Association between vascular FDG uptake during follow-up and the development of thoracic aortic aneurysms in giant cell arteritis

Background

A positive PET scan at diagnosis was associated with a greater yearly increase in ascending and descending aortic diameter and thoracic aortic volume in patients with giant cell arteritis (GCA). Radiologic and histopathologic vascular abnormalities persist in a subset of treated patients despite clinical remission. The aim of this study was to evaluate the association between vascular FDG uptake during follow-up and the development of thoracic aortic aneurysms.

Methods

We recently performed a prospective cohort study of 106 GCA patients, who underwent FDG PET and CT imaging at diagnosis and CT imaging yearly for a maximum of 10 years. In this post hoc analysis, GCA patients who also have had FDG PET imaging during follow-up were included. PET scans were visually scored (0-3) at 7 vascular areas. PET scans were considered positive in case of FDG uptake ≥grade 2 in any large vessel.

Results

Eighty-eight repeat PET scans were performed in 52 out of 106 GCA patients, who were included in the original prospective cohort. Fifty-five (63%) PET scans were done at the time of a relapse and 33 (38%) were done while in remission. Nine out of ten patients with an incident thoracic aortic aneurysm had both a positive PET scan at diagnosis and during follow-up.

Conclusion

In addition to the intensity and extent of the initial vascular inflammation, ongoing aortic inflammation may contribute to the development of thoracic aortic aneurysms in GCA. However, this hypothesis should be confirmed in a large prospective trial with repeat PET scans at predefined time points during follow-up.

Update on imaging in fever and inflammation of unknown origin: focus on infectious disorders

BACKGROUND

Fever of unknown origin (FUO) and inflammation of unknown origin (IUO) are diagnostic challenges that often require an extensive work-up. When first-line tests do not provide any or only misleading clues, second-line investigations such as specialized imaging techniques are often warranted.

OBJECTIVES

To provide an overview of the diagnostic value of imaging techniques that are commonly used in patients with FUO/IUO.

SOURCES

MEDLINE database was searched to identify the most relevant studies, trials, reviews, or meta-analyses until 31 March 2023.

CONTENT

The most important types of second-line imaging tests for FUO and IUO are outlined, including [67Ga]-citrate single-photon emission computed tomography/computed tomography (CT), labelled leukocyte imaging, [18F]-fluorodeoxyglucose positron emission tomography CT ([18F]-FDG-PET), and whole-body magnetic resonance imaging. This review summarizes the diagnostic yield, extends on potential future imaging techniques (pathogen-specific bacterial imaging and [18F]-FDG-PET/magnetic resonance imaging), discusses cost-effectiveness, highlights practical implications and pitfalls, and addresses future perspectives. Where applicable, we provide additional data specifically for the infection subgroup.

IMPLICATIONS

Although many imaging examinations are proven to be useful in FUO and IUO, [18F]-FDG-PET/CT is the preferred second-line test when available as it provides a high diagnostic yield in a presumably cost-effective way.

Comparison of diagnostic spectrum between inflammation of unknown origin and fever of unknown origin: A systematic review and meta-analysis

BACKGROUND

Patients with inflammation of unknown origin (IUO) and fever of unknown origin (FUO) are commonly considered a single population. Differences in underlying causes between both groups may steer the diagnostic work-up.

METHODS

PubMed, Embase, Web of Science, and ClinicalTrials.gov were searched from July 2009 through December 2023. Studies including both FUO and IUO patients with a sample size of ≥20 were considered. The primary outcome was the difference in the rate of patients affected by predefined diagnostic categories according to meeting FUO or IUO criteria. Data were pooled using random-effects models.

RESULTS

A total of 8 studies met criteria for inclusion, with a total of 1452 patients (466 with IUO and 986 with FUO). The median rate of IUO patients among the included studies was 32 % (range 25-39 %). Patients with IUO had a lower likelihood of infection (OR 0.59 [95 % CI; 0.36-0.95]; I2 0 %). There were no significant differences in the rate of noninfectious inflammatory disorders, malignancies, miscellaneous disorders, or remaining undiagnosed. Comparison of diagnostic subgroups revealed that IUO patients were less likely to have systemic autoinflammatory disorders (OR 0.17 [95 % CI, 0.05-0.58]; I2 42 %) and more likely to have vasculitis (OR 2.04 [95 % CI, 1.23-3.38]; I2 21 %) and rheumatoid arthritis or spondylarthritis (OR 3.52 [95 % CI, 1.16-10.69]; I2 0 %).

CONCLUSION

Based on our findings, there is little reason to assume that FUO and IUO patients would benefit from a different initial diagnostic approach.

Development of a Consensus-Based List of Potential Quality Indicators for Fever and Inflammation of Unknown Origin

With a growing emphasis on value-based reimbursement, developing quality indicators for infectious diseases has gained attention. Quality indicators for fever of unknown origin and inflammation of unknown origin are lacking. An assembled group of international experts developed 12 quality measures for these conditions, which could be validated with additional study.

Biallelic mutations in the CFHR genes underlying atypical hemolytic uremic syndrome in a patient with catastrophic adult-onset Still's disease and recurrent macrophage activation syndrome: A case report

We report the fatal case of a 20-year-old woman with refractory adult-onset Still's disease (AOSD) accompanied by fulminant macrophage activation syndrome (MAS) and atypical hemolytic uremic syndrome (aHUS). Anakinra and tocilizumab temporarily controlled AOSD. In 2021, she presented to ICU with generalized tonic-clonic seizure, lymphocytic aseptic meningitis, and acute kidney injury. Despite hemodialysis and methylprednisolone, she developed another seizure, MAS, and disseminated intravascular coagulation (DIC). Following brief control, MAS flares -reflected by increased plasma CXCL9 and CXCL10- re-emerged and were controlled through dexamethasone, etoposide, cyclosporin and tofacitinib. No mutations were detected in haemophagocytic lymphohistiocytosis (HLH)-associated genes, nor in genes associated with periodic fever syndromes. Post-mortem genetic testing revealed loss-of-function biallelic deletions in complement factor H-related proteins (CFHR) genes, predisposing aHUS. This case underscores the importance of prompt genetic assessment of complement-encoding alleles, in addition to HLH-related genes, in patients with severe AOSD with recurrent MAS and features of thrombotic microangiopathy (TMA).

A Narrative Review of the Neurological Manifestations of Human Adenosine Deaminase 2 Deficiency

Deficiency of human adenosine deaminase type 2 (DADA2) is a complex systemic autoinflammatory disorder characterized by vasculopathy, immune dysregulation, and hematologic abnormalities. The most notable neurological manifestations of DADA2 are strokes that can manifest with various neurological symptoms and are potentially fatal. However, neurological presentations can be diverse. We here present a review of the neurological manifestations of DADA2 to increase clinical awareness of DADA2 as the underlying diagnosis. We reviewed all published cases of DADA2 from 1 January 2014 until 19 July 2022 found via PubMed. A total of 129 articles describing the clinical features of DADA2 were included in the analysis. Six hundred twenty-eight patients diagnosed with DADA2 were included in the review. 50.3% of patients had at least signs of one reported neurological event, which was the initial or sole manifestation in 5.7% and 0.6%, respectively. 77.5% of patients with neurological manifestations had at least signs of one cerebrovascular accident, with lacunar strokes being the most common and 35.9% of them having multiple stroke episodes. There is a remarkable predilection for the brain stem and deep gray matter, with 37.3% and 41.6% of ischemic strokes, respectively. Other neurological involvement included neuropathies, focal neurological deficits, ophthalmological findings, convulsions, and headaches. In summary, neurological manifestations affect a significant proportion of patients with DADA2, and the phenotype is broad. Neurological manifestations can be the first and single manifestation of DADA2. Therefore, stroke, encephalitis, posterior reversible encephalopathy syndrome, mononeuropathy and polyneuropathy, and Behçet's disease-like presentations should prompt the neurologist to exclude DADA2, especially but not only in childhood.

Association Between Vascular 18F-Fluorodeoxyglucose Uptake at Diagnosis and Change in Aortic Dimensions in Giant Cell Arteritis : A Cohort Study

BACKGROUND

Previous studies have shown that patients with giant cell arteritis (GCA) who have vascular 18F-fluorodeoxyglucose (FDG) uptake at diagnosis are at increased risk for thoracic aortic complications.

OBJECTIVE

To measure the association between vascular FDG uptake at diagnosis and the change in aortic dimensions.

DESIGN

Prospective cohort study.

SETTING

University Hospitals Leuven.

PATIENTS

106 patients with GCA and FDG positron emission tomography (PET) imaging 3 days or less after initiation of glucocorticoids.

MEASUREMENTS

Patients had PET and computed tomography (CT) imaging at diagnosis and CT imaging yearly for a maximum of 10 years. The PET scans were scored 0 to 3 in 7 vascular areas and summed to a total vascular score (TVS). The PET scan results were positive when FDG uptake was grade 2 or greater in any large vessel. The association between vascular FDG uptake and aortic dimensions was estimated by linear mixed-effects models with random intercept and slope.

RESULTS

When compared with patients with a negative PET scan result, those with a positive scan result had a greater increase in the diameter of the ascending aorta (difference in 5-year progression, 1.58 mm [95% CI, 0.41 to 2.74 mm]), the diameter of the descending aorta (1.32 mm [CI, 0.38 to 2.26 mm]), and the volume of the thoracic aorta (20.5 cm³ [CI, 4.5 to 36.5 cm³]). These thoracic aortic dimensions were also positively associated with TVS. Patients with a positive PET scan result had a higher risk for thoracic aortic aneurysms (adjusted hazard ratio, 10.21 [CI, 1.25 to 83.3]).

LIMITATION

The lengthy inclusion and follow-up period resulted in missing data and the use of different PET machines.

CONCLUSION

Higher TVS was associated with greater yearly increase in thoracic aortic dimensions. Performing PET imaging at diagnosis may help to estimate the risk for aortic aneurysm formation.

PRIMARY FUNDING SOURCE

None.

Duration of Treatment With Glucocorticoids in Giant Cell Arteritis: A Systematic Review and Meta-analysis

ABSTRACT

The aim of this meta-analysis was to estimate the mean duration of glucocorticoid (GC) treatment in patients with giant cell arteritis. PubMed, EMBASE, and Cochrane databases were searched from inception until November 30, 2021. The outcome measures were the proportion of patients on GCs at years 1, 2, and 5 after diagnosis and the mean GC dose (in the entire cohort and expressed in prednisone equivalents) at these time points. Twenty-two studies involving a total of 1786 patients were included. The pooled proportions of patients taking GCs at years 1, 2, and 5 were 89.7% (95% confidence interval [CI], 83.2%-93.9%), 75.2% (95% CI, 58.7%-86.6%), and 44.3% (95% CI, 15.2%-77.6%), respectively. The pooled GC dose at years 1 and 2 was 9.1 mg/d (95% CI, 2.8-15.5 mg/d) and 7.8 mg/d (95% CI, 1.4-14.1 mg/d), respectively. The proportion of patients taking GCs at year 1 was lower in multicenter studies ( p = 0.003), in randomized controlled trials ( p = 0.01), and in studies using a GC-tapering schedule ( p = 0.01). There were no significant differences in the proportion of patients taking GCs at years 1 and 2 according to study design (retrospective vs. prospective), initial GC dose, use of pulse GCs, publication year, enrolment period, duration of follow-up, age, and sex. This meta-analysis showed that giant cell arteritis is a chronic disease that requires substantial and prolonged GC treatment in a considerable proportion of patients. A predefined GC-tapering schedule may help to avoid inadequately long GC treatment.

Diagnostic yield of combined cranial and large vessel PET/CT, ultrasound and MRI in giant cell arteritis: A systematic review and meta-analysis

OBJECTIVES

To estimate the diagnostic accuracy of combined cranial and large vessel imaging by PET/CT, ultrasound and MRI for giant cell arteritis (GCA).

METHODS

PubMed, Embase, Cochrane and Web of Science databases were searched from inception till August, 312,022. Studies were included if they involved patients with suspected GCA and assessed the diagnostic accuracy of combined cranial and large vessel imaging by PET/CT, ultrasound or MRI with the final clinical diagnosis as reference standard.

RESULTS

Eleven (1578 patients), 3 (149 patients) and 0 studies were included for the diagnostic accuracy of ultrasound, PET/CT and MRI, respectively. Combined cranial and large vessel ultrasound had a sensitivity of 86% (76-92%) and specificity of 96% (92-98%). PET/CT of both cranial and large vessels yielded a sensitivity of 82% (61-93%) and specificity of 79% (60-90%). No studies assessed both PET/CT and ultrasound, which precluded head-to-head comparison. Addition of large vessel ultrasound to ultrasound of the temporal arteries (7 studies) significantly increased sensitivity (91% versus 80%, p < 0.001) without decrease in specificity (96% versus 95%, p = 0.57). Evaluating cranial arteries in addition to large vessels on PET/CT (3 studies) tended to increase the sensitivity (82% versus 68%, p = 0.07) without decrease in specificity (81% versus 79%, p = 0.70).

CONCLUSION

Combined cranial and large vessel ultrasound and PET/CT provided excellent accuracy for the diagnosis of GCA. Either PET/CT or ultrasound may be preferred depending on setting, expertise and clinical presentation. The diagnostic accuracy of combined cranial and large vessel MRI needs to be determined in future studies.

Higher diagnostic yield of 18F-FDG PET in inflammation of unknown origin compared to fever of unknown origin

OBJECTIVE

18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) is an important imaging technique in the workup of fever of unknown origin (FUO) and inflammation of unknown origin (IUO). Studies comparing the diagnostic yield of 18F-FDG PET between both entities are lacking.

METHODS

Retrospective analysis of FUO/IUO patients who underwent 18F-FDG PET between 2000 and 2019 in the University Hospitals of Leuven (Belgium). 18F-FDG PET images were assessed for accuracy and contribution towards the final diagnosis. Logistic regression was performed to evaluate the association between meeting FUO or IUO criteria and diagnostic contribution of 18F-FDG PET with and without adjustment for confounders.

RESULTS

Out of 604 patients, 439 (73%, mean age 56 years, 43% female) underwent 18F-FDG PET imaging, including 349 (79%) classified as FUO and 90 (21%) as IUO. Noninfectious inflammatory disorders were significantly more frequent in the IUO group (37% versus 25%; P = 0.03). 18F-FDG PET imaging had a sensitivity of 93% (89-96%), a specificity of 35% (29-42%), and made a positive contribution to the final diagnosis in 25% (21-29%) of cases. IUO was significantly associated with contributive 18F-FDG PET imaging compared to FUO (aOR 2.21 [95% CI 1.31-3.72]; P = 0.003). Among those with contributive 18F-FDG PET imaging, giant cell arteritis (IUO 25% versus FUO 12%) and polymyalgia rheumatica (IUO 17% versus FUO 1%) were numerically more frequent in the IUO group.

CONCLUSION

The diagnostic contribution of 18F-FDG PET was higher among those with IUO, most likely due to differences in diagnostic spectrum.

Identification of new telomere- and telomerase-associated autoantigens in systemic sclerosis

PURPOSE

In up to 20% of patients with systemic sclerosis (SSc) no known autoantibody specificity can be identified. Recently discovered autoantigens, such as telomeric repeat binding factor 1 (TERF1), as well as established autoantigens, like RuvBL1/2, are associated with telomere and telomerase biology. We aimed to identify new telomere- and telomerase-associated autoantigens in patients with SSc without known autoantibody specificity.

METHODS

Unlabelled protein immunoprecipitation combined with gel-free liquid chromatography-tandem mass spectrometry (IP-MS) was performed with sera of 106 patients with SSc from two tertiary referral centres that had a nuclear pattern on HEp-2 indirect immunofluorescence without previously identified autoantibody. Telomere- or telomerase-associated proteins or protein complexes precipitated by individual sera were identified. Candidate autoantigens were confirmed through immunoprecipitation-western blot (IP-WB). A custom Luminex xMAP assay for 5 proteins was evaluated with sera from persons with SSc (n = 467), other systemic autoimmune rheumatic diseases (n = 923), non-rheumatic disease controls (n = 187) and healthy controls (n = 199).

RESULTS

Eight telomere- and telomerase-associated autoantigens were identified in a total of 11 index patients, including the THO complex (n = 3, all with interstitial lung disease and two with cardiac involvement), telomeric repeat-binding factor 2 (TERF2, n = 1), homeobox-containing protein 1 (HMBOX1, n = 2), regulator of chromosome condensation 1 (RCC1, n = 1), nucleolar and coiled-body phosphoprotein 1 (NOLC1, n = 1), dyskerin (DKC1, n = 1), probable 28S rRNA (cytosine(4447)-C(5))-methyltransferase (NOP2, n = 1) and nuclear valosin-containing protein-like (NVL, n = 2). A Luminex xMAP assay for THO complex subunit 1 (THOC1), TERF2, NOLC1, NOP2 and NVL revealed high reactivity in all index patients, but also in other patients with SSc and disease controls. However, the reactivity by xMAP assay in these other patients was not confirmed by IP-WB.

CONCLUSION

IP-MS revealed key telomere- and telomerase-associated proteins and protein complexes as autoantigens in patients with SSc.

Epidemiology and predictors of relapse in giant cell arteritis: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to estimate the timing of relapse, the prevalence of multiple relapses and the predictors of relapse in patients with giant cell arteritis (GCA).

METHODS

PubMed, Embase and Cochrane databases were searched from inception till November, 30 2021. Outcome measures include cumulative relapse rate (CRR) of first relapse at year 1, 2, and 5 after treatment initiation, CRR of second and third relapse and predictors of relapse.

RESULTS

Thirty studies (2595 patients) were included for timing of relapse, 16 studies (1947 patients) for prevalence of multiple relapses and 40 studies (4213 patients) for predictors of relapse. One-year, 2-year and 5-year CRRs were 32% [95% confidence interval (CI) 22-43%], 44% [95% CI 31-59%], and 47% [95% CI 27-67%], respectively. The duration of scheduled glucocorticoid therapy was negatively associated with the 1-year CRR (P=0.03). CRR of second and third relapse were 30% [95% CI 21-40] and 17% [95% CI 8-33%], respectively. Female sex (OR 1.43) and large vessel involvement (OR 2.04) were predictors of relapse.

CONCLUSION

Relapse occurred in almost half of GCA patients mainly during the first two years after diagnosis. One in three patients had multiple relapses. The optimal glucocorticoid tapering schedule, which seeks a balance between the lowest relapse risk and the shortest glucocorticoid duration, needs to be determined in future studies. Longer scheduled glucocorticoid therapy or early introduction of glucocorticoid-sparing agents may be warranted in female patients and patients with large vessel involvement.

Etiological spectrum and outcome of fever and inflammation of unknown origin. Does symptom duration matter?

OBJECTIVE

Evidence suggests that the symptom duration may affect the occurrence of certain fever (FUO) and inflammation (IUO) of unknown origin associated conditions. It is unclear if this could potentially guide diagnostic evaluations. We examined the association between symptom duration and diagnostic and prognostic outcomes in FUO/IUO.

METHODS

We retrospectively analyzed a cohort of adult patients meeting criteria for FUO/IUO from a tertiary care center in Belgium between 2000 and 2019. The association between symptom duration and outcomes of interest were estimated by Cox proportional hazards models.

RESULTS

Among 602 patients who met criteria for FUO/IUO (mean age 54 years, 43% female), 132 (22%) and 68 (11%) had symptoms for 3-12 months and >12 months, respectively. There were no significant differences in diagnosis or all-cause mortality between a symptom duration of <3 months and 3-12 months. In contrast, those who had a symptom duration of >12 months were less likely to receive a final diagnosis (aHR 0.42, 95% CI 0.30-0.60), in particular a diagnosis of infectious disorders (aHR 0.29, 95% CI 0.12-0.74), malignancies (aHR 0.11, 95% CI 0.03-0.46), and miscellaneous conditions (aHR 0.22, 95% CI 0.07-0.71), but no significant differences were seen in noninfectious inflammatory disorders (aHR 0.74, 95% CI 0.48-1.15) or all-cause mortality (aHR 0.55, 95% CI 0.19-1.54).

CONCLUSIONS

The symptom duration may be used to guide the diagnostic workup among patients with FUO and IUO, in particular those with longstanding symptoms.

Diagnostic accuracy and validation of 18F-fluorodeoxyglucose positron emission tomography scores in a large cohort of patients with polymyalgia rheumatica

Background

Several studies have shown that ¹⁸F-FDG PET may contribute to the diagnosis of polymyalgia rheumatica (PMR). Previously, we developed a composite PET score called the Leuven score, which was recently adapted to the more concise Leuven/Groningen score by van der Geest et al. The aim of this study is to validate and compare the diagnostic accuracy and cut-off points of both scores in a large cohort of PMR patients.

Methods

Patients with a possible clinical diagnosis of PMR and a PET scan prior to the initiation of glucocorticoids between 2003 and 2020 were included retrospectively. The gold standard for the diagnosis of PMR was the judgment of two experienced clinicians after a follow-up of at least 6 months. FDG uptake was scored visually in 12 articular regions (scores 0–2) and a total skeletal score was calculated by summing the individual scores (maximum of 24 for the Leuven score and 14 for the Leuven/Groningen score). Receiver operating characteristic (ROC) analysis and the Youden index were used to determine the diagnostic accuracy and optimal cut-off points.

Results

A total of 162 patients with PMR and 83 control patients were included. Both PET scores showed high diagnostic accuracy in the ROC analysis (area under the curve 0.986 and 0.980, respectively). The Leuven Score provided a sensitivity of 91.4%, specificity of 97.6% and accuracy of 93.5% at its predefined cut-off point of 16. With the newly determined cut-off point of 12 the sensitivity was 98.8%, the specificity 95.2% and the accuracy 97.6%. The Leuven/Groningen score had a sensitivity, specificity and accuracy of 93.2%, 95.2%, and 93.9%, respectively, with the pre-specified cut-off point of 8, and 96.9%, 92.8%, and 95.5% with the optimal cut-off point of 7.

Conclusion

The original Leuven score and the simplified Leuven/Groningen score both had excellent diagnostic accuracy. The latter may be easier to apply in clinical practice.

Rheumatic disorders among patients with fever of unknown origin: A systematic review and meta-analysis

OBJECTIVES

To conduct a systematic literature review and meta-analysis to estimate the proportion of fever of unknown origin (FUO) and inflammation of unknown origin (IUO) cases that are due to rheumatic disorders and the relative frequency of specific entities associated with FUO/IUO.

METHODS

We searched PubMed and EMBASE between January 1, 2002, and December 31, 2021, for studies with ≥50 patients reporting on causes of FUO/IUO. The primary outcome was the proportion of FUO/IUO patients with rheumatic disease. Secondary outcomes include the association between study and patient characteristics and the proportion of rheumatic disease in addition to the relative frequency of rheumatic disorders within this group. Proportion estimates were calculated using random-effects models.

RESULTS

The included studies represented 16884 patients with FUO/IUO. Rheumatic disease explained 22.2% (95%CI 19.6 - 25.0%) of cases. Adult-onset Still's disease (22.8% [95%CI 18.4-27.9%]), giant cell arteritis (11.4% [95%CI 8.0-16.3%]), and systemic lupus erythematosus (11.1% [95%CI 9.0-13.8%]) were the most frequent disorders. The proportion of rheumatic disorders was significantly higher in high-income countries (25.9% [95%CI 21.5 - 30.8%]) versus middle-income countries (19.5% [95%CI 16.7 - 22.7%]) and in prospective studies (27.0% [95%CI 21.9-32.8%]) versus retrospective studies (20.6% [95%CI 18.1-24.0%]). Multivariable meta-regression analysis demonstrated that rheumatic disease was associated with the fever duration (0.011 [95%CI 0.003-0.021]; P=0.01) and with the fraction of patients with IUO (1.05 [95%CI 0.41-1.68]; P=0.002).

CONCLUSION

Rheumatic disorders are a common cause of FUO/IUO. The care of patients with FUO/IUO should involve physicians who are familiar with the diagnostic workup of rheumatic disease.

OP0094 IDENTIFICATION OF NEW AUTOANTIGENS IN PATIENTS WITH SYSTEMIC SCLEROSIS THROUGH IMMUNOPRECIPITATION COMBINED WITH LIQUID CHROMATOGRAPHY-TANDEM MASS SPECTROMETRY

Background

In up to 20% of patients with systemic sclerosis (SSc) none of the established SSc-specific autoantibodies are present [1]. Notwithstanding, in many of these patients high-titer autoantibodies can be detected on the HEp-2 indirect immunofluorescence assay (HEp-2 IIFA) which suggests the presence of an autoantibody to an intracellular protein expressed by the HEp-2 cell line. Immunoprecipitation of unlabeled cell extract followed by gel-free liquid chromatography tandem mass-spectrometry analysis has the potential to identify new autoantigens in an unbiased manner.

Objectives

To identify new autoantigens through immunoprecipitation combined with liquid chromatography-tandem mass spectrometry (IP + LC-MS/MS) in HEp-2 IIFA-positive patients with SSc in whom none of the established SSc-specific autoantibody specificities are present.

Methods

Forty-nine patients from the University Hospitals Leuven that fulfilled the EULAR-ACR 2013 classification criteria for systemic sclerosis or LeRoy and Medsger’s criteria for early systemic sclerosis and who were negative on the EliA CTD Screen (Thermo Fisher Scientific, United States), which includes centromere protein B, topoisomerase I, RNA polymerase III, fibrillarin, PM-Scl and U1 ribonucleoprotein, were identified. Immunoprecipitation was performed by incubation of sera of these patients (1/30 in 300 µl Tris-buffered saline) with Pierce A/G magnetic beads, subsequent cross-linking with bissulfosuccinimidyl suberate (BS3) followed by incubation with nuclear extract of HeLa cells (100-150 µg) overnight at 4°C. The eluted protein was analyzed through liquid chromatography with tandem mass spectrometry. Mass spectrometry data were matched against the Uniprot Homo Sapiens database with the Mascot search engine. Candidate autoantigens were confirmed through immunoprecipitation followed by western blot of the eluate with target-specific polyclonal rabbit antibodies or western blot of recombinant protein incubated with sera of the index patients.

Results

We identified multiple new autoantigens, including the THO complex subunit 1 (THOC1) and other subunits of the THO complex in 3 patients, nuclear valosin-containing protein like-2 (NVL) in 2 patients, nucleolar and coiled-body phosphoprotein 1 (NOLC1) and multiple interacting proteins in 1 patient, probable 28S rRNA (cytosine(4447)-C(5))-methyltransferase (NOP2) in 1 patient, telomeric repeat-binding factor 2 (TERF2) and TERF2-interacting protein (TERF2IP) in 1 patient and regulator of chromosome condensation 1 (RCC1) in 1 patient. The new targets were confirmed through immunoprecipitation-western blot or western blot of recombinant protein incubated with sera (Figure 1). Furthermore, in 10 patients known SSc-associated autoantigens were strongly immunoprecipitated including multiple Th/To subunits in 5 patients, RuvBL1/2 in 2 patients, multiple PM-Scl subunits in 2 patients (who both were negative on the EliA CTD Screen), and fibrillarin in 1 patient (who was also negative on the EliA CTD .).

Figure 1.

Immunoprecipitation-western blot with target-specific rabbit polyclonal antibody (1/500-2000 dilution), numbers corresponding to order of description of patients, HC healthy control. NE nuclear extract. RP recombinant protein WB-RP western blot of recombinant protein incubated with patient’s sera.

Conclusion

Multiple new autoantigens were identified and confirmed in patients with SSc without previously identified autoantibody specificity. Further evaluation of reactivity against the newly identified autoantigens in patients with SSc with known autoantibody specificities and other cohorts is required. IP + LC-MS/MS can identify new and established autoantigens in patients with SSc.

References

[1]Meier FMP, Frommer KW, Dinser R, et al. Update on the profile of the EUSTAR cohort: an analysis of the EULAR Scleroderma Trials and Research group database. Ann Rheum Dis 2012;71:1355–60. doi:10.1136/annrheumdis-2011-200742

Disclosure of Interests

Jean-Baptiste Vulsteke: None declared, Daniel Blockmans: None declared, Petra De Haes: None declared, Steven Vanderschueren: None declared, Patrick Verschueren: None declared, Kristl G Claeys: None declared, Wim Wuyts Grant/research support from: Boehringer-Ingelheim, Galapagos, Roche, Jan Leo Lenaerts: None declared, Ellen De Langhe: None declared, Xavier Bossuyt Consultant of: Inova Diagnostics, Thermo Fisher Scientific.

Clinical characteristics of sarcoidosis patients in Belgium

BACKGROUND

Sarcoidosis is a non-caseating granulomatous disease, mostly affecting previously healthy persons in their fourth and fifth decade. In Belgium, there is a paucity of epidemiological data concerning sarcoidosis and it is unknown to what respect national data on sarcoidosis relates to the global epidemiology of the disease.

OBJECTIVES

In this cohort study we describe the patient population in an academic center of reference, serving both as a regional care center and a center for a tertiary referral.

METHODS

We collected epidemiological data among 234 consecutive patients consulting the outpatient sarcoidosis clinic during a two-year time period. We manually explored the electronic patient file for data retrieval.

RESULTS

Out of the 234 patients, 140 are male (60%) and 94 are female (40%) patients. Forced vital capacity showed a median decline of 2% during follow-up, whereas median diffusion capacity increased with 4% over the same period of time. Within our study cohort, we observed a preponderance in employment as construction workers (14%), the chemical industry (6%) and in the metal processing industry (6%).

CONCLUSION

The current study reports on epidemiological findings among the largest cohort of sarcoidosis patients in Belgium published to date.

Graphical abstract [Figure: see text].

Tick borne relapsing fever after travelling to a Greek island

A 23-year-old man presented to the emergency department with recurrent fever after returning from a camping trip on the Greek island of Tilos in the Aegean sea. In the last 2 months, four distinct episodes of fever, chills and myalgia occurred. A peripheral-blood smear revealed an unexpected guest.

Monogenic Adult-Onset Inborn Errors of Immunity

Inborn errors of immunity (IEI) are a heterogenous group of disorders driven by genetic defects that functionally impact the development and/or function of the innate and/or adaptive immune system. The majority of these disorders are thought to have polygenic background. However, the use of next-generation sequencing in patients with IEI has led to an increasing identification of monogenic causes, unravelling the exact pathophysiology of the disease and allowing the development of more targeted treatments. Monogenic IEI are not only seen in a pediatric population but also in adulthood, either due to the lack of awareness preventing childhood diagnosis or due to a delayed onset where (epi)genetic or environmental factors can play a role. In this review, we discuss the mechanisms accounting for adult-onset presentations and provide an overview of monogenic causes associated with adult-onset IEI.

In reply to 'clinical biochemistry test eliminator providing cost-effectiveness with five algorithms': the Casablanca strategy

In this journal, Ataman Gönel recently demonstrated that elimination of requested unnecessary tests by means of algorithms in an artificial intelligence program may contribute to the cost-effectiveness of medicine. However, test ordering is an essential part of clinical medicine and decision-making. Interns are responsible for a modest but significant excess in laboratory utilization and underestimate their control over laboratory testing. Even in the hands of experts, rational approaches to test ordering may be subverted by the Casablanca Strategy. Establishing a differential diagnosis and ordering only tests deemed necessary reflect the attainment of expertise in the clinical decision-making process. Residents and attendings in teaching roles should not underestimate the extent to which their clinical decision-making may be mimicked.

Associations between occupational and environmental exposures and organ involvement in sarcoidosis: a retrospective case-case analysis

Background

Sarcoidosis most commonly affects lungs and intrathoracic lymph nodes, but any other organ can be involved. In epidemiological studies, many occupational and environmental exposures have been linked to sarcoidosis but their relationship with the disease phenotype has barely been studied.

Objective

To investigate how occupational and environmental exposures prior to diagnosis relate to organ involvement in patients with sarcoidosis

Methods

We retrospectively studied patients seen at a sarcoidosis clinic between 2017 and 2020. Patients were included if they had a clinical presentation consistent with sarcoidosis and histologically confirmed epithelioid granulomas or had Löfgren syndrome. In a case–case analysis using multivariable logistic regression we calculated odds ratios (OR) of prespecified exposure categories (based on expert ascertainment) for cases with a given organ involvement versus cases without this organ involvement.

Results

We included 238 sarcoidosis patients. Sarcoidosis limited to pulmonary involvement was associated with exposure to inorganic dust prior to diagnosis (OR 2.11; 95% confidence interval [CI] 1.11–4.17). Patients with liver involvement had higher odds of contact with livestock (OR 3.68; 95% CI 0.91–12.7) or having jobs with close human contact (OR 4.33; 95% CI 1.57–11.3) than patients without liver involvement. Similar associations were found for splenic involvement (livestock: OR 4.94, 95% CI 1.46–16.1; close human contact: OR 3.78; 95% CI 1.47–9.46). Cardiac sarcoidosis was associated with exposure to reactive chemicals (OR 5.08; 95% CI 1.28–19.2) or livestock (OR 9.86; 95% CI 1.95–49.0). Active smokers had more ocular sarcoidosis (OR 3.26; 95% CI 1.33–7.79).

Conclusions

Our study indicates that, in sarcoidosis patients, different exposures might be related to different organ involvements—hereby providing support for the hypothesis that sarcoidosis has more than one cause, each of which may promote a different disease phenotype.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01818-5.

Spontaneous cervical swelling syndrome as a rare cause of neck edema: case series and literature review

Spontaneous cervical swelling syndrome (SCSS) is a rare disorder characterized by unprovoked, self-limiting and often unilateral cervical edema. SCSS is a recurrent disorder that predominantly affects adult women and is not associated with laboratory abnormalities. We report on eight female patients with a mean age of 56 (38–82) years at the time of the first presentation. The episodes were characterized by an acute onset in all patients and had a mean duration of 3.8 (1–7) days. Biochemical analysis did not reveal any related abnormalities. Imaging of the neck and chest demonstrated diffuse edema in the supraclavicular fossa and left infrahyoid region in all patients. At the time of the acute event, lymphatic scintigraphy revealed tracer accumulation in the left supraclavicular region in three patients and could not demonstrate any abnormalities in the in-between episodes in two patients.

Case Report: VEXAS Syndrome: From Mild Symptoms to Life-Threatening Macrophage Activation Syndrome

Recently, a novel disorder coined VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome was identified in patients with adult-onset inflammatory syndromes, often accompanied by myelodysplastic syndrome1. All patients had myeloid lineage-restricted somatic mutations in UBA1 affecting the Met41 residue of the protein and resulting in decreased cellular ubiquitylation activity and hyperinflammation. We here describe the clinical disease course of two VEXAS syndrome patients with somatic UBA1 mutations of which one with a mild phenotype characterized by recurrent rash and symmetric polyarthritis, and another who was initially diagnosed with idiopathic multicentric Castleman disease and developed macrophage activation syndrome as a complication of the VEXAS syndrome. The latter patients was treated with anti-IL6 therapy (siltuximab) leading to a resolution of systemic symptoms and reduction of transfusion requirements.

Cocaine-induced midline destruction

In patients presenting with nasal septum perforation, the differential diagnosis between ANCA-associated vasculitis and cocaine-induced midline destruction (CIMD) can be challenging. We describe the case of a 28-year old man who presented with a nasal septum perforation. He admitted the use of cocaine and showed no other symptoms of systemic inflammation. Perinuclear anti-neutrophilic cytoplasmatic antibodies (p-ANCAs) came back positive, as did anti-proteinase 3-antibodies. Further testing revealed antibodies to human neutrophil elastase (HNE), typically found in CIMD but rarely in ANCA-associated vasculitis. The combination of an atypical ANCA-pattern and the detection of HNE-antibodies led to the diagnosis of CIMD. In conclusion, HNE antibodies can be used to distinguish between CIMD and ANCA-associated vasculitis.

Systemic autoinflammatory disease in adults

Systemic autoinflammatory disorders comprise an expanding group of rare conditions. They are mediated by dysfunction of the innate immune system and share a core of phenotypic manifestations including recurrent attacks of fever, cutaneous signs, chest or abdominal pain, lymphadenopathy, vasculopathy, and musculoskeletal symptoms. Diagnosis is often established in childhood, but a growing number of adult patients are being recognized with systemic autoinflammatory disorders, including adult-onset disease. In this review, we provide a concise update on the pathophysiology, clinical presentation, and diagnostic approach of systemic autoinflammatory disorders with an emphasis on the adult patient population. Despite the recent advances in genetic testing, the diagnosis of autoinflammatory disease in adult patients is often based on a thorough knowledge of the clinical phenotype. Becoming acquainted with the clinical features of these rare disorders may assist in developing a high index of suspicion for autoinflammatory disease in patients presenting with unexplained episodes of fever or inflammation.

Impact of age at diagnosis in polymyalgia rheumatica: A retrospective cohort study of 218 patients

BACKGROUND

Polymyalgia rheumatica (PMR) is a common musculoskeletal inflammatory disease that may occur with giant-cell arteritis (GCA) or in an isolated form. While the incidence is highest in the elderly, there is a paucity of data on its presentation, clinical course and response to treatment in younger individuals.

METHODS

We conducted a retrospective review of 40 patients who were diagnosed with isolated PMR under the age of 60 and 178 patients diagnosed above this age, taking into account clinical and laboratory data and treatment history.

RESULTS

Patients who were diagnosed at a younger age had lower acute-phase reactant levels at diagnosis but not after initiation of treatment or at the time of relapse. The risk of relapse was lower in the group diagnosed under age 60 (35% vs 55%). Cumulative and maximal glucocorticoid doses, use of glucocorticoid-sparing agents and duration of glucocorticoid treatment, did not differ between the groups. In multivariate analysis, younger age at diagnosis was associated with cervical pain and male gender.

CONCLUSION

Compared to patients diagnosed above age 60, patients diagnosed with PMR at a younger age have a lower risk of relapse, but similar long-term outcomes with regards to continued need for treatment.

Mesenteric panniculitis as a presentation of Whipple's disease: case report and review of the literature

BACKGROUND

Whipple's disease is a rare, multi-organ disease caused by Tropheryma Whipplei. A classic presentation is characterized by arthropathy, diarrhea and weight loss but a broad spectrum of manifestations is possible. We present a case of a patient with mesenteric panniculitis as a manifestation of WD. A comprehensive review of the literature is provided.

PATIENT

A 50 year old male presented at the outpatient clinic after an episode of fever and abdominal pain abroad. CT scan showed mesenteric infiltration with associated lymphadenopathies consistent with mesenteric panniculitis. After receiving 6 months of antibiotic therapy abdominal and joint pains improved.

CONCLUSION

Clinicians should be aware of Whipple's disease. Mesenteric panniculitis is a rare presentation of this possible lethal infection. The golden standard for diagnosing WD is a PAS positive small bowel biopsy. Adequate antibiotic therapy is the cornerstone of treatment and usually leads to an amelioration of symptoms.

Adult-Onset ANCA-Associated Vasculitis in SAVI: Extension of the Phenotypic Spectrum, Case Report and Review of the Literature

STING-associated vasculopathy with onset in infancy (SAVI) is an autosomal dominant disorder due to gain-of-function mutations in STING1, also known as TMEM173, encoding for STING. It was reported as a vasculopathy of infancy. However, since its description a wider spectrum of associated manifestations and disease-onset has been observed. We report a kindred with a heterozygous STING mutation (p.V155M) in which the 19-year-old proband suffered from isolated adult-onset ANCA-associated vasculitis. His father suffered from childhood-onset pulmonary fibrosis and renal failure attributed to ANCA-associated vasculitis, and died at the age of 30 years due to respiratory failure. In addition, an overview of the phenotypic spectrum of SAVI is provided highlighting (a) a high phenotypic variability with in some cases isolated manifestations, (b) the potential of adult-onset disease, and (c) a novel manifestation with ANCA-associated vasculitis.

Long-term efficacy and safety of canakinumab in patients with colchicine-resistant familial Mediterranean fever: results from the randomised phase III CLUSTER trial

Objectives

To evaluate the long-term efficacy and safety of canakinumab to treat patients with colchicine-resistant familial Mediterranean fever (crFMF) during Epoch 4 (weeks 41 to 113) of the CLUSTER study.

Methods

Patients received open-label canakinumab 150 or 300 mg, every 4 or 8 weeks during a 72-week period. We evaluated disease activity every 8 weeks using the physician global assessment (PGA) of disease activity, counting the number of flares, and measuring concentrations of C reactive protein (CRP) and serum amyloid A (SAA). Safety was studied by determination and classification of observed adverse events (AEs). We analysed safety and efficacy separately in two subgroups of patients receiving a cumulative dose of less than 2700 mg, or equal or more than 2700 mg.

Results

Of the 61 patients that started the CLUSTER study, 60 entered Epoch 4 and 57 completed it. During the 72-week period, 35/60 (58.3%) patients experienced no flares, and 23/60 (38.3%) had one flare, as compared with a median of 17.5 flares per year reported at baseline. PGA scores indicated no disease activity for the majority of patients throughout the study. Median CRP concentrations were always lower than 10 mg/L, while median SAA concentrations remained over the limit of normal (10 mg/L) but under the 30 mg/L threshold. No new or unexpected AEs were reported.

Conclusion

crFMF patients treated with canakinumab during 72 weeks experienced a minimal incidence of flares and good control of clinical disease activity, with no new safety concerns reported.

Efficacy and safety of canakinumab treatment in schnitzler syndrome: A systematic literature review

BACKGROUND

Schnitzler syndrome is a rare autoinflammatory disorder characterized by chronic urticarial rash and a monoclonal gammopathy, accompanied by intermittent fever, bone pain, and arthralgia or arthritis. Canakinumab is a fully human monoclonal anti-interleukin-1β (IL-1β) antibody proven to be effective in IL-1 driven autoinflammatory disorders.

METHODS

We systematically searched PubMed and Embase to include all types of studies on canakinumab treatment in Schnitzler syndrome published until March 16, 2020.

RESULTS

Since 2011, 7 publications have been reported on canakinumab treatment in 34 patients with Schnitzler syndrome. The cumulative follow-up was 253 months, and 5 studies had a follow-up duration of 12 months or more. A complete response during treatment was reported in 58.6% of patients; all other patients had a partial response. Two hundred and seven adverse events were reported in 23 patients. Infection (n = 79) was the most common adverse event. One patient died from sepsis due to atypical mycobacterial infection.

CONCLUSION

Based on the results of the current systematic review, canakinumab is an effective long-term treatment with a favorable safety profile in patients with Schnitzler syndrome.

OP0272 LONG-TERM EFFICACY AND SAFETY OF CANAKINUMAB IN PATIENTS WITH COLCHICINE-RESISTANT FAMILIAL MEDITERRANEAN FEVER: RESULTS FROM THE RANDOMISED PHASE 3 CLUSTER TRIAL

Background:

Familial Mediterranean Fever (FMF) is a hereditary autoinflammatory disease associated with mutations in theMEFVgene. Colchicine is the cornerstone of current therapy for FMF; however, a subset of patients are resistant or intolerant to it. Previously published results from the CLUSTER trial [NCT02059291] demonstrated that canakinumab, a fully human anti-interleukin-1β monoclonal antibody, was effective in controlling and preventing flares in patients with colchicine-resistant familial Mediterranean fever (crFMF).1

Objectives:

To evaluate the long-term efficacy and safety of canakinumab to treat patients with crFMF during Epoch 4 of the CLUSTER study.

Methods:

Patients with active crFMF (baseline flare) were enrolled in the CLUSTER study. During Epoch 4 (weeks 40 to 113), patients received open-label canakinumab 150 or 300 mg, every 4 or 8 weeks (q4w or q8w). Patients started Epoch 4 on the same regimen that they were receiving at the end of Epoch 3, and stepwise up-titration of canakinumab was allowed in patients who experienced a flare, to a maximum dose of 300 mg q4w. We evaluated disease activity every 8 weeks using the physician global assessment of disease activity (PGA), counting the number of flares (defined as PGA ≥2 and CRP >30 mg/L), and measuring serum concentrations of C reactive protein (CRP) and serum amyloid A (SAA). Safety was assessed by the determination and classification of adverse events (AEs). We analysed safety and efficacy separately in two subgroups of patients receiving a cumulative dose of canakinumab lower than 2700 mg, or equal or higher than 2700 mg.

Results:

Of the 61 patients with active crFMF who started the CLUSTER study, 60 entered Epoch 4 and 57 completed it. During the 72-week period, 35/60 (58.3%) patients experienced no flares, and 23/60 (38.3%) had one single flare, as compared with a median of 17.5 flares per year reported at baseline. The incidence of flares was similar in the two cumulative dose groups. PGA scores indicated no disease activity for the majority of patients throughout the study, in both cumulative dose groups. 23/57 (40%) of patients remained in the lower dosing group (150 mg q8w) until study end, whereas 9/57 (16%) required the highest dose allowed (300 mg q4w). Patients with higher body weight had an increased probability to require up-titration of canakinumab to control disease activity. Median CRP concentrations were lower than 10 mg/L at every time point in both cumulative dose groups, while median SAA concentrations remained in the 16-70 mg/L range, and were higher in the group receiving ≥2700 mg canakinumab (Figure 1). No opportunistic infections, renal disease caused by amyloidosis, new or unexpected AEs were reported.

Figure 1.

SAA and CRP blood levels in Epoch 4 of the CLUSTER study, in two subgroups of patients treated with a cumulative dose of canakinumab <2700 mg or ≥2700 mg

Conclusion:

Patients with crFMF treated with canakinumab during 72 weeks experienced a minimal incidence of flares and good control of clinical disease activity, with no new safety signals reported.

References:

[1]De Benedetti F et al.N Engl J Med2018;378:1908–19.

Disclosure of Interests:

Seza Özen Consultant of: Novartis, Pfizer, Speakers bureau: SOBI, Novartis, Eldad Ben-Chetrit Speakers bureau: Novartis, Ivan Foeldvari Consultant of: Novartis, Gil Amarilyo Grant/research support from: Novartis, Speakers bureau: Novartis, Huri Ozdogan: None declared, Steven Vanderschueren: None declared, Katherine Marzan Grant/research support from: Novartis, J Michelle Kahlenberg Grant/research support from: Celgene, BMS, Consultant of: Eli Lilly, AstraZeneca, BMS, Boehringer Ingleheim, Elise Dekker Employee of: Novartis, Fabrizio De Benedetti Grant/research support from: AbbVie, Pfizer, Novartis, Novimmune, Sobi, Sanofi, Roche, Speakers bureau: AbbVie, Novartis, Roche, Sobi, Isabelle Koné-Paut Consultant of: Novartis, Chugai, Pfizer, LFB, AbbVie, Novimmune, SOBI

Use of 18F-fluorodeoxyglucose positron emission tomography in the diagnosis of polymyalgia rheumatica-A prospective study of 99 patients

Objective

Previous studies have shown that the majority of patients with PMR have increased 18F-fluorodeoxyglucose (FDG) uptake around the shoulders, hips and processes of the cervical and lumbar spine on PET. The specificity of these findings for PMR is, however, not known.

Methods

We prospectively included 99 consecutive patients with a possible clinical diagnosis of PMR. All patients underwent 18F-FDG-PET scanning before treatment with glucocorticoids was started. The clinical suspicion of PMR was quantified by the treating physician on a scale from 1 to 5. FDG uptake was scored visually in 12 articular regions (scores 0-2) and a total skeletal score was calculated reflecting the FDG uptake in these 12 articular regions. Receiver operating characteristics analysis was performed to determine the optimal clinical and total skeletal score for diagnosing PMR. The gold standard for a diagnosis of PMR was the judgement of an experienced clinician after at least 6 months of follow-up.

Results

Sixty-seven patients were diagnosed with PMR while 32 patients got another diagnosis. A clinical score of 4 or more had a sensitivity of 67.2%, specificity of 87.5%, positive predictive value (PPV) of 91.8% and a negative predictive value (NPV) of 56.0% for the diagnosis of PMR. A total skeletal score of 16 or more had a sensitivity, specificity, PPV and NPV of, respectively, 85.1, 87.5, 93.4 and 73.7%.

Conclusion

18F-FDG-PET before starting glucocorticoid therapy improves the diagnostic accuracy compared with a clinical scoring system in patients with clinical suspicion of PMR.

Screening for connective tissue disease-associated antibodies by automated immunoassay

BACKGROUND

Antinuclear antibodies (ANAs) are useful for the diagnosis of ANA-associated systemic rheumatic disease (AASRD). The objective of this study was the evaluation of an immunoassay that detects antibodies to a mixture of 17 antigens as an alternative to indirect immunofluorescence (IIF).

METHODS

Nine thousand eight hundred and fifty-six consecutive patients tested for ANAs were tested by IIF and EliA connective tissue disease screen (Thermo-Fisher). Medical records were reviewed for 2475 patients, including all patients that tested positive/equivocal by either test and a selection of 500 patients that tested negative.

RESULTS

Concordance between IIF and EliA was 83.1%. AASRD was found in 12.8% of IIF-positive patients, 30.2% of EliA-positive patients and 0.4%, 46.6%, 5.8% and 3.0% of patients that tested, respectively, double negative, double positive, single positive for EliA and single positive for IIF. The association with AASRD increased with increasing antibody level. IIF and EliA were positive in, respectively, 90.4% and 69.9% of systemic lupus erythematosus (n=83), 100% and 84.1% of systemic sclerosis (n=63), 86.7% and 93.3% of Sjögren's syndrome (n=45), 88.2% and 52.9% of polymyositis/dermatomyositis (n=17), and in all cases of mixed connective tissue disease (n=8). The specificity was projected to be 94%-96% for EliA and 86% for IIF. When all AASRDs were taken together, the areas under the curve of receiver operator curves were similar between IIF and EliA.

CONCLUSIONS

The positive predictive value for AASRD was higher for EliA than for IIF, but, depending on the disease, EliA might fail to detect antibodies that are detected by IIF. Combining immunoassay with IIF adds value.