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

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.

Rheumatoid nodules: evaluation of the therapeutic response to intralesional fluorouracil and triamcinolone

Rheumatoid nodules are the most common extra-articular manifestation of rheumatoid arthritis and are present in around 20-25% of patients. Their etiology is unknown and although the nodules may undergo spontaneous remission during the treatment of rheumatoid arthritis, they usually constitute a therapeutic challenge. The present paper describes a case in which the response of rheumatoid nodules was evaluated by ultrasound following infiltration of triamcinolone acetonide and 5-fluorouracil.

Cutaneous nodules in patients with rheumatoid arthritis: a case report and review of literatures

We report a case of 57-year-old Japanese woman with an overlap syndrome of both rheumatoid arthritis (RA) and autoimmune hepatitis, who developed multiple skin nodules. An extensive biopsies of the nodules revealed rheumatoid neutrophilic dermatitis, showing panniculitis without vasculitis, combining with granulomatous formation histopathologically. Since cutaneous nodules in patients with RA are very complex, differential diagnosis should be done according to disease activities, medications used, and pathological findings. We suggest that the differences in histopathological findings of cutaneous nodules in patients with RA depend on their immunological conditions based on disease activities including therapeutic effects.

Pulmonary complications of tumor necrosis factor-targeted therapy

Tumor necrosis factor (TNF)-targeted therapies are increasingly being prescribed in the management of a variety of inflammatory and autoimmune diseases. The use of this class of medications also pose risks of developing an assortment of pulmonary side effects including infections (TB, bacterial, and fungal infections), pulmonary nodules, chronic pneumonitis/fibrosis, SLE-like reactions, vasculitis, and exacerbations of underlying lung disease. In addition to surveillance for tuberculosis prior to initiation of TNF-targeted therapy, a high level of vigilance should be maintained during administration for infectious and non-infectious complications, even years into a patient's course. The available evidence argues for caution in using these agents in patients with pre-existing lung disease and heightened suspicion of accelerated nodule formation in those with pre-existing rheumatoid nodules. Management centers on excluding infection, identifying confounders (especially methotrexate or pre-existing lung disease), and promptly discontinuing TNF-targeted therapy. In some instances, invasive procedures (e.g. bronchoscopy or VATS lung biopsy) will be necessary to establish the proper diagnosis, and the administration of steroids may be beneficial.

Colocalization of C4d deposits/CD68+ macrophages in rheumatoid nodule and granuloma annulare: immunohistochemical evidence of a complement-mediated mechanism in fibrinoid necrosis

Rheumatoid nodule (RN) represents a palisading granuloma with central fibrinoid necrosis, which is not only a classical manifestation of rheumatoid arthritis (RA) and part of the American College of Rheumatology (ACR)-criteria, but also is its diagnostic hallmark. The pathogenesis of RN is still not fully understood. At present, only data on serum analyses indicating a complement-mediated pathogenesis in the development of RA are available. Equivalent examinations for RN have not yet been performed. Granuloma annulare (GA) represents another type of palisading granuloma. A special subtype of GA, subcutaneous GA (SGA), is an important differential diagnosis to RN. Therefore, our aim was to examine RN and SGA regarding the complement deposition (C4d) by immunohistochemical means. All RN and GA were stained by hematoxylin/eosin and different special stains. In addition, all specimens were stained immunohistochemically with antibodies against CD68. Five GA and five RN were analyzed immunohistochemically with antibodies against C4d and CD68, and evaluated using single- and doublestaining immunohistochemistry. All RN and GA displayed depositions of C4d within their central necroses and between the surrounding palisading macrophages. Most importantly, C4d/CD68 double staining was visible in the palisading macrophages next to the necroses, while macrophages in the periphery were negative for C4d but positive for CD68. The main difference between RN and GA was a quantitative phenomenon with less positively reacting macrophages in a more incomplete palisade in GA. The positive reactions of all central necroses to C4d and colocalization of CD68 and C4d suggest that a complement-mediated mechanism may be operative in the formation of fibrinoid necrosis. This mechanism may be involved in any form of "fibrinoid necrosis", since no different patterns of C4d/CD68 expression could be observed in GA. This may explain why RG/GA are not distinguishable morphologically.

[Differential diagnosis of rheumatoid granuloma]

Rheumatoid granuloma (RG) is histomorphologically defined as a subcutaneous palisading granuloma with central fibrinoid necrosis. Clinically, it presents as a nodule typically localized at pressure points near the joints. From the rheumatic pathological point of view, the main diagnostic challenge is the differentiation of RG from granuloma anulare, especially if clinical information on the site of removal, known diseases, duration of illness, medication and existing American College of Rheumatology (ACR) criteria are missing. Other granulomatous lesions, such as mycobacterial infections, foreign body granulomas, necrobiosis lipoidica or sarcoidosis, can be differentiated from RG by histopathological criteria or by additional examinations such as pathogen specification or PCR. An immunohistochemical marker for the differential diagnosis of granulomas is not yet available. Diagnosis is based on conventional H-E staining, alcian blue-PAS staining, polarizing analysis or PCR. In the following article, the most important granulomatous entities in the differential diagnosis of RG are introduced and the main diagnostic characteristics are discussed.

Clinical efficacy of infliximab plus methotrexate in DMARD naive and DMARD refractory rheumatoid arthritis is associated with decreased synovial expression of TNF alpha and IL18 but not CXCL12

BACKGROUND

Tumour necrosis alpha (TNF alpha) blocking agents lead to pronounced clinical effects and reduced synovial infiltrate in rheumatoid arthritis. Laboratory and clinical studies suggest that TNF alpha independent pathways play a role in the disease.

OBJECTIVES

To evaluate the immunopathological effects of combination therapy on rheumatoid synovial tissue in order to identify TNF alpha independent mechanisms.

METHODS

12 rheumatoid patients, including four DMARD (disease modifying antirheumatic drug) naive patients with early disease, were studied for the effect of combination therapy with infliximab and methotrexate on the synovial infiltrate. Biopsies and clinical assessments (DAS28) were carried out before the first and after the third infusion of infliximab. Synovial inflammation was scored semiquantitatively. Co-expression of CD38(+) cells was studied by an immunofluorescent double labelling technique.

RESULTS

Marked clinical responses were associated with a global reduction in the synovial infiltrate and expression of cytokines, notably interleukin 18 and TNF alpha, but low grade disease activity persisted. There was no effect on the expression of CXC chemokine ligand (CXCL12), and germinal centre-like structures were still detectable in synovial tissue in two patients after treatment. CD38(+) activated T cells were more resistant to treatment than CD38(+) plasma cells. No differences in clinical response or effects on synovial infiltrate were observed between DMARD refractory and DMARD naive patients.

CONCLUSIONS

Persistent expression of CXCL12 and incomplete resolution of lymphocytic infiltrates after infliximab plus methotrexate indicates that TNF alpha independent mechanisms are operative in rheumatoid arthritis. This may contribute to low grade disease activity, even in DMARD naive patients with early disease.

How to diagnose and treat secondary forms of vasculitis

Vasculitis is considered to be secondary when it arises either in the context of a pre-existing connective tissue disease, as a result of direct infection with a limited range of organisms, especially viruses, or when it arises in response to exposure to a number of medications. Rheumatoid vasculitis is probably the most widely recognised form of secondary vasculitis, and in this article we review the incidence, clinical features and management of this condition. Infections may either trigger or cause some types of vasculitis. Drug therapy is a common cause of limited forms of vasculitis and may enhance our understanding of the mechanism of these diseases. The premature development of atherosclerosis in patients with existing connective tissue diseases or indeed primary vasculitis has been recognised for some time, and the underlying mechanisms are currently being studied. An appreciation of the complex and varied pathophysiology of secondary vasculitis may further our understanding of primary vasculitis.

Structure-modifying capacity of anti-tumour necrosis factor-alpha therapy in ankylosing spondylitis

Spondylarthropathies (SpA) present mainly with spondylitis, pauciarticular peripheral arthritis and enthesopathy. Ankylosing spondylitis (AS) is the prototype disease in this concept. Other entities include reactive arthritis, arthritis in patients with inflammatory bowel disease, some forms of psoriatic arthritis and undifferentiated SpA. NSAIDs are the classical cornerstone of medical therapy in patients with SpA. The effect of these drugs on disease progression, more specifically the ankylosis, is uncertain. Sulfasalazine can be combined with NSAIDs, particularly if peripheral arthritis symptoms persist. However, this combination therapy is not effective for the spondylitis symptoms. Indeed, AS is one of the rheumatic diseases for which no real disease-modifying antirheumatic treatment is available. Challenges in chronic autoimmune arthritis have changed dramatically, especially since biotechnological compounds became available. These compounds allow for a specific intervention in the immune cascade underlying the disease. Tumour necrosis factor (TNF)-alpha antagonists (monoclonal antibodies such as infliximab, or soluble receptors such as etanercept) are the first representative drugs in this category. Open-label studies have shown the efficacy of these new targeted drugs, which has been confirmed by controlled studies, at least in the short term. Improvements in several clinical parameters, function, quality of life, biological parameters, histopathological synovial characteristics and magnetic resonance imaging, have all been observed. As a result of these favourable results, anti-TNFalpha therapy has been approved for the treatment of AS and should be considered for patients with severe axial symptoms and elevated serological markers of inflammatory activity who have responded inadequately to conventional nonsteroidal therapy. There is evidence that this new therapeutic approach has a disease- and even structure-modifying effect in SpA. In this context, structure modification should not only be seen as inhibition of bone and cartilage destruction but more broadly as modulation of tissue histology. Some questions remain unanswered, such as the long-term efficacy and safety of anti-TNFalpha therapy, the extent of structural benefit and the cost effectiveness. However, despite these concerns, anti-TNFalpha therapy represents a major therapeutic advancement in the treatment of AS.