The type-I interferon response potentiates seeded tau aggregation and exacerbates tau pathology

INTRODUCTION

Signatures of a type-I interferon (IFN-I) response are observed in the post mortem brain in Alzheimer's disease (AD) and other tauopathies. However, the effect of the IFN-I response on pathological tau accumulation remains unclear.

METHODS

We examined the effects of IFN-I signaling in primary neural culture models of seeded tau aggregation and P301S-tau transgenic mouse models in the context of genetic deletion of the IFN-I receptor (IFNAR).

RESULTS

Polyinosinic:polycytidylic acid (PolyI:C), a synthetic analog of viral nucleic acids, evoked a potent cytokine response that enhanced seeded aggregation of tau in an IFN-I-dependent manner. IFN-I-induced vulnerability could be pharmacologically prevented and was intrinsic to neurons. Aged P301S-tau mice lacking Ifnar1 had significantly reduced tau pathology compared to mice with intact IFN signaling.

DISCUSSION

We identify a critical role for IFN-I in potentiating tau aggregation. IFN-I is therefore identified as a potential therapeutic target in AD and other tauopathies.

HIGHLIGHTS

Type-I IFN (IFN-I) promotes seeded tau aggregation in neural cultures. IFNAR inhibition prevents IFN-I driven sensitivity to tau aggregation. IFN-I driven vulnerability is intrinsic to neurons. Tau pathology is significantly reduced in aged P301S-tau mice lacking IFNAR.

Neuroprotective effects of hepatoma-derived growth factor in models of Huntington's disease

Huntington's disease (HD) is a movement disorder caused by a mutation in the Huntingtin gene that leads to severe neurodegeneration. Molecular mechanisms of HD are not sufficiently understood, and no cure is currently available. Here, we demonstrate neuroprotective effects of hepatoma-derived growth factor (HDGF) in cellular and mouse HD models. We show that HD-vulnerable neurons in the striatum and cortex express lower levels of HDGF than resistant ones. Moreover, lack of endogenous HDGF exacerbated motor impairments and reduced the life span of R6/2 Huntington's disease mice. AAV-mediated delivery of HDGF into the brain reduced mutant Huntingtin inclusion load, but had no significant effect on motor behavior or life span. Interestingly, both nuclear and cytoplasmic versions of HDGF were efficient in rescuing mutant Huntingtin toxicity in cellular HD models. Moreover, extracellular application of recombinant HDGF improved viability of mutant Huntingtin-expressing primary neurons and reduced mutant Huntingtin aggregation in neural progenitor cells differentiated from human patient-derived induced pluripotent stem cells. Our findings provide new insights into the pathomechanisms of HD and demonstrate neuroprotective potential of HDGF in neurodegeneration.

Super-resolution imaging unveils the self-replication of tau aggregates upon seeding

Tau is a soluble protein interacting with tubulin to stabilize microtubules. However, under pathological conditions, it becomes hyperphosphorylated and aggregates, a process that can be induced by treating cells with exogenously added tau fibrils. Here, we employ single-molecule localization microscopy to resolve the aggregate species formed in early stages of seeded tau aggregation. We report that entry of sufficient tau assemblies into the cytosol induces the self-replication of small tau aggregates, with a doubling time of 5 h inside HEK cells and 1 day in murine primary neurons, which then grow into fibrils. Seeding occurs in the vicinity of the microtubule cytoskeleton, is accelerated by the proteasome, and results in release of small assemblies into the media. In the absence of seeding, cells still spontaneously form small aggregates at lower levels. Overall, our work provides a quantitative picture of the early stages of templated seeded tau aggregation in cells.

Cytosolic antibody receptor TRIM21 is required for effective tau immunotherapy in mouse models

Aggregates of the protein tau are proposed to drive pathogenesis in neurodegenerative diseases. Tau can be targeted by using passively transferred antibodies (Abs), but the mechanisms of Ab protection are incompletely understood. In this work, we used a variety of cell and animal model systems and showed that the cytosolic Ab receptor and E3 ligase TRIM21 (T21) could play a role in Ab protection against tau pathology. Tau-Ab complexes were internalized to the cytosol of neurons, which enabled T21 engagement and protection against seeded aggregation. Ab-mediated protection against tau pathology was lost in mice that lacked T21. Thus, the cytosolic compartment provides a site of immunotherapeutic protection, which may help in the design of Ab-based therapies in neurodegenerative disease.

POS1259 AXIAL SPONDYLOARTHRITIS, AGE AND MALE GENDER IMPACT COVID VACCINATION AEs MORE THAN RHEUMATOID ARTHRITIS

Background

Rheumatologists recommend vaccination in rheumatoid arthritis (RA) and axial spondyloarthritis (axSpA) patients, but there are few studies on the occurrence of adverse events (AEs), particularly worsening disease related activity and unrelated immune reactions in these groups.

Objectives

To evaluate the uptake of COVID vaccination in RA and axSpA patients, compare the frequency of AEs, and identify risk factors associated with vaccine AEs in two prospective cohorts comprised of these patients.

Methods

The IMPACT study is a monthly survey of two prospective cohorts of established RA and axSpA patients in northern Alberta, Canada from November 2020-2021 who answered at least one or more Redcap surveys through de-identified email link surveying demographics, disease characteristics, COVID symptoms, treatment of RA and axSpA, health care utilization, vaccination status, vaccine AEs and use of cannabis. Univariate analyses evaluated independent variables associated with the dependent variables of (1) any AE, (2) any severe AE, (3) any arthritis flare, and (4) any severe arthritis flare, followed by multivariate analyses of these four dependant variables using all clinically relevant variables from the univariate analysis.

Results

773/2167 patients (RA 574, axSpA 197) responded to at least one survey. 32/663 (5%) were single vaccinated, 631 (95%) double vaccinated and 230 (54%) triple vaccinated with 80% receiving Pfizer, 24% Moderna, 28% AstraZeneca and 30% “other”. 456 (69%) reported at least one AE (Figure 1) with 21 (3%) patients seeing a physician for their AE. Increased age was associated with all AEs. RA patients had lower reported AEs versus axSpA patients for all AE definitions except for severe arthritis flares. Generally, males reported worse AEs (Table 1). “Any arthritis flare” was lower in patients reporting cannabis use.

Table 1.

Summary of Multivariate Level Mixed-Effect Logistic Regression Models Evaluating the IMPACT of RA and axSpA Disease Characteristics on Vaccine AEs

VariableAny Adverse EventOR (95 % CI) p valueSevere Adverse Event* OR 95 % CI) p valueAny Arthritis Flare or Joint Ache Adverse Event OR (95 % CI) p valueAny Severe Arthritis Flare or Joint Ache* OR (95 % CI) p valueGenderMale1.47 (0.89 – 2.43)p=0.132.10 (1.30-3.41)p=0.0032.05 (1.20 – 3.50) p=0.013.97 (1.84 – 8.57)p=0.0004FemaleAge1.06 (1.04 – 1.08)p<0.011.05 (1.03 – 1.06)p<0.011.03 (1.01 – 1.04)p=0.0031.03 (1.01 – 1.06)p=0.004Rheumatic Disease TypeRA0.42 (0.23 – 0.76)p=0.050.55 (0.31 – 0.98)p=0.040.52 (0.28 – 0.98)p=0.040.78 (0.34 – 1.78)p=0.55axSpASteroidsYes0.85 (0.40 – 1.83) P=0.680.66 (0.32 – 1.35) p=0.250.84 (0.36 – 1.95) p=0.690.38 (0.15 – 0.97)p=0.04NoNSAIDSYes1.11 (0.81 – 1.52) p=0.511.03 (0.75 – 1.41)p=0.861.05 (0.74 – 1.48)p=0.801.17 (0.73 – 1.89)p=0.52NoCurrent Disease Activity0.95 (0.88 – 1.03) p=0.230.90 (0.83 – 0.97)p=0.190.92 (0.85 – 1.00)p=0.060.82 (0.74 – 0.92)p=0.001HAQ1.08 (0.73 – 1.61) p=0.700.77 (0.52 – 1.14)p=0.010.74 (0.48 – 1.13)p=0.170.65 (0.38 – 1.11)p=0.12Nicotine productsYes1.33 (0.75 – 2.37) p=0.341.42 (0.80 – 2.52)p=0.241.15 (0.60 – 2.01)p=0.760.97 (0.43 – 2.17)p=0.94NoCannabis productsYes0.78 (0.49 – 1.25) p=0.300.87 (0.55 – 1.38)p=0.550.51 (0.31 – 0.83)p=0.070.66 (0.35 – 1.26)p=0.21NoDMARDsYes1.98 (1.28 – 3.06)p=0.0021.52 (1.01 – 2.28)p=0.051.43 (0.91 – 2.23) p=0.121.86 (1.03 – 3.36)p=0.04NoBiologic DMARDYes0.72 (0.42 – 1.25) p=0.240.79 (0.45 – 1.41) p=0.431.20 (0.66 – 2.18 p=0.541.39 (0.63 – 3.08)p=0.42No

*Severe = Any of the following: ranked moderate to severe and/or lasting more than 7 days and/or saw physician

Conclusion

RA and axSpA patients showed high uptake of COVID vaccination with largely minor AEs. Older age and male gender were associated with more general and arthritis specific AEs. The association of any AE and/or arthritis-specific AEs in SpA versus RA patients is a novel finding which may correlate with the male predominance of SpA. The association of cannabis with fewer arthritis AEs may reflect the nociceptive properties of cannabis.

Acknowledgements

Epidemiology Coordinating and Research (EPICORE) Centre provided support for the REDCAP survey and biostatistical analyses.

Disclosure of Interests

Stephanie Keeling Speakers bureau: Pfizer, Abbvie, GSK, UCB, Consultant of: Abbvie, GSK, UCB, AstraZeneca, Sandoz, Pfizer, Grant/research support from: Abbvie, Sandoz, Merck, UCB, Bo Pan: None declared, Edna Hutchings Shareholder of: BMS, Stephanie Wichuk: None declared, Mohammed Osman Speakers bureau: Boehringer Ingelheim, Takeda Pharmaceuticals, Grant/research support from: Boehringer Ingelheim and CSL-Behring, Ameeta Singh: None declared, Ashlesha Sonpar Speakers bureau: Novartis, Ilan Swartz: None declared, Walter P Maksymowych Speakers bureau: Abbvie, Janssen, Novartis, Pfizer, UCB, Consultant of: Abbvie, Boehringer Ingelheim, Celegene, Eli-Lilly, Galapagos, Novartis, Pfizer, UCB, Grant/research support from: Abbvie, Novartis, Pfizer, UCB

POS1258 LESS THAN EXPECTED IMPACT OF RHEUMATOID ARTHRITIS AND AXIAL SPONDYLOARTHRITIS DISEASE ON COVID SEVERITY

Background

Throughout the pandemic, there has been ongoing concern that people with autoimmune diseases such as rheumatoid arthritis (RA) and axial spondyloarthritis (axSpA) will have more severe COVID-19 disease due to immune dysfunction associated with autoimmune diseases and their treatment.

Objectives

We aimed to compare the severity of COVID-19 in patients with RA versus axSpA and characterize the predictors of COVID-19 severity during the pre-Omicron pandemic phases.

Methods

The IMPACT (IMPact of inflammatory Arthritis on COVID Outcomes STudy) study is a monthly survey of two established northern Alberta, Canada prospective cohorts of RA and axSpA patients from November 2020-2021 who answered Redcap surveys through de-identified email link surveying patient demographics, disease characteristics, COVID-19 symptoms, treatment of RA and axSpA, health care utilization, vaccination status and vaccine adverse events. Descriptive and univariate analyses (dependent variable = severe COVID-19) were performed followed by multivariate analyses of all significant and clinically relevant independent variables from the univariate analysis. Infection severity was defined as any patient with COVID-19 symptoms who visited a doctor, ER or required hospital admission.

Results

773 of 2167 (36%) patients (RA n=574, axSpA n=197) registered in both cohorts answered at least one baseline survey, 28 (4%) reporting positive COVID-19 tests (24 positive once). Of 442 reporting COVID-19 symptoms during the survey, 11 (3%) were admitted for a mean of 4 days, 2 requiring ICU or blood clot treatment and 1 requiring advanced therapy. 116 (26%) visited a physician for Covid symptoms. Univariate analysis showed that the use of steroids, NSAIDs and increased disease activity were associated with having less severe infection but these associations were not significant in the multivariate analysis (Table 1). There were no significant impacts of RA vs axSpA, age, gender, treatment, disease activity, or smoking.

Table 1.

Multivariate Level Mixed-Effect Logistic Regression Model: IMPACT of RA and axSpA Disease Characteristics on COVID Infection Severity Defined as Patients with COVID Symptoms Requiring Visit to Doctor, Emergency Room and/or Hospital Admission.

VariableCoefficient (S.E)Odds Ratio (95 % Confidence Interval)P-valueGenderMale0.17 (0.34)1.18 (0.61 – 2.31)0.6193FemaleReferenceAge-0.01 (0.01)0.99 (0.97 – 1.01)0.2543Rheumatic Disease TypeRA0.18 (0.40)1.20 (0.58 – 2.48)0.6213SpAReferenceSteroidsYes-0.40 (0.56)0.67 (0.23 – 2.01)0.4757NoReferenceNSAIDSYes-0.20 (0.26)0.82 (0.49 – 1.37)0.4508NoReferenceCurrent Disease Activity-0.04 (0.06)0.96 (0.85 – 1.09)0.5275HAQ-0.03 (0.29)0.97 (0.55 – 1.70)0.9041Nicotine productsYes-0.67 (0.37)0.51 (0.25 – 1.06)0.0714NoReferenceCannabis productsYes-0.45 (0.31)0.64 (0.35 – 1.18)0.1510NoReferenceDMARDsYes0.26 (0.30)1.30 (0.72 – 2.35)0.3860NoReferenceBiologic DMARDYes-0.46 (0.43)0.63 (0.27 – 1.46)0.2813NoReference

Conclusion

Possible disease related risk factors for increased COVID-19 severity in RA and axSpA patients preceding the onset of the Omicron variant including use of steroids or DMARDs were not associated with severe infection. These findings are consistent with other international studies whereby other non-rheumatic disease comorbidities played a greater role in infection severity.

Acknowledgements

Epidemiology Coordinating and Research (EPICORE) Centre provided support for the REDCAP survey and biostatistical anayses.

Disclosure of Interests

Stephanie Keeling Speakers bureau: Abbvie, GSK, Pfizer, UCB, Consultant of: Abbvie, GSK, Pfizer, Sandoz, UCB, Eli-Lilly, Galapagos, Novartis, Grant/research support from: Abbvie, UCB, Sandoz, Pfizer, Merck, Bo Pan: None declared, Edna Hutchings Shareholder of: BMS, Stephanie Wichuk: None declared, Mohammed Osman Speakers bureau: Boehringer Ingelheim, Takeda Pharmaceuticals, Grant/research support from: Yes, Boehringer Ingelheim and CSL-Behring, Ameeta Singh: None declared, Ashlesha Sonpar Speakers bureau: Novartis, Ilan Swartz: None declared, Walter P Maksymowych Speakers bureau: Abbvie, Janssen, Novartis, Pfizer, UCB

, Consultant of: Abbvie, Boehringer Ingelheim, Celegene, Eli-Lilly, Galapagos, Novartis, Pfizer, UCB, Grant/research support from: Abbvie, Novartis, Pfizer, UCB

Cholesterol determines the cytosolic entry and seeded aggregation of tau

Assemblies of tau can transit between neurons, seeding aggregation in a prion-like manner. To accomplish this, tau must cross cell-limiting membranes, a process that is poorly understood. Here, we establish assays for the study of tau entry into the cytosol as a phenomenon distinct from uptake, in real time, and at physiological concentrations. The entry pathway of tau is cell type specific and, in neurons, highly sensitive to cholesterol. Depletion of the cholesterol transporter Niemann-Pick type C1 or extraction of membrane cholesterol renders neurons highly permissive to tau entry and potentiates seeding even at low levels of exogenous tau assemblies. Conversely, cholesterol supplementation reduces entry and almost completely blocks seeded aggregation. Our findings establish entry as a rate-limiting step to seeded aggregation and demonstrate that dysregulated cholesterol, a feature of several neurodegenerative diseases, potentiates tau aggregation by promoting entry of tau assemblies into the cell interior.

POS0037 DOES IMAGING OF THE SACROILIAC JOINT DIFFER IN PATIENTS PRESENTING WITH UNDIAGNOSED BACK PAIN AND PSORIASIS, ACUTE ANTERIOR UVEITIS, AND COLITIS: AN INCEPTION COHORT STUDY

Background:

Axial spondyloarthritis (axSpA) presents diagnostic challenges incurring a delay of up to a decade and relies considerably on radiographic and MRI evidence of sacroiliitis which has led to the development of classification criteria which also rely on imaging. However, it has been suggested that such criteria may not be appropriate for axSpA patients presenting with other forms of SpA, especially psoriatic, because imaging features may vary in frequency and/or may be atypical. This hypothesis has never been tested in a prospective inception cohort of patients presenting with undiagnosed back pain.

Objectives:

We aimed to compare the spectrum of radiographic and MRI abnormalities in the sacroiliac joint (SIJ) of an inception cohort of patients presenting with undiagnosed back pain and psoriasis, iritis, and colitis.

Methods:

We used data from the prospective multicenter Screening for Axial Spondyloarthritis in Psoriasis, Iritis, and Colitis (SASPIC) Study, which is aimed at early detection of axial SpA in patients referred by the respective specialist after first presenting with these disorders. Consecutive patients ≤45 years of age with ≥3 months undiagnosed back pain with any one of psoriasis, AAU, or colitis undergo routine clinical evaluation by a rheumatologist for axial SpA followed by imaging. In SASPIC I, MRI evaluation of the SIJ was ordered per rheumatologist decision. In SASPIC II, MRI evaluation was ordered for all patients. Radiographs and MRI scans were assessed by two central readers and comparisons of the three groups were based on concordant assessments of imaging features. Evaluation of MRI scans included both global assessment for presence/absence of axSpA with confidence scale (-10 to +10), active and structural lesions typical of axSpA per recent ASAS definitions, and granular assessment of individual lesions according to SIJ quadrants and halves in consecutive semicoronal slices through the SIJ. Groups were compared by ANOVA and the chi-square test.

Results:

A total of 240 patients were recruited, 143 from SASPIC I and 97 from SASPIC II, 101 (42.1%) being diagnosed with axSpA (65.3% male, mean age 34.4 years, mean symptom duration 8.7 years, B27 positive 55.4%). Mean age of colitis (N=101), psoriasis (N=61), iritis (N=78) patients were 33.4, 36.6, 34.3 years, respectively, mean symptom duration was 6.8, 7.2, 9.4 years, respectively, and % males were 45.5%, 52.5%, 51.3%, respectively. There were no significant group differences for unilateral versus bilateral radiographic sacroiliitis and no significant differences in the frequencies, type, or distribution of MRI lesions (Table 1).

Conclusion:

Data from the SASPIC prospective inception cohort does not support the view that imaging of the SIJ differs in psoriatic axSpA, which appears similar to axSpA associated with iritis or colitis. These data support the umbrella concept of axSpA.

Imaging FeatureColitis (n=30)Psoriasis (n=19)Iritis (n=52)P valueUnilateral sacroiliitis (grade ≥2), N(%)1 (3.3%)0 (0%)2 (3.8%)0.69mNY criteria +, N(%)5 (16.7%)6 (31.2%)15 (28.8%)0.39Grade of sacroiliitis, mean(SD)1.8 (2.2)2.1 (2.7)2.2 (2.4)0.76MRI indicative of axSpA, N(%)15 (50.0%)11 (57.9%)32 (61.5%)0.60MRI indicative of axSpA (confidence ≥5/10), N(%)14 (46.7%)10 (52.6%)30 (57.7%)0.63MRI active lesion typical of axSpA, N(%)6 (20.0%)6 (31.6%)18 (34.6%)0.37MRI structural lesion typical of axSpA, N(%)11 (36.7%)7 (36.8%)18 (34.6%)0.98MRI with unilateral lesion (any)2 (6.7%)3 (15.8%)11 (21.2%)0.22MRI with unilateral lesion (BME)1 (3.3%)2 (10.5%)5 (9.6%)0.54MRI with unilateral lesion (Erosion)0 (0%)0 (0%)3 (5.8%)0.23MRI with unilateral lesion (Sclerosis)1 (3.3%)1 (5.3%)3 (5.8%)0.89MRI with unilateral lesion (Fat)0 (0%)0 (0%)0 (0%)NAMRI with iliac lesion17 (56.7%)12 (63.2%)32 (61.5%)0.88MRI with sacral lesion12 (40.0%)11 (57.9%)31 (59.6%)0.21

Disclosure of Interests:

Walter P Maksymowych Speakers bureau: Abbvie, Janssen, Novartis, Pfizer, UCB, Consultant of: Abbvie, BMS, Boehringer, Galapagos, Gilead, Lilly, Novartis, Pfizer, UCB, Grant/research support from: Abbvie, Novartis, Pfizer, Ulrich Weber: None declared, Jon Chan: None declared, Raj Carmona: None declared, James Yeung: None declared, Sibel Aydin: None declared, Jodie Reis: None declared, Liam Martin: None declared, Ariel Masetto: None declared, Olga Ziouzina: None declared, Dianne Mosher: None declared, Stephanie Keeling: None declared, Sherry Rohekar: None declared, Rana Dadashova: None declared, Joel Paschke: None declared, Amanda Carapellucci: None declared, Robert G Lambert: None declared.

Extensive Plasmid Library to Prepare Tau Protein Variants and Study Their Functional Biochemistry

Tau neurofibrillary tangles are key pathological features of Alzheimer's disease and other tauopathies. Recombinant protein technology is vital for studying the structure and function of tau in physiology and aggregation in pathophysiology. However, open-source and well-characterized plasmids for efficiently expressing and purifying different tau variants are lacking. We generated 44 sequence-verified plasmids including those encoding full length (FL) tau-441, its four-repeat microtubule-binding (K18) fragment, and their respective selected familial pathological variants (N279K, V337M, P301L, C291R, and S356T). Moreover, plasmids for expressing single (C291A), double (C291A/C322A), and triple (C291A/C322A/I260C) cysteine-modified variants were generated to study alterations in cysteine content and locations. Furthermore, protocols for producing representative tau forms were developed. We produced and characterized the aggregation behavior of the triple cysteine-modified tau-K18, often used in real-time cell internalization and aggregation studies because it can be fluorescently labeled on a cysteine outside the microtubule-binding core. Similar to the wild type (WT), triple cysteine-modified tau-K18 aggregated by progressive β-sheet enrichment, albeit at a slower rate. On prolonged incubation, cysteine-modified K18 formed paired helical filaments similar to those in Alzheimer's disease, sharing morphological phenotypes with WT tau-K18 filaments. Nonetheless, cysteine-modified tau-K18 filaments were significantly shorter (p = 0.002) and mostly wider than WT filaments, explainable by their different principal filament elongation pathways: vertical (end-to-end) and lateral growth for WT and cysteine-modified, respectively. Cysteine rearrangement may therefore induce filament polymorphism. Together, the plasmid library, the protein production methods, and the new insights into cysteine-dependent aggregation should facilitate further studies and the design of antiaggregation agents.

SAT0378 THE RELATIVE DIAGNOSTIC UTILITY OF INFLAMMATORY BACK PAIN CRITERIA IN AN INCEPTION COHORT OF PATIENTS WITH PSORIASIS, IRITIS, AND COLITIS PRESENTING WITH UNDIAGNOSED BACK PAIN

Background:

Clinicians rely on the elicitation of features of inflammatory back pain (IBP) for diagnosis of axial spondyloarthritis (axSpA) but the utility of IBP criteria in patients presenting with extra-articular features of axSpA remains unclear. Assessment of utility should include not only rheumatologist diagnosis as benchmark but imaging to address the circularity between elicitation of IBP and clinical diagnosis.

Objectives:

To assess the diagnostic utility of all criteria for IBP in patients with psoriasis, iritis, or colitis and undiagnosed back pain using the rheumatologist diagnosis and imaging as benchmarks.

Methods:

Consecutive patients (n=246) with undiagnosed back pain ≤45 years of age, ≥3 months, with any one of psoriasis (n=46), acute anterior uveitis (AAU)(n=73), or colitis (n=127) had diagnostic evaluation by a rheumatologist. Majority central reader assessment of MRI indicative of axSpA and diagnosis by the rheumatologist were external standards for testing the utility of these IBP criteria: ASAS, Berlin, Calin, rheumatologist global for IBP >5 (0-10 scale).

Results:

AxSpA was diagnosed in 44.4%, 61.6%, and 41.8% of patients with psoriasis, iritis, and IBD, respectively. Diagnostic utility for all IBP criteria was comparably poor (Table 1). MRI was indicative of axSpA in 21.2%, 43.5%, and 19.7% of patients with psoriasis, iritis, and IBD. The utility of the IBP criteria was even worse using MRI as the external reference (Table 2), especially in patients with psoriasis. Only 14% of psoriasis patients with a positive MRI reported “improvement with exercise but not rest” as compared to 70% and 62% of patients with iritis and IBD, respectively.

Table 1.

Rheumatologist diagnosis as external reference.

SensitivitySpecificityLR+LR-PsoriasisASAS IBP65.00%52.00%1.350.67Berlin IBP80.00%36.00%1.250.56Calin IBP80.00%28.00%1.110.71All 3 criteria sets60.00%56.00%1.360.71IBP global >585.00%36.00%1.330.42AAUASAS IBP84.44%42.86%1.480.36Berlin IBP80.00%57.14%1.870.35Calin IBP93.33%17.86%1.140.37All 3 criteria sets77.78%60.71%1.980.37IBP global >586.67%57.14%2.020.23IBDASAS IBP78.43%45.07%1.430.48Berlin IBP82.35%52.11%1.720.34Calin IBP84.31%19.72%1.050.80All 3 criteria sets70.59%57.75%1.670.51IBP global >580.39%66.20%2.380.30Table 2.

Central assessment that MRI is indicative of axSpA as external reference.

SensitivitySpecificityLR+LR-PsoriasisASAS IBP28.57%38.46%0.461.86Berlin IBP42.86%15.38%0.513.71Calin IBP71.43%23.08%0.931.24All 3 criteria sets14.29%42.31%0.252.03IBP global >585.71%23.08%1.110.62AAUASAS IBP75.00%26.92%1.030.93Berlin IBP70.00%38.46%1.140.78Calin IBP90.00%15.38%1.060.65All 3 criteria sets65.00%38.46%1.060.91IBP global >575.00%38.46%1.220.65IBDASAS IBP92.31%37.74%1.480.20Berlin IBP76.92%39.62%1.270.58Calin IBP92.31%16.98%1.110.45All 3 criteria sets76.92%45.28%1.410.51IBP global >592.31%47.17%1.750.16

Conclusion:

All IBP criteria have poor diagnostic utility for diagnosis of axSpA, especially in patients with psoriasis. This reinforces the desirability of less subjective assessment tools, especially imaging.

Disclosure of Interests:

Georg Kröber: None declared, Ulrich Weber: None declared, Raj Carmona: None declared, James Yeung: None declared, Jon Chan: None declared, Sibel Aydin: None declared, Liam Martin: None declared, Ariel Masetto: None declared, Stephanie Keeling: None declared, Olga Ziouzina: None declared, Sherry Rohekar: None declared, Rana Dadashova: None declared, Joel Paschke: None declared, Amanda Carapellucci: None declared, Robert G Lambert: None declared, Walter P. Maksymowych Grant/research support from: AbbVie, Novartis, Pfizer, and UCB, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, and UCB, Employee of: Chief Medical Officer of CARE Arthritis Limited, Speakers bureau: AbbVie, Janssen, Novartis, Pfizer, and UCB

SAT0383 ENHANCED PERFORMANCE OF THE ASAS CLASSIFICATION CRITERIA BY DELETION OF NON-DISCRIMINATORY CLINICAL ITEMS: DATA FROM THE SCREENING IN AXIAL SPONDYLOARTHRITIS IN PSORIASIS, IRITIS, AND COLITIS COHORT

Background:

The ASAS classification criteria for axial spondyloarthritis (axSpA) have overall sensitivity/specificity of 82.9%/84.4% but component imaging and clinical arms differ in performance (66.2%/97.3% and 56.6%/83.3%, respectively)1.

Objectives:

We aimed to demonstrate that a data-driven elimination of SpA clinical features that were non-discriminatory in comparisons of patients diagnosed with and without axSpA in a prospective cohort of patients with undiagnosed back pain could enhance the performance of the criteria.

Methods:

We used data from the prospective multicenter Screening for Axial Spondyloarthritis in Psoriasis, Iritis, and Colitis (SASPIC) Study. Consecutive patients ≤45 years of age with ≥3 months undiagnosed back pain with any one of psoriasis, AAU, or colitis undergo routine diagnostic evaluation by a rheumatologist for axial SpA, including imaging assessed by central readers. Univariable and multivariable logistic regression analysis was performed to determine which clinical SpA features were/were not discriminatory for the final diagnosis of axSpA. We then compared the sensitivity and specificity of the ASAS criteria with and without these features.

Results:

A total of 246 patients were recruited, 47.6% being diagnosed with axSpA (61.5% male, age 33.7 years, symptom duration 7.6 years, B27 positive 52.1%). The following clinical SpA features were non-discriminatory between axSpA/not axSpA: NSAID response, family history of SpA, heel enthesitis, peripheral arthritis, dactylitis. Specificity of the clinical arm and the overall criteria increased from 82.2% to 86.8% without impacting sensitivity. This effect was particularly noteworthy in patients with lower degree of symptomatology (back pain severity <5/10, specificity increases from 76.7% to 90.7%), short symptom duration (<5 years, specificity increases from 78% to 84.7%), and in females (specificity increases from 80.6% to 86.1%).

Conclusion:

In a prospective cohort with a high pre-test probability of axSpA certain clinical SpA features were not helpful in discriminating a diagnosis of SpA from not-SpA. Deletion of these features from the list of SpA features used in the ASAS classification criteria enhanced the performance of the criteria, especially in female patients and those with early disease.

References:

[1]Rudwaleit et al. Ann Rheum Dis 2009;68: 777-83

Patient CategoryNumberASAS criteriaImaging armClinical armSenSpecSenSpecSensSpecAll patients2466582.236.897.750.482.2High confidence in diagnosis19073.884.547.598.256.384.5Patients with back pain ≥5/1016563.384.934.298.851.984.9Patients with back pain <58168.476.742.195.347.476.7Patients with symptom duration ≥5 years10371.285.735.697.156.285.7Patients with symptom duration <5 years14354.57838.698.340.978Males12968.184.247.298.248.684.2Females1176080.62097.253.380.6After deletion of ‘NSAID response’, ‘Family Hx SpA’, ‘heel enthesitis’, ‘peripheral arthritis’, ‘dactylitis’ SpA featuresAll patients2466586.836.897.750.486.8High confidence in diagnosis19073.887.347.598.256.387.3Patients with back pain ≥5/1016563.384.934.298.851.984.9Patients with back pain <58168.490.742.195.347.490.7Patients with symptom duration ≥5 years10371.288.635.697.156.288.6Patients with symptom duration <5 years14354.584.738.698.340.984.7Males12968.187.747.298.248.687.7Females1176086.12097.253.386.1

Disclosure of Interests:

Walter P. Maksymowych Grant/research support from: AbbVie, Novartis, Pfizer, and UCB, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, and UCB, Employee of: Chief Medical Officer of CARE Arthritis Limited, Speakers bureau: AbbVie, Janssen, Novartis, Pfizer, and UCB, Raj Carmona: None declared, Jon Chan: None declared, James Yeung: None declared, Sibel Aydin: None declared, Liam Martin: None declared, Ariel Masetto: None declared, Olga Ziouzina: None declared, Stephanie Keeling: None declared, Sherry Rohekar: None declared, Rana Dadashova: None declared, Joel Paschke: None declared, Amanda Carapellucci: None declared, Robert G Lambert: None declared

FRI0298 ASAS MODIFICATION OF THE BERLIN ALGORITHM AND THE DUET ALGORITHM FOR DIAGNOSING AXIAL SPONDYLOARTHRITIS: RESULTS FROM THE SCREENING IN AXIAL SPONDYLOARTHRITIS FOR PSORIASIS, IRITIS, AND COLITIS COHORT

Background:

Patients presenting with back pain and psoriasis, iritis, or colitis, represent a high-risk population for the presence of axial spondyloarthritis (axSpA). The Dublin Evaluation Tool (DUET)1, the Berlin algorithm2, and the ASAS modification of this algorithm3are recommended referral strategies aimed at early diagnosis of axSpA. DUET was developed for patients presenting with AAU. Validation of these algorithms in inception cohorts is limited.

Objectives:

1. To assess the performance of referral algorithms for diagnosis of axSpA when tested against the final local rheumatologist diagnosis in an inception cohort of patients presenting with undiagnosed back pain and extra-articular manifestations. 2. To determine whether different criteria for inflammatory back pain (IBP) impact the performance of the algorithms.

Methods:

The multicenter Screening for Axial Spondyloarthritis in Psoriasis, Iritis, and Colitis (SASPIC) Study at 11 sites is aimed at early detection of axial SpA in patients presenting with undiagnosed back pain to the rheumatologist. Consecutive patients ≤45 years of age with ≥3 months undiagnosed back pain with any one of psoriasis, acute anterior uveitis (AAU), or colitis diagnosed by the relevant specialist undergo routine clinical evaluation by a rheumatologist for axial SpA. The rheumatologist determines the presence or absence of axial SpA at 3 consecutive stages: 1. After the clinical evaluation; 2. After the results of labs (B27, CRP) and radiography; 3. After the results of MRI evaluation. Final diagnosis by the rheumatologist was used as external standard to test the performance of the algorithms. We tested the following criteria for IBP in the algorithm: ASAS, Berlin, rheumatologist global for likelihood of IBP >5 (0-10 scale), and DUET algorithm in AAU patients.

Results:

A total of 246 patients were recruited, 73 presented with iritis, 46 with psoriasis, and 127 with colitis, 47.6% were diagnosed with axSpA. The diagnosis of axSpA was established in 45.7%, 61.6%, and 40.2% of patients with psoriasis, AAU, and IBD, respectively. The performance of the ASAS-modification of the Berlin algorithm was superior to the original algorithm as reported previously3, primarily for enhanced sensitivity, and this was observed irrespective of the criteria used to define IBP (Table 1). Conversely, the performance of the Duet algorithm in the subset of patients with AAU was substantially worse than previously reported1.

Conclusion:

The ASAS modification of the Berlin algorithm is the preferred referral strategy for patients presenting with undiagnosed back pain to the rheumatologist.

References:

[1]Haroon M, et al. Ann Rheum Dis 2015; 74: 1990-5

[2]Poddubnyy D, et al. J Rheumatol 2011; 38: 2452–60

[3]Van den Berg R, et al. Ann Rheum Dis 2013;72:1646–53

AlgorithmSensitivity (%)Specificity (%)Correct diagnosis (%)False negative (%)False positive (%)Original Berlin(ASAS criteria for IBP)65.376.671.116.712.2Original Berlin(Berlin criteria for IBP)64.476.670.717.112.2Original Berlin(IBP global >5)67.878.173.215.411.4ASAS Modification of Berlin algorithm (ASAS criteria for IBP)73.775.874.812.612.6ASAS Modification of Berlin algorithm (Berlin criteria for IBP)73.775.074.412.613.0ASAS Modification of Berlin algorithm(IBP global >5)76.377.376.811.411.8DUET84.450.071.29.619.2

Disclosure of Interests:

Ulrich Weber: None declared, Georg Kröber: None declared, Raj Carmona: None declared, James Yeung: None declared, Jon Chan: None declared, Sibel Aydin: None declared, Liam Martin: None declared, Ariel Masetto: None declared, Stephanie Keeling: None declared, Olga Ziouzina: None declared, Sherry Rohekar: None declared, Rana Dadashova: None declared, Amanda Carapellucci: None declared, Joel Paschke: None declared, Robert G Lambert: None declared, Walter P. Maksymowych Grant/research support from: AbbVie, Novartis, Pfizer, and UCB, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, and UCB, Employee of: Chief Medical Officer of CARE Arthritis Limited, Speakers bureau: AbbVie, Janssen, Novartis, Pfizer, and UCB

What investigations are needed to optimally monitor for malignancies in SLE?

Objective

The overall cancer incidence risk in systemic lupus erythematosus (SLE) is approximately 15%–20% more than in the general population. Nevertheless, to date, the optimal malignancy screening measures in SLE remain undefined. Our objective is to determine what investigations are needed to optimally monitor for malignancies in SLE in order to inform upcoming Canadian Rheumatology Association recommendations.

Methods

We conducted a systematic search looking at three scientific sources, Embase, Medline and Cochrane, in an attempt to identify cancer screening recommendations for patients with SLE. We used a filter for observational studies and included articles published in 2000 and onward.

Results

The initial search strategy led to 986 records. After removal of duplicates and articles unrelated to SLE, we were left with 497 titles. From those, 79 research articles on cancer incidence in SLE were isolated and reviewed. Of the 79 original research papers, 25 offered screening recommendations, 14 suggested additional cancer screening whereas 11 studies simply promoted adherence to general population screening measures. The suggestions for more rigorous screening included recommending human papilloma virus testing in addition to routine cervical screening, and/or that cervical screening should be performed annually and/or suggested urine cancer screening in SLE patients with a history of cyclophosphamide exposure.

Conclusions

We found no original research studies directly comparing cancer screening strategies in SLE. Generally, authors recommend adherence to general population screening measures, particularly cervical screening. This, possibly with adding targeted screening in special cases (e.g. annual urine cytology in patients with prior cyclophosphamide exposure, and considering existing lung cancer screening guidelines for past heavy smokers), may be a reasonable approach for cancer screening in SLE.

Development of real-time PCR assays for detection of megalocytiviruses in imported ornamental fish

Megalocytiviruses have been associated globally with severe systemic disease and economic loss in farmed food fish and ornamental fish. The viruses have been spread internationally by translocation of live fish. In New Zealand, megalocytiviruses are regarded as exotic. A potential pathway for introduction has been identified, namely imported ornamental fish. In the present study, real-time PCR assays were developed for detection of megalocytiviruses using a conserved major capsid protein gene. A SYBR green assay was developed to target all known megalocytiviruses. A second real-time PCR assay using a molecular beacon was developed to specifically target gourami, Trichogaster trichopterus, iridovirus, a species of iridovirus previously linked to ornamental fish imports in Australia. The analytical sensitivity for the SYBR green and molecular beacon assays were 10 and 100 fg, respectively. The analytical specificity of the real-time PCR assays determined using genomic DNA templates from three target viruses, 12 non-target viruses and 25 aquatic bacterial species were 100%. The intra-run and inter-run coefficients of variation of both assays were <5%. The real-time PCR assays developed in this study provide rapid, sensitive, and specific detection of megalocytiviruses and gourami iridovirus.

Minimizing macrovessel signal in cerebral perfusion imaging using independent component analysis

The pronounced susceptibility effect of macrovessels in MR bolus-tracking studies induces spots of artificially high blood flow and volume in perfusion parameter images. These high-intensity regions impede the detection of perfusion changes and lead to elevated perfusion parameters in adjacent tissues. The purpose of this work was to explore postprocessing methods to reduce the influence of macrovessel signal in dynamic MRI. After data reduction was performed with the use of a principal component analysis (PCA), an independent component analysis (ICA) was applied to separate signal components of different compartments. Based on this decomposition, the dynamic time series were reconstructed with minimized contributions of macrovessel signal and noise. The influence of the temporal resolution and signal-to-noise ratio (SNR) of the source data were investigated by means of a simulation study. A region-of-interest (ROI)-based analysis of corrected and uncorrected in vivo data demonstrated that the influence of arteries and veins was reduced at least by 50%, while gray matter (GM) and white matter (WM) tissues were nearly unaffected by the correction process. Hemodynamic parameter images of the cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) were calculated from corrected and uncorrected scans. The corrected parameter images showed a clearly reduced macrovessel signal and an improved perceptibility of microvascular perfusion changes compared to the uncorrected ones.

Episodic ataxia type 2. Three novel truncating mutations and one novel missense mutation in the CACNA1A gene

We analysed the CACNA1A gene, located on chromosome 19p13, in three unrelated families and one sporadic case with episodic ataxia type 2 (EA-2). In two of the families and the sporadic patient, novel truncating mutations, which disrupt the reading frame and result in a premature stop of the CACNA1A protein, were identified in exons 14, 16 and 26. In the remaining family, a novel missense mutation (H253Y) was found. Of the twenty two EA-2 mutations identified thus far, including those of the present study, seventeen are truncating mutations and five are missense mutations, all resulting in an EA-2 clinical phenotype.

Technical factors accounting for stability of a bilateral sagittal split osteotomy advancement: wire osteosynthesis versus rigid fixation

OBJECTIVE

Relapse after bilateral sagittal split osteotomy has been attributed to various technical factors that are inherent in the surgical procedure. The purpose of this article was to analyze technical factors that predispose to relapse when wire or rigid fixation is used.

STUDY DESIGN

Patients were randomized to either rigid or wire osteosynthesis. Cephalometric radiographs were obtained and digitized at multiple time periods before and after surgery. Data were analyzed through use of 2-sample t tests and stepwise regression analyses.

RESULTS

Multivariate analysis indicated that the following factors correlated with relapse: initial advancement, change in ramus in inclination, change in the mandibular plane, and fixation type.

CONCLUSIONS

Relapse increased with the amount of initial advancement and, to a lesser extent, with control of the proximal segment and change in the mandibular plane. These factors are similar for wire osteosynthesis and rigid fixation.

Effects of sialoadenectomy and exogenous EGF on molar drift and orthodontic tooth movement in rats

Effects on bone remodeling have been attributed to epidermal growth factor (EGF). Sialoadenectomy (SX) removes the major source of EGF in rodents and decreases both salivary and serum EGF levels. EGF effects on rat alveolar bone remodeling manifested by molar drift (MD) and orthodontic tooth movement (OTM) were examined using the following two approaches: 1) EGF depletion by SX and replacement by orally administered EGF (50 micrograms.animal-1.day-1); 2) sham rats supplemented with matching amounts of EGF. MD and OTM were measured using cephalometric radiographs; bone formation was measured histomorphometrically using tetracycline labeling. Normal MD was not detected after SX, and alveolar bone formation was significantly reduced both around the tooth and in nondental sites. Replacement EGF given to SX rats and supplemental EGF administered to sham rats changed the direction and enhanced the rate of MD. A mesially directed orthodontic force applied to the molars of SX animals increased bone formation on the distal aspect of the tooth roots. Supplemental EGF did not significantly affect OTM. EGF affects alveolar bone remodeling, as manifested clinically by alterations in normal maxillary MD.

Maintenance therapy for duodenal ulcer--a trial comparing cimetidine with a prostaglandin synthetase promoter

The effect of treatment on maintenance of remission was examined in 90 patients with healed duodenal ulcer shown by endoscopy. They were randomized to take treatment for 6 months with a prostaglandin synthetase promoter (263E) 500 mg three times daily or cimetidine 400 mg at night or an identical placebo. Sixty-five patients completed the trial or had a relapse of symptoms. The percentage of patients who had recurrent ulcers or duodenitis alone on endoscopy was 29% on 263E, 36% with cimetidine, and 50% on placebo. These figures did not differ significantly. Trials of this design are now difficult to conduct because patients take and H2 receptor antagonist soon after recurrence of symptoms, before their next clinic appointment.