Effectiveness of two different doses of rituximab for the treatment of rheumatoid arthritis in an international cohort: data from the CERERRA collaboration

BACKGROUND

The approved dose of rituximab (RTX) in rheumatoid arthritis is 1000 mg × 2, but some data have suggested similar clinical efficacy with 500 mg × 2. The purpose of this study was to compare the effectiveness of the regular and low doses given as first treatment course.

METHODS

Twelve European registries participating in the CERERRA collaboration (The European Collaborative Registries for the Evaluation of Rituximab in Rheumatoid Arthritis) submitted anonymized datasets with demographic, efficacy and treatment data for patients who had started RTX. Treatment effectiveness was assessed by DAS28 reductions and EULAR responses after 6 months.

RESULTS

Data on RTX dose were available for 2,873 patients, of whom 2,625 (91.4 %) and 248 (8.6 %) received 1000 mg × 2 and 500 mg × 2, respectively. Patients treated with 500 mg × 2 were significantly older, had longer disease duration, higher number of prior DMARDs, but lower number of prior biologics and lower baseline DAS28 than those treated with 1000 mg × 2. Fewer patients in the low-dose group received concomitant DMARDs but more frequently received concomitant corticosteroids. Both doses led to significant clinical improvements at 6 months. DAS28 reductions at 6 months were comparable in the 2 dose regimens [mean DeltaDAS28 ± SD -2.0 ± 1.3 (high dose) vs. -1.7 ± 1.4 (low dose), p = 0.23 adjusted for baseline differences]. Similar percentages of patients achieved EULAR good response in the two dose groups, 18.4 % vs. 17.3 %, respectively (p = 0.36).

CONCLUSIONS

In this large observational cohort initial treatment with RTX at 500 mg × 2 and 1000 mg × 2 led to comparable clinical outcomes at 6 months.

Achievement of Remission and Low Disease Activity Definitions in Patients with Rheumatoid Arthritis in Clinical Practice: Results from the NOR-DMARD Study

Objective.

To examine the frequency of 6 definitions for remission and 4 definitions for low disease activity (LDA) after starting a disease-modifying antirheumatic drug (DMARD) in patients with rheumatoid arthritis (RA) in clinical practice, and to study whether predictors for achieving remission after 6 months are similar for these definitions.

Methods.

Remission and LDA were calculated according to the 28-joint Disease Activity Score (DAS28), the Clinical Disease Activity Index (CDAI), the Simplified Disease Activity Index (SDAI), the Routine Assessment of Patient Index Data (RAPID3), and both the American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Boolean remission definitions 3 and 6 months after 4992 DMARD prescriptions for patients enrolled in the NOR-DMARD, a 5-center Norwegian register. Prediction of remission after 6 months was also studied.

Results.

After 3 months, remission rates varied between definitions from 8.7% to 22.5% and for LDA from 35.5% to 42.7%, and increased slightly until 6 months of followup. DAS28 and RAPID3 gave the highest and ACR/EULAR, SDAI, and CDAI the lowest proportions for remission. Positive predictors for remission after 6 months were similar across the definitions and included lower age, male sex, short disease duration, high level of education, current nonsmoking, nonerosive disease, treatment with a biological DMARD, being DMARD-naive, good physical function, little fatigue, and LDA.

Conclusion.

In daily clinical practice, the DAS28 and RAPID3 definitions identified remission about twice as often as the ACR/EULAR Boolean, SDAI, and CDAI. Predictors of remission were similar across remission definitions. These findings provide additional evidence to follow treatment recommendations and treat RA early with a DMARD.

Perinatal characteristics, older siblings, and risk of ankylosing spondylitis: a case-control study based on national registers

Background

The effect of circumstances and exposures early in life on the risk of developing ankylosing spondylitis (AS) is largely unknown. The purpose of this study was to determine whether perinatal characteristics predict development of AS.

Methods

AS cases (n = 1960; 59 % men) were defined as listed with a diagnosis of AS at least once in the Swedish National Patient Register and registered in the Swedish Medical Birth Register (born ≥1973). Population controls were retrieved from the Swedish Population Register (n = 8378; mean 4.3 controls/case), matched on birth year, sex and county. Odds ratios (OR) for developing AS were determined through conditional logistic regression, with regard to: birth weight, birth order, season of birth, maternal age, gestational length, size for gestational age, type of birth, mode of delivery, congenital malformations, mothers’ country of birth, mothers’ civil status and size of delivery unit.

Results

In the univariate analyses statistically significant increases in risk for developing AS were observed for having older siblings (OR 1.18; 95 % Cl 1.06–1.30). No association was observed for the remainder of analysed exposures, although there was a weak association with birth weight below 3000 g (OR 1.19; 95 % CI 1.04–1.37), though not for “low birth weight” <2500 g (OR 0.90; 95 % CI 0.70–1.16). The increase in risk associated with having older siblings was consistent in a multivariate analysis adjusting for possible confounders (OR 1.23; 95 % Cl 1.09–1.39). The direction and magnitude of the point estimates were also consistent in several sensitivity analyses and when stratifying by sex.

Conclusions

Having older siblings was associated with an increased risk for developing AS. These results need to be repeated and confirmed in other cohorts.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-0917-1) contains supplementary material, which is available to authorized users.

Effectiveness and Feasibility Associated with Switching to a Second or Third TNF Inhibitor in Patients with Psoriatic Arthritis: A Cohort Study from Southern Sweden

Objective.

Because new modes of action for the treatment of psoriatic arthritis (PsA) are emerging, it is important to understand the use of switching to a second or third antitumor necrosis factor (anti-TNF) agent. This study investigated drug survival and treatment response rates of patients with PsA undergoing second- and third-line anti-TNF therapy.

Methods.

Patients with PsA were monitored in a prospective, observational study. Patients who switched anti-TNF therapy once (first-time switchers, n = 217) or twice (second-time switchers, n = 57) between January 2003 and March 2012 were studied. American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) good response at 3 and 6 months, as well as drug survival, were reported and further analyzed using the Cox and logistic regression models.

Results.

Median age for first-time switchers was 47 years and 42% were men. The corresponding values for second-time switchers were 48 years and 40% men. Three-month ACR20 Lund Efficacy Index (LUNDEX) response was achieved by 47% of first-time and 22% of second-time switchers; ACR50 LUNDEX rates were 21% and 14%, ACR70 LUNDEX rates were 12% and 2%, and EULAR good LUNDEX rates were 26% and 10%, respectively. Median drug survival time for patients switching anti-TNF for the first time was 64 months (95% CI 31–97) compared with 14 months (95% CI 5–23) for second-time switchers. Identified baseline predictor of ACR20 response to second-line treatment was the 28-joint Disease Activity Score values at baseline (OR 1.45, 95% CI 1.01–2.10), while higher Health Assessment Questionnaire scores predicted premature drug withdrawal (HR 1.60, 95% CI 1.03–2.48).

Conclusion.

Response rates of first-time anti-TNF switchers are moderate, while the inferior response rates of second-time switchers suggest other therapeutic options should be considered in this situation.

Mortality in ankylosing spondylitis: results from a nationwide population-based study

OBJECTIVES

Information on mortality in ankylosing spondylitis (AS) is scarce. Our study therefore aimed to assess: (1) mortality in AS versus the general population, and (2) predictors of death in the AS population.

METHODS

Nationwide cohorts of patients with AS diagnosed at rheumatology or internal medicine outpatient clinics (n=8600) and age-matched, sex-matched and county-matched general population comparators (n=40 460) were identified from the National Patient Register and the census register, respectively. The follow-up period began on 1 January 2006 or at the first date of registered diagnosis thereafter and extended until death, emigration or 31 December 2012, whichever occurred first. Socioeconomic variables, AS-related clinical manifestations, joint surgery, comorbidities and medication were identified from other national registers. Cox regression models were used to determine mortality and predictors for death in the AS cohort.

RESULTS

There were 496 deaths in the AS cohort and 1533 deaths in the control cohort resulting in an age-adjusted and sex-adjusted HR of 1.60 (95% CI 1.44 to 1.77), with increased mortality for men (age-adjusted HR=1.53, 95% CI 1.36 to 1.72) and women (age-adjusted HR=1.83, 95% CI 1.50 to 2.22). Within the AS cohort, statistically significant predictors for death were a lower level of education, general comorbidities (diabetes, infections, cardiovascular, pulmonary and malignant diseases) and previous hip replacement surgery.

CONCLUSIONS

Mortality was increased for male and female patients with AS. Predictors of death within the AS cohort included socioeconomic status, general comorbidities and hip replacement surgery.

First step in the development of an ultrasound joint inflammation score for rheumatoid arthritis using a data-driven approach

OBJECTIVES

To develop and validate candidate sets of joints and tendons for assessment of ultrasound (US) joint inflammation in rheumatoid arthritis (RA).

METHODS

Patients were included in one of two cohorts from 2010 to June 2013: disease-modifying antirheumatic drug naïve early RA or established RA starting/switching biologics. An extensive US examination was performed by experienced sonographers using a validated grey-scale (GSUS) and power Doppler (PDUS) semiquantitative scoring system with scores 0-3 for both GSUS and PDUS in 36 joints and four tendons. We performed factor analysis in the early RA US data and selected candidate joint/tendon sets based on these results. The proportion of information in the total US scores retained in these candidate sets was assessed by R(2) from linear regression analysis. Finally, the candidate sets and previously proposed joint scores were tested in the established RA cohort, and we also evaluated the sensitivity to change with standardised response means.

RESULTS

227 patients with early RA and 212 patients with established RA were included. We identified two candidate sets of joints/tendons: candidate set A consisted of seven joints/two tendons (meatacarpophalangeal 1 (MCP1), MCP2, proximal interphalangeal 3, radiocarpal, elbow, metatarsophalangeal 1 (MTP1), MTP2, tibialis posterior tendon, extensor carpi ulnaris tendon) and set B of nine joints/two tendons (MCP5 and MTP5 added to set A). Unilateral reduced scores retained 78%-85% of the information in total score, while bilateral reduced scores retained 89%-93%, and both sets performed better than previously proposed reduced joint scores, and similar or slightly better regarding sensitivity to change.

CONCLUSIONS

The reduced GSUS and PDUS scores retained most of the information from the total score and performed well in a validation cohort of established RA.

TRIAL REGISTATION NUMBER

NCT01205854, ACTRN12610000284066.

The impact of patient heterogeneity and socioeconomic factors on abatacept retention in rheumatoid arthritis across nine European countries

Background

There are substantial differences in accessibility to biological disease modifying antirheumatic drugs (bDMARDs) across countries. The objective of this study was to analyse the impact of patient demographics, disease characteristics and gross domestic product (GDP) on abatacept (ABA) retention in patients with rheumatoid arthritis (RA) treated in clinical practice.

Methods

Data from nine European observational RA cohorts of patients treated with ABA were pooled. Kaplan-Meier analysis was used to compare drug retention across registries. Specific causes of drug retention were investigated using competing risks multivariate Cox regression.

Results

A total of 3961 patients treated with ABA, with 6188 patient-years of follow-up, were included. Patients in the different national registries had similar demographic features, but varied in baseline disease characteristics. ABA drug retention differed between countries, with median drug retention rates ranging from 1.2 to more than 6 years. The differences in drug retention were marginally explained by disparities in disease characteristics, while the national GDP per capita was strongly associated with drug retention (correlation coefficient −0.74; p=0.02).

Conclusions

Patient characteristics at ABA initiation vary across Europe, probably reflecting differences in eligibility criteria and prescription patterns. However, the difference in ABA drug retention between countries was not primarily explained by disparities in patient characteristics. Lower ABA retention was observed in countries with a more liberal access to bDMARDs and higher GDP. National differences need to be accounted for when pooling data on treatment with bDMARDs from various countries.

Hydroxylated polychlorinated biphenyls decrease circulating steroids in female polar bears (Ursus maritimus)

As a top predator in the Arctic food chain, polar bears (Ursus maritimus) are exposed to high levels of persistent organic pollutants (POPs). Because several of these compounds have been reported to alter endocrine pathways, such as the steroidogenesis, potential disruption of the sex steroid synthesis by POPs may cause implications for reproduction by interfering with ovulation, implantation and fertility. Blood samples were collected from 15 female polar bears in Svalbard (Norway) in April 2008. The concentrations of nine circulating steroid hormones; dehydroepiandrosterone (DHEA), androstenedione (AN), testosterone (TS), dihydrotestosterone (DHT), estrone (E1), 17α-estradiol (αE2), 17β-estradiol (βE2), pregnenolone (PRE) and progesterone (PRO) were determined. The aim of the study was to investigate associations among circulating levels of specific POP compounds and POP-metabolites (hydroxylated PCBs [OH-PCBs] and hydroxylated PBDEs [OH-PBDEs]), steroid hormones, biological and capture variables in female polar bears. Inverse correlations were found between circulating levels of PRE and AN, and circulating levels of OH-PCBs. There were no significant relationships between the steroid concentrations and other analyzed POPs or the variables capture date and capture location (latitude and longitude), lipid content, condition and body mass. Although statistical associations do not necessarily represent direct cause-effect relationships, the present study indicate that OH-PCBs may affect the circulating levels of AN and PRE in female polar bears and that OH-PCBs thus may interfere with the steroid homeostasis. Increase in PRO and a decrease in AN concentrations suggest that the enzyme CYP17 may be a potential target for OH-PCBs. In combination with natural stressors, ongoing climate change and contaminant exposure, it is possible that OH-PCBs may disturb the reproductive potential of polar bears.

The effect of comedication with conventional synthetic disease modifying antirheumatic drugs on TNF inhibitor drug survival in patients with ankylosing spondylitis and undifferentiated spondyloarthritis: results from a nationwide prospective study

Objective

To assess the effect of comedication with conventional synthetic disease modifying antirheumatic drugs (csDMARDs) on retention to tumour necrosis factor inhibitor (TNFi) therapy in patients with ankylosing spondylitis (AS) and undifferentiated spondyloarthritis (uSpA).

Methods

Data on patients with a clinical diagnosis of AS or uSpA starting treatment with adalimumab, etanercept or infliximab as their first TNFi during 2003–2010 were retrieved from the Swedish national biologics register and linked to national population based registers. Five-year drug survival was analysed by Cox regression with age, sex, baseline csDMARD comedication, TNFi type, prescription year and covariates representing frailty and socioeconomic status. AS and uSpA were analysed separately. Sensitivity analyses included models with csDMARD as a time-dependent covariate and adjustments for additional potential confounders.

Results

1365 patients with AS and 1155 patients with uSpA were included, of whom 40.8% versus 50.3% used csDMARD comedication at baseline. In the unadjusted analyses superior drug survival was observed for patients using versus not using csDMARD comedication among patients with AS (p<0.001) but not among patients with uSpA (p=0.175). In the multivariable Cox regression analyses comedication with csDMARD was associated with better retention to TNFi therapy both in AS (HR 0.71, p<0.001) and uSpA (HR 0.82, p=0.020). The results were similar with csDMARD comedication as a time-dependent covariate, and the associations were retained when adjusting for erythrocyte sedimentation rate, C-reactive protein, patient global, swollen joints, uveitis, psoriasis and inflammatory bowel disease.

Conclusions

In this large register study of patients with AS and uSpA, use of csDMARD comedication was associated with better 5-year retention to the first TNFi.

Cost-effectiveness of TNF inhibitors vs synthetic disease-modifying antirheumatic drugs in patients with rheumatoid arthritis: a Markov model study based on two longitudinal observational studies

Objective. The objective of this study was to estimate the additional costs and health benefits of adding a TNF inhibitor (TNFi) (adalimumab, certolizumab, etanercept, golimumab, infliximab) to a synthetic DMARD (sDMARD), e.g. MTX, in patients with RA.

Methods. We developed the Norwegian RA model as a Markov model simulating 10 years of treatment with either TNFi plus sDMARDs (TNFi strategy) or sDMARDs alone (synthetic strategy). Patients in both strategies started in one of seven health states, based on the Short Form-6 Dimensions (SF-6D). The patients could move to better or worse health states according to transition probabilities. In the TNFi strategy, patients could stay on TNFi (including switch of TNFi), or switch to non-TNFi-biologics (abatacept, rituximab, tocilizumab), sDMARDs or no DMARD. In the synthetic strategy, patients remained on sDMARDs. Data from two observational studies were used for the assessment of resource use and utilities in the health states. Health benefits were evaluated using the EuroQol-5 Dimensions (EQ-5D) and SF-6D.

Results. The Norwegian RA model predicted that 10-year discounted health care costs totalled €124 942 (€475 266 including production losses) for the TNFi strategy and €65 584 (€436 517) for the synthetic strategy. The cost per additionally gained quality-adjusted life-year of adding a TNFi was €92 557 (€60 227 including production losses) using SF-6D and €61 285 (€39 841) using EQ-5D. Including health care costs only, the probability that TNFi treatment was cost-effective was 90% when using EQ-5D, assuming a Norwegian willingness-to-pay level of €67 300.

Conclusion. TNFi treatment for RA is cost-effective when accounting for production losses. Excluding production losses, TNFi treatment is cost-effective using EQ-5D, but not SF-6D.

The EULAR Study Group for Registers and Observational Drug Studies: comparability of the patient case mix in the European biologic disease modifying anti-rheumatic drug registers

OBJECTIVE

Under the auspices of the European League Against Rheumatism (EULAR), a study group of investigators representing European biologic DMARD (bDMARD) registers was convened. The purpose of this initial assessment was to collect and compare a cross section of patient characteristics and collate information on the availability of potential confounders within these registers.

METHODS

Baseline characteristics of patients starting their first bDMARD in an arbitrary year (2008) for the treatment of RA, including demographic and disease characteristics, bDMARD drug details and co-morbidities, were collected and compared across 14 European bDMARD registers.

RESULTS

A total of 5320 patients were included. Half the registers had restricted recruitment to certain bDMARDs during the study year. All registers` collected data on age, gender, disease duration, seropositivity for IgM-RF and 28-joint DAS (DAS28). The mean DAS28 ranged from 4.2 to 6.6 and the mean HAQ from 0.8 to 1.9. Current smoking ranged from 9% to 34%. Nine registers reported co-morbidities with varying prevalence.

CONCLUSION

In addition to demonstrating European-wide collaboration across rheumatology bDMARD registers, this assessment identified differences in prescribing patterns, recruitment strategies and data items collected. These differences need to be considered when applying strategies for combined analysis. The lack of a common data model across Europe calls for further work to harmonize data collection across registers.

Is there a role for sulphasalazine in axial spondyloarthritis in the era of TNF inhibition? Data from the NOR-DMARD longitudinal observational study

OBJECTIVES

The objectives of this study were to characterize patients with predominantly axial SpA who received SSZ as their first DMARD, compare the response to treatment in patients with and without peripheral disease and identify predictors of discontinuation of SSZ. We also investigated response to TNF inhibitor (TNFi) after SSZ failure.

METHODS

We included DMARD-naive patients with predominantly axial SpA starting SSZ or TNFi treatment from a Norwegian, multicentre longitudinal observational study (NOR-DMARD). In patients starting SSZ, we compared the 3-month responses between patients with and without swollen joints and identified predictors of discontinuation by Cox regression analysis. Sixty-six SSZ-treated patients later switched to a TNFi, and we compared their 3-month responses and drug survival to patients starting a TNFi as their first DMARD.

RESULTS

Patients receiving SSZ (n = 181) as their first DMARD had shorter disease duration, were more frequently female and had more swollen joints than those starting TNFi (n = 543). There was a trend toward better 3-month responses to SSZ in patients with peripheral joint swelling, and they had significantly better 3-year drug survival than patients without swollen joints at baseline. Predictors of SSZ discontinuation were no peripheral joint swelling, higher CRP and higher BASDAI back pain score. TNFi response was similar in patients previously treated with SSZ, as in DMARD-naive patients.

CONCLUSION

Our findings support current recommendations of SSZ as an optional treatment in SpA patients with peripheral disease, although overall responses were modest. Initial treatment with SSZ does not seem to impair later TNFi response.

NOR-DMARD data management: implementation of data capture from electronic health records

OBJECTIVES

The use of electronic health records (EHR) is an essential part of modern health care, and electronic data capture (EDC) has become essential for managing clinical trials. Usually, these two entities are independent of each other, and transfer from one system to another is done manually. Our aim was to develop a method to capture data directly from the EHR system and transfer them into an EDC system for the NORwegian Disease-Modifying Anti-Rheumatic Drugs (NOR-DMARD) registry.

METHODS

All rheumatology departments contributing to NOR-DMARD had implemented a structured EHR system. Data are extracted locally and securely transferred to the study data management once a month. The study data management then parse the data into a readable format for the EDC and import the data. Once the data is in the EDC, they are available to all authorized researchers and downloadable in a preferred format.

RESULTS

From May 2012 to August 2014 almost 6400 visits in 3400 patients treated with biologics have been successfully registered in the EDC system. Previously, NOR-DMARD used standard paper-based case report forms (CRFs), with a substantial cost for data entry. Setting up and maintaining the EDC system required some investments, but the amount saved from avoiding paper handling has made the shift into EDC profitable. In addition to this, gains have been made in administration and data quality.

CONCLUSIONS

The transition from paper and pencil format to a fully electronic data management system in NOR-DMARD has had obvious advantages regarding feasibility, cost, data quality and accessibility of the data.

Levels and patterns of persistent organic pollutants (POPs) in tilapia (Oreochromis sp.) from four different lakes in Tanzania: geographical differences and implications for human health

In Tanzania fish is one of the most important protein sources for the rapidly increasing population. Wild fish is threatened by overfishing and pollution from agriculture, industries, mining, household effluents and vector control. To monitor possible implications for public health, the geographical differences of the occurrence and levels of persistent organic pollutants (POPs) in tilapia fish (Oreochromis sp.) from four different Tanzanian lakes were investigated in 2011. Concentrations of organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), polybrominated diphenyls (PBDEs) and hexabromocyclododecane (HBCDD) were determined in pooled samples of tilapia muscle from Lake (L) Victoria, L. Tanganyika, L. Nyasa (also called L. Malawi) and L. Babati in Tanzania in 2011. Levels of Σ-DDTs (274 ng/g lipid weight (lw)) and sum of 7 indicator PCBs (Σ-7PCBs) (17 ng/g lw) were significantly higher in tilapia from L. Tanganyika compared to the other lakes. The highest levels of Σ-endosulfan (94 ng/g lw) were detected in tilapia from L. Victoria. Toxaphenes were detected in low levels in fish from L. Tanganyika and L. Babati. Results revealed a geographic difference in the use of DDT and endosulfan between L. Victoria and L. Tanganyika. Low ratios of DDE/DDT in tilapia from L. Tanganyika indicated an on-going use of DDT in the area. Median levels of ΣBDEs, including BDE-209, were highest in L. Victoria (19.4 ng/g lw) and BDE-209 was present in 68% of the samples from this lake. The presence of BDE-209 indicates increasing influence of imported products from heavy industrialized countries. The measured POP levels in the studied tilapia were all below MRLs of EU or were lower than recommended levels, and thus the fish is considered as safe for human consumption. They may, however, pose a risk to the fish species and threaten biodiversity.

Establishing a core domain set to measure rheumatoid arthritis flares: report of the OMERACT 11 RA flare Workshop

OBJECTIVE

The OMERACT Rheumatoid Arthritis (RA) Flare Group (FG) is developing a data-driven, patient-inclusive, consensus-based RA flare definition for use in clinical trials, longterm observational studies, and clinical practice. At OMERACT 11, we sought endorsement of a proposed core domain set to measure RA flare.

METHODS

Patient and healthcare professional (HCP) qualitative studies, focus groups, and literature review, followed by patient and HCP Delphi exercises including combined Delphi consensus at Outcome Measures in Rheumatology 10 (OMERACT 10), identified potential domains to measure flare. At OMERACT 11, breakout groups discussed key domains and instruments to measure them, and proposed a research agenda. Patients were active research partners in all focus groups and domain identification activities. Processes for domain selection and patient partner involvement were case studies for OMERACT Filter 2.0 methodology.

RESULTS

A pre-meeting combined Delphi exercise for defining flare identified 9 domains as important (>70% consensus from patients or HCP). Four new patient-reported domains beyond those included in the RA disease activity core set were proposed for inclusion (fatigue, participation, stiffness, and self-management). The RA FG developed preliminary flare questions (PFQ) to measure domains. In combined plenary voting sessions, OMERACT 11 attendees endorsed the proposed RA core set to measure flare with ≥78% consensus and the addition of 3 additional domains to the research agenda for OMERACT 12.

CONCLUSION

At OMERACT 11, a core domain set to measure RA flare was ratified and endorsed by attendees. Domain validation aligning with Filter 2.0 is ongoing in new randomized controlled clinical trials and longitudinal observational studies using existing and new instruments including a set of PFQ.

Brucella pinnipedialis hooded seal (Cystophora cristata) strain in the mouse model with concurrent exposure to PCB 153

Brucellosis, a worldwide zoonosis, is linked to reproductive problems in primary hosts. A high proportion of Brucella-positive hooded seals (Cystophora cristata) have been detected in the declined Northeast Atlantic stock. High concentrations of polychlorinated biphenyls (PCBs) have also been discovered in top predators in the Arctic, including the hooded seal, PCB 153 being most abundant. The aim of this study was to assess the pathogenicity of Brucella pinnipedialis hooded seal strain in the mouse model and to evaluate the outcome of Brucella spp. infection after exposure of mice to PCB 153. BALB/c mice were infected with B. pinnipedialis hooded seal strain or Brucella suis 1330, and half from each group was exposed to PCB 153 through the diet. B. pinnipedialis showed a reduced pathogenicity in the mouse model as compared to B. suis 1330. Exposure to PCB 153 affected neither the immunological parameters, nor the outcome of the infection. Altogether this indicates that it is unlikely that B. pinnipedialis contribute to the decline of hooded seals in the Northeast Atlantic.