The Death of Pyotr Ilyich Tchaikovsky: The Result of Treatment with Arsenic?

No abstract applicable.

Proteasome inhibition and mechanism of resistance to a synthetic, library-based hexapeptide.

Background The hexapeptide 4A6 (Ac-Thr(tBu)-His(Bzl)-Thr(Bzl)-Nle-Glu(OtBu)-Gly-Bza) was isolated from a peptide library constructed to identify peptide-based transport inhibitors of multidrug resistance (MDR) efflux pumps including P-glycoprotein and Multidrug Resistance-associated Protein 1. 4A6 proved to be a substrate but not an inhibitor of these MDR efflux transporters. In fact, 4A6 and related peptides displayed potent cytotoxic activity via an unknown mechanism. Objective To decipher the mode of cytotoxic activity of 4A6. Methods Screening of 4A6 activity was performed against the NCI60 panel of cancer cell lines. Possible interactions of 4A6 with the 26S proteasome were assessed via proteasome activity and affinity labeling, and cell growth inhibition studies with leukemic cells resistant to the proteasome inhibitor bortezomib (BTZ). Results The NCI60 panel COMPARE analysis revealed that 4A6 had an activity profile overlapping with BTZ. Consistently, 4A6 proved to be a selective and reversible inhibitor of ß5 subunit (PSMB5)-associated chymotrypsin-like activity of the 26S proteasome. This conclusion is supported by several lines of evidence: (i) inhibition of chymotrypsin-like proteasome activity by 4A6 and related peptides correlated with their cell growth inhibition potencies; (ii) 4A6 reversibly inhibited functional ß5 active site labeling with the affinity probe BodipyFL-Ahx3L3VS; and (iii) human myeloid THP1 cells with acquired BTZ resistance due to mutated PSMB5 were highly (up to 287-fold) cross-resistant to 4A6 and its related peptides. Conclusion 4A6 is a novel specific inhibitor of the ß5 subunit-associated chymotrypsin-like proteasome activity. Further exploration of 4A6 as a lead compound for development as a novel proteasome-targeted drug is warranted.

Cardiovascular risk management in rheumatoid arthritis patients still suboptimal: the Implementation of Cardiovascular Risk Management in Rheumatoid Arthritis project.

Objective: To assess the 10-year cardiovascular (CV) risk score and to identify treatment and undertreatment of CV risk factors in patients with established RA. Methods: Demographics, CV risk factors and prevalence of cardiovascular disease (CVD) were assessed by questionnaire. To calculate the 10-year CV risk score according to the Dutch CV risk management guideline, systolic blood pressure was measured and cholesterol levels were determined from fasting blood samples. Patients were categorized into four groups: indication for treatment but not treated; inadequately treated, so not meeting goals (systolic blood pressure ⩽140 mmHg and/or low-density lipoprotein ⩽2.5 mmol/l); adequately treated; or no treatment necessary. Results: A total of 720 consecutive RA patients were included, 375 from Reade and 345 from the Antonius Hospital. The mean age of patients was 59 years (s.d. 12) and 73% were female. Seventeen per cent of the patients had a low 10-year CV risk (<10%), 21% had an intermediate risk (10-19%), 53% a high risk (⩾20%) and 9% had CVD. In total, 69% had an indication for preventive treatment (cholesterol-lowering or antihypertensive drugs). Of those, 42% received inadequate treatment and 40% received no treatment at all. Conclusion: Optimal CV risk management remains a major challenge and better awareness and management are urgently needed to reduce the high risk of CVD in the RA population.

One-year effects of glucocorticoids on bone density: a meta-analysis in cohorts on high and low-dose therapy.

BACKGROUND: Bone loss during glucocorticoid (GC) therapy is poorly quantified. OBJECTIVE: Quantification of bone loss in GC-treated patients with chronic inflammatory diseases (CID; low dose) and transplants (high dose). METHODS: Meta-analysis of cohorts: PubMed, Cochrane, EMBASE and bibliographic searches (1995-2012). Eligible studies prospectively included GC-treated patients with two dual X-ray absorptiometry measurements of spine or hip over a period of at least 12 months. Only supplementation with calcium or vitamin D3 was allowed. 5602 titles yielded 285 articles: 51 study arms in CID (N=1565), 18 study arms in transplantation (N=571). Prednisone-equivalent GC doses and inverse variance weighted mean bone changes were used in a random effects model. RESULTS: In CID, the mean GC dose was 8.7 mg/day (range 1.2-16.4). The mean 1-year bone loss in the lumbar spine was -1.7% (95% CI -2.2% to -1.2%); in the femoral neck: -1.3 (-1.8 to -0.7). In transplantation, the mean GC dose was 18.9 mg/day (range 6.0-52.7). Bone loss in the lumbar spine was -3.6% (-5.2% to -2.0%); in the femoral neck: -3.1% (-5.1% to -1.1%). Within the two groups, bone loss was not related to GC dose. CONCLUSION: In CID, GC-related bone loss appears limited and manageable if current anti-osteoporotic strategies are fully implemented. In transplantation, and probably also other high-dose settings, bone loss is considerable and represents unmet need. The heterogeneity probably reflects the important influence of other factors, most notably the underlying disease and the efficacy of GC treatment.

Etanercept Increases Bone Mineral Density in Ankylosing Spondylitis, but Does Not Prevent Vertebral Fractures: Results of a Prospective Observational Cohort Study.

OBJECTIVE: Ankylosing spondylitis (AS) is characterized by chronic inflammation leading to ankylosis, but also to low bone mineral density (BMD) and vertebral fractures (VFx). Treatment with tumor necrosis factor-α blockers decreases inflammation and has shown to be effective in increasing BMD. We studied the effects of etanercept (ETN) on BMD and VFx in patients with AS after 2 years of treatment. Further, we studied changes in bone turnover markers and radiological damage. METHODS: Patients with active AS, treated with ETN for 2 years, were included. BMD lumbar spine and hip were measured at baseline and after 2 years, as well as radiological damage (modified Stoke Ankylosing Spondylitis Spinal Score with the addition of the thoracic spine), VFx (Genant method), and change in bone turnover markers. RESULTS: Forty-nine patients with AS were included. After 2 years of ETN, hip BMD increased by 2.2% (p = 0.014) and lumbar spine BMD by 7.0% (p < 0.001). The Bath Ankylosing Spondylitis Disease Activity Index decreased significantly (p < 0.001), as well as C-reactive protein and erythrocyte sedimentation rate (p < 0.001). Despite ETN therapy, the number of patients with VFx more than doubled (from 6 to 15 patients, p = 0.003). Also, the radiological damage increased significantly over time (from 12.1 to 18.5, p < 0.001); however, no significant change in bone turnover markers was found. CONCLUSION: This prospective longitudinal observational cohort study showed that after 2 years of ETN, BMD of the hip and spine increased significantly, but the number of patients with VFx and the severity of VFx increased as well. Besides that, radiological progression, including the thoracic spine, increased significantly. Thus, the favorable bone-preserving effect is accompanied by unfavorable outcomes on VFx and radiological damage.

Objective evaluation of physical functioning after tumor necrosis factor inhibitory therapy in patients with ankylosing spondylitis: a selection of 3 feasible performance-based tests.

OBJECTIVE: (1) To select a limited number of performance-based tests that are reliable, show improvement in physical functioning after tumor necrosis factor inhibitor (TNFi) therapy in patients with ankylosing spondylitis (AS), and generate information equivalent to the full set of tests, and (2) are feasible for use in daily clinical practice. METHODS: Eight performance-based tests were evaluated. To eliminate redundant testing, the tests that showed adequate reliability, the highest standardized response mean (SRM), and the largest proportion of patients with an improved performance-based physical functioning were selected. The selected tests were combined into a new criterion for improvement in physical functioning (AS Performance-based Improvement; ASPI). The number and percentage of improved patients identified with the ASPI and identified with the full set of performance tests were compared. RESULTS: Reliability for all tests was adequate to excellent (ICC 0.73-0.96). The tests for bending, putting on socks, and getting up from the floor had the highest SRM (0.52-0.74) and showed the largest proportion of improved patients after TNFi therapy. The combination of these 3 tests was feasible in daily clinical practice and showed improved physical functioning after TNFi therapy in 67% of the patients. CONCLUSION: The 3 selected tests are recommended for use in daily practice because they generate information comparable to the full set. They are reliable and feasible, and the combination of these tests showed improved physical functioning after TNFi therapy in 67% of the patients. Evaluation of physical functioning might be improved by adding these tests to other AS outcome measures.

Imported Armillifer pentastomiasis: report of a symptomatic infection in The Netherlands and mini-review.

We report a case of symptomatic visceral Armillifer pentastomiasis in a 23-year-old female Liberian immigrant to The Netherlands. The patient was referred to the gynecologist because of lower abdominal pain. During laparotomy, multiple adhesions were seen in the lower pelvis and a hydrosalpinx with an encapsulated Armillifer nymph, most likely Armillifer armillatus, was found. Key features of the parasite's cuticle which facilitate the diagnosis of pentastomiasis, are presented. Symptomatic pentastomiasis is uncommon, and most cases are diagnosed incidentally during surgery for other reasons, or at autopsy. With regard to increasing international migration, other imported pentastomiasis cases to Europe and North America are reviewed, and more cases are likely to be seen in the future.

A non-inferiority trial of an attenuated combination strategy ('COBRA-light') compared to the original COBRA strategy: clinical results after 26 weeks.

BACKGROUND: Early, intensive treatment of rheumatoid arthritis (RA) with the combination of (initially high dose) prednisolone, methotrexate and sulfasalazine (COBRA therapy) considerably lowers disease activity and suppresses radiological progression, but is infrequently prescribed in daily practice. Attenuating the COBRA regimen might lessen concerns about side effects, but the efficacy of such strategies is unknown. OBJECTIVE: To compare the 'COBRA-light' strategy with only two drugs, comprising a lower dose of prednisolone (starting at 30 mg/day, tapered to 7.5 mg/day in 9 weeks) and methotrexate (escalated to 25 mg/week in 9 weeks) to COBRA therapy (prednisolone 60 mg/day, tapered to 7.5 mg/day in 6 weeks, methotrexate 7.5 mg/week and sulfasalazine 2 g/day). METHOD: An open, randomised controlled, non-inferiority trial in 164 patients with early active RA, all treated according to a treat to target strategy. RESULTS: At baseline patients had moderately active disease: mean (SD) 44-joint disease activity score (DAS44) 4.13 (0.81) for COBRA and 3.95 (0.9) for COBRA-light. After 6 months, DAS44 significantly decreased in both groups (-2.50 (1.21) for COBRA and -2.18 (1.10) for COBRA-light). The adjusted difference in DAS44 improvement between the groups, 0.21 (95% CI -0.11 to 0.53), was smaller than the predefined clinically relevant difference of 0.5. Minimal disease activity (DAS44 <1.6) was reached in almost half of patients in both groups (49% and 41% in COBRA and COBRA-light, respectively). CONCLUSIONS: At 6 months COBRA-light therapy is most likely non-inferior to COBRA therapy. CLINICAL TRIAL REGISTRATION NUMBER: 55552928.

What do we miss? ASAS non-responders on anti-TNF therapy show improvement in performance-based physical function.

OBJECTIVE: A prospective study was conducted in order to establish whether AS patients, who are defined as non-responders after 3 months of anti-TNF therapy, show improvement on performance-based tests of physical functioning. METHODS: At baseline and 3 months after the start of anti-TNF therapy, AS patients completed seven performance-based tests of physical functioning, questionnaires on self-reported physical functioning (BASFI) and disease activity (BASDAI), and a pain and a global patient assessment. The concordance between ≥ 20% intra-individual improvement on the performance-based test of physical functioning and (i) response to anti-TNF therapy [Assessment of SpondyloArthritis International Society 20% (ASAS20) response] and (ii) ≥ 20% intra-individual improvement on self-reported physical functioning (BASFI) was assessed. RESULTS: One hundred AS patients were included, of which 82 patients completed all tests at both time points. After 3 months of anti-TNF therapy, 27 (32.9%) patients were categorized as non-responders according to the ASAS20 response criteria. Improvement in performance-based physical functioning was seen in 13 of the 27 non-responders (48.1%) (i.e. n = 13/82 = 15.9% of the total group). Furthermore, 30 (36.6%) patients showed no improvement on self-reported physical functioning (BASFI). However, 17 of the 30 (56.7%) patients did improve on the performance-based tests of physical functioning (i.e. n = 17/82 = 20.7% of the total group). CONCLUSION: After 3 months of anti-TNF therapy, performance-based tests of physical functioning showed improvement in 48.1% of the ASAS20 non-responders. With these performance-based tests, new information on outcome after anti-TNF therapy can be generated. Using performance-based tests alongside the BASFI could have additional value in the evaluation of outcomes for patients receiving anti-TNF therapy.

Overcoming bortezomib resistance in human B cells by anti-CD20/rituximab-mediated complement-dependent cytotoxicity and epoxyketone-based irreversible proteasome inhibitors.

BACKGROUND: In clinical and experimental settings, antibody-based anti-CD20/rituximab and small molecule proteasome inhibitor (PI) bortezomib (BTZ) treatment proved effective modalities for B cell depletion in lymphoproliferative disorders as well as autoimmune diseases. However, the chronic nature of these diseases requires either prolonged or re-treatment, often with acquired resistance as a consequence. METHODS: Here we studied the molecular basis of acquired resistance to BTZ in JY human B lymphoblastic cells following prolonged exposure to this drug and examined possibilities to overcome resistance by next generation PIs and anti-CD20/rituximab-mediated complement-dependent cytotoxicity (CDC). RESULTS: Characterization of BTZ-resistant JY/BTZ cells compared to parental JY/WT cells revealed the following features: (a) 10-12 fold resistance to BTZ associated with the acquisition of a mutation in the PSMB5 gene (encoding the constitutive ß5 proteasome subunit) introducing an amino acid substitution (Met45Ile) in the BTZ-binding pocket, (b) a significant 2-4 fold increase in the mRNA and protein levels of the constitutive ß5 proteasome subunit along with unaltered immunoproteasome expression, (c) full sensitivity to the irreversible epoxyketone-based PIs carfilzomib and (to a lesser extent) the immunoproteasome inhibitor ONX 0914. Finally, in association with impaired ubiquitination and attenuated breakdown of CD20, JY/BTZ cells harbored a net 3-fold increase in CD20 cell surface expression, which was functionally implicated in conferring a significantly increased anti-CD20/rituximab-mediated CDC. CONCLUSIONS: These results demonstrate that acquired resistance to BTZ in B cells can be overcome by next generation PIs and by anti-CD20/rituximab-induced CDC, thereby paving the way for salvage therapy in BTZ-resistant disease.

HDL protein composition alters from proatherogenic into less atherogenic and proinflammatory in rheumatoid arthritis patients responding to rituximab.

OBJECTIVE: An atherogenic lipid profile is an established risk factor for cardiovascular (CV) diseases. Interestingly, high inflammatory states as present in rheumatoid arthritis (RA) are associated with unfavourable lipid profile. Data about effects of novel immunomodulating agents as rituximab (RTX) on lipid profile are limited. Therefore, changes in lipids in RTX treated RA patients were evaluated. METHODS: In 49 consecutive RTX treated RA patients, serum and EDTA plasma samples were collected at baseline, 1, 3 and 6 months. In these samples, lipid and levels were assessed to determine changes in time. Surface-enhanced laser desorption/ionisation time-of-flight (SELDI-TOF) MS analysis was performed in six good and six non-responding RA patients to study functional high density lipoprotein (HDL) protein composition changes in time. RESULTS: In the total group (n=49), the atherogenic index decreased from 4.3 to 3.9 (∼9%) after 6 months. Testing for effect modification revealed a difference in the effect on lipid levels between responders and non-responders upon RTX (p<0.001). ApoB to ApoA-I ratios decreased significantly (∼9%) in good responding (n=32) patients. SELDI-TOF MS analysis revealed a significant decrease in density of mass charge (m/z) marker 11743, representing a decrease in serum amyloid A, in good responding patients. CONCLUSION: This study indicates beneficial effects on cholesterol profile upon RTX treatment along with improvement of disease activity. Proteomic analysis of the HDL particle reveals composition changes from proatherogenic to a less proatherogenic composition during 6 months RTX treatment. Whether these HDL particle alterations during immunotherapies result in a lower CV event rate remains to be established.

The interferon type I signature towards prediction of non-response to rituximab in rheumatoid arthritis patients.

INTRODUCTION: B cell depletion therapy is efficacious in rheumatoid arthritis (RA) patients failing on tumor necrosis factor (TNF) blocking agents. However, approximately 40% to 50% of rituximab (RTX) treated RA patients have a poor response. We investigated whether baseline gene expression levels can discriminate between clinical non-responders and responders to RTX. METHODS: In 14 consecutive RA patients starting on RTX (test cohort), gene expression profiling on whole peripheral blood RNA was performed by Illumina® HumanHT beadchip microarrays. Supervised cluster analysis was used to identify genes expressed differentially at baseline between responders and non-responders based on both a difference in 28 joints disease activity score (ΔDAS28 < 1.2) and European League against Rheumatism (EULAR) response criteria after six months RTX. Genes of interest were measured by quantitative real-time PCR and tested for their predictive value using receiver operating characteristics (ROC) curves in an independent validation cohort (n = 26). RESULTS: Genome-wide microarray analysis revealed a marked variation in the peripheral blood cells between RA patients before the start of RTX treatment. Here, we demonstrated that only a cluster consisting of interferon (IFN) type I network genes, represented by a set of IFN type I response genes (IRGs), that is, LY6E, HERC5, IFI44L, ISG15, MxA, MxB, EPSTI1 and RSAD2, was associated with ΔDAS28 and EULAR response outcome (P = 0.0074 and P = 0.0599, respectively). Based on the eight IRGs an IFN-score was calculated that reached an area under the curve (AUC) of 0.82 to separate non-responders from responders in an independent validation cohort of 26 patients using Receiver Operator Characteristics (ROC) curves analysis according to ΔDAS28 < 1.2 criteria. Advanced classifier analysis yielded a three IRG-set that reached an AUC of 87%. Comparable findings applied to EULAR non-response criteria. CONCLUSIONS: This study demonstrates clinical utility for the use of baseline IRG expression levels as a predictive biomarker for non-response to RTX in RA.

Bone formation rather than inflammation reflects ankylosing spondylitis activity on PET-CT: a pilot study.

INTRODUCTION: Positron Emission Tomography - Computer Tomography (PET-CT) is an interesting imaging technique to visualize Ankylosing Spondylitis (AS) activity using specific PET tracers. Previous studies have shown that the PET tracers [18F]FDG and [11C](R)PK11195 can target inflammation (synovitis) in rheumatoid arthritis (RA) and may therefore be useful in AS. Another interesting tracer for AS is [18F]Fluoride, which targets bone formation. In a pilot setting, the potential of PET-CT in imaging AS activity was tested using different tracers, with Magnetic Resonance Imaging (MRI) and conventional radiographs as reference. METHODS: In a stepwise approach different PET tracers were investigated. First, whole body [18F]FDG and [11C](R)PK11195 PET-CT scans were obtained of ten AS patients fulfilling the modified New York criteria. According to the BASDAI five of these patients had low and five had high disease activity. Secondly, an extra PET-CT scan using [18F]Fluoride was made of two additional AS patients with high disease activity. MRI scans of the total spine and sacroiliac joints were performed, and conventional radiographs of the total spine and sacroiliac joints were available for all patients. Scans and radiographs were visually scored by two observers blinded for clinical data. RESULTS: No increased [18F]FDG and [11C](R)PK11195 uptake was noticed on PET-CT scans of the first 10 patients. In contrast, MRI demonstrated a total of five bone edema lesions in three out of 10 patients. In the two additional AS patients scanned with [18F]Fluoride PET-CT, [18F]Fluoride depicted 17 regions with increased uptake in both vertebral column and sacroiliac joints. In contrast, [18F]FDG depicted only three lesions, with an uptake of five times lower compared to [18F]Fluoride, and again no [11C](R)PK11195 positive lesions were found. In these two patients, MRI detected nine lesions and six out of nine matched with the anatomical position of [18F]Fluoride uptake. Conventional radiographs showed structural bony changes in 11 out of 17 [18F]Fluoride PET positive lesions. CONCLUSIONS: Our PET-CT data suggest that AS activity is reflected by bone activity (formation) rather than inflammation. The results also show the potential value of PET-CT for imaging AS activity using the bone tracer [18F]Fluoride. In contrast to active RA, inflammation tracers [18F]FDG and [11C](R)PK11195 appeared to be less useful for AS imaging.

Moving instead of asking? Performance-based tests and BASFI-questionnaire measure different aspects of physical function in ankylosing spondylitis.

INTRODUCTION: Ankylosing Spondylitis (AS) is characterised by limitations in physical function. The Bath Ankylosing Spondylitis Functional Index (BASFI) is considered to be the gold-standard to assess physical function in AS patients. However, the BASFI questionnaire is a self-reported outcome measure and susceptible to subjective interpretation (under- or over-estimation). More objective outcome measures, like performance-based tests, could provide an objective outcome measurement for the evaluation of limitations in physical function. Therefore, the primary aim of this study was to determine the association between performance-based measures and the BASFI questionnaire. METHODS: In this cross-sectional study 126 AS patients completed the BASFI questionnaire and eight performance-based tests based on BASFI-items. Each test received three scores: one for performance (time or points) and a score for exertion and pain experienced during performance (using modified Borg-scale and VAS 0-100 mm, respectively). Linear regression analyses were used to assess the associations between the BASFI questionnaire and performance-based tests. RESULTS: The univariable association between performance and BASFI-score was moderate with a R-square of 0.31 and Beta of 0.56 (p's < 0.05). In a multivariable analysis, the association between performance, exertion and pain on the one hand and BASFI-score on the other was assessed; R-square increased to 0.54: the Beta's for exertion and pain during performance were 0.38 and 0.26, respectively; the Beta for performance decreased to 0.19 (p's < 0.05). CONCLUSIONS: This study demonstrates that alongside actual performance, patients seem to incorporate exertion and pain in their assessment of perceived physical function on the BASFI questionnaire. Performance-based tests could provide an objective outcome measurement for the evaluation of physical function and give relevant new information in addition to the BASFI questionnaire.

Sustained drug-free remission in rheumatoid arthritis after DAS-driven or non-DAS-driven therapy: a comparison of two cohort studies.

OBJECTIVES: To compare the prevalence of and predictors for sustained drug-free remission in two cohorts of patients with recent-onset RA treated with DAS-driven therapy or non-DAS-driven therapy. METHODS: Sustained drug-free remission was assessed after 5 years of follow-up in 508 patients treated with DAS-driven therapy (DAS ≤ 2.4) in a randomized treatment cohort, and in 424 patients who received non-DAS-driven therapy in a prospective inception cohort. The design of the DAS-driven cohort required systematic joint assessments with DAS-driven restart of therapy. Predictors for remission were identified by univariable and multivariable logistic regression in each cohort separately and in a combined multivariate logistic regression analysis corrected for propensity scores, including a sensitivity analysis on patients receiving initial monotherapy. RESULTS: Patients in the DAS-driven cohort had more active disease at baseline, but the prevalence of sustained drug-free remission was similar after DAS-driven (9.8%) and non-DAS-driven therapy (10.6%). Among patients with ACPA, drug-free remission was more frequently achieved after DAS-driven than after non-DAS-driven therapy (5.4 vs. 2.1%, OR = 2.68, 95% CI 0.97, 7.43). Absence of ACPA and short symptom duration were independent predictors for sustained drug-free remission in both cohorts. Initial treatment choice and inclusion period were not predictive. The sensitivity analysis yielded comparable results. CONCLUSION: Retrospectively comparing a DAS-driven to a non-DAS-driven therapy cohort, the occurrence and predictors of sustained drug-free remission were similar. The DAS-driven cohort had a more unfavourable prognosis. DAS-driven therapy may improve the chance of sustained drug-free remission in ACPA-positive patients with recent-onset RA.

Parvovirus B19 in pregnancy: prenatal diagnosis and management of fetal complications.

PURPOSE OF REVIEW: Parvovirus B19 infection is often considered a mild and self-limiting disease of minor clinical importance. This review aims to raise awareness of recently discovered potentially devastating consequences of this infection in pregnancy, and provides updated guidelines on diagnosis and management. RECENT FINDINGS: In contrast to previous beliefs, parvovirus B19 infection during any stage of pregnancy may not only cause fetal death, but may also result in severe and irreversible neurological sequelae in survivors. Improved diagnostic techniques allow more reliable and earlier diagnosis of fetal disease. SUMMARY: Clinicians need to be aware of the risk of adverse outcome of parvovirus B19 infection in pregnancy, and sometimes the long interval between exposure and fetal symptoms. Accurate diagnosis using PCR and weekly ultrasound checks ups with Doppler measurement of middle cerebral artery flow velocity up to 20 weeks postexposure may improve detection of fetal disease. More timely treatment likely results in improved outcome.

Inactivating PSMB5 mutations and P-glycoprotein (multidrug resistance-associated protein/ATP-binding cassette B1) mediate resistance to proteasome inhibitors: ex vivo efficacy of (immuno)proteasome inhibitors in mononuclear blood cells from patients with rheumatoid arthritis.

Bortezomib (BTZ), a registered proteasome inhibitor (PI) for multiple myeloma, has also been proposed as a potential antirheumatic agent. Its reported side effects, however, make it unappealing for long-term administration, and resistance may also develop. To overcome this, second-generation PIs became available. Here, we investigated whether a novel class of peptide epoxyketone-based PIs, including carfilzomib, N-((S)-3-methoxy-1-(((S)-3-methoxy-1-(((S)-1-((R)-2-methyloxiran-2-yl)-1-oxo-3-phenylpropan-2-yl)amino)-1-oxopropan-2-yl)amino)-1-oxopropan-2-yl)-2-methylthiazole-5-carboxamide (ONX0912), and (S)-3-(4-methoxyphenyl)-N-((S)-1-((S)-2-methyloxiran-2-yl)-1-oxo-3-phenylpropan-2-yl)-2-((S)-2-(2-morpholinoacetamido)propanamido)propanamide (ONX0914), might escape two established BTZ-resistance mechanisms: 1) mutations in the proteasome ß5 subunit (PSMB5) targeted by these PIs, and 2) drug efflux mediated by ATP-binding cassette transporters. THP1 myeloid sublines with acquired resistance to BTZ (54- to 235-fold) caused by mutations in the PSMB5 gene displayed marked cross-resistance but less pronounced cross-resistance to carfilzomib (9- to 32-fold), ONX0912 (39- to 62-fold), and ONX0914 (27- to 97-fold). As for ATP-binding cassette transporter-mediated efflux, lymphoid CEM/VLB cells with P-glycoprotein (Pgp)/multidrug resistance 1 overexpression exhibited substantial resistance to carfilzomib (114-fold), ONX0912 (23-fold), and ONX0914 (162-fold), whereas less resistance to BTZ (4.5-fold) was observed. Consistently, ß5 subunit-associated chymotrypsin-like proteasome activity was significantly less inhibited in these CEM/VLB cells. Ex vivo analysis of peripheral blood mononuclear cells from therapy-naive patients with rheumatoid arthritis revealed that, although basal Pgp levels were low, P-glycoprotein expression compromised the inhibitory effect of carfilzomib and ONX0914. However, the use of P121 (reversin 121), a Pgp transport inhibitor, restored parental cell inhibitory levels in both CEM/VLB cells and peripheral blood mononuclear cells. These results indicate that the pharmacologic activity of these PIs may be hindered by drug resistance mechanisms involving PSMB5 mutations and PI extrusion via Pgp.

Macrophage positron emission tomography imaging as a biomarker for preclinical rheumatoid arthritis: findings of a prospective pilot study.

OBJECTIVE: To conduct a prospective pilot study to determine whether macrophage targeting by 11C-(R)-PK11195 positron emission tomography (PET) can visualize subclinical synovitis in arthralgia patients who have anti-citrullinated protein antibodies (ACPAs). METHODS: Twenty-nine arthralgia patients who were positive for ACPAs but did not have clinical arthritis were studied. High (spatial)-resolution 11C-(R)-PK11195 PET scans of the hands and wrists were performed. For all metacarpophalangeal, proximal interphalangeal, and wrist joints (i.e., 22 joints per patient), tracer uptake was scored semiquantitatively (0-3 scale) by 2 observers who were blinded with regard to the clinical data. Patients were followed up prospectively for 24 months to investigate the development of clinical arthritis. RESULTS: Overall agreement and kappa values for the readings of the 2 observers were, respectively, 97% and 0.91 (95% confidence interval [95% CI] 0.74-1) at the patient level and 99% and 0.81 (95% CI 0.65-0.96) at the joint level. In 4 patients, at least 1 and as many as 5 PET-positive joints (score≥1) were found at baseline. Within 2 years of followup, 9 patients had developed clinical arthritis. This included all 4 patients with positive findings on the 11C-(R)-PK11195 scan, who developed clinical arthritis in the hand/wrist region, as identified on PET scans. Of the 5 remaining arthritis patients with negative findings on PET scans, 2 developed arthritis in the hand joints and 3 developed arthritis at locations outside the field of view of the PET scanner. CONCLUSION: Subclinical arthritis in ACPA-positive arthralgia patients could be visualized by 11C-(R)-PK11195 PET scanning and was associated with development of arthritis within 2 years of followup. This indicates that 11C-(R)-PK11195 PET may be useful in determining arthritis activity in the preclinical phase of RA.