Preclinical characterisation of the GM-CSF receptor as a therapeutic target in rheumatoid arthritis.

OBJECTIVE: Previous work has suggested that the granulocyte macrophage colony stimulating factor (GM-CSF)-GM-CSF receptor α axis (GM-CSFRα) may provide a new therapeutic target for the treatment of rheumatoid arthritis (RA). Therefore, we investigated the cellular expression of GM-CSFRα in RA synovial tissue and investigated the effects of anti-GM-CSFRα antibody treatment in vitro and in vivo in a preclinical model of RA. METHODS: We compared GM-CSFRα expression on macrophages positive for CD68 or CD163 on synovial biopsy samples from patients with RA or psoriatic arthritis (PsA) to disease controls. In addition, we studied the effects of CAM-3003, an anti-GM-CSFR antibody in a collagen induced arthritis model of RA in DBA/1 mice. The pharmacokinetic profile of CAM-3003 was studied in naïve CD1(ICR) mice (see online supplement) and used to interpret the results of the pharmacodynamic studies in BALB/c mice. RESULTS: GM-CSFRα was expressed by CD68 positive and CD163 positive macrophages in the synovium, and there was a significant increase in GM-CSFRα positive cells in patients in patients with RA as well as patients with PsA compared with patients with osteoarthritis and healthy controls. In the collagen induced arthritis model there was a dose dependent reduction of clinical arthritis scores and the number of F4/80 positive macrophages in the inflamed synovium after CAM-3003 treatment. In BALB/c mice CAM-3003 inhibited recombinant GM-CSF mediated margination of peripheral blood monocytes and neutrophils. CONCLUSIONS: The findings support the ongoing development of therapies aimed at interfering with GM-CSF or its receptor in various forms of arthritis, such as RA and PsA.

Rheumatoid arthritis synovial tissue harbours dominant B-cell and plasma-cell clones associated with autoreactivity.

OBJECTIVE: To identify potential autoreactive B-cell and plasma-cell clones by quantitatively analysing the complete human B-cell receptor (BCR) repertoire in synovium and peripheral blood in early and established rheumatoid arthritis (RA). METHODS: The BCR repertoire was screened in synovium and blood of six patients with early RA (ERA) (<6 months) and six with established RA (ESRA) (>20 months). In two patients, the repertoires in different joints were compared. Repertoires were analysed by next-generation sequencing from mRNA, generating >10 000 BCR heavy-chain sequence reads per sample. For each clone, the degree of expansion was calculated as the percentage of the total number of reads encoding the specific clonal sequence. Clones with a frequency ≥ 0.5% were considered dominant. RESULTS: Multiple dominant clones were found in inflamed synovium but hardly any in blood. Within an individual patient, the same dominant clones were detected in different joints. The majority of the synovial clones were class-switched; however, the fraction of clones that expressed IgM was higher in ESRA than ERA patients. Dominant synovial clones showed autoreactive features: in ERA in particular the clones were enriched for immunoglobulin heavy chain gene segment V4-34 (IGHV4-34) and showed longer CDR3 lengths. Dominant synovial clones that did not encode IGHV4-34 also had longer CDR3s than peripheral blood. CONCLUSIONS: In RA, the synovium forms a niche where expanded--potentially autoreactive--B cells and plasma cells reside. The inflamed target tissue, especially in the earliest phase of disease, seems to be the most promising compartment for studying autoreactive cells.

The cellular composition of lymph nodes in the earliest phase of inflammatory arthritis.

OBJECTIVES: Rheumatoid arthritis (RA) is an immune-mediated inflammatory disease of unknown aetiology. Recent work has shown that systemic autoimmunity precedes synovial inflammation, and animal models have suggested that changes in the lymph nodes may precede those in the synovial tissue. Therefore, we investigated the cellular composition of the lymph node in the earliest phases of inflammatory arthritis. METHODS: Thirteen individuals positive for immunoglobulin M (IgM) rheumatoid factor and/or anticitrullinated protein antibodies without arthritis were included. Additionally, we studied 14 early arthritis patients (arthritis duration ≤6 months, naïve for disease-modifying antirheumatic drugs), and eight healthy controls. All subjects underwent ultrasound-guided inguinal lymph node biopsy. Different T- and B-lymphocyte subsets were analysed by multicolour flow cytometry. RESULTS: There was an increase in activated CD69 CD8 T cells and CD19 B cells in early arthritis patients compared with healthy controls. We also observed a trend towards increased CD19 B cells in autoantibody-positive individuals without arthritis compared with healthy controls. CONCLUSIONS: This exploratory study suggests that there is increased immune cell activation within lymph nodes of early arthritis patients as well as in autoantibody-positive individuals at risk of developing RA. This method provides a unique tool to investigate immunological changes in the lymph node compartment in the earliest phases of inflammatory arthritis.

The clinical picture of rheumatoid arthritis according to the 2010 American College of Rheumatology/European League Against Rheumatism criteria: is this still the same disease?

OBJECTIVE: To examine the implications of using the new classification criteria for rheumatoid arthritis (RA) in clinical practice in a cohort of patients with very early arthritis. METHODS: The study group comprised 301 disease-modifying antirheumatic drug-naive patients with early arthritis. The baseline diagnosis was assessed by applying the 1987 American College of Rheumatology (ACR) and 2010 ACR/European League Against Rheumatism (EULAR) criteria for RA as well as established diagnostic criteria for other rheumatic diseases. Diagnostic and prognostic data were collected after 2 years of followup. Fulfillment of the 2010 ACR/EULAR criteria was evaluated in the subset of patients in whom undifferentiated arthritis (UA) was diagnosed when the 1987 ACR criteria were applied, and fulfillment of RA criteria over time was tested by applying the 2 different criteria sets. RESULTS: The median arthritis duration at baseline was 4 months (range 0-12 months). At baseline, 28% of the patients fulfilled the 1987 ACR criteria, and 45% fulfilled the 2010 ACR/EULAR criteria for RA. Among the patients classified as having UA at baseline according to the 1987 ACR criteria, 36% had fulfilled the 2010 ACR/EULAR criteria already at baseline. Among the patients classified as having UA at baseline but who fulfilled the 1987 ACR criteria after 2 years of followup, 85% had fulfilled the 2010 ACR/EULAR criteria at baseline. Patients with early disease who fulfilled the 2010 ACR/EULAR criteria were less likely to be autoantibody positive and more likely to have monarthritis at presentation than those fulfilling the 1987 ACR criteria. CONCLUSION: Use of the 2010 ACR/EULAR criteria clearly allows earlier diagnosis of RA, although the clinical picture is slightly different on the group level, and RA may be falsely diagnosed in some patients with self-limiting disease.

Treatment-specific changes in circulating adipocytokines: a comparison between tumour necrosis factor blockade and glucocorticoid treatment for rheumatoid arthritis.

OBJECTIVE: There is increasing evidence that adipocytokines may exert proinflammatory and destructive effects in rheumatoid arthritis (RA). Hence, the authors investigated the relationship between adipocytokines and several features associated with RA (inflammation, joint destruction and cardiovascular disease), as well as the effect of treatment with a tumour necrosis factor inhibitor or glucocorticoids (GCs) hereupon. METHODS: Serum levels of adiponectin, leptin, resistin, visfatin, vaspin and lipids were determined in a well-defined cohort of patients with RA before and after 16 weeks of adalimumab treatment (adalimumab cohort). The same parameters were analysed in two other cohorts of patients with RA before and after 2 weeks of high-dose prednisolone (high GC cohort) and before and after 22 weeks of treatment with a combination regimen with tapered high-dose prednisolone (COBRA -GC cohort). Radiographs of hands and feet (adalimumab and COBRA-GC cohorts) were assessed at baseline and after treatment. RESULTS: Treatment with adalimumab or GC showed opposing effects on vaspin and visfatin levels. Lipid levels improved after several months of adalimumab or GC treatment; in the adalimumab cohort, this was related to reduced visfatin levels, independent of C reactive protein levels. After long-term adalimumab or GC treatment, resistin levels declined, which was associated with a decrease in inflammation markers. In the adalimumab cohort, baseline resistin levels were predictive of baseline radiological damage, independent of anticitrullinated peptide antibodies status or C reactive protein levels. CONCLUSION: Changes in serum adipocytokine levels were treatment specific, further strengthening the role of visfatin and resistin in several disease manifestations of RA.

Inflamed target tissue provides a specific niche for highly expanded T-cell clones in early human autoimmune disease.

OBJECTIVE: To profile quantitatively the T-cell repertoire in multiple joints and peripheral blood of patients with recent onset (early) or established rheumatoid arthritis (RA) using a novel next-generation sequencing protocol to identify potential autoreactive clones. METHODS: Synovium of patients with recent onset (early) RA (<6 months) (n=6) or established RA (>18 months) (n=6) was screened for T-cell clones by sequencing over 10 000 T-cell receptors (TCR) per sample. T cells from paired blood samples were analysed for comparison. From two patients synovial T cells were obtained from multiple inflamed joints. The degree of expansion of each individual clone was based on its unique CDR3 sequence frequency within a sample. Clones with a frequency of over 0.5% were considered to be highly expanded clones (HEC). RESULTS: In early RA synovium, the T-cell repertoire was dominated by 35 HEC (median, range 2-70) accounting for 56% of the TCR sequenced. The clonal dominance in the synovium was patient specific and significantly greater than in established RA (median of 11 HEC (range 5-24) in established RA synovium accounting for 9.8% of T cells; p<0.01). 34% (range 28-40%) of the most expanded T-cell clones were shared between different joints in the same patients, compared with only 4% (range 0-8%) between synovium and blood (p=0.01). CONCLUSIONS: In RA, a systemic autoimmune disease, the inflamed synovium forms a niche for specific expanded T-cell clones, especially in early disease. This suggests that, at least in RA, autoreactive T cells should be addressed specifically in the inflamed tissue, preferably in the early phase of the disease.

Safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of the monoclonal antibody ASK8007 blocking osteopontin in patients with rheumatoid arthritis: a randomised, placebo controlled, proof-of-concept study.

OBJECTIVES: Osteopontin is an extracellular matrix protein with diverse immunomodulatory functions. The authors assessed the safety, tolerability, pharmacokinetics, pharmacodynamics and initial efficacy of the humanised monoclonal antibody ASK8007, which blocks osteopontin. METHODS: In this double-blind, multicentre, combined first-in-man, single-dose escalation (phase I, part A) and proof-of-concept, multiple-dose (phase IIA, part B) study, rheumatoid arthritis (RA) patients with active disease were randomly assigned to receive ASK8007 or placebo intravenously. Safety monitoring, pharmacokinetic and pharmacodynamic analyses and clinical assessments were performed throughout the study. The expression of phenotypic cell markers was evaluated in synovial tissue biopsy samples obtained at baseline and 43 days after initiation of treatment (part B) by immunohistochemistry and digital image analysis. Two co-primary efficacy endpoints were the change from baseline in the disease activity score evaluated in 28 joints (DAS28) and the change from baseline in the number of CD68 synovial sublining macrophages, both assessed on day 43 (part B). RESULTS: ASK8007 was overall safe and well tolerated up to the highest studied dose (20 mg/kg). Quantifiable concentrations of ASK8007 were detected in synovial fluid. No differences were observed for changes from baseline in DAS28 and CD68 sublining macrophages between ASK8007 and placebo-treated patients. Within the ASK8007 treatment group, there were also no apparent clinical responses or changes in sublining macrophages. In addition, ASK8007 treatment did not change other assessed biomarkers. CONCLUSIONS: Osteopontin blockade is well tolerated and not related to safety concerns. These results consistently show that osteopontin blockade is unlikely to induce robust clinical improvement in RA patients.

Monocyte migration to the synovium in rheumatoid arthritis patients treated with adalimumab.

OBJECTIVES: The mechanism of action of treatment with tumour necrosis factor (TNF) blockers in rheumatoid arthritis (RA) is still not completely understood. The aim of this study was to test if adalimumab treatment could affect the influx of monocytes into the synovium. METHODS: A novel technique was used to analyse the migration of labelled autologous monocytes before and 14 days after initiation of adalimumab treatment using scintigraphy. CD14 monocytes were isolated from patients with RA, using a positive selection procedure with magnetic-activated cell sorting, and labelled with technetium-99m-hexamethylpropylene-amino-oxime. Scintigraphic scans were made 1, 2 and 3 h after re-infusion. RESULTS: As early as 14 days after the start of treatment with adalimumab a significant decrease in disease activity score evaluated in 28 joints was shown. There was no significant decrease in the influx of monocytes into the joint at this time. CONCLUSIONS: This study indicates that adalimumab treatment does not reduce the influx of monocytes into the synovium early after initiation of treatment. As previous studies showed a rapid decrease in macrophage infiltration after TNF-antibody therapy, which could not be explained by increased cell death, this points to an important role for enhanced efflux of inflammatory cells from the synovium.

Different stages of rheumatoid arthritis: features of the synovium in the preclinical phase.

BACKGROUND: The aetiology of rheumatoid arthritis (RA), a prototype immune-mediated inflammatory disorder, is poorly understood. It is currently unknown whether the disease process starts in the synovium, the primary target of RA, or at other sites in the body. OBJECTIVE: To examine, in a prospective study, the presence of synovitis in people with an increased risk of developing RA. METHODS: Thirteen people without evidence of arthritis, who were positive for IgM rheumatoid factor and/or anticitrullinated protein antibodies, were included in the study. To evaluate synovial inflammatory changes, all participants underwent dynamic contrast-enhanced MRI and arthroscopic synovial biopsy sampling of a knee joint at inclusion. Results were compared with knee MRI data and synovial biopsy data of 6 and 10 healthy controls, respectively. RESULTS: MRI findings evaluated by measurement of maximal enhancement, rate of enhancement, synovial volume and enhancement shape curve distribution were similar between the autoantibody-positive subjects and the healthy controls. Consistent with these findings, all but one autoantibody-positive subject showed very low scores for phenotypic markers, adhesion molecules and vascularity, all in the same range as those in normal controls. The one person with higher scores had patellofemoral joint space narrowing. CONCLUSION: Subclinical inflammation of the synovium does not coincide with the appearance of serum autoantibodies during the pre-RA stage. Thus, systemic autoimmunity precedes the development of synovitis, suggesting that a 'second hit' is involved. This study supports the rationale for exploring preventive strategies aimed at interfering with the humoral immune response before synovial inflammation develops.

Pharmacogenomics of infliximab treatment using peripheral blood cells of patients with rheumatoid arthritis.

To provide insight into the pharmacological changes in the peripheral blood (PB) molecular profile induced by tumor necrosis factor (TNF)-blockade in patients with rheumatoid arthritis (RA), blood was obtained in PAXgene tubes from 33 RA patients before and 1 month after TNF-blocking therapy (infliximab). From 15 randomly chosen patients pre- and post-treatment gene expression profiles were determined. The remaining 18 RA patients served as validation cohort. A group-based paired analysis of the gene expression profiles from the post- vs pre-treatment samples revealed a signature of genes significantly regulated by TNF-blockade. Downregulated genes reflected several biological pathways such as inflammation, angiogenesis, B- and T-cell activation. Further analysis revealed that the pharmacological response signature was significantly regulated in all treated patients, irrespective of clinical response, which is indicative for the presence of an active TNF pathway in all RA patients. The data imply that all patients carried features of TNF bioactivity irrespective of clinical response. These results favor a model for the parallel presence of TNF-dependent and TNF-independent pathways in the individual RA patient. Clinical response status to TNF-blockade may be dependent on the relative contribution of TNF-independent effector pathways.

Clinical response, pharmacokinetics, development of human anti-chimaeric antibodies, and synovial tissue response to rituximab treatment in patients with rheumatoid arthritis.

OBJECTIVES: To analyse whether persistence of synovial B lineage cells and lack of clinical response to rituximab treatment in patients with rheumatoid arthritis (RA) are associated with low rituximab serum levels and anti-rituximab antibody (ARA) formation. METHODS: Fifty-eight patients with RA were treated with rituximab. The clinical response was determined 24 weeks after each treatment course using the Disease Activity Score evaluated in 28 joints (DAS28) and EULAR response criteria. Rituximab serum levels, ARAs and synovial B lineage cell numbers were determined before and after treatment. RESULTS: Four weeks after treatment rituximab serum levels were highly variable. Low rituximab levels were associated with ARA formation (in five patients (8.6%)) and high baseline erythrocyte sedimentation rate. Interestingly, serum rituximab levels were not related to persistence of synovial B lineage cells or clinical response. Furthermore, response to treatment and re-treatment was similar in ARA-positive and ARA-negative patients. CONCLUSION: There is clear variability in serum levels after rituximab treatment, but rituximab levels are not lower in patients with persistence of synovial B lineage cells or lack of clinical response. The current treatment schedule suffices to induce and maintain a clinical response, even when ARAs are formed.

Bone mineral density in rheumatoid arthritis patients 1 year after adalimumab therapy: arrest of bone loss.

OBJECTIVE: To explore the effects of anti-tumour necrosis factor (TNF)alpha antibody therapy on bone mineral density (BMD) of the lumbar spine and femur neck in patients with rheumatoid arthritis (RA). METHODS: A total of 50 patients with active RA (DAS28> or =3.2) who started adalimumab (40 mg subcutaneously/2 weeks) were included in an open label prospective study. All patients used stable methotrexate and were allowed to use prednisone (< or =10 mg/day). The BMD of the lumbar spine and femur neck was measured before and 1 year after start of treatment. RESULTS: Disease activity at baseline (28-joint Disease Activity Score (DAS28)) and disease duration were inversely correlated with femoral neck BMD and lumbar spine BMD (p<0.05). Mean BMD of lumbar spine and femur neck remained unchanged after 1 year of adalimumab therapy (+0.3% and +0.3%, respectively). Of interest, a beneficial effect of prednisone on change in femur neck BMD was observed with a relative increase with prednisone use (+2.5%) compared to no concomitant prednisone use (-0.7%), (p = 0.015). CONCLUSION: In contrast to the progressive bone loss observed after conventional disease-modifying antirheumatic drug therapy, TNF blockade may result in an arrest of general bone loss. Consistent with previous observations, the data also suggest that the net effect of low-dose corticosteroids on BMD in RA may be beneficial, possibly resulting from their anti-inflammatory effects.

Sustained changes in lipid profile and macrophage migration inhibitory factor levels after anti-tumour necrosis factor therapy in rheumatoid arthritis.

BACKGROUND: Macrophage migration inhibitory factor (MIF) has recently emerged as an important cytokine possibly linking rheumatoid arthritis (RA) and atherogenesis. Because atherogenesis is accelerated in RA this study was conducted to investigate whether anti-tumour necrosis factor (TNF) therapy could lead to sustained downregulation of systemic MIF levels and improvement in lipid profiles. METHODS: Fifty RA patients with active disease (disease activity score in 28 joints (DAS28) >or=3.2), who started adalimumab therapy at 40 mg every other week, were included. At baseline, weeks 16 and 52 serum levels of MIF and lipids were assessed. In addition, the DAS28 and serum C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR) were determined. RESULTS: After 16 weeks of adalimumab therapy, both DAS28 and MIF levels were significantly decreased (p<0.001 and p = 0.020, respectively). This was sustained up to week 52 (p<0.001 and p = 0.012, respectively). CRP levels and ESR were significantly reduced after 16 and 52 weeks of adalimumab therapy (p<0.001). High-density lipoprotein cholesterol levels increased at week 16 (p<0.001), but returned to baseline at week 52. Apolipoprotein (apo) A-I levels increased at week 16 (p<0.001) and remained stable (p = 0.005). This resulted in an improved apo B/A-I ratio. CONCLUSIONS: The results underline the sustained downregulation of MIF as a potential new mechanism by which anti-TNF therapy might reduce vascular inflammation, and as such perhaps cardiovascular morbidity in RA patients. This hypothesis is supported by an improved apo B/A-I ratio as well as reduced CRP levels in these patients.

A prospective, randomised, placebo-controlled study to identify biomarkers associated with active treatment in psoriatic arthritis: effects of adalimumab treatment on synovial tissue.

OBJECTIVE: To determine which of the changes in synovial tissue correlates best with clinical response associated with effective therapy (adalimumab) to facilitate the planning of future studies with therapeutic agents for psoriatic arthritis (PsA). METHODS: A total of 24 patients with active PsA were randomised to receive adalimumab (n = 12) or placebo (n = 12) for 4 weeks. Synovial biopsies were obtained before and after 4 weeks of treatment. Immunohistochemical analysis was performed to characterise the cell infiltrate, expression of cytokines and matrix metalloproteinases (MMPs) and vascularity. Sections were analysed by digital image analysis. Statistical analysis was performed using covariance analysis. RESULTS: The mean Disease Activity Score in 28 joints (DAS28) after 4 weeks was 1.92 units lower (95% confidence interval (CI) 1.07 to 2.77) after adalimumab therapy compared with placebo. Paired pretreatment and post-treatment synovial samples were available from 19 patients. Many cell types were reduced after adalimumab treatment compared to placebo. After applying a ranked analysis of covariance (ANCOVA) model to correct for baseline imbalances, a significant effect of treatment was observed on CD3-positive cells: there was a median reduction of 248 cells/mm(2) after adalimumab versus placebo treatment (p = 0.035). In addition, the expression of MMP13 was significantly reduced after active treatment: the integrated optical density (IOD)/mm(2) was 18 190 lower after adalimumab treatment as compared to placebo (p = 0.033). CONCLUSION: Adalimumab therapy in PsA is associated with a marked reduction in T cell infiltration and MMP13 expression in synovial tissue, suggesting that these parameters could be used as biomarkers that are sensitive to change after active treatment in small proof of concept studies in PsA.

Myeloid Dendritic Cells Are Enriched in Lymph Node Tissue of Early Rheumatoid Arthritis Patients but not in At Risk Individuals.

Lymph nodes (LNs) are highly organized structures where specific immune responses are initiated by dendritic cells (DCs). We investigated the frequency and distribution of human myeloid (mDCs) and plasmacytoid (pDCs) in LNs and blood during the earliest phases of rheumatoid arthritis (RA). We included 22 RA-risk individuals positive for IgM rheumatoid factor and/or anti-citrullinated protein antibodies, 16 biological-naïve RA patients and 8 healthy controls (HCs). DC subsets (CD1c+ mDCs and CD304+ pDCs) in LN tissue and paired peripheral blood were analyzed using flow cytometry and confocal microscopy. In blood of RA patients a significant decreased frequency of pDCs was found, with a similar trend for mDCs. In contrast, mDC frequencies were higher in RA compared with HCs and RA-risk individuals, especially in LN. Frequency of mDCs seemed higher in LNs compared to paired blood samples in all donors, while pDCs were higher in LNs only in RA patients. As expected, both mDCs and pDCs localized mainly in T-cell areas of LN tissue. In conclusion, compared with RA-risk individuals, mDCs and pDCs were enriched in the LN tissue of early-RA patients, while their frequency in RA-risk individuals was comparable to HCs. This may suggest that other antigen-presenting cells are responsible for initial breaks of tolerance, while mDCs and pDCs are involved in sustaining inflammation.

Tumour necrosis factor blockade increases lymphangiogenesis in murine and human arthritic joints.

OBJECTIVE: To investigate the presence and regulation of lymphatic vessels in inflamed joints of mice with experimental arthritis as well as patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA). METHODS: Lymphatic vessels and blood vessels were assessed in synovial tissue of human tumour necrosis factor transgenic (TNFtg) mice and synovial biopsies from patients with RA and SpA by immunohistochemistry for podoplanin and CD31, respectively. Assessments were performed before and after TNF blockade in all biopsies. RESULTS: Lymphatic vessels were abundantly present in the synovial tissue of hTNFtg mice as well as patients with RA and SpA. The number of lymphatic vessels was positively related to the severity of synovial inflammation. Treatment with infliximab led to an increase in the formation of lymphatic vessels in murine and human inflammatory tissue. CONCLUSIONS: This study shows that TNF blockade promotes the proliferation of lymphatic vessels in the inflamed synovium of RA and SpA. This finding leads to the assumption that promotion of lymphangiogenesis may play an important part in efflux of cells and fluid out of the inflamed tissue.

Synovial tissue response to rituximab: mechanism of action and identification of biomarkers of response.

OBJECTIVE: To investigate the synovial tissue in patients with rheumatoid arthritis (RA) treated with rituximab and to identify possible predictors of clinical response. METHODS: A total of 24 patients with RA underwent synovial biopsy before, 4 and 16 weeks after initiation of rituximab treatment (without peri-infusional corticosteroids to prevent bias). Immunohistochemical analysis was performed and stained sections were analysed by digital image analysis. Linear regression analysis was used to identify predictors of clinical response. RESULTS: The 28-joint Disease Activity Score (DAS28) was unaltered at 4 weeks, but significantly reduced at 16 and 24 weeks. Serum levels of IgM-rheumatoid factor (RF) decreased significantly at 24 weeks and anti-citrullinated peptide antibody (ACPA) levels at 36 weeks. Peripheral blood B cells were depleted at 4 weeks and started to return at 24 weeks. Synovial B cells were significantly decreased at 4 weeks, but were not completely depleted in all patients; there was a further reduction at 16 weeks in some patients. We found a significant decrease in macrophages at 4 weeks, which was more pronounced at 16 weeks. At that timepoint, T cells were also significantly decreased. The reduction of plasma cells predicted clinical improvement at 24 weeks. CONCLUSIONS: The results support the view that B cells orchestrate local cellular infiltration. The kinetics of the serological as well as the tissue response in clinical responders are consistent with the notion that rituximab exerts its effects in part by an indirect effect on plasma cells associated with autoantibody production, which could help explain the delayed response after rituximab treatment.

[Prolonged effect of intra-articularly administered corticosteroids in combination with arthroscopic lavage in patients with an inflammatory arthritis of the knee]. / Verlenging van het effect van intra-articulair toegediende corticosteroïden door combinatie hiervan met artroscopische lavage bij patiënten met een inflammatoire artritis van de knie.

Arthroscopic lavage of a joint with saline followed by the administration of corticosteroids intra-articularly could lead to an improved functioning of the joint. In a recent study published in this issue the results of arthrocentesis with intra-articular administration of corticosteroids was compared with lavage with or without intra-articular administration of corticosteroids in patients with a non-infectious inflammatory arthritis of the knee joint. The results confirm earlier reports, which demonstrated that the beneficial therapeutic effects of corticosteroids administered intra-articularly can be prolonged by a therapeutic lavage in patients with non-infectious inflammatory arthritis, provided the lavage is performed with a sufficient amount of saline.

Single vagus nerve stimulation reduces early postprandial C-peptide levels but not other hormones or postprandial metabolism.

A recent study in rheumatoid arthritis (RA) patients using electrical vagus nerve stimulation (VNS) to activate the inflammatory reflex has shown promising effects on disease activity. Innervation by the autonomic nerve system might be involved in the regulation of many endocrine and metabolic processes and could therefore theoretically lead to unwanted side effects. Possible effects of VNS on secretion of hormones are currently unknown. Therefore, we evaluated the effects of a single VNS on plasma levels of pituitary hormones and parameters of postprandial metabolism. Six female patients with RA were studied twice in balanced assignment (crossover design) to either VNS or no stimulation. The patients selected for this substudy had been on VNS therapy daily for at least 3 months and at maximum of 24 months. We compared 10-, 20-, and 30-min poststimulus levels to baseline levels, and a 4-h mixed meal test was performed 30 min after VNS. We also determined energy expenditure (EE) by indirect calorimetry before and after VNS. VNS did not affect pituitary hormones (growth hormone, thyroid stimulating hormone, adrenocorticotropic hormone, prolactin, follicle-stimulating hormone, and luteinizing hormone), postprandial metabolism, or EE. Of note, VNS reduced early postprandial insulin secretion, but not AUC of postprandial plasma insulin levels. Cortisol and catecholamine levels in serum did not change significantly. Short stimulation of vagal activity by VNS reduces early postprandial insulin secretion, but not other hormone levels and postprandial response. This suggests VNS as a safe treatment for RA patients.