Macrophage migration and maturation within rheumatoid nodules

[Pre-iliac tumor mass syndrome: An atypical rheumatoid nodule]

Rheumatoid arthritis (RA) is a polymorphous chronic inflammatory disease that is common in general population and is responsible for the occurrence of subcutaneous or visceral rheumatoid nodules. Their typical clinical presentations and localizations do not generally pose any diagnostic or therapeutic problem. We report here an atypical fistulized presentation of an unusual iliac rheumatoid nodule in a 65-year-old female patient. The evolution was favorable without recurrence at 6 months after complete surgical resection and appropriate antibiotherapy.

Cutaneous Manifestations of Rheumatoid Arthritis: Diagnosis and Treatment

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disorder characterized by inflammatory arthritis and periarticular structural damage. Available evidence suggests that RA results from complex interactions between genetic susceptibility (e.g., HLA-DRB1), environmental factors (e.g., smoking), and immune dysregulation. Alongside joint-related symptoms, individuals with RA may also experience a wide array of skin issues, including the development of nodules, neutrophilic dermatoses, vasculitis, and vasculopathy. Treatment strategies for these manifestations vary but routinely involve corticosteroids, disease-modifying anti-rheumatic drugs, and biologics, with individualized approaches guided by disease severity. In this review, we provide comprehensive insights into the skin-related issues associated with RA, outlining their clinical characteristics and histopathological findings. Our aim is to facilitate early diagnosis and personalized treatment to improve the quality of life of affected individuals.

Natural Products for the Treatment of Autoimmune Arthritis: Their Mechanisms of Action, Targeted Delivery, and Interplay with the Host Microbiome

Rheumatoid arthritis (RA) is a chronic, debilitating illness characterized by painful swelling of the joints, inflammation of the synovial lining of the joints, and damage to cartilage and bone. Several anti-inflammatory and disease-modifying drugs are available for RA therapy. However, the prolonged use of these drugs is associated with severe side effects. Furthermore, these drugs are effective only in a proportion of RA patients. Hence, there is a need to search for new therapeutic agents that are effective yet safe. Interestingly, a variety of herbs and other natural products offer a vast resource for such anti-arthritic agents. We discuss here the basic features of RA pathogenesis; the commonly used animal models of RA; the mainstream drugs used for RA; the use of well-characterized natural products possessing anti-arthritic activity; the application of nanoparticles for efficient delivery of such products; and the interplay between dietary products and the host microbiome for maintenance of health and disease induction. We believe that with several advances in the past decade in the characterization and functional studies of natural products, the stage is set for widespread clinical testing and/or use of these products for the treatment of RA and other diseases.

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.

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.

Rheumatoid Nodule

Rheumatoid nodules are the most common extra-articular manifestation of rheumatoid arthritis. Dermatologist may be concerned with the diagnosis and management of rheumatoid nodules, although most patients will probably be under the care of a rheumatologist. This article focuses in clinical, pathogenic, diagnostic, and therapeutic aspects of rheumatoid nodules. Classic rheumatoid nodules commonly occur in genetically predisposed patients with severe, seropositive arthritis. However, they may appear in other clinical settings. Accelerated rheumatoid nodulosis, especially involving the hands, has been reported in patients receiving methotrexate, antitumor necrosis factor alpha biologic drugs or leflunomide therapy for rheumatoid arthritis. Rheumatoid nodulosis is characterized by multiple rheumatoid nodules, recurrent joint symptoms with minimal clinical or radiologic involvement, and a benign clinical course. Pseudorheumatoid nodules have been reported in healthy children. Although histologically almost indistinguishable from true rheumatoid nodules, some consider these lesions to be a form of deep granuloma annulare.

Rheumatoid arthritis: a review of the cutaneous manifestations

Rheumatoid arthritis is a chronic inflammatory arthritis with significant extra-articular manifestations. Of note are unique cutaneous manifestations that the dermatologist may encounter. This article will make the dermatologist more cognizant of these skin findings in patients with this systemic inflammatory disorder. It examines rheumatoid arthritis, focusing on the general nonspecific and disease-specific rheumatoid arthritic skin changes. Classic rheumatoid nodules, accelerated rheumatoid nodulosis, rheumatoid nodulosis, rheumatoid vasculitis, Felty syndrome, pyoderma gangrenosum, interstitial granulomatosus dermatitis with arthritis, palisaded neutrophilic and granulomatosis dermatitis, rheumatoid neutrophilic dermatitis, juvenile rheumatoid arthritis, and adult-onset Still disease are reviewed. Understanding the cutaneous expressions of rheumatoid arthritis may lead to early diagnosis, prompt treatment, and lower morbidity and mortality for the affected persons. Learning objective At the completion of this learning activity, participants should be able to describe rheumatoid arthritis in terms of its epidemiology, etiology, pathogenesis, and general and specific cutaneous manifestations.

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.

Macrophages in rheumatoid arthritis

The abundance and activation of macrophages in the inflamed synovial membrane/pannus significantly correlates with the severity of rheumatoid arthritis (RA). Although unlikely to be the 'initiators' of RA (if not as antigen-presenting cells in early disease), macrophages possess widespread pro-inflammatory, destructive, and remodeling capabilities that can critically contribute to acute and chronic disease. Also, activation of the monocytic lineage is not locally restricted, but extends to systemic parts of the mononuclear phagocyte system. Thus, selective counteraction of macrophage activation remains an efficacious approach to diminish local and systemic inflammation, as well as to prevent irreversible joint damage.

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

OBJECTIVE

To investigate the production of proinflammatory cytokines and expression of cell adhesion molecules in the rheumatoid nodule.

METHODS

Cytokine content (tumor necrosis factor alpha [TNFalpha], interleukin-1beta [IL-1beta], and IL-1 receptor antagonist [IL-1Ra]), at the messenger RNA (mRNA) and protein levels, and cell adhesion molecule expression were studied in 16 rheumatoid nodules and 6 synovial membranes.

RESULTS

Macrophages in the rheumatoid nodules contained TNFalpha, IL-1beta, and IL-1Ra mRNA and protein, particularly in perivascular cells of the stroma and in the palisading layer. All cell adhesion molecules studied were expressed in both the rheumatoid nodules and synovial membranes, with increased expression of E-selectin in the rheumatoid nodule compared with the synovial membrane, and with the absence of vascular cell adhesion molecule 1 expression on cells of the palisading layer in the rheumatoid nodule.

CONCLUSION

The presence of similar proinflammatory cytokines and cell adhesion molecules in the rheumatoid nodule and synovial membrane suggests that similar pathogenic processes result in the chronic inflammation and tissue destruction in these lesions.

A comparative phenotypical analysis of rheumatoid nodules and rheumatoid synovium with special reference to adhesion molecules and activation markers

OBJECTIVES

(1) To analyse the in situ expression of adhesion molecules in rheumatoid nodules. (2) To compare the endothelial expression of adhesion molecules in synovial tissue and subcutaneous nodules obtained from the same patients. (3) To compare the expression of adhesion molecules and activation markers on T cell lines from nodules and synovium.

METHODS

(1) Immunohistochemical analysis by APAAP technique of E selectin, CD44, ICAM-1, PECAM-1, and VCAM-1 was performed on 10 rheumatoid nodules from seven patients with rheumatoid arthritis (RA); nodules and synovium were simultaneously analysed from three patients. (2) T cell lines were generated from RA nodules (n = 7) and synovium (n = 7) by interleukin 2 expansion, and subsequently characterised by flow cytometry for surface expression of alpha E beta 7, alpha 4 beta 7, CD44, L selectin, LFA-1a, PECAM-1, and CD30.

RESULTS

(1) In rheumatoid nodules, the palisading layer strongly stains for ICAM-1 and PECAM-1, but less pronounced for CD44. VCAM-1 staining was usually negative. ICAM-1 is upregulated in the vessels surrounding the central zone of fibrinoid necrosis. The immunohistological picture in different nodules derived from the same patient was similar. (2) The endothelial expression of adhesion molecules is comparable in RA nodules and synovium on an individual level, except for E selectin, which is overexpressed in nodule endothelium. (3) T cell lines from nodules and synovium display similar adhesion molecule profiles. However, the expression of CD30, a T cell activation marker linked with Th2 subsets, is higher in nodules compared with synovium.

CONCLUSION

These data support a recirculation hypothesis of T cells between articular and extra-articular manifestations in RA, although the activation state of the T cells in each of these localisations may differ.

Adenosine A1 receptor promotion of multinucleated giant cell formation by human monocytes: a mechanism for methotrexate-induced nodulosis in rheumatoid arthritis

OBJECTIVE

To determine why methotrexate (MTX) exacerbates rheumatoid nodules in some patients, despite the effective suppression of synovial inflammation.

METHODS

Phorbol myristate acetate (PMA)-induced differentiation of monocytes into multinucleated giant cells was used as an in vitro model to study the effects of adenosine on nodulosis.

RESULTS

MTX at 200-2,000 nM or the adenosine A1 agonist N5-cyclopentyl adenosine (CPA) (10(-12) to 10(-9) M) or the A2 antagonist 3,7-dimethyl-1-propargylxanthine markedly enhanced giant cell formation, whereas the adenosine A1 antagonist 8-cyclopentyl-dipropylxanthine completely reversed these effects. PMA, CPA, and MTX induced adenosine release by cultured monocytes at concentrations consistent with those associated with predominantly A1 effects. Furthermore, surface expression of A1 receptors was found to remain unchanged on the differentiating cells throughout the culture period.

CONCLUSION

Agents that inhibit adenosine A1 receptors might be useful in the treatment of MTX-induced rheumatoid nodulosis, while still potentiating the A2-mediated antiinflammatory effects of MTX on synovitis.

Changes in the phenotype of monocytes/macrophages and expression of cytokine mRNA in peripheral blood and synovial fluid of patients with rheumatoid arthritis

Data from a previous study suggested that peripheral blood monocytes in patients with rheumatoid arthritis (RA) may be activated. Therefore, in this study we sought further evidence of 'presynovial' activation of monocytes. Our results show that phenotypic changes are demonstrable in peripheral blood monocytes in patients with RA, including increased expression of CR3 (CD11b/CD18) and FcRI (CD64). However, changes are most extensive in synovial monocytes/macrophages and especially for HLA-DR and intercellular adhesion molecule-1 (ICAM-1) (CD54). We conclude that monocyte/macrophage activation is most evident within the joint, and that 'presynovial' changes occur but are of limited extent.

Macrophage phenotype within simple ganglia

Immunohistological staining of the connective tissue stroma of simple ganglia using monoclonal antibodies demonstrated infiltrating mononuclear phagocytes. These cells were characterised by positive staining for the leukocyte common antigen, the monocyte associated CD14 phenotype and HLA-class II antigens. There was only occasional expression of an epitope associated with macrophage maturity, and of the iC3b receptor. No expression of the C3b receptor, the high affinity Fc receptor, the p150.95 adhesion molecule or the p8.14 molecule was observed. Polymorphonuclear leukocytes and lymphocytes were absent. The restricted epitope expression by the mononuclear phagocyte population of simple ganglia may be a reflection of the absence of other inflammatory cells and indicates that the micro-environment within inflammatory lesions such as subcutaneous rheumatoid nodules is very different to that present in ganglia.

Increased expression of p150,95 and CR3 leukocyte adhesion molecules by mononuclear phagocytes in rheumatoid synovial membranes. Comparison with osteoarthritic and normal synovial membranes

The expression of leukocyte adhesion molecules CR3 (CD11b) and p150,95 (CD11c) in synovial tissue was evaluated immunohistochemically. Although a significant proportion of synoviocytes in normal and osteoarthritic synovial membranes expressed the leukocyte common antigen and CR3, very few expressed the p150,95 molecule. In contrast, p150,95 was more evident in rheumatoid synovial membranes. Expression of this molecule was strongest in synovial membranes with a prominent macrophage infiltrate and accumulation of mononuclear phagocytes at the joint surface; p150,95 was also present on interdigitating cells in lymphoid collections. The patterns of expression suggest that these leukocyte adhesion molecules may be important in the diapedesis of mononuclear phagocytes into and through inflamed synovial membranes, as well as in cellular interactions within rheumatoid synovial membranes.

Immunological and immunohistochemical analysis of rheumatoid nodules

An attempt was made to examine the pathophysiology of the rheumatoid nodule. Significant amounts of interleukin 1-like activity and prostaglandin E2 were detected in the supernatants from in vitro organ cultures of rheumatoid nodule tissue. When fresh (but not old) rheumatoid nodules were minced and cultured in vitro prominent outgrowths of cells were observed. These cells expressed both HLA-DR and CD14 antigens but lacked conventional differentiation antigens for T cells and B cells, suggesting that they are of monocyte-macrophage origin. These data suggest that interleukin 1 and prostaglandin E2 may be deeply involved in the formation of rheumatoid nodules.

Comparison of phenotype expression by mononuclear phagocytes within subcutaneous gouty tophi and rheumatoid nodules

The mononuclear phagocyte infiltrate which occupies the gout tophus has been compared with that of the subcutaneous rheumatoid nodule. In the gout tophus, macrophage migration appears to be at a relatively low level and effectively terminates once these cells have been recruited into the corona. In the nodule the evidence suggests that both macrophage and granulocyte populations continuously migrate towards, and are progressively incorporated into, the necrotic centres. These observations indicate that chemotactic activity in rheumatoid nodules is at a higher level than in gout tophi, or that the rheumatoid mononuclear phagocyte is more responsive to such stimuli.