNP079 (43)0003 (2)0082 (6)

*IIM patients negative for the tested autoantibodies.

Figure 1.

Forest plot of significant associations of HLA. *DRB1 alleles with autoantibody-defined subgroups. Scandinavia includes patients from Denmark, Norway, and Sweden.

Conclusion

Our study reveals that certain subgroups of IIM patients are characterized by overlap of myositis -specific and -associated autoantibodies, which in turn are associated with different HLA-DRB1 alleles including potential novel associations. These results point to different disease mechanisms in the subgroups, as well as suggest that IIM classification could be improved by integrating broader serological and genetic data.

References

[1]Parker MJS, Oldroyd A, Roberts ME, et al. The performance of the European League Against Rheumatism/American College of Rheumatology idiopathic inflammatory myopathies classification criteria in an expert-defined 10 year incident cohort. Rheumatology (Oxford). 2019;58(3):468-475.

Acknowledgements

We thank all the patients who participated in the study.

Disclosure of Interests

Valerie Leclair: None declared, Angeles Shunashy Galindo-Feria: None declared, Simon Rothwell: None declared, Olga Kryštůfková: None declared, Heřman Mann: None declared, Louise Pyndt Diederichsen: None declared, helena andersson: None declared, Martin Klein: None declared, Sarah Tansley: None declared, Neil McHugh: None declared, Janine Lamb: None declared, Jiří Vencovský Speakers bureau: Abbvie, Biogen, Boehringer, Eli Lilly, Gilead, MSD, Novartis, Pfizer, Roche, Sanofi, UCB, Werfen, Consultant of: Abbvie, Argenx, Boehringer, Eli Lilly, Gilead, Octapharma, Pfizer, UCB, Grant/research support from: Abbvie, Hector Chinoy: None declared, Marie Holmqvist: None declared, Leonid Padyukov: None declared, Ingrid E. Lundberg Shareholder of: Roche and Novartis, Consultant of: Corbus Pharmaceuticals Inc, Astra Zeneca, Bristol Myer´s Squibb, Corbus Pharmaceutical, EMD Serono Research & Development Institute, Argenx, Octapharma, Kezaar, Orphazyme, and Janssen, Grant/research support from: Astra Zeneca, Lina M. Diaz-Gallo: None declared

P221 Autoantibodies are common in patients with idiopathic interstitial lung disease, suggesting a high prevalence of undiagnosed autoimmune connective tissue disease

Background/Aims

In some patients, interstitial lung disease (ILD) may be the dominant or even sole manifestation of an otherwise unrecognised autoimmune connective tissue disease (CTD). Accurate diagnosis can be challenging given considerable overlap of the clinical, radiological and histological disease features. Distinguishing CTD related ILD (CTD-ILD) from idiopathic ILD, enables appropriate immunosuppressive treatment, informs prognosis and facilitates monitoring for other CTD associated complications. Occasionally a lung biopsy may be necessary to ensure accurate diagnosis. Autoantibodies are a hallmark feature of CTD, are highly disease specific and their presence is strongly suggestive of covert CTD-ILD. We investigated patients with idiopathic ILD for the presence of autoantibodies that may suggest misdiagnosis.

Methods

The serum from three subgroups of patients recruited to UK Biomarkers of Interstitial Lung Disease (BILD) were analysed: 171 with a diagnosis of idiopathic ILD and non-specific organising pneumonia on HRCT and 27 with a diagnosis of idiopathic ILD and cryptogenic organising pneumonia on HRCT. Autoantibody status was determined by radio-immunoprecipitation.

Results

Results are summarised in Table 1. Overall CTD-autoantibodies were identified in 15.6% of patients with idiopathic ILD, and were more common in those with NSIP, see table. Autoantibodies identified included those readily detectable e.g. anti-Jo1, in addition to rarer antibodies not included in standard assays e.g. anti-EIF3. Nearly half of all autoantibodies detected were anti-synthetase autoantibodies.

Conclusion

Covert-CTD is likely to be common amongst patients diagnosed with idiopathic ILD, particularly idiopathic NSIP. More specific guidance on autoantibody testing could improve diagnosis and ensure patients receive appropriate immunosuppressive treatment.

Disclosure

S. Tansley: None. C. Cotton: None. F.K. McMorrow: None. H. Lu: None. R.P. New: None. L.G. Spencer: None. N.J. McHugh: None. R.G. Cooper: None.

P290 Baseline monocyte count may help make a diagnosis of giant cell arteritis: results of routinely collected audit data from two centres

Background/Aims

Giant cell arteritis is a large vessel vasculitis classically affecting the head and neck. If untreated it leads to permanent vision loss. Diagnosis of GCA is based on clinical judgement of the likelihood of GCA combined with blood tests, imaging and/or temporal artery biopsy. Biopsy is considered the gold standard, but access has been restricted at many centres during the pandemic. It is recognised that some patients will have a negative ultrasound but still deemed to have GCA based on the clinical history and physical findings. In a previous audit at Yeovil District Hospital, we evaluated factors associated with biopsy-proven GCA to explore how routine tests help guide diagnosis, particularly in cases where initial imaging is negative and biopsy is unavailable. This audit found that the baseline monocyte count had good diagnostic accuracy compared to classical inflammatory markers and clinical parameters (area under the curve [AUC] 0.81, 95% confidence interval [CI] 0.67-0.95, p = 0.0034). Although novel, this finding involved a small number of patients and requires further investigation. We aimed to repeat the audit in a larger cohort and investigate blood biomarkers, including monocytes, in GCA patients as defined by physician diagnosis.

Methods

At the Royal National Hospital for Rheumatic Diseases, data were collected retrospectively on patients that were referred between 01/2020 and 09/2021 from hospital records, the GP referral, and pathology systems. A positive diagnosis of GCA was determined by presentation, inflammatory response, vascular imaging and clinical course, and was confirmed by a rheumatologist. Sensitivity, specificity and ROC analysis were calculated for each biomarker, including monocyte count, platelets, CRP, and plasma viscosity (PV).

Results

301 referrals were made to the GCA clinic over the period audited. 109/301 (36%) were diagnosed with GCA, of which 98/109 (90%) had imaging studies and 62/98 (67%) had had a positive test. 55/301 referrals had already started glucocorticoids before baseline blood monitoring. ROC analysis found monocyte count was predictive of GCA (AUC 0.83, 95%CI 0.77-0.90, p < 0.0001). A cut-off value of ≥ 0.9 x 106/L gave a specificity of > 95% and a positive likelihood ratio (LR) of 10 for a diagnosis of GCA in this cohort. However, monocytes were heavily influenced by glucocorticoids and after ≥1 dose there was a drop in sensitivity of 20%.

Conclusion

In a second, larger cohort of GCA cases, we have again identified monocytes as a potential biomarker of GCA. However, they appear to be highly sensitive to glucocorticoids and their use as a biomarker may be limited to glucocorticoid-naïve patients. A prospective research study is now being planned to take these findings further.

Disclosure

B. Mulhearn: None. J. Ellis: None. T. Somoskeoy: None. A. Bourn: None. S. Knights: None. S. Skeoch: None. S. Tansley: None.

P224 Anti-PARP1 as a novel autoantibody in myositis

Background/Aims

Idiopathic inflammatory myopathies (IIM) are multisystem diseases characterised by muscle inflammation. Over 60% of patients with IIM have a myositis-related autoantibody. Our laboratory specialises in autoantibody testing. We offer an extended spectrum autoantibody testing diagnostic service and have also screened over 3000 myositis patients enrolled in research studies for the presence of autoantibodies. We noticed a recurring pattern following K562 cell radio-immunoprecipitation that was present in several myositis patient sera and in a handful of samples that came to us via the diagnostic service. We set out to determine the antigenic target of this novel autoantibody.

Methods

We have previously screened 1319 serum/plasma samples from IIM patients enrolled in the UKMyoNet and 380 from patients with juvenile onset IIM enrolled in the JDCBS for autoantibodies by immunoprecipitation. Additional cohorts similarly investigated include >150 healthy control sera and >400 SLE patient sera. Patients with the novel autoantibody of interest were identified by a distinctive 120kDa band associated with a ‘smear’ on autoradiography following K562 cell immunoprecipitation and separation of autoantigens by SDS PAGE. ESI-QTOF mass spectrometry was used to identify the antigenic target in an example serum. Using a commercial anti-PARP1 antibody as a control, western blotting of K562 and PARP1 overexpressed cell lysate was used to confirm the antigenic target in remaining samples of interest. Indirect immunofluorescence was performed on HEp-2 cells according to manufacturers’ instructions.

Results

11 patient samples were identified as having the 120 complex ‘smear’ pattern of interest: six had been received via the diagnostic service and five were enrolled in UKMyoNet. Prevalence in the UKMyoNet cohort was 0.4%. Mass spectrometry identified PARP1 as the antigenic target. This was confirmed in all remaining samples by western blot. Table 1 shows available clinical data.

Conclusion

PARP1 is an autoantigen target in myositis patients in addition to those with other rheumatic diseases. Where data was available, patients with anti-PARP1 had features suggesting an anti-synthetase syndrome phenotype, but this may primarily relate to the other autoantibodies present. Further work is needed to determine the prevalence of anti-PARP1 in other cohorts and its clinical associations.

Disclosure

V. Riddell: Grants/research support; Bath Institute of Rheumatic Disease. Z. Betteridge: None. E. Bowler: None. H. Chinoy: None. P. Gordon: None. L. Wedderburn: None. S. Bagby: None. N. Mchugh: None. S. Tansley: None.

A systematic review and meta-analysis to inform cancer screening guidelines in idiopathic inflammatory myopathies

Objectives

To identify clinical factors associated with cancer risk in the idiopathic inflammatory myopathies (IIMs) and to systematically review the existing evidence related to cancer screening.

Methods

A systematic literature search was carried out on Medline, Embase and Scopus. Cancer risk within the IIM population (i.e. not compared with the general population) was expressed as risk ratios (RR) for binary variables and weighted mean differences (WMD) for continuous variables. Evidence relating to cancer screening practices in the IIMs were synthesized via narrative review.

Results

Sixty-nine studies were included in the meta-analysis. DM subtype (RR 2.21), older age (WMD 11.19), male sex (RR 1.53), dysphagia (RR 2.09), cutaneous ulceration (RR 2.73) and anti-transcriptional intermediary factor-1 gamma positivity (RR 4.66) were identified as being associated with significantly increased risk of cancer. PM (RR 0.49) and clinically amyopathic DM (RR 0.44) subtypes, Raynaud’s phenomenon (RR 0.61), interstitial lung disease (RR 0.49), very high serum creatine kinase (WMD −1189.96) or lactate dehydrogenase (WMD −336.52) levels, and anti-Jo1 (RR 0.45) or anti-EJ (RR 0.17) positivity were identified as being associated with significantly reduced risk of cancer. Nine studies relating to IIM-specific cancer screening were included. CT scanning of the thorax, abdomen and pelvis appeared to be effective in identifying underlying asymptomatic cancers.

Conclusion

Cancer risk factors should be evaluated in patients with IIM for risk stratification. Screening evidence is limited but CT scanning could be useful. Prospective studies and consensus guidelines are needed to establish cancer screening strategies in IIM patients.

OP0281 EXCESS GIANT CELL ARTERITIS CASES ARE ASSOCIATED WITH PEAKS IN COVID-19 PREVALENCE

Background:

Immediately following the first wave of the COVID-19 pandemic, the number of giant cell arteritis (GCA) diagnoses noticeably increased at the Royal National Hospital for Rheumatic Diseases in Bath, UK. Furthermore, there was an increase in the proportion of patients with visual complications [1]. The finding supports the viral hypothesis of GCA aetiopathogenesis as previously described [2]. This not only has ramifications for understanding the underlying disease mechanisms in GCA but also has implications for the provision of local GCA services which may have already be affected by the pandemic.

Objectives:

The objective of the study was to estimate the incidence of giant cell arteritis during the COVID-19 pandemic years of 2020 – 2021 and compare it to 2019 data. Given that there have now been two distinct peaks of COVID-19 as reflected by hospital admissions of COVID-19-positive patients this has allowed us to investigate if there is a temporal relationship between the prevalence of COVID-19 and the incidence of GCA.

Methods:

The incidence of GCA was calculated by assessing emailed referrals to the GCA service and the hospital electronic medical records to identity positive cases from 2019 to the current date. Local COVID-19 prevalence was estimated by measuring the number of hospital beds taken up by COVID-19 positive patients, available publicly in a UK Government COVID-19 dataset [3].

Results:

There were 61 (95% Poisson distribution confidence interval [CI] 47 - 78) probable or definite GCA diagnoses made in 2020 compared to 28 (CI 19 – 40) in 2019 (Figure 1). This is an excess of 33 cases in 2020, or an increase in 118%. Given that 41% of the hospital’s catchment population is over 50, this equates to an annual incidence rate of 13.7 per 100,000 in 2019 and 29.8 per 100,000 in 2020. This compares to a previously estimated regional incidence rate of 21.6 per 100,000 for the South West of the UK [4].

Figure 1.

Prevalence of hospital COVID-19 and incidence of GCA (2019 – 2021). Graph showing the number of hospital beds occupied by COVID-19-positive patients in 2020 – 2021 (blue circles), number of daily GCA diagnoses in 2020 – 2021 (red circles), and previous GCA diagnoses in 2019 (green circles). The broken lines represent moving averages with a period of 7 days for COVID-19 cases and 28 days for GCA diagnoses.

A peak in COVID-19-positive inpatients was seen on 10th April 2020 with a corresponding peak of GCA diagnoses on 29th May 2020, giving a lag period of approximately 6 weeks between these peaks (Figure 1).

Conclusion:

The incidence of GCA in Bath was significantly increased in 2020 compared to 2019. This may be the result of the widespread infection of the local population with the COVID-19 virus as a precipitating factor. Possible mechanisms include, but are not limited to, endothelial disruption by the virus, immune system priming towards T helper cell type 1 (Th1) cellular immunity and/or activation of the monocyte-macrophage system. More work is currently underway to assess the causal relationship between the two diseases.

There was a lag period of 6 weeks between the peak during the first wave of the pandemic and the rise in GCA cases. We shall be closely monitoring the number of referrals that follow the current wave of the pandemic.

References:

[1]Luther R, Skeoch S, Pauling JD, et al. Increased number of cases of giant cell arteritis and higher rates of ophthalmic involvement during the era of COVID-19. Rheumatol Adv Pract 2020;4:1–4. doi:10.1093/rap/rkaa067

[2]Russo MG, Waxman J, Abdoh AA, et al. Correlation between infection and the onset of the giant cell (temporal) arteritis syndrome. Arthritis Rheum 1995;38:374–80. doi:10.1002/art.1780380312

[3]England PH. GOV.UK Coronavirus (COVID-19) in the UK. 2021.https://coronavirus.data.gov.uk/details/download (accessed 25 Jan 2021).

[4]Smeeth L, Cook C, Hall AJ. Incidence of diagnosed polymyalgia rheumatica and temporal arteritis in the United Kingdom, 1990-2001. Ann Rheum Dis 2006;65:1093–8. doi:10.1136/ard.2005.046912

Disclosure of Interests:

Ben Mulhearn Speakers bureau: Novartis UK, 2019, Grant/research support from: Chugai, 2019, Jessica Ellis: None declared, Sarah Skeoch: None declared, John Pauling: None declared, Sarah Tansley: None declared

POS0288 A KEY TIF1γ EPITOPE MAY FACILITATE THE IDENTIFICATION OF PATIENTS AT HIGHEST RISK OF CANCER ASSOCIATED MYOSITIS

Background:

The myositis specific autoantibody anti-TIF1γ targets TRIM33, a TRIM family proetin with a PHDBromo domain at the C terminal end. Anti-TIF1γ is strongly associated with malignancy in adult patients with idiopathic inflammatory myopathies (IIM). Intriguingly, anti-TIF1γ is also the most common autoantibody in juvenile-onset IIM but younger patients with anti-TIF1γ do not have an increased risk of cancer (1-3). Genetic studies have consistently shown human leukocyte antigen (HLA) to be the strongest risk factor for IIM. Adult and juvenile-onset patients with anti-TIF1γ have recently been shown to have different associations at the HLA-DQB1 locus (4). This could be due to differences in the key TIF1γ epitopes and may relate to differences in aetiology, such as malignancy in adults versus other environmental factors in juvenile onset disease.

Objectives:

To identify key epitopes targeted by anti-TIF1γ antibody in patients with IIM and establish if different TIF1γ epitopes are targeted in patients with and without malignancy.

Methods:

Patient plasma/serum samples were obtained from UK Juvenile Dermatomyositis Cohort and Biomarker and UKMyoNet studies. Autoantibody status had previously been determined by immunoprecipitation. Cancer data was collated from the UK Health and Social Care Information Centre and cancer associated IIM (CAM) defined as that occurring within 3 years of IIM diagnosis.

An in house ELISA was developed using a purified TIF1γ fragment comprising residues 882-1090, produced in E.coli, corresponding to the PHDBromo protein domain. An ELISA cut-off of 5SD above the mean of 38 healthy control samples was used.

Results:

38 healthy controls, and 117 anti-TIF1γ IIM patient sera (60 juvenile onset) were analysed for reactivity to the TIF1γ PHDbromo domain.

No healthy controls were positive. Anti-TIF1γPHDbromo was more common in JDM: 18 (30%) juvenile patients and 6 (10.5%) adult patients were positive, p=0.01.

Additional data was available for 39 adult patients (82% female, median age 52 (IQR 38-64)). Anti-TIF1γPHDbromo was only found in CAM patients plus one young adult non-CAM patient aged 27 years at disease onset, p =0.07 (p=0.02 for patients >30 years at disease onset), see Table 1. No juvenile patients had a history of malignancy.

Table 1.

Anti-TIF1γPHDbromo in 39 adult patients with cancer data available

anti-TIF1γPHDbromo positiveanti-TIF1γPHDbromo negativeCancer associated myositis n(%)5a (83)12(36)Myositis not associated with cancer n(%)1b(17)21(64)Total633

a. Median age 64 yearsb. Age 27 years

Conclusion:

The TIF1γ PHDBromo domain is an important epitope and autoantibody reactivity is more common in patients with juvenile-onset disease and adults with CAM. The distinction between adult and juvenile-onset IIM is arbitrary and it is relevant that the only adult with anti-TIF1γPHDbromo not to have malignancy was just 27 years old. Our numbers are small and further work is needed to establish if anti-TIF1γPHDbromo, and indeed other TIF1γ epitopes, could help identify patients at highest risk of malignancy, and how this relates to our understanding of IIM aetiopathogenesis. Our findings may add weight to the theory that the development of IIM in younger patients occurs after immune-mediated resolution of a pre-cancer event.

References:

[1]Oldroyd A, Sergeant JC, New P et al. The temporal relationship between cancer and adult onset anti-transcriptional intermediary factor 1 antibody-positive dermatomyositis. Rheumatology. 2019;58(4):650-655

[2]Tansley SL, Simou S, Shaddick G et al. Autoantibodies in juvenile-onset myositis: Their diagnostic value and associated clinical phenotype in a large UK cohort. J Autoimmun. 2017;84:55-64

[3]Fujimoto M, Hamaguchi Y, Kaji K et al. Myositis-specific anti-155/140 autoantibodies target transcription intermediary factor 1 family proteins. Arthritis Rheum. 2012;64(2):513-22.

[4]Rothwell S, Chinoy H, Lamb JA et al. Focused HLA analysis in Caucasians with myositis identifies significant associations with autoantibody subgroups. Ann Rheum Dis. 2019;78(7):996-1002.

Disclosure of Interests:

None declared

Anti-Cytosolic 5'-Nucleotidase 1A Autoantibodies Are Absent in Juvenile Dermatomyositis

Objective

To assess anti–cytosolic 5′‐nucleotidase 1A (anti–cN‐1A) autoantibodies in children with juvenile dermatomyositis (DM) and healthy controls, using 3 different methods of antibody detection, as well as verification of the results in an independent cohort.

Methods

Anti–cN‐1A reactivity was assessed in 34 Dutch juvenile DM patients and 20 healthy juvenile controls using the following methods: a commercially available full‐length cN‐1A enzyme‐linked immunosorbent assay (ELISA), a synthetic peptide ELISA, and immunoblotting with a lysate from cN‐1A–expressing HEK 293 cells. Sera from juvenile DM patients with active disease and those with disease in remission were analyzed. An independent British cohort of 110 juvenile DM patients and 43 healthy juvenile controls was assessed using an in‐house full‐length cN‐1A ELISA.

Results

Anti–cN‐1A reactivity was not present in sera from juvenile DM patients or healthy controls when tested with the commercially available full‐length cN‐1A ELISA or by immunoblotting, in either active disease or disease in remission. Additionally, in the British juvenile DM cohort, anti–cN‐1A reactivity was not detected. Three Dutch juvenile DM patients had weakly positive results for 1 of 3 synthetic cN‐1A peptides measured by ELISA.

Conclusion

Juvenile DM patients and young healthy individuals did not show anti–cN‐1A reactivity as assessed by different antibody detection techniques.

Increased number of cases of giant cell arteritis and higher rates of ophthalmic involvement during the era of COVID-19

Objectives

Our centre offers a fast-track assessment service for patients with suspected GCA and this service continued to operate during the coronavirus disease 2019 (COVID-19) pandemic. During and immediately following the peak of the COVID-19 pandemic in the UK we observed an increase in the number of patients diagnosed with GCA as well as an increased number of patients with visual complications. Our aim was to investigate this further.

Methods

The electronic medical records of all patients referred for GCA fast-track assessment from January 2019 were reviewed. A complete list of patients undergoing temporal artery ultrasound and temporal artery biopsy for investigation of GCA dating back to 2015 was also available.

Results

In the 12 week period between April and June 2020, 24 patients were diagnosed with GCA. Six (25%) had associated visual impairment. In contrast, during 2019, 28 new diagnoses of GCA were made in total and just 10% of patients suffered visual involvement. The number of patients diagnosed with GCA in April–June 2020 was nearly 5-fold that of the same time period the previous year. GCA diagnoses between April and June 2020 were supported by imaging (temporal artery ultrasound or CT-PET) in 72% of cases. We noted a higher proportion of male patients and a lower median age but no clear difference in the duration of symptoms prior to assessment.

Conclusions

The reasons behind our observations remain unclear. However, our findings support the viral aetiopathogenesis hypothesis for GCA and demonstrate the importance of maintaining access to urgent rheumatology services during periods of healthcare disruption.

Frequency, mutual exclusivity and clinical associations of myositis autoantibodies in a combined European cohort of idiopathic inflammatory myopathy patients

Objectives

To determine prevalence and co-existence of myositis specific autoantibodies (MSAs) and myositis associated autoantibodies (MAAs) and associated clinical characteristics in a large cohort of idiopathic inflammatory myopathy (IIM) patients.

Methods

Adult patients with confirmed IIM recruited to the EuroMyositis registry (n = 1637) from four centres were investigated for the presence of MSAs/MAAs by radiolabelled-immunoprecipitation, with confirmation of anti-MDA5 and anti-NXP2 by ELISA. Clinical associations for each autoantibody were calculated for 1483 patients with a single or no known autoantibody by global linear regression modelling.

Results

MSAs/MAAs were found in 61.5% of patients, with 84.7% of autoantibody positive patients having a sole specificity, and only three cases (0.2%) having more than one MSA. The most frequently detected autoantibody was anti-Jo-1 (18.7%), with a further 21 specificities each found in 0.2–7.9% of patients. Autoantibodies to Mi-2, SAE, TIF1, NXP2, MDA5, PMScl and the non-Jo-1 tRNA-synthetases were strongly associated (p < 0.001) with cutaneous involvement. Anti-TIF1 and anti-Mi-2 positive patients had an increased risk of malignancy (OR 4.67 and 2.50 respectively), and anti-SRP patients had a greater likelihood of cardiac involvement (OR 4.15). Interstitial lung disease was strongly associated with the anti-tRNA synthetases, anti-MDA5, and anti-U1RNP/Sm. Overlap disease was strongly associated with anti-PMScl, anti-Ku, anti-U1RNP/Sm and anti-Ro60. Absence of MSA/MAA was negatively associated with extra-muscular manifestations.

Conclusions

Myositis autoantibodies are present in the majority of patients with IIM and identify distinct clinical subsets. Furthermore, MSAs are nearly always mutually exclusive endorsing their credentials as valuable disease biomarkers.

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Myositis specific autoantibodies very rarely coexist in the one individual allowing endotypes to be more precisely defined.

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The association of anti-TIF1 and cancer-associated myositis is confirmed with a cut-off age of over 58 years.

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In a large combined European myositis cohort associations of anti-SRP with carditis and anti-Mi-2 with cancer have emerged.

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Myositis associated autoantibodies are strongly associated with having myositis in association with another connective tissue disease.

Effective induction therapy for anti-SRP associated myositis in childhood: A small case series and review of the literature

BACKGROUND

Anti-Signal Recognition Particle associated myopathy is a clinically and histopathologically distinct subgroup of Juvenile Idiopathic Inflammatory Myositis, which is under-recognised in children and fails to respond to conventional first line therapies. We present three cases where remission was successfully induced using combination therapy with intensive rehabilitation.

CASE PRESENTATIONS

Three new patients are reported. All 3 cases presented with profound, rapid-onset, proximal myopathy and markedly raised CK, but no rash. Histology revealed a destructive myopathy characterized by scattered atrophic and necrotic fibres with little or no inflammatory infiltrate. All 3 patients responded to induction with cyclophosphamide, IVIG and rituximab, in conjunction with intensive physiotherapy and methotrexate as the maintenance agent. Our patients regained near-normal strength (MMT > 70/80), in contrast with the current literature where >50% of cases reported severe residual weakness. A literature search on paediatric anti-SRP myositis was performed to June 2016; PubMed was screened using a combination of the following terms: signal recognition particle, autoantibodies, antibodies, myositis, muscular diseases, skeletal muscle, childhood, paediatric, juvenile. Articles in a foreign language were excluded. Nine case studies were found.

CONCLUSION

This paper supports the hypothesis that anti-SRP myositis is distinct from other JIIM. It is an important differential to JDM and should be considered where there is severe weakness without rash or if highly elevated muscle enzymes (CK > 10,000 U/l) are found. Early identification is essential to initiate aggressive medical and physical therapy. Greater international collaboration and long-term follow-up data is needed to establish the most effective treatment strategy for this rare group of patients.

Developing standardised treatment for adults with myositis and different phenotypes: an international survey of current prescribing preferences

OBJECTIVES

The evidence base for treatment of the idiopathic inflammatory myopathies is extremely limited. The rarity and heterogeneity of these diseases has hampered the development of good quality clinical trials and while a range of immunomodulatory treatments are commonly used in clinical practice, as yet there are no clear guidelines directing their use. We aimed to establish current prescribing regimens used to treat adults with myositis internationally.

METHODS

An electronic survey based on different clinical scenarios was distributed internationally to clinicians involved in the treatment of patients with myositis. Participants were asked to select their first-line treatment preferences in each situation. A multinomial regression analysis was used to assess the influence of clinical scenario, respondent expertise and country of origin on first-line treatment choice.

RESULTS

107 survey responses were received. 57% of respondents considered themselves an expert in myositis and the majority of respondents were rheumatologists although responses from other specialities were also received. Pharmacological treatment with steroids and additional immunotherapy was the preference in most scenarios. First-line immunosuppressant choice was significantly influenced by the clinical scenario, the expertise of the treating physician and country of practice. Azathioprine, methotrexate and mycophenolate mofetil were the most commonly chosen agents.

CONCLUSIONS

In the absence of available evidence, clinical experience and expert consensus often forms the basis of treatment guidelines. These results suggest that an international consensus approach would be possible in myositis and would overcome an urgent, yet unmet need for patients suffering with this difficult disease.

CD38 as a prognostic marker in chronic lymphocytic leukaemia at a single New Zealand centre: patient survival in comparison to age- and sex-matched population data

AIM

The aim of this study is to determine whether the analysis of CD38 expression by chronic lymphocytic leukaemia (CLL) cells provides useful additional prognostic information.

METHODS

Clinical, laboratory, overall survival (OS) and treatment-free survival (TFS) data were collected on 130 CLL patients who had CD38 expression analysed at Canterbury Health Laboratories, New Zealand (NZ) during 1998-2008.

RESULTS

The detection of any level of CD38 expression by CLL cells was associated with a significantly shorter OS and TFS. When analysis was restricted to Binet stage A patients, CD38 expression identified a subset of patients (21%) who, in common with Binet stage B/C patients, had a significantly shorter OS and TFS (P<0.0015), and a TFS at 4 years of <10%. In contrast, CD38-negative Binet stage A patients had an OS that was not significantly different from that of an age/sex-matched NZ population and a 5-year TFS of 77%.

CONCLUSION

This study indicates that, when combined with clinical staging, the presence of any detectable CD38 expression can be used to further improve the identification of CLL patients with more aggressive disease (i.e. Binet stage B/C or Binet stage A and CD38 positive). This will allow better identification of those patients requiring more intensive monitoring and also allow improved patient counselling regarding prognosis.