Hypereosinophilic Syndrome with Endomyocarditis: Identification by Next-Generation Sequencing of the JAK2-V617F Mutation

Hypereosinophilic syndrome requires a peripheral absolute eosinophil count of ≥1.5 × 109 /L with clinical manifestations attributable to peripheral or tissue hypereosinophilia. Clinical manifestations can vary greatly, with the majority of patients relatively asymptomatic and the eosinophilia detected incidentally. However, in a minority of hypereosinophilia cases, they may present with severe lifethreatening organ dysfunction affecting skin, lung, heart, gastrointestinal tract, and nervous system. A case of hypereosinophilia with potentially life-threatening cardiovascular involvement is discussed. Initial laboratory investigations showed an elevated white blood cell count with 60% eosinophils. An endomyocardial biopsy revealed eosinophilic endomyocarditis with granuloma, rare giant cells, and no vasculitis, microorganisms, or malignancy. Her presentation met the criteria for either hypereosinophilic syndrome or eosinophilic granulomatosis with polyangitis. Molecular genetic analysis was negative for myelodysplastic syndrome panel/ Platelet Derived Growth Factor Receptor Beta (PDGFRB) (5q32)/Fibroblast Growth Factor Receptor 1 (FGFR1) Fluorescence In Situ Hybridization (FISH), Feline McDonough Sarcoma-related Tyrosine Kinase 3 (FLT3) Internal Tandem Duplication (ITD) mutation, Calregulin (CALR) exon 9 mutation, and T-cell gene rearrangement/polymerase chain reaction. Bone marrow biopsy revealed a mildly hypocellular marrow with multilineage hematopoiesis,+ megakaryocyte dysplasia, and focal eosinophilia. No excess blasts, no monotypic B-cell population, and no discrete pan T-cell aberrancies were found. Bone marrow cytogenetic studies showed a normal signal pattern for myeloproliferative neoplasms panel/Sec1 Family Domain Containing 2 (SCFD2)-Ligand of Numb Protein-X (LNX)-Platelet-derived Growth Factor Receptor Alpha (PDGFRA) fluorescence in situ hybridization with a normal karyotype of 46 XX. Next-generation sequencing, however, was positive for the JAK2-V617F mutation, a rare molecular abnormality in hypereosinophilic syndrome. The prevalence ranges from approximately 0% to 4%. The JAK2 point mutation leads to aberrant tyrosine phosphorylation and increased cytokine activation. The case demonstrates the complexity and challenging nature of advanced diagnostic opportunities in hypereosinophilia and the potential use, in select subsets, of targeted treatments such as tyrosine kinase inhibitors.

Microscopic polyangiitis with dermatomyositis

Dermatomyositis is a rare autoimmune disease with a heterogeneous presentation that often has multiple extramuscular manifestations, although it does not typically involve the renal function. A 62-year-old female presented with proximal muscle weakness and rashes, which are classic symptoms of dermatomyositis without creatine kinase (CK) elevation. Initial serologic evaluation revealed a positive p-ANCA, although she did not develop renal failure for several months, at which point renal biopsy findings were consistent with microscopic polyangiitis. The patient was initially treated with cyclophosphamide, maintained with rituximab, and has been in remission for more than 2 years. Dermatomyositis and microscopic polyangiitis are both uncommon diseases, but are concomitantly present in this patient. A positive p-ANCA and development of renal insufficiency should be promptly evaluated in dermatomyositis patients.

Biosimilars in rheumatic diseases: structural and functional variability that may impact clinical and regulatory decisions

Biologics as therapeutic interventions for human disease represent both a distinctly modern novelty and an echo of ancient, or at least old, medical practice. The similarity lies in the sense that in both the synthetic effort occurs in living organisms (an extract of a plant, animal tissue, or a cell culture) while the difference is apparent in the bioengineering required in modern methods and the corresponding flexibility to customize the therapeutic product. Although the concept of looking to living systems as a source of medically useful compounds either for research or for actual patient care has never vanished, the development of biochemistry and advances in medicinal chemistry made production by total synthesis the standard for a safe, reliable, and commercial drug production at sufficient scale. In this interval was where much of the modern apparatus for approving medical therapies came to be developed, and as such, the most proper extension of the regulatory regime to modern biologics is not entirely obvious. In particular, the notion of generics for off-patent conventional pharmaceuticals and their role in the marketplace with respect to increasing the accessibility of treatment is not congruent with the relationship between what are known as biosimilars and off-patent originating biologics. In this article, we review elements of the scientific basis for challenges in the production, use, and regulation of biosimilars. In light of these advances, we propose suggestions to modify constraints on biosimilar regulations in the interest of patient care and access to therapies.

Suppression of collagen-induced arthritis with a serine proteinase inhibitor (serpin) derived from myxoma virus

Many viruses encode virulence factors to facilitate their own survival by modulating a host's inflammatory response. One of these factors, secreted from cells infected with myxoma virus, is the serine proteinase inhibitor (serpin) Serp-1. Because Serp-1 had demonstrated anti-inflammatory properties in arterial injury models and viral infections, it was cloned and evaluated for therapeutic efficacy in collagen-induced arthritis (CIA). Clinical severity was significantly lower in the Serp-1 protocols (p<0.0001) and blinded radiographs indicated that the Serp-1 group had significantly less erosions than the controls (p<0.01). Delayed-type hypersensitivity was lower in the Serp-1 group but antibody titers to type II collagen were not significantly altered. Recipients had minimal histopathologic synovial changes and did not develop neutralizing antibodies to Serp-1. These results indicate that Serp-1 impedes the pathogenesis of CIA and suggests that the therapeutic potential of serine proteinase inhibitors in inflammatory joint diseases, such as rheumatoid arthritis, should be investigated further.

Advances in rheumatoid arthritis animal models

Experimental models of rheumatoid arthritis have contributed immensely to our understanding of the pathogenesis as well as the treatment of this debilitating autoimmune disease. Significant progress has been made in the past few years in defining the role of newer cytokines and regulatory T cells, of inflammation-mediated bone and cartilage damage, and of the cholinergic anti-inflammatory pathway in modulating the disease process in arthritis. Furthermore, new therapeutic targets, including specific tyrosine kinases and proteasome subunits, have been explored. These advances offer renewed optimism for continued improvements in the management of rheumatoid arthritis.

A 24-week, randomized, double-blind, placebo-controlled, parallel group study of the efficacy of oral SCIO-469, a p38 mitogen-activated protein kinase inhibitor, in patients with active rheumatoid arthritis

OBJECTIVE

To evaluate the efficacy, safety, and tolerability of oral SCIO-469, a p38 MAPK inhibitor that blocks tumor necrosis factor-α, interleukin-1ß, and cyclooxygenase-2 synthesis in patients with active rheumatoid arthritis (RA).

METHODS

Patients were randomized to receive SCIO-469 at either 30 or 60 mg three times daily in an immediate-release (IR) formulation or at 100 mg once daily in an extended-release (ER) formulation, or placebo for 24 weeks. The primary endpoint was American College of Rheumatology (ACR)20 response at Week 12. Safety was monitored through Week 26.

RESULTS

Overall, 302 patients were randomized: 76 to placebo, 75 to 30 mg IR, 73 to 60 mg IR, and 78 to 100 mg ER. There were no significant differences in ACR20 responses at Week 12 between SCIO-469 and placebo. Declines in C-reactive protein and erythrocyte sedimentation rate during early treatment did not persist to Week 12 and were not a consequence of decreased SCIO-469 plasma levels. The 60 mg IR regimen showed a dose-limiting toxicity manifested by elevations in alanine aminotransferase. Adverse events were common in all groups (79.7% and 86.7% through 13 and 26 weeks, respectively). Twenty-one patients reported 28 serious adverse events (SAE). SAE were more common with IR SCIO-469 than with placebo (7% vs 4%) but were not reported with ER SCIO-469.

CONCLUSION

In all regimens tested, SCIO-469 showed no greater efficacy compared to placebo in patients with RA. The transient effect of SCIO-469 on acute-phase reactants suggests a complex role of p38 MAPK in inflammation.

Systemic sclerosis: bilateral improvement of Raynaud's phenomenon with unilateral digital sympathectomy

OBJECTIVES

To demonstrate that unilateral digital sympathectomy, in patients with Raynaud's phenomenon (RP) and systemic sclerosis (SSc), may result in bilateral resolution of RP and digital ulcerations.

METHODS

We report a case of SSc and RP that had bilateral benefits from unilateral digital sympathectomy. A computer-assisted Medline/PubMed search of the medical literature was performed for 1960 through June 2009 using the keywords sympathectomy, Raynaud's phenomenon, systemic sclerosis, CREST, and digital ulcers. These searches were also combined with text words unilateral, ipsilateral, bilateral, digital sympathectomy, selective sympathectomy, autonomic nervous system, hyperhidrosis, etiology, pathogenesis, hypothesis, and treatment. Only pertinent literature, primarily in the English language, was included.

RESULTS

The majority of patients with SSc have RP and many suffer from digital ulcerations. Medical and behavioral management may have limited benefit and surgical intervention can be considered in recalcitrant cases, although efficacy data are sparse. We describe a man with limited SSc who underwent unilateral digital sympathectomy but manifested bilateral benefit. To our knowledge, this is the first published report of contralateral response with this procedure. The patient ultimately demonstrated these digital benefits when stressed with extreme cold and hypoxia while mountaineering. Despite the onset of high-altitude sickness and cerebral edema, his fingers remained unaffected while other mountaineers sustained severe frostbite or died of hypothermia.

CONCLUSIONS

Selective unilateral sympathectomy in SSc, for RP with digital ulcerations, can result in bilateral benefits despite intense challenge with cold and hypoxia.

Modulation of p38 MAPK activity in regulatory T cells after tolerance with anti-DNA Ig peptide in (NZB x NZW)F1 lupus mice

Treatment of (NZB x NZW)F(1) (NZB/W) lupus-prone mice with the anti-DNA Ig-based peptide pConsensus prolongs the survival of treated animals and effectively delays the appearance of autoantibodies and glomerulonephritis. We have previously shown that part of these protective effects associated with the induction of CD4(+)CD25(+)Foxp3(+) regulatory T cells (Tregs) that suppressed autoantibody responses. Because the effects of pConsensus appeared secondary to qualitative rather than quantitative changes in Tregs, we investigated the molecular events induced by tolerance in Tregs and found that signaling pathways including ZAP70, p27, STAT1, STAT3, STAT6, SAPK, ERK, and JNK were not significantly affected. However, peptide tolerization affected in Tregs the activity of the MAPK p38, whose phosphorylation was reduced by tolerance. The pharmacologic inhibition of p38 with the pyridinyl imidazole inhibitor SB203580 in naive NZB/W mice reproduced in vivo the effects of peptide-induced tolerance and protected mice from lupus-like disease. Transfer experiments confirmed the role of p38 in Tregs on disease activity in the NZB/W mice. These data indicate that the modulation of p38 activity in lupus Tregs can significantly influence the disease activity.

Angiogenesis inhibitors for the treatment of chronic autoimmune inflammatory arthritis

Angiogenesis, the formation of new blood vessels, is closely linked with both the initiation and progression of rheumatoid arthritis (RA). Rheumatoid joints contain elevated levels of proangiogenic molecules, such as VEGF, basic FGF, hypoxia-inducible factor 1 and angiopoietins. Increased angiogenesis is also associated with malignancies and proliferative retinopathies, and targeting this process therapeutically has proven beneficial in treating several of these diseases including colorectal, kidney and lung cancer. Adapting such a therapeutic strategy to the treatment of RA may prove beneficial, as data from preclinical studies have demonstrated that angiogenesis inhibitors reduce pannus formation, inflammation and joint erosion. New therapies that inhibit angiogenesis by blocking VEGFR tyrosine kinase signaling, integrin interactions, microtubule formation and endothelial cell proliferation may be applicable to the treatment of RA. There are several angiogenesis inhibitors that have been approved by the FDA or are currently being assessed in clinical trials which are safe for use in humans, although their effects on RA remain untested. This review discusses the potential of angiogenesis inhibition in the context of treating RA.

Involution of collagen-induced arthritis with an angiogenesis inhibitor, PPI-2458

Pannus formation, in both rheumatoid arthritis (RA) and collagen-induced arthritis (CIA), is angiogenesis-dependent. PPI-2458 [(1R)-1-carbamoyl-2-methyl]-carbamic acid-(3R,3S,5S, 6R)-5-methoxy-4-[(2R,3R)-2-methyl-3-(3-methyl-but-2-enyl)oxiranyl]-1-oxaspiro(2*5)oct-6-yl ester], a new fumagillin derivative known to inhibit methionine aminopeptidase 2 (MetAP-2) and endothelial proliferation at the late G(1) phase, was evaluated in CIA rats to study its potential to involute synovitis. Arthritic syngeneic LOU rats received either a vehicle control or various dosages of oral, intravenous, or subcutaneous PPI-2458. Plasma samples were analyzed to determine a pharmacokinetic profile of PPI-2458, and whole blood was evaluated by flow cytometry to assess the effect on lymphocyte subsets. At 15 mg/kg i.v., 30 mg/kg s.c., or 100 mg/kg p.o., there was a significant reduction in clinical severity scores (p < 0.001) and blinded radiographic scores (p < 0.001) compared with vehicle control groups. Structural damage was virtually eliminated with PPI-2458. Continuous inhibition of MetAP-2 was needed to maintain benefits, although pannus involution could be achieved with the inhibitor when escape flares occurred. Pharmacokinetic analysis after a single p.o. dose showed a rapid T(max) value of 15 min followed by biphasic elimination (t(1/2), approximately 20 min and t(1/2), approximately 5 h) and an estimated oral bioavailability of approximately 15%. Flow cytometry revealed a dose-dependent decrease in white blood cells and lymphocytes manifested as decreases in circulating CD3+ T cells and natural killer cells. PPI-2458, however, did not seem to be immunosuppressive, as determined by delayed-type hypersensitivity or IgG antibody assays. These studies indicate that the MetAP-2 inhibitor PPI-2458 can regress established CIA and that angiogenic mechanisms might be important targets in the treatment of other pannus-mediated diseases such as RA.

Inflammatory lipids as a target for therapy in the rheumatic diseases

As patients with autoimmune rheumatic diseases live longer due to improved therapies and preventive measures, death and disability from cardiovascular events are increasing. Patients with rheumatoid arthritis and systemic lupus erythematosus have an increased risk of atherosclerosis that persists even after accounting for traditional cardiac risk factors. Recent studies strongly suggest that the mechanism is due in part to increased levels of oxidized lipids (such as oxidized low density lipoprotein and pro-inflammatory high density lipoproteins) which cause the inflammatory cascade that ultimately leads to plaque formation. The objective of this review is to discuss how inflammatory lipids contribute to the increased risk of atherosclerosis in rheumatoid arthritis and systemic lupus erythematosus, as well as to propose that these oxidized lipids are a rational target for therapeutic intervention in autoimmune diseases. Published literature was examined to review treatments for pro-inflammatory lipids in autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus. In conclusion, it is possible that these oxidized lipids may also contribute to increased disease manifestations in rheumatic conditions. Several new and existing therapies, including statins and high density lipoprotein-associated protein peptide mimetics such as D-4F (apoA-1) target these oxidized lipids and may be useful in both preventing atherosclerosis and treating inflammation in patients with rheumatic diseases.

Treatment with an apolipoprotein A-1 mimetic peptide in combination with pravastatin inhibits collagen-induced arthritis

To evaluate the therapeutic potential of an apolipoprotein A-1 (apoA-1) mimetic peptide, D-4F, in combination with pravastatin in collagen-induced arthritis (CIA), syngeneic Louvain rats were immunized with type II collagen and randomized to vehicle control, D-4F monotherapy, pravastatin monotherapy, or D-4F + pravastatin combination therapy. Clinical arthritis activity was evaluated and radiographs, type II collagen antibody titers, cytokine/chemokine levels, and HDL function analysis were obtained. There was significant reduction in clinical severity scores in the high and medium dose D-4F + pravastatin groups compared to controls (p< or =0.0001). Reduction in erosive disease occurred in the medium/high dose combination groups compared to non-combination groups (p< or =0.01). Favorable changes in cytokines/chemokines were noted with treatment, and response to combination D-4F/pravastatin therapy was associated with improvement in HDL's anti-inflammatory properties. Combination D-4F/pravastatin significantly reduced clinical disease activity in CIA, and may have dual therapeutic potential in other autoimmune diseases with increased cardiovascular morbidity and mortality.

Angiogenesis inhibition as a therapeutic approach for inflammatory synovitis

Angiogenesis inhibition, long studied in the treatment of malignancies, has begun to emerge as a potential therapeutic approach in managing inflammatory arthritis, particularly rheumatoid arthritis. The growth of new vessels is required for the development of the rheumatoid pannus, which then leads to extensive synovial inflammation and joint destruction. Vascular endothelial growth factor is the best studied mediator of angiogenesis, and several therapies have been developed that specifically target this molecule. Several other angiogenesis mediators, such as the angiopoietin-TIE system, hypoxia inducible factor and integrin alpha(V)beta(3), as well as naturally occurring inhibitors of angiogenesis, are also being investigated as potential therapeutic targets. Additionally, there are a number of drugs, including paclitaxel, 2-methoxyestradiol and fumagillin analogs, that might have a role in inhibiting angiogenesis and, thus, in treating proliferative synovitis.

Vanadate, an inhibitor of stromelysin and collagenase expression, suppresses collagen induced arthritis

OBJECTIVE

Collagen induced arthritis (CIA) is a model of chronic inflammatory synovitis with pannus, neovascularization, and joint destruction similar to rheumatoid arthritis (RA). Matrix metalloproteinases (MMP) are involved in degradation of the extracellular matrix and joint destruction in RA. c-fos and c-jun are protooncogenes whose products combine to form activating protein (AP-1), a regulatory protein that is required for cell proliferation and the transcription of a variety of genes, including MMP such as collagenase and stromelysin. Administration of vanadium compounds suppresses c-fos/c-jun expression and AP-1 activity, resulting in inhibition of MMP expression in response to factors such as interleukin 1 (IL-1). We evaluated whether a vanadium AP-1 inhibitor could reduce MMP expression and subsequent joint damage in CIA.

METHODS

Vanadate [bis (maltolato) oxovanadium (IV) (BMOV; 10 mg/kg/day)] and the reducing agent N-acetyl cysteine (NAC; 100 mg/kg/day) were given subcutaneously daily in an attempt to suppress established CIA in rats. NAC in combination with vanadate appeared to increase the efficacy of c-fos/c-jun inhibition, while decreasing toxicity. Controls were given NAC alone. Clinical, radiographic, and histologic measures were evaluated as well as synovial MMP and IL-1a expression.

RESULTS

BMOV therapy, initiated on the day of onset of clinical arthritis, significantly reduced clinical arthritis within 2 days (p <0.05) compared to controls. Significance was maintained to the termination of the study on Day 18 post-arthritis onset (p < 0.005), with a maximum difference seen on Day 5 (p < 0.00001). Blinded radiographic scores at the completion of the protocols indicated less joint destruction in the experimental group compared to the control group (p < 0.005). Scanning and transmission electron microscopy confirmed the preservation of articular cartilage with therapy. In BMOV-treated rats, synovial mRNA expression of collagenase, stromelysin, and IL-la were reduced by 78%, 58%, and 85%, respectively, compared to controls.

CONCLUSION

This is the first study of vanadate as a potential antirheumatic agent. Further study of this AP-1 and MMP inhibitor may lead to new treatment options in RA.

Inflammation and bone erosion are suppressed in models of rheumatoid arthritis following treatment with a novel Syk inhibitor

Spleen tyrosine kinase (Syk), a key mediator of immunoreceptor signaling in inflammatory cells, is essential for immune complex-mediated signal transduction initiated by activated receptors for immunoglobulin G. In collagen-induced arthritis, R788/R406, a novel and potent small molecule Syk inhibitor suppressed clinical arthritis, bone erosions, pannus formation, and synovitis. Serum anti-collagen type II antibody levels were unaltered, while the half-life of exogenous antibody was extended when co-administered with R406. Expression of the targeted kinase (Syk) in synovial tissue correlated with the joint level of inflammatory cell infiltrates and was virtually undetectable in treated rats. Syk inhibition suppressed synovial cytokines and cartilage oligomeric matrix protein (COMP) in serum, suggesting a sensitive and reliable biomarker for R406 activity. These results highlight the role of activating Fcgamma receptors in inflammatory synovitis and suggest that interruption of the signaling cascade with a novel Syk inhibitor may be a useful addition to immunosuppressive disease-modifying anti-rheumatic drugs currently used in the treatment of human autoimmune diseases such as rheumatoid arthritis.

Association of increased interferon-inducible gene expression with disease activity and lupus nephritis in patients with systemic lupus erythematosus

OBJECTIVE

To study 5 type I interferon (IFN)-inducible genes (LY6E, OAS1, OASL, MX1, and ISG15) in patients with systemic lupus erythematosus (SLE) and to correlate expression levels with disease activity and/or clinical manifestations.

METHODS

Peripheral blood cells were obtained from 48 SLE patients, 48 normal controls, and 22 rheumatic disease controls, and total RNA was extracted and reverse transcribed into complementary DNA. Gene expression levels were measured by real-time polymerase chain reaction, standardized to a housekeeping gene, and summed to an IFN score. Disease activity was determined by the Safety of Estrogens in Lupus Erythematosus: National Assessment-Systemic Lupus Erythematosus Disease Activity Index (SELENA-SLEDAI) composite.

RESULTS

Each gene was highly expressed in SLE patients compared with normal controls (P < or = 0.0003) or disease controls (P < or = 0.0008 except for MX1). IFN scores were positively associated with the SELENA-SLEDAI instrument score (P = 0.001), the SELENA-SLEDAI flare score (P = 0.03), and the physician's global assessment score (P = 0.005). Compared with patients without nephritis, lupus nephritis patients had higher IFN scores (overall P < 0.0001), especially during active renal disease. IFN scores were weakly associated with neurologic manifestations. Elevated IFN scores were positively associated with the current presence of anti-double-stranded DNA (anti-dsDNA) antibodies (P = 0.007) or hypocomplementemia (P = 0.007). LY6E expression levels distinguished active from inactive lupus nephritis (P = 0.02) and were positively associated with proteinuria (P = 0.009).

CONCLUSION

The 5 IFN-inducible genes were highly expressed in SLE patients, and increased levels were correlated with disease activity defined by several methods. IFN scores, or LY6E levels, were elevated in lupus nephritis patients, especially during active renal disease, and in patients with anti-dsDNA antibody positivity and hypocomplementemia. IFN scores, or LY6E levels, may be useful as a biomarker for lupus nephritis therapy.

New antiangiogenic strategies for the treatment of proliferative synovitis

Angiogenesis inhibition, which has been extensively studied for the treatment of various malignancies, is beginning to emerge as a new potential therapy for proliferative synovitis, particularly rheumatoid arthritis (RA). The rheumatoid pannus, the site of inflammation and joint destruction in the rheumatoid synovium, relies on the development of new vasculature to sustain its growth. A host of mediators have been shown to induce angiogenesis at the site of the inflamed synovium; these include vascular endothelial growth factor, fibroblast growth factor, integrin alpha(V)beta3, angiopoietin, prosta-glandin E1 and prostaglandin E2, and matrix metalloproteinases. In addition, hypoxia at the site of synovial inflammation contributes to angiogenesis stimulation. Several naturally-occurring inhibitors exist, such angiostatin and endostatin. There are a number of drugs undergoing study in the treatment of proliferative synovitis, which capitalise on the correlation between angiogenesis inhibition and the reduction of signs and symptoms of RA. Paclitaxel and an anti-integrin alpha(V)beta3 antibody, LM-609, are currently in clinical trials. Other drugs that may inhibit angiogenesis in RA include TNP-470 (formerly called AGM-1470), PPI-2458, PTK-787, bevacizumab and thalidomide. Many of these drugs have shown promise for the treatment of oncologic disorders, and are now being evaluated for the treatment of proliferative synovitis.

Angiocentric T cell lymphoma of the central nervous system in a patient with Sjögren's syndrome

Patients with Sjögren's syndrome (SS) have an increased risk of developing lymphoproliferative disorders, mainly non-Hodgkin's lymphoma and pseudolymphoma. We describe a young Caucasian woman with a 7 year history of SS, who presented with meningeal signs and symptoms and was found to have non-Hodgkin's lymphoma of the central nervous system.

Environmental modulation of autoimmune arthritis involves the spontaneous microbial induction of T cell responses to regulatory determinants within heat shock protein 65

Both genetic and environmental factors are believed to be involved in the induction of autoimmune diseases. Adjuvant arthritis (AA) is inducible in susceptible rat strains by injection of Mycobacterium tuberculosis, and arthritic rats raise T cell responses to the 65-kDa mycobacterial heat-shock protein (Bhsp65). We observed that Fischer 344 (F344) rats raised in a barrier facility (BF-F344) are susceptible to AA, whereas F344 rats maintained in a conventional facility (CV-F344) show significantly reduced incidence and severity of AA, despite responding well to the arthritogenic determinant within Bhsp65. The acquisition of protection from AA can be circumvented if rats are maintained on neomycin/acidified water. Strikingly, naive unimmunized CV-F344 rats but not BF-F344 rats raised T cell responses to Bhsp65 C-terminal determinants (BCTD) (we have previously shown that BCTD are involved in regulation of acute AA in the Lewis rat); however, T cells of naive CV-F344 and BF-F344 gave a comparable level of proliferative response to a mitogen, but no response at all to an irrelevant Ag. Furthermore, adoptive transfer into naive BF-F344 rats of splenic cells of naive CV-F344 rats (restimulated with BCTD in vitro) before induction of AA resulted in a considerably reduced severity of AA. These results suggest that spontaneous (inadvertent) priming of BCTD-reactive T cells, owing to determinant mimicry between Bhsp65 and its homologues in microbial agents in the conventional environment, is involved in modulating the severity of AA in CV-F344 rats. These results have important implications in broadening understanding of the host-microbe interaction in human autoimmune diseases.

Taxol (paclitaxel) involution of articular cartilage destruction in collagen induced arthritis: an ultrastructural demonstration of an increased superficial chondroprotective layer

OBJECTIVE

To determine the ultastructural changes of Taxol (paclitaxel) involution of articular cartilage destruction in collagen induced arthritis (CIA) and to compare with articular cartilage from normal rats.

METHODS

Forty-five Louvain rats were randomized to one of 3 protocols for structural analysis: (1) control group, (2) CIA group, and (3) Taxol treated CIA group. The latter group received 10 mg/kg body weight of Taxol at Days 10, 12, and 14 and 7.5 mg/kg body weight of Taxol on Days 16, 18, and 20 postimmunization with collagen type II. Eight days later, each group was examined by light microscopy and scanning and transmission electron microscopy.

RESULTS

In Taxol treated rats, the morphology of the articular cartilage reverted to that observed in naive rats except for a striking increase in the thickness of the superficial amorphous layer covering the articular surface.

CONCLUSION

The involution of CIA by Taxol suggests that this agent may be useful in the clinical treatment of RA.

Suppression of coronary vasculitis in a murine model of Kawasaki disease using an angiogenesis inhibitor

Coronary arteritis can be induced in C57BL/6 mice with a single intraperitoneal (ip) injection of Lactobacillus casei cell fragments. Histologic sections resemble the vasculitis and aneurysms observed in the medium-sized coronary arteries of children with Kawasaki disease. Since endothelial cells could play an important role in the development of vasculitis, a recently described angiogenesis inhibitor that is not an immunosuppressive agent, AGM-1470 (derived from Aspergillus fumigatus), was used to evaluate its therapeutic potential in this model. A total of 32 mice were administered 0.5 mg of sterile L. casei preparation ip on day 0 and randomized to either a treatment (AGM-1470, 27mg/kg sc alternate days) or a control (vehicle only) protocol. Hearts were harvested on day 14 (early disease) or at the end of the study on day 28 (established disease). Histologic sections were scored blindly for vasculitis. Day 14 sections from both protocols manifested only minimal disease, indicating that the vasculitis had not yet matured. By day 28, the AGM-1470 group had significantly less coronary vasculitis than the control group (0.7 vs 2.6, p < 0.005, respectively). These studies suggest that endothelial cells may play an active role in this pathologic process and that angiogenesis inhibitors, such as AGM-1470, could be useful tools for the treatment and understanding of vasculitis.

Collagen induced arthritis: reversal by mercaptoethylguanidine, a novel antiinflammatory agent with a combined mechanism of action

OBJECTIVE

We recently identified mercaptoethylguanidine (MEG) as an antiinflammatory agent with a combined mechanism of action. Its effects include inhibition of the inducible isoform of nitric oxide synthase (iNOS), scavenging peroxynitrite, a cytotoxic oxidant species produced from nitric oxide (NO) and superoxide, and inhibition of cyclooxygenase (COX). We investigate the effect of MEG in collagen induced arthritis (CIA).

METHODS

Syngeneic LOU rats were immunized with native type II collagen on Day 0. After clinical signs of arthritis developed on Day 10, treatment with MEG was initiated (30 mg/kg ip tid) and continued until sacrifice on Day 28. Serum nitrite/nitrate was measured in control animals, at arthritis onset and 2 days after the start of MEG treatment. Clinical scores were obtained daily. At Day 28, radiographic scores were obtained, and joints were harvested for the measurement of mRNA for tumor necrosis factor-alpha (TNF-alpha), collagenase, and stromelysin.

RESULTS

Serum nitrite/nitrate increased from 7.9+/-0.7 mM (baseline) to 13.5+/-2.6 at arthritis onset (p < 0.05). Within 48 h of MEG treatment, nitrite/nitrate levels fell to 7.2+/-1.1 (p < 0.05). By Day 28, clinical arthritis scores (measured on a scale of 0-8) were 7.1+/-0.6 in the vehicle group compared to 1.4+/-0.6 in the MEG treated group (p < 0.0001). Radiographic scores (scale 0-6) on Day 28 were reduced from 4.9+/-0.6 to 0.6+/-0.4 (p < 0.0002) by MEG treatment. MEG reduced the synovial expression of mRNA for TNF-alpha, collagenase, and stromelysin by 72, 67, and 52%, respectively.

CONCLUSION

These data show that MEG has beneficial effects on established CIA. The mechanism of action may be related to inhibition of synovial iNOS expression or activity, inhibition of COX, scavenging of peroxynitrite, with subsequent inhibition of angiogenesis, metalloproteinase, and TNF-alpha expression.

The effect of thalidomide and 2 analogs on collagen induced arthritis

OBJECTIVE

Thalidomide has been described as an inhibitor of both angiogenesis (which may account for its teratogenic effects on limb bud formation) and tumor necrosis factor-alpha (TNF-alpha) production. We evaluated its therapeutic potential in collagen induced arthritis (CIA), a rat model of rheumatoid arthritis (RA).

METHODS

Rats were administered orally 200 mg/kg/day thalidomide (n = 10) or either of 2 analogs, EM-12 (n = 9) or supidimide (n = 9). An additional group was given thalidomide (n = 10) at 200 mg/kg twice daily, and a control group (n = 13) was given vehicle only. At completion of the protocols, serum levels of TNF-alpha and vascular endothelial growth factor (VEGF) were measured.

RESULTS

Suppression of inflammatory synovitis by clinical and radiographic criteria was significantly lower in all experimental protocols except the lower dose thalidomide group. The EM-12 analog was the most efficacious, and twice daily thalidomide was better than once daily. The incidence of arthritis onset was comparable among all groups. Strong cell mediated and humoral responses to type II collagen, measured by a radiometric delayed type hypersensitivity assay and anti-type II collagen IgG ELISA, respectively, were similar in the experimental and control groups. TNF-alpha and VEGF levels were increased in all rats immunized with collagen compared to naive controls.

CONCLUSION

Thalidomide and its analogs can suppress the clinical severity of rat CIA, but the mechanism of action is not a result of TNF-alpha or VEGF downregulation.

Transgenic mice expressing a truncated Peromyscus leucopus TNF-alpha gene manifest an arthritis resembling ankylosing spondylitis

Several studies have implicated tumor necrosis factor-alpha (TNF-alpha) in autoimmune diseases, such as rheumatoid arthritis (RA). To elucidate further the role of TNF-alpha in inflammatory arthritis, we generated transgenic mice harboring a truncated Peromyscus leucopus TNF-alpha (Pe-TNF) gene. An arthritic phenotype closely resembling human ankylosing spondylitis was observed only in transgenic lines expressing the Pe-TNF transgene at the mRNA level. We characterized the arthritic phenotype in detail by radiographic and histologic techniques. It consisted of severe axial skeletal kyphosis and ankylosis, accompanied by an inflammatory and fibrotic process at the end plates and enthesis. Peripheral joint lesions were absent in mice expressing the P. leucopus TNF-alpha gene, in contrast to the RA-like phenotype described in transgenic mice expressing a truncated human TNF-alpha gene. The Pe-TNF transgenic mouse model provides a unique opportunity to explore potential mechanisms whereby TNF-alpha may initiate an autoimmune arthritis resembling ankylosing spondylitis.

Model studies directed toward the application of boron neutron capture therapy to rheumatoid arthritis: boron delivery by liposomes in rat collagen-induced arthritis

The application of boron neutron capture therapy to rheumatoid arthritis requires the selective delivery of the boron-10 isotope to the synovitic tissue. The use of liposomes as a boron delivery method has been explored through the measurement of the time course biodistribution of boron in rats with collagen-induced arthritis (CIA). Small unilamellar vesicles were composed of a 1:1 mixture of distearoylphosphatidylcholine and cholesterol, incorporated K[nido-7-CH3(CH2)15-7,8-C2B9H11] as an addend in the lipid bilayer and encapsulated Na3[a2-B20H17NH2CH2CH2NH2] in the aqueous core. The tissue concentration of boron delivered by liposomes was determined by inductively coupled plasma-atomic emission spectroscopy after intravenous injection of liposome suspensions into Louvain rats with CIA. With the low injected doses of boron used [13-18 mg of boron per kg (body weight)], the peak boron concentration observed in arthritic synovium was 29 microg of boron per g of tissue. The highest synovium/blood boron ratio observed was 3.0, when the synovial boron concentration was 22 microg of boron per g of tissue. In an attempt to increase the synovium/blood boron ratio by lowering the blood boron concentration, a liposomal formulation characterized by a shorter blood clearance time was examined. Thus, the biodistribution of liposomes with additional K[nido-7-CH3(CH2)15-7, 8-C2B9H11] incorporated in the vesicle membrane not only demonstrated more rapid blood clearance and slightly higher synovium/blood boron ratios but also exhibited reduced boron uptake in synovial tissue. These studies with boron neutron capture therapy for CIA suggest that this form of therapy may be feasible in the treatment of rheumatoid arthritis.

Taxol involution of collagen-induced arthritis: ultrastructural correlation with the inhibition of synovitis and neovascularization

Collagen-induced arthritis (CIA) is an animal model of rheumatoid arthritis (RA) that can be regressed with Taxol (paclitaxel), a chemotherapeutic agent. To identify structural changes that occur with involution, the synovium from naive, untreated CIA, and Taxol-treated CIA rats were evaluated by light microscopy plus transmission and scanning electron microscopy. Analysis included detailed images of vascular networks using polymeric corrosion casts. The CIA synovium was morphologically similar to human RA synovium. In CIA, the integrity of the intimal lining is lost by Type-B synoviocytes becoming highly elongated and polarized toward the joint space, resulting in non-overlapping cellular processes and the elimination of the basal lamina. In addition, the lining expanded from a width of 6-10 microns in naives to 200-250 microns in CIA due primarily to increased numbers of both Type-A and -B synoviocytes and more interstitial matrix. Vascular corrosion casts of CIA synovium illustrated a marked increase in blood vessel volume and an extensive interconnecting vascular architecture; neovascular arrays were observed to project toward the synovial surface. In Taxol-treated CIA, the synoviocyte and neovascular components reverted to the naive synovium morphology, suggesting that this agent might be useful in the therapy of RA.

Rheumatoid arthritis: current clinical and research directions

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by synovitis and joint erosions. It affects approximately 1% of the adult population in a female/male ratio ranging from 2:1 to 4:1. RA is an insidious disease, typically having an onset of symmetric joint swelling and reaching a peak incidence in the fourth and fifth decades. Extraarticular manifestations include pulmonary, ocular, and vascular disease. The etiology of RA remains unknown. Attempts to discover infectious causes have proven unsuccessful, although environmental influences may trigger a response leading to the development of this autoimmune disease. Genetic associations have been identified, particularly with the major histocompatibility complex class II antigens. Furthermore, twin studies have shown a 30%-50% concordance rate for monozygotic twins. Approximately 70%-80% of patients with RA have rheumatoid factor present in the blood, although its role remains unclear. Hormonal status may influence RA. The majority of RA patients are women, and in 75% of them, the disease improves during pregnancy. RA has significant financial and social implications associated with treatment costs, lost wages, disability, and increased mortality. Mainstays of medical therapy have included nonsteroidal anti-inflammatory and immunosuppressive agents, such as prednisone and methotrexate. Recent advances in the treatment of RA include specific inhibitors of cyclooxygenase II, T cells, blood vessels, cytokines (such as tumor necrosis factor-alpha [TNF-alpha] or interleukin-1 [IL-1]), and adhesion molecules. Additional studies are ongoing with combination interventions. It is anticipated that a better understanding of the basic pathophysiologic mechanisms critical in RA pathogenesis will provide more precise and efficacious therapy.

Diversification of T cell responses to carboxy-terminal determinants within the 65-kD heat-shock protein is involved in regulation of autoimmune arthritis

The T cell response to the 65-kD mycobacterial heat-shock protein (Bhsp65) has been implicated in the pathogenesis of autoimmune arthritis. Adjuvant arthritis (AA) induced in the Lewis rat (RT-1(l)) by injection of Mycobacterium tuberculosis serves as an experimental model for human rheumatoid arthritis (RA). However, the immunological basis of regulation of acute AA, or of susceptibility/resistance to AA is not known. We have defined the specificity of the proliferative T cell responses to Bhsp65 during the course of AA in the Lewis rat. During the early phase of the disease (6-9 d after onset of AA), Lewis rats raised T cell responses to many determinants within Bhsp65, spread throughout the molecule. Importantly, in the late phase of the disease (8-10 wk after onset of AA), there was evidence for diversification of the T cell responses toward Bhsp65 carboxy-terminal determinants (BCTD) (namely, 417-431, 441-455, 465-479, 513-527, and 521-535). Moreover, arthritic rats in the late phase of AA also raised vigorous T cell responses to those carboxy-terminal determinants within self(rat) hsp65 (Rhsp65) that correspond in position to the above BCTD. These results suggest that the observed diversification is possibly triggered in vivo by induction of self(Rhsp65)-reactive T cells. Interestingly, another strain of rat, the Wistar Kyoto (WKY/NHsd) rat (RT-1(l)), with the same major histocompatibility complex class II molecules as the Lewis rat, was found to be resistant to AA. In WKY rats, vigorous responses to the BCTD, to which the Lewis rat responded only in the late phase of AA, were observed very early, 10 d after injection of M. tuberculosis, Strikingly, pretreatment with the peptides comprising the set of BCTD, but not its amino-terminal determinants, provided significant protection to naive Lewis rats from subsequent induction of AA. Thus, T cell responses to the BCTD are involved in regulating inflammatory arthritis in the Lewis rat and in conferring resistance to AA in the WKY rat. These results have important implications in understanding the pathogenesis of RA and in devising new immunotherapeutic strategies for this disease.

Combination therapy in rheumatoid arthritis: the animal model perspective

Attempts to improve antirheumatic agent efficacy have resulted in exploration of treatment protocols with combinations of 2 or more agents. Hypothetically, an ideal combination therapy would have greater efficacy and less toxicity than any of its component agents used individually. However, even a limited number of available drugs can produce a daunting number of possible combination protocols, each requiring clinical evaluation. Intelligent selection of combination protocols, based on a firm understanding of each agent's specific mechanism(s) of action, may help identify potentially useful regimens. Autoimmune animal models of inflammatory synovitis provide a unique opportunity to study the etiology, pathophysiology, and treatment of rheumatoid arthritis (RA). Induction of chronic inflammatory synovitis in susceptible inbred strains can allow for in vivo study under reproducible controlled conditions, using experimental protocols not possible in humans. Although animal models can only approximate human rheumatic disease in its complete form, they are nonetheless important for developing new therapeutic strategies. We review the 3 most common animal models of RA, the streptococcal cell wall, adjuvant, and collagen arthritis rat models. Surprisingly, few published studies evaluate combination therapy in RA animal models. We discuss these investigations, which use interventions aimed at angiogenesis, microtubule function, and immune regulation, as examples of animal models to assess and develop effective therapeutic combinations of antirheumatic agents.

Suppression of collagen-induced arthritis by an angiogenesis inhibitor, AGM-1470, in combination with cyclosporin: reduction of vascular endothelial growth factor (VEGF)

Pannus formation characterized by neovascularization is a prominent pathologic finding in both rheumatoid arthritis (RA) and rat collagen-induced arthritis (CIA). CIA is a T-cell-dependent process induced by immunization of inbred LOU rats with native type II collagen in incomplete Freund's adjuvant. AGM-1470 is a highly specific inhibitor of new blood vessel formation by its effects on endothelial cell migration, endothelial cell proliferation, and capillary tube formation. Cyclosporin A (CSA) is an immunomodulating agent that inhibits IL-2 and other cytokine production involved in early antigen activation of T-cells. In this study the effects of single and combination therapy with AGM-1470 (27 mg/kg alternate days) and low-dose CSA (4 mg/kg/day continuous infusion via osmotic pump) on established CIA (total n = 62) were examined. At Day 18 post arthritis onset, clinical arthritis was significantly reduced in rats treated with single-agent AGM-1470 (1.88 +/- 0.33) or combination therapy (1.13 +/- 0.32) (P < 0.00001 and 0.000001, respectively) versus control. Single-agent CSA-treated rats, even if given CSA beginning on the day of immunization, did not attenuate arthritis severity. THe longitudinal mean arthritis score of combination-treated rats was significantly lower than that of rats receiving AGM-1470 (P < 0.0001), reflecting a more moderate early disease course in combination-treated rats. Disease severity in rats treated with single-agent CSA was not significantly different from control rats. Mean WBC counts, differentials, and delayed-type hypersensitivity responses were similar in all groups. CII antibody levels were lower in AGM-1470 protocols compared to CSA or controls. Flow cytometry of peripheral blood, spleen, and lymph nodes demonstrated decreased levels of CD4+ cells in rats given CSA. TNF-alpha levels remained elevated, even in treated rats, while vascular endothelial growth factor levels were reduced in rats receiving AGM-1470 compared to both arthritic controls and naive rats. Both single-agent and combination therapies were well tolerated. This is the first study to examine the effects of AGM-1470 together with CSA. Combination therapy was more effective than single-agent therapy. The results suggest that the use of interventions with distinct mechanisms of action may be efficacious in the treatment of RA.

A novel angiogenesis inhibitor suppresses rat adjuvant arthritis

Rat adjuvant arthritis (AA) is an animal model of rheumatoid arthritis in which pannus formation and destruction of joints occur after immunization with complete Freund's adjuvant. Neovascularization is present within the synovium and may be critical for pannus growth. In this study the effects of a novel angiogenesis inhibitor, AGM-1470, on AA were evaluated. Lewis rats were immunized with CFA to induce arthritis. AGM-1470 treatment was initiated prior to arthritis onset (preventative protocol) or administered to rats with established disease (suppressive protocol). The severity of synovitis and the immunologic status of all rats were then evaluated. Using clinical and radiographic criteria, AGM-1470 significantly reduced arthritis incidence (preventative protocol) (P < 0.01) and disease severity (both protocols, P < 0.001, compared to controls) without affecting T cell function in vitro or phenotype in vivo. Additionally, histologic sections from control rats revealed marked pannus formation, destruction of bone/cartilage, and neovascularization. These findings were absent in AGM-1470-treated rats. AGM-1470 may offer a new treatment option for rheumatoid arthritis and other angiogenesis-dependent diseases.

Systemic lupus erythematosus: calciphylaxis induced cardiomyopathy

A 31-year-old woman with systemic lupus erythematosus (SLE), diabetes mellitus, and chronic renal failure developed digital ischemia, myocardial dysfunction, abnormal ECG, and elevated CPK levels. Radiographic studies revealed calcification of the peripheral vasculature although coronary angiography was unremarkable. An endomyocardial biopsy demonstrated intra and extracellular myocardial calcification without evidence of vasculitis or primary myocarditis. A diagnosis of calciphylaxis, as a result of secondary hyperparathyroidism, was made. This case demonstrates that calciphylaxis can mimic the cardiovascular manifestations of SLE. Early differentiation of these disparate diseases is important because treatment strategies employed in SLE may exacerbate calciphylaxis.

Suppression of collagen-induced arthritis using an angiogenesis inhibitor, AGM-1470, and a microtubule stabilizer, taxol

Collagen-induced arthritis (CIA) is a T-cell-dependent rat model of rheumatoid arthritis (RA) that is induced by injection of collagen type II in incomplete Freund's adjuvant. Neovascularization within the synovium is a prominent feature of CIA and RA. The novel angiogenesis inhibitor AGM-1470 and the microtubule-stabilizing agent Taxol represent two new classes of agents with specific mechanisms of action. AGM-1470 inhibits fibroblast growth factor-induced stimulation of endothelial cell migration, endothelial cell proliferation, and capillary tube formation, resulting in effective suppression of new blood vessel formation. By enhancing microtubule polymerization, Taxol interferes with normal microtubule function in cell mitosis, migration, chemotaxis, and intracellular transport. Using a suppression protocol in established CIA, the effects of AGM-1470 and Taxol as single agents and in combination were evaluated. Combination therapy significantly reduced clinical arthritis compared to control rats (P < 0.00001). The combination therapy group also experienced earlier and significantly greater reduction of clinical arthritis compared to either single agent-treated groups (P < 0.05). Blinded radiographic scores at the end of the study demonstrated less soft tissue swelling and joint destruction using combination therapy than either single agent. This is the first use of AGM-1470 and Taxol in combination therapy. Further study of agents with distinct mechanisms of action may lead to more effective treatment options in chronic inflammatory arthritis and to a better understanding of the pathophysiologic processes of pannus formation.

Regression of collagen-induced arthritis with taxol, a microtubule stabilizer

OBJECTIVE

To investigate the capacity of taxol, a microtubule stabilizer, to inhibit collagen-induced arthritis (CIA), a model of rheumatoid arthritis.

METHODS

Louvain rats were immunized with type II collagen (day 0) to induce arthritis. Taxol was administered beginning on day 2 (prevention protocol) or at arthritis onset on day 9 (in either a high-dose or low-dose suppression protocol). Rats were assessed clinically and radiographically for arthritis severity. Cellular and humoral immune responses to type II collagen were also evaluated.

RESULTS

Institution of taxol prior to arthritis onset completely precluded the development of CIA (P < 0.0001 versus controls). It also suppressed established clinical disease (high-dose protocol P < 0.0000001; low-dose protocol P < 0.0001) and radiographic erosions (high-dose protocol P < 0.00001; low-dose protocol P < 0.001) compared with controls. Levels of IgG antibodies, but not delayed-type hypersensitivity, to type II collagen were reduced after taxol administration.

CONCLUSION

Taxol completely prevented the induction of CIA and caused significant regression of existing arthritis.

Prevention of experimental autoimmune arthritis with a peptide fragment of type II collagen

Collagen arthritis is induced in inbred rats with the injection of native type II collagen. The pathogenesis of this experimental autoimmune disease is T cell dependent. This study demonstrates that collagen-specific T cells, derived from pathogenic and nonpathogenic rat T cell lines, both recognize the same peptide epitope. The epitope, consisting of amino acids 58-73 of cyanogen bromide fragment 11 of type II collagen, was as effective as whole collagen in stimulating a panel of collagen-specific rat/mouse T cell hybridomas. This peptide may, therefore, constitute a dominant epitope for CD4+ rat T cells in their response to type II collagen. Administration of the peptide to either neonatal or adult rats prevented the subsequent induction of experimental arthritis with whole collagen, demonstrating that the in vivo response to this dominant epitope is, therefore, relevant in the pathogenesis of arthritis. Despite its ability to prevent collagen-induced arthritis, administration of this peptide in incomplete Freund's adjuvant intradermally did not induce disease.

Effects of tumor necrosis factor alpha (TNF-alpha) on collagen arthritis

Louvain rats were administered tumor necrosis factor alpha (TNF-alpha) via a continuous osmotic infusion pump. These rats were then immunized with native type II collagen (CII) to determine the effects of exogenous TNF-alpha on collagen-induced arthritis (CIA), an animal model of rheumatoid arthritis (RA). In this highly susceptible strain, 100% of experimental and control rats developed arthritis although TNF-alpha-treated rats had more severe disease as judged by both clinical and blinded radiographic parameters. Humoral responses to collagen were high in both groups, but cellular responses to CII were augmented by TNF-alpha. Serum IL-6 levels were significantly increased in all arthritic rats. This study suggests that TNF-alpha is a proinflammatory cytokine in CIA and that future studies targeting TNF-alpha might be therapeutic.

Angiogenesis inhibition suppresses collagen arthritis

Neovascularization is observed in a spectrum of diseases such as solid tumors, diabetic retinopathy, and rheumatoid arthritis. It is also evident in rat collage-induced arthritis (CIA), an animal model with histologic, clinical, and radiographic manifestations resembling rheumatoid arthritis. To evaluate the effects of angioinhibition in CIA, Louvain rats were immunized with type II collagen to induce arthritis and then administered an angiogenesis inhibitor, AGM-1470, in an attempt to either prevent arthritis or suppress established disease. Using clinical and radiographic criteria, AGM-1470 prevented CIA and significantly suppressed established disease without evidence of immunosuppression. Histologic sections from control ankle joints manifested pannus and neovascularization, which were absent in experimental animals. This is the first study to investigate this novel agent in an autoimmune disease, and additional evaluation of this promising compound in other diseases that are potentially angiogenesis dependent, such as rheumatoid arthritis, might be warranted.

Suppression of collagen arthritis with antibodies to an arthritogenic, oligoclonal T cell line

Rats immunized with type II collagen (CII) develop an immunologically mediated polyarthritis. T cells have been implicated in the pathogenesis of this model since they can adoptively transfer the disease. A CII-specific T cell line (VA), consisting of three distinct clones by Southern blot analysis, has been shown to be arthritogenic. Antibodies specific for this line were generated by immunizing rabbits. In an attempt to prevent collagen-induced arthritis (CIA), Louvain rats were injected with 1 ml of anti-VA ip on Days -1, +1, +3 and 0.5 ml on Day +5 (early treatment). To evaluate its effect on existing disease, rats received anti-VA on the day of arthritis onset and subsequently on 4 successive alternate days using the same dosage protocol (late treatment). Control rats received no therapeutic injections or were administered normal rabbit serum. All rats were immunized with CII on Day 0 to induce CIA. Rats administered antibodies using the early anti-VA treatment protocol had a significantly diminished incidence of arthritis compared to controls. Established arthritis was significantly diminished compared to controls in rats given the late anti-VA treatment. In both protocols, radiographic evidence of joint destruction was significantly reduced compared to controls. T cell phenotyping using flow cytometry analysis demonstrated that the anti-VA antibody therapy selectively eliminated a small subset of T cells since there was little difference in total T cell counts in the experimental versus control groups. Delayed type hypersensitivity and IgG antibody titers to CII were minimally decreased in the experimental versus control group. These results suggest that antibodies raised to an oligoclonal arthritogenic T cell line can suppress collagen arthritis. This may have implications with respect to 1) the size of the T cell receptor repertoire involved in the pathogenesis of collagen arthritis and 2) immunospecific protocols for CIA and other autoimmune diseases.

Suppression of collagen-induced arthritis by combination cyclosporin A and methotrexate therapy

Louvain (LOU) rats were administered either methotrexate (MTX; 0.3 mg/kg/week or 0.8 mg/kg/week intraperitoneally), cyclosporin A (CSA; 4 mg/kg/day or 10 mg/kg/day continuous infusion via osmotic pump), or a combination of both agents. The rats were immunized with native type II collagen (CII) to determine the effects of these agents on collagen-induced arthritis, an animal model of rheumatoid arthritis. A significant decrease in the incidence (P less than 0.01) and severity of arthritis by clinical (P less than 0.05) and radiographic assessments (P less than 0.05) was found in recipients of combination therapy, compared with controls. Delayed-type hypersensitivity reactions to CII were measured on day 26, and production of IgG antibody to CII was measured on days 7, 14, and 26. IgG antibody was evident by day 7, and titers were near-maximal by day 14. Both delayed-type hypersensitivity and antibodies to CII were reduced in animals that received the higher dosage of CSA. Liver, kidney, and spleen specimens obtained from rats treated with CSA and MTX demonstrated no histologic abnormalities on light microscopy, compared with controls. These studies indicate that CSA and MTX in combination is a safe and effective therapy for collagen-induced arthritis and may be useful in the treatment of rheumatoid arthritis.

Animal models of rheumatoid arthritis. Clues to etiology and treatment

Animal models of rheumatoid arthritis (RA) provide useful systems for the characterization of the immunopathogenic mechanisms of chronic inflammatory synovitis. Although at least eight models have been described, the adjuvant arthritis, streptococcal cell wall-induced arthritis, and collagen-induced arthritis models have provided the most useful insights. Each of these three models has contributed clues to our understanding of RA and have yielded promising new approaches to treatment. These include combination pharmacotherapy, antigen-specific therapy, cell-specific therapy, and monoclonal antibody therapy. All of these immunotherapeutic interventions have been shown to be beneficial in one or more animal systems. This suggests that future therapies for RA and other human autoimmune diseases may be more immunoselective and, potentially, less toxic.

Characterization of collagen-specific T cells derived from pathogenic and nonpathogenic rat T cell lines

Rat/mouse T-T hybridomas have been developed from an arthritogenic and a nonarthritogenic T cell line. These hybridomas express alpha beta TCR and are CD4+, CD8-, and MRC OX-22-. They have type II collagen reactivity as assessed by an IL-2 release assay. Southern blot analysis of DNA extracted from these hybridomas demonstrates that each T cell line contains at least three different collagen-reactive clones. The data suggest that the spectrum of TCR beta gene rearrangements is limited, as one hybridoma from the nonpathogenic line shares an identically sized productive TCR beta gene rearrangement with two hybridomas from the pathogenic line. Both cell lines as well as one hybridoma from the pathogenic line are autoreactive to rat type II collagen. The anti-collagen responses of all the hybridomas are restricted to the rat class II MHC RT1.B gene loci. The hybridomas, like their parental cell lines, do not respond preferentially to either native or denatured type II collagen. These hybridomas recognize a specific type II collagen epitope and not repetitive collagen-like sequence motifs. They require antigen processing to respond to both native and denatured type II collagen.

Systemic lupus erythematosus and concurrent cytomegalovirus vasculitis: diagnosis by antemortem skin biopsy

A 45-year-old woman with a 4-year history of systemic lupus erythematosus (SLE) developed fever, decreased visual acuity and skin ulceration. A biopsy of a cutaneous ulcer demonstrated small vessel vasculitis with characteristic cytomegalovirus (CMV) inclusions in the vascular endothelium. The presence of CMV was confirmed by DNA hybridization immuno-histochemistry. Retinal artery vasculitis, previously associated with flares of her SLE, was also noted on ophthalmologic examination. Our case demonstrates that CMV infection can mimic the cutaneous manifestations of collagen vascular disease and that early identification can be made by biopsy of suspicious skin lesions.

Experimental synovitis induced by collagen-specific T cell lines

Type II collagen (CII) and ovalbumin (OV) reactive T cell lines were developed from the lymph node cells of Louvain rats previously immunized with the respective antigen. Histologic sections of rat knees injected intraarticularly (ia) with 10(6) cells from line CII (VA) or CII (VII) were graded blindly. Significant synovitis (P less than 0.000001 and 0.004, respectively) was evident compared to OV line recipients. Pannus developed within 48 hr, persisted for at least 4 to 6 weeks, was inducible with fewer than 10(3) CII cells, and required viable lymphocytes. The process was independent of anticollagen antibodies and was associated with the lines' capacity to elaborate a previously described 65-kDa CII-binding arthritogenic lymphokine. Line CII (VIII), which could not elicit a synovitis, did not produce detectable quantities of this factor. A line- and antigen-specific synovitis, comparable to the ia injection protocol, was also induced by intravenous administration of 2 x 10(7) CII (VA) cells and ia challenge with soluble collagen. These studies demonstrate that CII lines bearing the T helper phenotype can evoke a sustained synovitis and suggest that this experimental process is associated with the release of an arthritogenic lymphokine and not dependent on the formation of antibodies to CII.