Pathogenic mechanisms in the rheumatoid nodule: comparison of proinflammatory cytokine production and cell adhesion molecule expression in rheumatoid nodules and synovial membranes from the same patient

Rheumatoid nodules: a narrative review of histopathological progression and diagnostic consideration

Rheumatoid nodules (RNs) are the most common extra-articular manifestation of rheumatoid arthritis and are also seen in patients with other autoimmune and inflammatory diseases. The development of RNs includes histopathological stages of acute unspecified inflammation, granulomatous inflammation with no or minimal necrosis, necrobiotic granulomas typically with central fibrinoid necrosis surrounded by palisading epithelioid macrophages and other cells, and likely an advanced stage of "ghost" lesions containing cystic or calcifying/calcified areas. In this article, we review RN pathogenesis, histopathological features in different stages, diagnostically related clinical manifestations, as well as diagnosis and differential diagnosis of RNs with an in-depth discussion about challenges in distinguishing RNs from their mimics. While the pathogenesis of RN formation remains elusive, it is hypothesized that some RNs with dystrophic calcification may be in transition and may be in coexistence or collision with another lesion in patients with RA or other soft tissue diseases and comorbidities. The diagnosis of typical or mature RNs in usual locations can be readily made by clinical findings often with classic RN histopathology, but in many cases, particularly with atypical or immature RNs and/or unusual locations, the clinical and histopathological diagnosis can be challenging requiring extensive examination of the lesional tissue with histological and immunohistochemical markers to identify unusual RNs in the clinical context or other lesions that may be coexisting with classic RNs. Proper diagnosis of RNs is critical for appropriate treatment of patients with RA or other autoimmune and inflammatory diseases.

Drug-induced accelerated nodulosis: review of the literature

Accelerated nodulosis, the rapid progression/extension of preexisting nodules, is a recognized complication of immunomodulatory therapy, occurring mostly in patients with rheumatoid arthritis treated with methotrexate. As of today, its physiopathology remains incompletely understood, and there are no standardized guidelines regarding its management. Here, we conduct a literature review of the reported cases of drug-induced accelerated nodulosis and add our case of a 79-year-old female with an atypical clinical presentation.

Oxidative Phosphorylation-Mediated E-Selectin Upregulation Is Associated With Endothelia-Monocyte Adhesion in Human Coronary Artery Endothelial Cells Treated With Sera From Patients With Kawasaki Disease

Background and aims: E-selectin is a cell adhesion molecule of the vascular endothelium that mediates leukocyte rolling in the early inflammatory responses in many diseases including Kawasaki disease (KD). Previous studies have demonstrated that the expression levels of E-selectin was significantly increased in the sera of KD patients and in endothelial cells of KD patient's autopsy. In this study, we aimed to examine E-selectin levels in endothelial cells treated with sera from KD patients and explore the underlying mechanisms. Methods: Human coronary artery endothelial cells (HCAECs) were randomly incubated with sera from either healthy children [healthy control (HC group)] or pediatric KD patients [assigned as KD with coronary artery lesion (KD-CAL+ group) and KD without coronary artery lesion (KD-CAL- group)]. E-selectin levels were determined by RT-qPCR, Western blotting, and immunofluorescence. Cell adhesion assay was performed to quantify the role of E-selectin in intercellular adhesion. High-throughput cell RNA sequencing followed by functional validation was performed to explore the underlying mechanism. Results: E-selectin levels were significantly increased in KD-CAL+ group vs. HC group and KD-CAL- group. Compared with the KD-CAL- group, endothelia-monocyte adhesion was increased in the KD-CAL+ group, while E-selectin-specific siRNA could significantly rescue it. High-throughput cell RNA sequencing analysis also found a significant difference in oxidative phosphorylation (OXPHOS) levels between KD-CAL+ group and KD-CAL- group. Functional validation results further confirmed that the OXPHOS was upregulated in the KD-CAL+ group and KD-CAL- group compared to that in the HC group, while the KD-CAL+ group exhibited a higher OXPHOS than the KD-CAL- group. We also found that the E-selectin levels and endothelia-monocyte adhesion were significantly decreased by OXPHOS inhibitor oligomycin in the KD-CAL+ group and KD-CAL- group, respectively. Conclusion: Sera from KD patients stimulate OXPHOS levels and enhance E-selectin expression in HCAECs, which may contribute to the development of CAL in KD patients.

Superficial Ulcerating Rheumatoid Necrobiosis Associated with Methotrexate Use in a Patient with Rheumatoid Arthritis

Methotrexate, a disease-modifying antirheumatic drug, is fundamental to limiting progression in several rheumatic diseases such as rheumatoid arthritis (RA). However, methotrexate is also associated with various significant adverse effects. Of note, there are several dermatologic manifestations attributed to methotrexate therapy. In particular, accelerated nodulosis and panniculitis are linked to methotrexate therapy in the current literature. The authors present the case of a 55-year-old Caucasian female with seropositive erosive RA who developed superficial ulcerating rheumatoid necrobiosis (SURN), secondary to methotrexate therapy. The patient’s treatment consisted of methotrexate discontinuation, topical clobetasol, and initiation of leflunomide as a replacement of methotrexate. Follow-up evaluation confirmed resolution of SURN over time and maintained low disease RA activity with leflunomide.Few cases describe SURN in the setting of RA and there are currently no cases published that suggest methotrexate’s possible role in SURN. Methotrexate-induced SURN is plausible in this case because of the correlation with therapy initiation and remission after therapy discontinuation. SURN has significant histological overlap with other methotrexate-induced dermatologic manifestations, allowing for a possible correlation. Most dermatological side effects of methotrexate are linked to a genetic predisposition of the HLA-DRB1 gene. Additionally, methotrexate’s mechanism of action for rheumatologic disease paradoxically stimulates adenosine-1 receptors and activates neutrophil chemotaxis and phagocytosis. Adenosine-1 receptor stimulation is hypothesised to be the source of rheumatoid-accelerated nodulosis and possibly SURN. Furthermore, the location of manifestation, genetic predisposition, and comorbid features in the patient all possibly have a role in this unique dermatological side effect.

A case of rheumatoid arthritis with multiple lung rheumatoid nodules successfully treated with tofacitinib

Sporadic cases of rheumatoid nodules (RNs) in the lung during treatment with tumour necrosis factor (TNF) inhibitors have been reported, but no treatment has been established. Here, we report a case of symptomatic lung RNs refractory to abatacept (ABT) and intravenous cyclophosphamide (IVCY) that improved with tofacitinib (TOF) treatment. A 75-year-old Japanese woman with a 10-year history of rheumatoid arthritis (RA) presented with a cough and haemoptysis during treatment with etanercept (ETN). Radiographic examinations revealed multiple nodules that were diagnosed as lung RNs via biopsy. The ETN was discontinued and ABT followed by IVCY was introduced; however, neither was sufficiently effective against the lung RNs. Thereafter, TOF was started and the lung RNs improved rapidly. The precise mechanisms that induce RNs during treatment with TNF inhibitors are unknown. Cytokines (IL-23 and IL-6) are suspected to be involved. TOF may be a reasonable strategy for treating symptomatic lung RNs.

Thoracic Manifestations of Rheumatoid Arthritis

Rheumatoid arthritis (RA) is commonly associated with pulmonary disease that can affect any anatomic compartment of the thorax. The most common intrathoracic manifestations of RA include interstitial lung disease, airway disease, pleural disease, rheumatoid nodules, and drug-induced toxicity. Patients with RA with thoracic involvement often present with nonspecific respiratory symptoms, although many are asymptomatic. Therefore, clinicians should routinely consider pulmonary disease when evaluating any patient with RA, particularly one with known risk factors. The optimal screening, diagnostic, and treatment strategies for RA-associated pulmonary disease remain uncertain and are the focus of ongoing investigation.

Clinicopathologic features of rheumatoid nodules: a retrospective analysis

OBJECTIVES

The clinical and histopathologic features of patients that have been diagnosed with rheumatoid nodules were investigated.

METHODS

This study included patients with rheumatoid nodules, confirmed by histologic assessment, between 2005 and 2018 at the Hanyang University Hospital. Each patient had a total score of 6 or more according to the American College of Rheumatology criteria.

RESULTS

A total of 57 cases were included in this study. The median age of the patients at the time of diagnosis was 57 years (range, 39-70 years). The average duration between the onset of treatment and occurrence of rheumatoid nodule was 11.6 years. Bone erosion was observed in 44 patients (77.2%). Among 57 patients, 56 (98.2%) were treated with disease-modifying anti-rheumatic drugs; most of the patients (87.7%) showed high-positive rheumatoid factor or high-positive anti-citrullinated protein antibodies. The foot, hand, and wrist, in order of decreasing frequencies, were the anatomical sites with the highest occurrence of rheumatoid nodules, whereas, the soft tissue adjacent to the joint, subcutis, dermis, lung parenchyma, and submucosal layer of the supraglottic area, also in an order of highest frequency, were the histological sites with the highest occurrence. Microscopically, central necrobiosis was present in all cases. Stromal fibrosis (96.5%), palisading of histiocytes (82.5%), perivascular lymphocytic infiltration (68.4%), and cleft or cystic degeneration (63.2%) were also observed.

CONCLUSIONS

A clinicopathological review of cases diagnosed with rheumatoid nodules histologically was performed to confirm characteristics that can help clinicians understand the pathophysiology of the condition and make accurate diagnoses of rheumatoid nodules. Key Points • We reviewed the clinical, imaging, and histologic features of rheumatoid nodule. • The average duration between the onset of treatment and occurrence of rheumatoid nodule was 11.6 years. • Among 57 rheumatoid nodule patients, 98.2% were treated with disease-modifying anti-rheumatic drugs.

Accelerated Nodulosis in a Patient With Rheumatoid Arthritis

In patients with rheumatoid arthritis (RA), subcutaneous nodules are the most frequently seen extra-articular findings that are seen in areas of extensor pressure. In this article, we present the case of a RA patient with accelerated nodulosis that started with the use of methotrexate and exacerbated with etanercept and leflunomide treatment.

Digital-PCR for gene expression: impact from inherent tissue RNA degradation

Subtle molecular differences indicate the heterogeneity present in a number of disease settings. Digital-PCR (dPCR) platforms achieve the necessary levels of sensitivity and accuracy over standard quantitative RT-PCR (qPCR) that promote their use for such situations, detecting low abundance transcript and subtle changes from gene expression. An underlying requisite is good quality RNA, principally dictated by appropriate tissue handling and RNA extraction. Here we consider the application of dPCR to measures of gene expression in pathological tissues with inherent necrosis, focusing on rheumatoid subcutaneous nodules. Variable RNA fragmentation is a feature of RNA from such tissues. Increased presence of transcript fragmentation is reflected in a proportionate decrease in Agilent DV₂₀₀ metric and downstream, a reduction in endogenous control genes' expression, measured by RT-dPCR. We show that normalisation of target gene expression to that for endogenous control genes sufficiently corrects for the variable level of fragmented RNA. Recovery of target gene values was achieved in samples comprising as much as 50 percent fragmented RNA, indicating the suitability and appropriate limitation of such data treatment when applied to samples obtained from inherently necrotic tissues.

Therapeutic Mechanisms of Human Adipose-Derived Mesenchymal Stem Cells in a Rat Tendon Injury Model

BACKGROUND

Although survival of transplanted stem cells in vivo and differentiation of stem cells into tenocytes in vitro have been reported, there have been no in vivo studies demonstrating that mesenchymal stem cells (MSCs) could secrete their own proteins as differentiated tenogenic cells. Purpose/Hypothesis: Using a xenogeneic MSC transplantation model, we aimed to investigate whether MSCs could differentiate into the tenogenic lineage and secrete their own proteins. The hypothesis was that human MSCs would differentiate into the human tenogenic lineage and the cells would be able to secrete human-specific proteins in a rat tendon injury model.

STUDY DESIGN

Controlled laboratory study.

METHODS

The Achilles tendons of 57 Sprague Dawley rats received full-thickness rectangular defects. After the modeling, the defective tendons were randomly assigned to 3 groups: (1) cell group, implantation with human adipose-derived mesenchymal stem cells (hASCs) and fibrin glue (10⁶ cells in 60 μL); (2) fibrin group, implantation with fibrin glue and same volume of cell media; and (3) sham group, identical surgical procedure without any treatment. Gross observation and biomechanical, histopathological, immunohistochemistry, and Western blot analyses were performed at 2 and 4 weeks after modeling.

RESULTS

hASCs implanted into the defective rat tendons were viable for 4 weeks as detected by immunofluorescence staining. Tendons treated with hASCs showed better gross morphological and biomechanical recovery than those in the fibrin and sham groups. Furthermore, the expression of both human-specific collagen type I and tenascin-C was significantly higher in the cell group than in the other 2 groups.

CONCLUSION

Transplantation of hASCs enhanced rat tendon healing biomechanically. hASCs implanted into the rat tendon defect model survived for at least 4 weeks and secreted human-specific collagen type I and tenascin-C. These findings suggest that transplanted MSCs may be able to differentiate into the tenogenic lineage and contribute their own proteins to tendon healing.

CLINICAL RELEVANCE

In tendon injury, MSCs can enhance tendon healing by secreting their own protein and have potential as a therapeutic option in human tendinopathy.

Subcutaneous nodules are associated with cardiovascular events in patients with rheumatoid arthritis: results from a large US registry

Subcutaneous nodules are the most common conspicuous extra-articular manifestation of rheumatoid arthritis (RA). Cardiovascular disease (CVD) is the leading cause of death in patients with RA. The objective of this study is to examine the possibility of a relationship between subcutaneous nodules and "first ever" cardiovascular disease event, i.e., myocardial infarction (MI), stroke, or cardiovascular death in a large registry-cohort of patients with RA. Patient information was collected from the CORRONA registry from October 2001 to September 2011. A total of 26,042 patients with RA were studied for the presence or absence of subcutaneous nodules. Cox proportional hazards regression models were constructed to estimate the hazard ratios (HR) for CVD events in relation to subcutaneous nodules at baseline. Three statistical models were used to examine the association between subcutaneous nodules and CVD: Model A adjusted for age and sex associated risk, model B adjusted for traditional CV risk factors, and model C adjusted for factors in models A and B plus underlying RA-specific measures. The definition of primary exposure was "subcutaneous nodules at baseline." A total of 3908 patients had subcutaneous nodules at baseline. Of the 566 total composite CVD events, 138 occurred in the group that had SCN at baseline. Incidence rate-ratio values (patients with subcutaneous nodules at baseline vs. no subcutaneous nodules at baseline) for composite CVD events, MI, stroke, and cardiovascular death were 1.55, 1.65, 1.37, and 1.68, respectively. Adjusted HR values (95 % CI) for composite CVD events based on "subcutaneous nodules-status at baseline" (primary exposure) were as follows: 1.35 (1.11-1.63) for model A, 1.25 (1.03-1.52) for model B, and 1.03 (0.831-1.277) for model C. Subcutaneous nodules were associated with increased CVD events in RA. This association persisted after adjusting for age, sex, and traditional CV risk factors.

MMP expression in rheumatoid inflammation: the rs11568818 polymorphism is associated with MMP-7 expression at an extra-articular site

Matrix metalloproteinases (MMPs) contribute to the joint damage in rheumatoid arthritis (RA). Less is known of the involvement of MMPs at extra-articular sites of rheumatoid inflammation. We assessed the relative contribution from MMP-1, MMP-3, MMP-7 and MMP-12 to joint and extra-articular tissue destruction and inflammation by comparing gene expression in joint synovia and subcutaneous rheumatoid nodules from RA patients. Expression of MMP-1 and MMP-3 predominated in synovia, whereas MMP-12 expression was significantly higher in rheumatoid nodules. Markedly higher MMP-7 expression distinguished a subgroup of nodules that featured infiltrating monocyte/macrophage-producing MMP-7 protein. The high MMP-7 expression in nodules was associated with the single-nucleotide polymorphism (SNP) rs11568818 (-181A>G, MMP-7 promoter) and more active inflammation within the nodule lesions. Patients with such nodules had significantly earlier age of RA onset. Our findings indicate that the expression of MMP-1 and MMP-3 occurs relatively independent of the tissue microenvironment with substantial expression also at extra-articular sites. MMP-12 expression reflects the involvement of monocyte/macrophages in rheumatoid inflammation. Evidence for the association between the rs11568818 SNP and increased MMP-7 expression is restricted to nodules, which indicates that consequences of the MMP-7 polymorphism are likely to manifest within aspects of immune/inflammatory activity that are monocyte/macrophage-mediated.

Cutaneous necrobiotic conditions associated with rheumatoid arthritis: important extra-articular involvement

Rheumatoid arthritis (RA) presents with various skin conditions as extra-articular manifestations. Rheumatoid nodule is the representative specific skin lesion, histologically exhibiting central necrosis (necrobiosis) surrounded by palisaded macrophages, and being further perivascularly infiltrated with inflammatory cells in the outer regions. Also, there are several skin lesions which histologically show necrobiotic conditions with altered connective tissue degeneration. Necrobiosis may be closely associated with the pathogenesis of RA, i.e., collagen degeneration, recruitment of activated neutrophils, production of various cytokines, and vascular injury. On the other hand, rheumatoid nodule is suggested to develop during therapies with certain drugs such as methotrexate and biologics. These findings may be a clue to understanding the pathomechanisms of rheumatoid nodules. This paper describes several necrobiotic conditions associated with RA, and also discusses the possible pathogenesis and differential diagnosis of rheumatoid nodules. Necrobiosis is the major pathologic condition of cutaneous involvement associated with RA.

Microchimerism in the rheumatoid nodules of patients with rheumatoid arthritis

OBJECTIVE

The rheumatoid nodule is a lesion commonly found on extraarticular areas prone to mechanic trauma. When present with inflammatory symmetric polyarthritis, it is pathognomonic of rheumatoid arthritis (RA), an autoimmune disease in which naturally acquired microchimerism has previously been described and can sometimes contribute to RA risk. Since RA patients harbor microchimerism in the blood, we hypothesized that microchimerism is also present in rheumatoid nodules and could play a role in rheumatoid nodule formation. This study was undertaken to investigate rheumatoid nodules for microchimerism.

METHODS

Rheumatoid nodules were tested for microchimerism by real-time quantitative polymerase chain reaction (qPCR). The rheumatoid nodules of 29 female patients were tested for a Y chromosome-specific sequence. After HLA genotyping of patients and family members, rheumatoid nodules from 1 man and 14 women were tested by HLA-specific qPCR, targeting a nonshared HLA allele of the potential microchimerism source. Results were expressed as genome equivalents of microchimeric cells per 10(5) patient genome equivalents (GE/10(5)).

RESULTS

Rheumatoid nodules from 21% of the female patients contained male DNA (range <0.5, 10.3 GE/10(5)). By HLA-specific qPCR, 60% of patients were microchimeric (range 0, 18.5 GE/10(5)). Combined microchimerism prevalence was 47%. A fetal or maternal source was identified in all patients who tested positive by HLA-specific qPCR. Unexpectedly, a few rheumatoid nodules also contained microchimerism without evidence of a fetal or maternal source, suggesting alternative sources.

CONCLUSION

Our findings indicate that microchimerism is frequently present in the rheumatoid nodules of RA patients. Since microchimerism is genetically disparate, whether microchimerism in rheumatoid nodules serves as an allogeneic stimulus or allogeneic target warrants further investigation.

FcγRIIIa expression on monocytes in rheumatoid arthritis: role in immune-complex stimulated TNF production and non-response to methotrexate therapy

OBJECTIVE

The expression of FcγRIIIa/CD16 may render monocytes targets for activation by IgG-containing immune complexes (IC). We investigated whether FcγRIIIa/CD16 was upregulated in rheumatoid arthritis (RA), associated with TNF production in response to IC-stimulation, and if this predicted response to methotrexate therapy.

METHODS

FcγRIIIa/CD16 expression on CD14(low) and CD14++ monocytes was measured by flow cytometry in healthy controls and RA patients (early and long-standing disease). Intracellular TNF-staining was carried out after in vitro LPS or heat-aggregated immunoglobulin (HAG) activation. FcγRIIIa/CD16 expression pre- and post-steroid/methotrexate treatment was examined.

RESULTS

Increased FcγRIIIa/CD16 expression on CD14++ monocytes in long-standing RA patients compared to controls was demonstrated (p = 0.002) with intermediate levels in early-RA patients. HAG-induced TNF-production in RA patients was correlated with the percentage of CD14++ monocytes expressing FcγRIIIa/CD16 (p<0.001). The percentage of CD14++ monocytes expressing FcγRIIIa/CD16 at baseline in early DMARD-naïve RA patients was negatively correlated with DAS28-ESR improvement 14-weeks post-methotrexate therapy (p = 0.003) and was significantly increased in EULAR non-responders compared to moderate (p = 0.01) or good responders (p = 0.003). FcγRIIIa/CD16 expression was not correlated with age, presence of systemic inflammation or autoantibody titers.

CONCLUSION

Increased FcγRIIIa/CD16 expression on CD14++ monocytes in RA may result in a cell that has increased responsiveness to IC-stimulation. This monocyte subset may contribute to non-response to methotrexate therapy.

E-selectin as a target for drug delivery and molecular imaging

E-selectin, also known as CD62E, is a cell adhesion molecule expressed on endothelial cells activated by cytokines. Like other selectins, it plays an important part in inflammation and in the adhesion of metastatic cancer cells to the endothelium. E-selectin recognizes and binds to sialylated carbohydrates present on the surface proteins of certain leukocytes. E-selectin has been chosen as a target for several therapeutic and medical imaging applications, based on its expression in the vicinity of inflammation, infection or cancer. These systems for drug delivery and molecular imaging include immunoconjugates, liposomes, nanoparticles, and microparticles prepared from a wide range of starting materials including lipids, synthetic polymers, polypeptides and organo-metallic structures. After a brief introduction presenting the selectin family and their implication in physiology and pathology, this review focuses on the formulation of these new delivery systems targeting E-selectin at a molecular level.

Apoptosis in the rheumatoid arthritis synovial membrane: modulation by disease-modifying anti-rheumatic drug treatment

OBJECTIVES

RA is characterized at the synovial tissue level by synovial lining hyperplasia, angiogenesis and mononuclear cell infiltrates. A failure of apoptotic pathways may explain these pathological changes in RA synovial tissue. This study aims to demonstrate the presence of initiators and inhibitors of apoptosis in RA synovial tissue and the effect of treatment with DMARDs on apoptotic pathways in RA.

METHODS

Synovial biopsy specimens were obtained at arthroscopy from 16 RA patients before and at 3- or 6-month intervals after commencing treatment with a DMARD. Apoptosis (by the terminal deoxynucleotidyl transferase mediated dUTP nick end labelling method and polyADP-ribose polymerase staining), proteins regulating apoptosis [Fas, FADD-like IL1b converting enzyme inhibitory protein (FLIP), Bcl-2, Survivin and X-linked inhibitor of apoptosis protein (XIAP)] and the presence of activated caspases (caspases 3 and 8) were detected by immunohistochemistry and quantified using image analysis and semiquantitative techniques.

RESULTS

Fifteen patients responded to treatment, with an ACR response of > or =20%, 13 achieving an ACR response of > or =50% and 3 achieving an ACR remission. There was a significant reduction in SM macrophages and memory T cells, with an increase in fibroblast-like synovial lining cells following DMARD treatment. Apoptosis was not detected in the inflamed synovial tissue of RA patients before starting treatment, despite evidence of caspase activation, but was detectable after successful treatment with DMARDs. Inhibitors of activated caspases (FLIP, Survivin and XIAP) were detected in RA synovial tissue and were down-modulated with successful DMARD treatment.

CONCLUSIONS

Apoptotic pathways are defective in RA synovial tissue from patients with active disease, despite the presence of activated caspases, possibly due to the abundant expression of inhibitors of the caspase pathway in RA synovial tissue. DMARD treatment can modulate apoptosis in the RA SM, which may lead to restoration of the SM architecture towards that of normal synovial tissue.

Pulmonary Nodulosis and Aseptic Granulomatous Lung Disease Occurring in Patients with Rheumatoid Arthritis Receiving Tumor Necrosis Factor-α-Blocking Agent: A Case Series

Objective.

To describe cases of development of pulmonary nodulosis or aseptic granulomatous lung disease in patients with rheumatoid arthritis (RA) receiving anti-tumor necrosis factor-α (TNF-α) therapy.

Methods.

A call for observation of such cases was sent to members of the French “Club Rhumatismes et Inflammation.” The cases had to occur after introduction of TNF-α-blocking therapy.

Results.

Eleven cases were examined: 6 patients were treated with etanercept, 2 with infliximab, and 3 with adalimumab. Pulmonary nodular lesions were observed after a mean treatment period of 23.3 ± 15.3 months. Clinical symptoms were observed in 5 cases. Radiographs or computed tomography of the chest showed single or multiple nodular lesions in 10 cases and hilar adenopathies in 1 case. Biopsy of the nodular chest lesions or mediastinal lymphadenopathies were performed in 8 patients, and revealed typical rheumatoid nodules in 4 cases and noncaseating granulomatous lesions in 4 cases. Mycobacterial or opportunistic infections were excluded for all cases. Outcome was favorable for all the patients, with either discontinuation or maintenance of anti-TNF-α treatment.

Conclusion.

Aseptic pulmonary nodular inflammation corresponding to rheumatoid nodules or noncaseating granulomatous inflammation can occur during anti-TNF-α therapy for RA, mainly etanercept. The mechanism explaining such a reaction is not clear but certainly includes different processes. These cases of pulmonary nodular inflammation generally have a benign course and do not systematically require withdrawal of treatment.

Cutaneous manifestations associated with rheumatoid arthritis

Rheumatoid arthritis presents various cutaneous manifestations, either specific or nonspecific skin features, which are induced by the activation of inflammatory cells (neutrophils, lymphocytes, macrophages), vasculopathy, vasculitis, acral deformity, drugs, and so on. These include (1) specific findings, (2) findings due to vascular impairment, (3) findings due to immune dysfunction, (4) characteristic neutrophilic conditions, and (5) miscellaneous conditions. On the other hand, some of the specific manifestations show common histopathological features such as palisading granulomas with necrobiosis. It is important to recognize the common and/or uncommon skin conditions of RA for all clinicians associated with RA therapy.

Significance of serum TRACP in rheumatoid arthritis

Human serum contains two related isoforms of TRACP: TRACP 5a and TRACP 5b. Serum TRACP 5a protein is increased in about one third of rheumatoid arthritis (RA) sera. This study was undertaken to examine the significance of serum TRACP isoforms 5a and 5b as disease markers of inflammation and bone destruction in RA. One hundred eighteen patients were recruited including 50 with RA (25 with nodules), 26 with osteoarthritis (OA), and 42 with other rheumatic diseases. Twenty-six healthy adults served as controls. Serum TRACP 5a activity, TRACP 5a protein, and TRACP 5b activity were determined by in-house immunoassays. C-reactive protein (CRP) was determined by in-house immunoassay using commercial antibodies and CRP. Other commercial markers included bone-specific alkaline phosphatase (BALP), C-telopeptides of type-I collagen (ICTP), cartilage glycoprotein-39 (YKL-40), and IgM rheumatoid factors (IgM-RF). Mean TRACP 5a protein was significantly elevated only in RA compared with healthy controls and other disease groups. TRACP 5a protein correlated significantly only with IgM-RF in RA. Among RA patients, mean TRACP 5a protein and IgM RF were significantly higher in nodule formers. In contrast, TRACP 5b activity was slightly elevated in RA and correlated with BALP, ICTP, and YKL-40 but not with IgM-RF or CRP. Mean TRACP 5b activity was no different in RA patients with or without nodules. TRACP isoforms could be useful disease markers in RA; TRACP 5a protein may be a measure of systemic inflammatory macrophage burden and disease severity. TRACP 5b activity is a marker for osteoclast number and perhaps local or systemic bone destruction.

Characterisation of a dendritic cell subset in synovial tissue which strongly expresses Jak/STAT transcription factors from patients with rheumatoid arthritis

OBJECTIVES

To characterise the phenotype of the putative dendritic cells strongly expressing Jak3 and STAT4, which have been previously identified in the synovial tissue of patients with active rheumatoid arthritis (RA).

METHODS

Synovial biopsy specimens were obtained at arthroscopy from 30 patients with active RA (42 synovial biopsies). Immunohistological analysis was performed using monoclonal antibodies to detect dendritic cell subsets, including activation markers and cytokines relevant to dendritic cell function. Co-localisation of cell surface markers and cytokines was assessed primarily using sequential sections, with results confirmed by dual immunohistochemistry and immunofluorescence with confocal microscopy.

RESULTS

The dendritic cells identified in RA synovial tissue that strongly express Jak3 also strongly express STAT4 and STAT 6 and are correlated with the presence of serum rheumatoid factor. These cells are not confined to a single dendritic cell subset, with cells having phenotypes consistent with both myeloid- and plasmacytoid-type dendritic cells. The activation status of these dendritic cells suggests that they are maturing or mature dendritic cells. These dendritic cells produce IL12 as well as interferon alpha and gamma.

CONCLUSIONS

The close correlation of these dendritic cells with the presence of serum rheumatoid factor, a prognostic factor for worse disease outcome, and the strong expression by these cells of components of the Jak/STAT transcription factor pathway suggest a potential therapeutic target for the treatment of RA.

Anakinra: an inhibitor of IL-1 for the treatment of rheumatoid arthritis

Anakinra (Amgen, Inc.) is a specific receptor antagonist of IL-1 that differs from naturally occurring IL-1 receptor antagonist by the presence of a methionine group. Anakinra has been shown to be of benefit in patients with active rheumatoid arthritis, either when given alone or in combination with methotrexate, as assessed by improvement in clinical signs and symptoms, decreased radiographic progression and improvement in patient function, pain and fatigue, although it appears to be effective in fewer patients than anti-TNF agents. It has a favourable safety profile as demonstrated in clinical trials. The physician and patient must be cognizant of serious infectious episodes. Many of the rare side effects seen with TNF blockers, such as tuberculosis, other opportunistic infections, worsening of congestive heart failure and the development of demyelinating disease, have not been seen in patients treated with anakinra. Anakinra should not be given in combination with anti-TNF agents.

Accelerated Cutaneous Nodulosis During Infliximab Therapy in a Patient With Rheumatoid Arthritis

Up to one fourth of patients with rheumatoid arthritis (RA) may have extraarticular findings such as subcutaneous nodules. These are discrete subcutaneous granulomatous nodules located on extensor surfaces, especially of the elbows. Over the past 10 to 15 years, there have been reports of accelerated cutaneous nodulosis in patients receiving methotrexate therapy. Recently, antitumor necrosis factor alpha (anti-TNFalpha) biologic therapy has become commonplace in the management of RA, especially in methotrexate-resistant or toxic patients. There have been recent reports of accelerated nodulosis in patients with RA on etanercept. We describe what we believe is the first case of accelerated cutaneous nodulosis resulting from infliximab anti-TNFalpha therapy in a patient with RA. One year after the initiation of infliximab, with RA in remission, our patient noted the rapid development of rheumatoid nodules of both hands. A biopsy was characteristic of a rheumatoid nodule, revealing palisading granulomas and fibrinoid necrosis.

Factors regulating osteoclast formation in human tissues adjacent to peri-implant bone loss: expression of receptor activator NFkappaB, RANK ligand and osteoprotegerin

Aseptic bone loss adjacent to orthopedic joint implants is a common cause of joint implant failure in humans. This study investigates the expression of key regulators of osteoclast formation, receptor activator NFkappaB (RANK), Receptor activator of NFkappaB ligand (RANKL) and osteoprotegerin (OPG), in the peri-implant tissues of patients with osteolysis compared with levels in synovial tissues from osteoarthritic and healthy subjects. Immunohistochemical studies demonstrated that significantly higher levels of RANKL protein (p<0.05) were found in the peri-implant tissues of patients with implant failure than in similar tissues from osteoarthritic and healthy subjects. In contrast, OPG protein levels were similar in all tissues. RANKL, expressed as mRNA and protein, was predominantly associated with cells containing wear particles. Dual labeling studies showed that the cells expressing RANKL protein were macrophages. In situ hybridization studies confirmed that mRNA encoding for these proteins is also expressed by cells in the peri-implant tissues. In addition, RANK mRNA was expressed in cells that contained wear particles. These findings show that abnormally high levels of RANKL are expressed in peri-implant tissues of patients with prosthetic loosening and that these abnormal levels of RANKL may significantly contribute to aseptic implant loosening.

Tumour necrosis factor alpha independent disease mechanisms in rheumatoid arthritis: a histopathological study on the effect of infliximab on rheumatoid nodules

BACKGROUND

It has been suggested that the immunopathology of rheumatoid nodules parallels that of inflamed synovium in rheumatoid arthritis (RA).

OBJECTIVE

To analyse the effect of infliximab on the immunopathology of rheumatoid nodules in order to provide new insights into the relationship between synovial inflammation and rheumatoid nodules.

MATERIALS AND METHODS

Nodules were present at baseline in six patients with RA and after infliximab treatment in five patients, including paired nodules before and after treatment in three patients. In one patient, the nodule appeared during treatment. Paraffin sections were used for histological analysis. Frozen sections were stained by immunohistochemistry for cellular markers (CD3, CD4, CD8, CD16, CD20, CD68), blood vessels (CD146, vWF, alphavbeta3), and adhesion molecules (E-selectin, VCAM-1, ICAM-1).

RESULTS

No manifest immunopathological differences were found between the nodules before and after infliximab treatment. All nodules depicted the classical structure with a central necrotic zone, surrounding the palisade layer, and an outer connective tissue zone. Immunohistochemistry showed the presence of CD68+ and CD16+ macrophages in the palisade and the connective tissue zone, as well as a small number of CD3+, CD4+ T lymphocytes in the perivascular areas. Small vessels were seen in the connective tissue and were sometimes positive for the neovascularisation marker alphavbeta3. They expressed no VCAM-1, E-selectin weakly, but ICAM-1 strongly. ICAM-1 was also strongly expressed on palisade cells.

CONCLUSIONS

Despite an improvement of articular symptoms, infliximab treatment had no distinct effect on the histopathology of rheumatoid nodules, suggesting that different pathogenetic mechanisms mediate the two disease manifestations in RA.

Receptor activator NF kappaB ligand (RANKL) and osteoprotegerin (OPG) protein expression in periodontitis

OBJECTIVES AND BACKGROUND

This study investigated the expression of key mediators that regulate differentiation of osteoclasts, receptor activator of nuclear factor kappaB ligand (RANKL), and its natural inhibitor, osteoprotegerin (OPG), in periodontitis. We aimed to compare the levels of the RANKL and OPG in the granulomatous tissue adjacent to areas of alveolar bone loss from patients with periodontitis to that present in tissue from patients without periodontitis. In addition, we aimed to determine the types of cells expressing these factors in these tissues and to demonstrate the expression of the osteoclastic markers, RANK and tartrate-resistant acid phosphatase (TRAP), in periodontitis.

MATERIALS AND METHODS

Frozen biopsy specimens were analysed using specific monoclonal antibodies and were evaluated by semiquantitative analysis and digital image analysis to compare levels of RANKL and OPG protein expression. Double labelling of frozen sections with antibodies to different cell lineage specific markers was used to determine the types of cells expressing these proteins. In situ hybridization was used to detect cells expressing RANK mRNA.

RESULTS

Semiquantitative image analysis demonstrated that significantly higher levels of RANKL protein (P < 0.05) were expressed in the periodontitis tissue. Conversely, OPG protein was significantly lower (P < 0.05) in the periodontitis tissues. RANKL protein was associated with lymphocytes and macrophages. OPG protein was associated with endothelial cells in both tissues. Many leukocytes expressing RANK mRNA and TRAP were observed in periodontitis tissues.

CONCLUSION

The change in the levels of these key regulators of osteoclast differentiation may play a major role in the bone loss seen in periodontitis.

Cytokine profile of the rheumatoid nodule suggests that it is a Th1 granuloma

OBJECTIVE

To define the cytokine profile within rheumatoid subcutaneous nodules, and to determine whether the destructive inflammatory process in this lesion displays features of a lymphocyte-driven Th1 or Th2 granuloma.

METHODS

Subcutaneous nodules excised from 10 patients with rheumatoid arthritis were examined. Transcripts for interleukin 1beta (IL-1beta) IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, IL-15, IL-18, and for tumor necrosis factor alpha (TNFalpha) and interferon-gamma (IFNgamma) were detected by reverse transcription-polymerase chain reaction of extracted RNA.

RESULTS

Nine of 10 nodules contained transcripts for IFNgamma. We observed no evidence for the expression of IL-2, IL-4, or IL-5 among the lymphokine genes analyzed. Transcripts for TNFalpha, IL-1beta, IL-10, IL-15, and IL-18 were present in all 10 nodules. Transcripts for IL-12 were present in all but one nodule. Expression of IL-13 messenger RNA was observed in only 5 nodules.

CONCLUSION

The cytokine profile within the rheumatoid nodule (i.e., presence of IFNgamma but not IL-2, and prominent expression of IL-1beta and TNFalpha together with IL-12, IL-18, IL-15, and IL-10) is similar to the profile of cytokines in the synovial lesion of rheumatoid arthritis, which is generally accepted as being attributable to a Th1-mediated inflammatory mechanism. Our results suggest that damage to affected synovial membrane or subcutaneous tissue is caused by the same inflammatory mechanisms, and that the nodule is a Th1 granuloma.

Receptor activator NF-kappaB ligand (RANKL) expression in synovial tissue from patients with rheumatoid arthritis, spondyloarthropathy, osteoarthritis, and from normal patients: semiquantitative and quantitative analysis

OBJECTIVES

To compare receptor activator of NF-kappaB ligand (RANKL) production in the synovial tissue from patients with active rheumatoid arthritis (RA), inactive RA, spondyloarthropathies (SpA), osteoarthritis, and from normal subjects. In addition, to establish the cell lineages expressing RANKL in these tissues.

METHODS

Immunohistological analysis of frozen synovial tissue biopsy specimens was performed using a monoclonal antibody (mAb) to detect RANKL. Sections were evaluated by computer assisted image analysis and semiquantitative analysis to compare RANKL expression between groups. Dual and sequential labelling with mAb RANKL and cell lineage specific monoclonal antibodies were used to determine the types of cells expressing RANKL.

RESULTS

Higher levels of RANKL were expressed in tissues from patients with active RA and SpA than in tissues from patients with inactive RA, osteoarthritis, and from normal subjects. RANKL protein was associated with CD3 antigen-positive lymphocytes and some macrophages. RANKL was predominantly associated with activated, memory T cells (CD45Ro positive cells) in patients with active RA and spondyloarthropathy (SpA).

CONCLUSIONS

The highest levels of RANKL were detected in patients with RA with active synovitis and in some patients with SpA. An increase in RANKL in the inflamed joint of patients with RA, produced by infiltrating activated T cells and macrophages, is likely to be an important cause of joint erosions in RA.

Investigation of the cellular uptake of E-Selectin-targeted immunoliposomes by activated human endothelial cells

In the present study the cellular uptake of targeted immunoliposomes by interleukin-1 activated human endothelial cells has been analysed by several spectroscopical and microscopical fluorescence techniques. Previous in vitro experiments demonstrated that the targeting of immunoliposomes to vascular selectins is a potential way for a selective drug delivery at inflammatory sites. In attempts to further adapt the targeting experiments to physiological conditions, we demonstrate that E-Selectin-directed immunoliposomes are able to bind their target cells under the simulated shear force conditions of capillary blood flow cumulatively for up to 18 h. In order to consequently follow the fate of liposomes after target binding, we analysed the route and degree of liposome internalization of the cells concentrating on cell activation state or various liposomal parameters, e.g., sterical stabilization, type of antibody or antibody coupling strategy. The use of NBD-labelled liposomes and subsequent fluorescence quenching outside the cells with dithionite show that circa 25% of the targeted immunoliposomes were internalized. According to inhibition experiments with agents that interfered with the endocytotic pathway, we found out that the major mechanism of liposome entry is endocytic. The entry involves, at least in part, receptor-mediated endocytosis via E-Selectin, a liposome accumulation in the endosomes and their acidification was proved by pyranine spectroscopic results. Furthermore, microscopical investigations demonstrate that also a fusion of liposomes with the cell membrane occurs followed by a release of entrapped calcein into the cytoplasm. These observations gain insight into the behaviour of E-Selectin-targeted immunoliposomes and indicate that these immunoliposomes have great potential to be used as drug carriers for intracellular drug delivery at inflammatory sites.

Familial lupus erythematosus. Clinical and immunologic features of 125 multiplex families

Evidence for a genetic susceptibility to systemic lupus erythematosus (SLE) in humans is based on the high concordance rate observed in identical twins and on the relatively high incidence of familial cases. Although recent genetic studies have lead to significant advances in the identification of new susceptibility genes in SLE, no large clinico-pathologic study of familial SLE has been reported to date. In the present study, we describe the main clinical and immunologic features of 125 lupus multiplex families including at least 2 cases of SLE and/or discoid lupus erythematosus (DLE), recruited through a French national survey starting in July 1997. Medical records of all affected members were reviewed by the same investigator, all available family members were interviewed using the same standardized procedure, and blood was drawn for autoantibodies typing. Clinical and immunologic features of 90 probands from multiplex SLE families were compared with those of 100 sporadic SLE patients sharing the same French Caucasian origin. The 125 lupus multiplex families included 282 affected members (2.3 patients per family); of the 125 families, 96 were of French Caucasian origin. One hundred multiplex families included 2 affected relatives, while 25 included 3 or more affected individuals. The relationship between affected members was sibs (45%), parent-offspring (31%), and second-degree (24%). An autosomal dominant mode of inheritance was strongly suggested in 1 extended pedigree with 6 clinically affected members, and a recessive pattern was suspected in 5 other families. No obvious mode of inheritance could be suspected in most of the remainder. Among French Caucasians, sex ratio, mean age at onset, and clinical and biologic SLE-related manifestations were not significantly different in multiplex compared with sporadic SLE cases. The analysis of these 125 multiplex families suggests a genetic heterogeneity that should be considered for ongoing genomic screening.

The development of clinical signs of rheumatoid synovial inflammation is associated with increased synthesis of the chemokine CXCL8 (interleukin-8)

Paired synovial tissue samples were obtained from both clinically uninvolved (CU) and clinically involved (CI) knee joints of eight rheumatoid arthritis (RA) patients. In addition, biopsies were taken from five control subjects. We observed the expression of the chemokines CXCL8, CXCL9, CXCL10, CCL2 and CCL4 in CI and CU joints of RA patients. In particular, CXCL8 protein levels were specifically increased in CI joints compared with CU joints, which was confirmed by immunohistochemistry and in situ hybridization.

Fcgamma receptor type IIIA is associated with rheumatoid arthritis in two distinct ethnic groups

OBJECTIVE

To investigate a possible association between a functional polymorphism in the intermediate-affinity receptor for IgG called Fc-gamma receptor type IIIA (FcgammaRIIIA [CD16]) and rheumatoid arthritis (RA).

METHODS

This was an allelic association study in which a single nucleotide polymorphism in FcgammaRIIIA was examined as a susceptibility and/or severity factor for RA. The FcgammaRIIIA-158V/F polymorphism was genotyped by direct sequencing in 2 well-characterized ethnic groups, UK Caucasians (141 RA patients and 124 controls) and North Indians and Pakistanis (108 RA patients and 113 controls).

RESULTS

The FcgammaRIIIA-158V/F polymorphism was associated with RA in both ethnic groups (P = 0.028 for UK Caucasians, P = 0.050 for North Indians and Pakistanis, and P = 0.003 for both groups combined). FcgammaRIIIA-158VF and -158W individuals had an increased risk of developing RA in both populations (UK Caucasians odds ratio [OR] 1.6, P = 0.050; North Indians and Pakistanis OR 1.9, P = 0.023; and combined groups OR 1.7, P = 0.003). In the UK Caucasian group, the highest risk was for nodular RA, a more severe disease subset, associated with homozygosity for the FcgammaRIIIA-158V allele (OR 4.4, P = 0.004). There was also evidence for an interaction between the RA-associated HLA-DRB1 allele and the presence of at least 1 FcgammaRIIIA-158V allele in predicting susceptibility to RA (OR 5.5, P = 0.000).

CONCLUSION

We have demonstrated that the FcgammaRIIIA-158V/F polymorphism is a susceptibility and/or severity marker for RA in 2 distinct ethnic groups. This finding may ultimately provide additional insights into the pathogenesis of RA and other autoantibody/immune complex-driven autoimmune diseases.

Quantification of the cell infiltrate in synovial tissue by digital image analysis

OBJECTIVE

The experience with digital image analysis (DIA) in the assessment of synovial inflammation is limited. In this study we compared DIA with two currently applied methods for the evaluation of the synovium.

METHODS

Synovial tissue (ST) specimens were obtained by arthroscopy from knee joints of rheumatoid arthritis (RA) patients with variable disease expression and in control subjects. CD68+ macrophages and CD3+ T-cells were detected by immunohistochemical staining using two different labelling techniques. The labelled ST sections were quantified using three different analysis techniques: manual cell counting (MC), semi-quantitative analysis (SQA) and DIA.

RESULTS

We observed strongly positive correlations between the three methods when examining T-cell infiltration: between MC and SQA: sigma=0.91 (P<0. 0001), between MC and DIA: sigma=0.95 (P<0.0001), and between SQA and DIA: sigma=0.83 (P<0.0001). Similarly, for the analysis of synovial intimal macrophages, positive correlations were noted between MC and SQA (sigma=0.62; P=0.002), MC and DIA (sigma=0.56; P<0.01), and SQA and DIA (sigma=0.79; P<0.0001). Finally, the analysis of synovial sublining macrophages revealed positive correlations between MC and SQA (sigma=0.95; P<0.0001), MC and DIA (sigma=0.64; P=0.001) and SQA and DIA (sigma=0.69; P<0.0001).

CONCLUSION

These three different methods generated similar results. DIA offers the opportunity of a reliable and time-efficient analysis of the synovial infiltrate.