Experimental Models Of Systemic Sclerosis Research Articles

Intravenous immunoglobulins improve skin fibrosis in experimental models of systemic sclerosis

Systemic sclerosis (SSc) is the most severe systemic autoimmune disease with currently no cure. Intravenous immunoglobulins (IVIg) are an attractive candidate in this disease to counteract inflammation and fibrosis but data are scarce and conflicting. This study, assessed the effects of IVIg in a murine HOCl-induced model of SSc. We showed that IVIg prevented skin inflammation and fibrosis, by mitigating the immune cell infiltration (p = 0.04), proinflammatory cytokines gene overexpression (IL1β, p = 0.04; TNFα, p = 0.04; IL6, p = 0.05), skin and dermal thickening (p = 0.003 at d21 and p = 0.0003 at d42), the expression markers of fibrosis, such as αSMA (p = 0.031 for mRNA and p = 0.05 for protein), collagen (p = 0.05 for mRNA and p = 0.04 for protein, p = 0.05 for the hydroxyproline content) and fibronectin (p = 0.033 for mRNA). Moreover, IVIg prevented HOCl-induced alterations in splenic cell homeostasis. When administered in curative mode, despite their ability to reduce skin and dermal thickness (p < 0.0001 and p = 0.0002), IVIg showed partial or more mixed effects on skin inflammation and established fibrosis. These data favor further clinical trials in SSc patients on the potential efficiency of early and/or repeated IVIg administration.

THE COMPLEX EFFECT OF VITAMIN D AND ALPHA TOCOPHEROL ACETATE ON THE LUNG MICROCIRCULATION IN THE EXPERIMENTAL INDUCTION OF SYSTEMIC SCLEROSIS

Abstract. The aim of the study was to investigate the effects of vitamin D3 (vitamin D) and alpha-tocopherol acetate (vitamin E) on the microcirculatory vessels of the lungs in an experimental model of systemic sclerosis (SSc).&#x0D; Methods. We divided the experimental animals into four separate groups: an intact group (IG) consisting of 15 animals, a control group (CG) of 20 animals, experimental group 1 (EG1) and experimental group 2 (EG2) consisting of of 25 animals each. Randomization of groups was carefully performed using the weight variance minimization method. To induce SSc in laboratory animals of EG1, subcutaneous injections of 0.5 ml of 5% sodium hypochlorite (NaClO) were administered 3 times a week for 6 weeks in a row. The CG of rats received an isotonic solution following the same scheme, while the IG was not subjected to any injections. In addition to NaClO, the EG2 received intramuscular injections of vit E (10 mg/100 g) and vit D (1000 IU/100 g) for three weeks during the second half of the experiment.&#x0D; After 8 weeks, the animals were euthanized, and lung tissue samples were obtained for histological and electron microscopic analysis. The histological preparations were examined using light microscopy and photographed using a Leica DME light microscope, a DCM 900 digital microscope camera, and a Nicon Coolpix P5100 camera. Meanwhile, the electron microscopy was performed to visualize the ultrastructural characteristics of the lung tissue by use of "PEM-125K" (Selmi, Ukraine) with subsequent photography at magnifications from 2000 to 20000 times.&#x0D; All animal procedures were carried out in strict compliance with bioethical principles. The Ethics Commission of the IFNMU granted approval for the study under document number 117/20 on November 19, 2020.&#x0D; Results. The histological analysis of the lung specimens of CG animals showed a normal morphological structure. In the EG1, the lungs exhibited abnormalities in the structure of the hemocapillaries, including narrowing of the vessel lumen due to thickening of the vascular wall, edema, and infiltration of polymorphonuclear cells. However, in the EG2, there was an improvement in the histological features, with a reduction in edematous processes and a decrease in the intensity of polymorphonuclear cell infiltration.&#x0D; The electron microscopic examination of the lung samples from EG1 animals revealed the presence of platelet adhesion and aggregation, as well as aggregates of erythrocytes within the hemocapillary lumen. Swelling of endothelial cells and narrowing of the hemocapillary lumen were also observed, along with uneven thickening of the basement membrane. In contrast, the combination of vitamins D and E in EG2 animals resulted in improved rheological properties of blood and ultrastructural characteristics of the hemomicrocirculatory elements. The lumen of the hemocapillaries contained single erythrocytes and inactive platelets. The endothelial cells’ membraines showed minimal alterations, with clear contours and no micropinocytotic vesicles or cytoplasmic growths. The nuclei of the endothelial cells had a fine-grained matrix with evenly distributed chromatin granules.&#x0D; Conclusions. This study proves that the combined use of vitamins D and E has a positive effect on the state of the microcirculatory vessels in the lungs of experimentally induced systemic sclerosis.

Neuropeptide Cortistatin Regulates Dermal and Pulmonary Fibrosis in an Experimental Model of Systemic Sclerosis

Introduction: Scleroderma, or systemic sclerosis, is a complex connective tissue disorder characterized by autoimmunity, vasculopathy, and progressive fibrosis of the skin and internal organs. Because its aetiology is unknown, the identification of genes/factors involved in disease severity, differential clinical forms, and associated complications is critical for understanding its pathogenesis and designing novel treatments. Neuroendocrine mediators in the skin emerge as potential candidates. We investigated the role played by the neuropeptide cortistatin in a preclinical model of scleroderma. Methods: Dermal fibrosis was induced by repetitive intradermal injections of bleomycin in wild-type and cortistatin-deficient mice. The histopathological signs and expression of fibrotic markers were evaluated in the skin and lungs. Results: An inverse correlation between cortistatin levels and fibrogenic activation exists in the damaged skin and dermal fibroblasts. Bleomycin-challenged skin lesions of mice that are partially and totally deficient in cortistatin showed exacerbated histopathological signs of scleroderma, characterized by thicker and more fibrotic dermal layer, enlarged epidermis, and increased inflammatory infiltration in comparison to those of wild-type mice. Cortistatin deficiency enhanced dermal collagen deposits, connective tissue growth factor expression, loss of microvessels, and predisposition to suffer severe complications that co-occur with dermal exposition to bleomycin, including pulmonary fibrotic disease and increased mortality. Treatment with cortistatin mitigated these pathological processes. Discussion/Conclusion: We identify cortistatin as an endogenous break of skin inflammation and fibrosis. Deficiency in cortistatin could be a marker of poor prognosis of scleroderma and associated complications. Cortistatin-based therapies emerge as attractive candidates to treat severe forms of systemic sclerosis and to manage fibrosis-related side effects of bleomycin chemotherapy in oncologic patients.

INOS Activity Is Required for the Therapeutic Effect of Mesenchymal Stem Cells in Experimental Systemic Sclerosis.

Objectives: Fibrosis is a hallmark of systemic sclerosis (SSc), an intractable disease where innovative strategies are still being sought. Among novel anti-fibrotic approaches, mesenchymal stromal/stem cell (MSC)-based therapy appears promising. Previously, we reported anti-fibrotic effects of MSC in an experimental model of SSc, through various mechanisms (tissue remodeling, immunomodulation, anti-oxidant defense). Since immunomodulation is a pivotal mechanism for MSC therapeutic effects, we investigated the specific role of critical molecules associated with MSC immunosuppressive properties and hypothesized that MSC defective for these molecules would be less effective in reducing fibrosis in SSc.Methods: SSc was induced by 6-week daily intradermal injections of hypochlorite (HOCl) in mice. MSC were isolated from the bone marrow of wild type mice (WT) or mice knockout for IL1RA, IL6, or iNOS (IL1RA−/−, IL6−/−, or iNOS−/− MSC, respectively). Treated-mice received 2.5 × 105 MSC intravenous infusion at d21. Skin thickness, histological and biological parameters were evaluated in skin and blood at d42.Results: IL1RA−/− and IL6−/− MSC exerted similar anti-fibrotic properties as WT MSC, with a reduction of skin thickness together with less collagen deposition. Conversely, iNOS−/− MSC did not exert anti-fibrotic functions as shown by a similar skin thickness progression as non-treated HOCl-SSc mice. Compared with WT MSC, iNOS−/− MSC kept some immunosuppressive and tissue remodeling properties, but lost their capacity to reduce oxidative stress in HOCl-SSc mice.Conclusion: Our study highlights the crucial role of iNOS, whose activity is required for the anti-fibrotic properties of MSC in experimental SSc, with a special emphasis on NO-related anti-oxidant functions.

Intravenous immunoglobulins prevents experimental fibrosis in a murine model of systemic sclerosis

Introduction Systemic sclerosis (SSc) is an autoimmune disease characterized by an extensive multi-organs fibrosis. Immunosuppressants are effective in some extent but their incomplete efficacy is hampered by a higher infection risk. Intravenous immunoglobulins (IVIG) have a good safety profile, exhibit immunomodulatory and antifibrotic properties and hence could be a relevant treatment for SSc. The purpose of this study was to investigate the effects of IVIG in an experimental model of SSc. Materiels et methodes SSc was induced in 6 weeks old Balb/c mice by subcutaneous injections of HOCl five days a week during six weeks (n = 20), whereas control mice received subcutaneous injections of PBS (n = 20). Human IVIG was administrated intravenously by single retro-orbital injection at a dose of 2 g/kg the first day of HOCl administration (n = 20). A control group received an injection of 2% maltose (n = 20). Skin thickness was assessed during the protocol until the sacrifice (day 42). Skin tissues were collected in 4% PFA and processed for histological analysis. Dermal thickness was measured by performing a May-Grunwald–Giemsa staining of 4 μm skin sections; collagen deposition was assessed by performing a Picrosirius red-staining and quantified by using a color deconvolution method. In addition, immunostaining of skin sections was performed in order to evaluate the α-smooth muscle actin (α-SMA) expression. Frozen skin tissues were analyzed to also assess the mRNA expression of main inflammatory and pro-fibrotic genes (by quantitative reverse transcription polymerase chain reaction). Collagen deposition was also evaluated by measuring the content of hydroxyproline in 10 mg of frozen tissue. Resultats Mice exposed to HOCl developed a diffuse cutaneous SSc with higher dermal thickness compared to the PBS group. IVIG significantly reduced dermal thickness and collagen deposition in HOCl-receiving mice. The amount of α-SMA positive cells evaluated by immunofluorescence was reduced in the HOCl treated mice receiving IVIG. The mRNA expression profile of various markers of fibrosis (fibronectin, TGFβ) or inflammation (TNFα, IL-1β, IL-6) were also significantly decreased in the skin of HOCl mice treated with IVIG compared to HOCl-treated mice receiving 2% maltose. Conclusion These results demonstrate the efficacy of IVIG in preventing experimental fibrosis in a HOCl murine model of SSc.

B Cell Homeostasis and Functional Properties Are Altered in an Hypochlorous Acid-Induced Murine Model of Systemic Sclerosis.

During systemic sclerosis (SSc), peripheral B cells display alterations in subset homeostasis and functional properties and are a promising therapeutic target. However, there is only few data regarding whether these anomalies are accurately reproduced in animal models of SSc. In this work, we assessed the B cell homeostasis modifications in an experimental model of SSc [hypochlorous acid (HOCl)-induced mouse], both at a phenotypic and functional level, during the course of the disease. Balb/c mice underwent daily intradermal injections of HOCl (or phosphate-buffered saline) and were then sacrificed at day 21 (early inflammatory stage) or day 42 (late fibrotic stage). For phenotypic studies, the distribution of the main spleen cell subsets (B cells, T CD4 and CD8 cells, NK cells, macrophages) and splenic B cell subsets (immature, mature naïve, germinal center, antibody-secreting, memory, B1) was assessed by flow cytometry. For functional studies, splenic B cells were immediately MACS-sorted. Production of interleukin (IL)-6, CCL3, IL-10, and transforming growth factor (TGF)-β was assessed ex vivo by RT-PCR and after 48 h of culture by ELISA. Regulatory B cell (Breg) counts were quantified by flow cytometry. Phenotypic analyses showed an early expansion of transitional B cells, followed by a late expansion of the mature naive subset and decrease in plasmablasts and memory B cells. These anomalies are similar to those encountered in SSc patients. Functional analyses revealed a B-cell overproduction of pro-inflammatory cytokines (IL-6 and CCL3) and an impairment of their anti-inflammatory capacities (decreased production of IL-10 and TGF-β, reduced levels of Bregs) at the early inflammatory stage; and an overproduction of pro-fibrotic cytokines (TGF-β and IL-6) at the late fibrotic stage. These results approximate the anomalies observed in human SSc. This work reports the existence of anomalies in B cell homeostasis and functional properties in an animal model of SSc that approximate those displayed by SSc patients. These anomalies vary over the course of the disease, which pleads for their participation in inflammatory and fibrotic events. This makes the HOCl mouse a relevant experimental model for the study of B cells, and therefore, B-cell-targeted therapies in SSc.

Paquinimod reduces skin fibrosis in tight skin 1 mice, an experimental model of systemic sclerosis

BackgroundSystemic Sclerosis (SSc) is an autoimmune disease characterized by vascular and immune dysfunction. A hallmark of SSc is the excessive accumulation of extracellular matrix in the skin and in internal organs. There is a high and unmet medical need for novel therapies in this disease. The pathogenesis of SSc is complex and still poorly understood, but the innate immune system has emerged as an important factor in the disease. SSc patients show increased numbers of macrophages/monocytes in the blood and in the skin compared to healthy individuals and these cells are important sources of profibrotic cytokines and chemokines. Paquinimod belongs to a class of orally active quinoline-3-carboxamide (quinoline) derivatives with immunomodulatory properties and has shown effects in several models of autoimmune/inflammatory disorders. Paquinimod is currently in clinical development for treatment of SSc. The immunomodulatory effects of paquinimod is by targeting the myeloid cell compartment via the S100A9 protein. ObjectiveIn this study we investigate whether targeting of myeloid cells by paquinimod can effect disease development in an experimental model of SSc, the tight skin 1 (Tsk-1) mouse model. MethodsSeven weeks old female B6.Cg-Fbn1Tsk/J (Tsk-1) mice were treated with vehicle or paquinimod at the dose of 5 or 25mg/kg/day in the drinking water for 8 weeks. The effect of paquinimod on the level of skin fibrosis and on different subpopulations within the myeloid cell compartment in skin biopsies were evaluated by using histology, immunohistochemisty, a hydroxyproline assay and real-time PCR. Furthermore, the level of IgG in serum from treated animals was also analysed. The statistical analyses were performed using Mann-Whitney nonparametric two tailed rank test. ResultsThe results show that treatment with paquinimod reduces skin fibrosis measured as reduction of skin thickness and decreased number of myofibroblasts and total hydroxyproline content. The effect on fibrosis was associated with a polarization of macrophages in the skin from a pro-fibrotic M2 to a M1 phenotype. Paquinimod treatment also resulted in a reduced TGFβ-response in the skin and an abrogation of the increased auto-antibody production in this SSc model. ConclusionsPaquinimod reduces skin fibrosis in an experimental model of SSc, and this effect correlates with local and systemic effects on the immune system.

FRI0496 An Open-Label Study to Evaluate Biomarkers and Safety in Systemic Sclerosis (SSC) Patients Treated with Paquinimod (ABR-215757)

BackgroundPaquinimod (ABR-215757) is an oral small molecule compound that belongs to the quinoline-3-carboxamide derivatives, a class of structurally related compounds with immunomodulatory properties. Paquinimod has shown beneficial effects in several...

Vascular endothelial growth factor aggravates fibrosis and vasculopathy in experimental models of systemic sclerosis

ObjectivesHigh levels of vascular endothelial growth factor (VEGF), a key angiogenic factor, are present in patients with systemic sclerosis (SSc), but its role in the pathogenesis of fibrosis and its...

SAT0032 The synthetic cannabinoid ajulemic acid exerts potent anti-fibrotic effects in experimental models of systemic sclerosis

BackgroundCannabinoids are able to modulate fibrogenesis in scleroderma. Ajulemic acid (AjA) is a non-psychoactive synthetic analogue of tetrahydrocannabinol (THC), able to bind the peroxisome proliferator-activated receptor-γ (PPAR-γ) (1). Recent evidence...

Synthetic cannabinoid ajulemic acid exerts potent antifibrotic effects in experimental models of systemic sclerosis

BackgroundCannabinoids modulate fibrogenesis in scleroderma. Ajulemic acid (AjA) is a non-psychoactive synthetic analogue of tetrahydrocannabinol that can bind the peroxisome proliferator-activated receptor-γ (PPAR-γ). Recent evidence suggests a key role for...

Stimulation of soluble guanylate cyclase reduces experimental dermal fibrosis

BackgroundFibrosis and vascular disease are cardinal features of systemic sclerosis (SSc). Stimulators of soluble guanylate cyclase (sGC) are vasoactive drugs that are currently being evaluated in phase III clinical trials...

Inhibition of glycogen synthase kinase 3β induces dermal fibrosis by activation of the canonical Wnt pathway

ObjectiveGlycogen synthase kinase 3β (GSK-3) regulates the phosphorylation and subsequent degradation of β-catenin, thereby preventing aberrant activation of the canonical Wnt pathway. A study was undertaken to define the role...

Tyrosine Kinase Inhibitors in the Treatment of Systemic Sclerosis: From Animal Models to Clinical Trials

Efficient antifibrotic therapies are not available for patients with systemic sclerosis (SSc). This review summarizes the current preclinical and clinical evidence for imatinib and related tyrosine kinase inhibitors as potential antifibrotic therapies for SSc and other fibrotic diseases. In experimental models of SSc, imatinib, nilotinib, and dasatinib demonstrated strong antifibrotic effects. Imatinib not only prevented fibrosis in the bleomycin-induced model of dermal fibrosis and the tight skin mouse-1 model but also reduced established fibrosis in a modified bleomycin model. Open-label, proof-of-concept trials in SSc showed moderate effects on skin fibrosis, biological measures of skin fibrosis, and lung fibrosis compared with baseline measures. However, whether this reflects the natural course of the disease or is a result of treatment effects is unclear and needs to be analyzed in larger, multicenter, randomized, placebo-controlled trials. Toxicity is expected from cancer trials with frequent mild to moderate adverse events.

Are tyrosine kinase inhibitors promising for the treatment of systemic sclerosis and other fibrotic diseases?

Tissue fibrosis causes organ failure and death in patients with systemic sclerosis (SSc), but clearly effective anti-fibrotic therapies are not available. The tyrosine kinase inhibitor (TKI) imatinib, which blocks the pro-fibrotic c-Abl kinase and PDGF receptor, is currently evaluated in clinical proof-of-concept trials for the treatment of patients with SSc. In experimental models, imatinib efficiently prevented and reduced tissue fibrosis. First clinical case studies demonstrated anti-fibrotic effects of imatinib in selected patients with SSc and other fibrotic diseases, and observational studies in sclerotic chronic graft-versus-host disease showed promising results. Besides imatinib, the two novel TKIs of c-Abl and PDGF receptor nilotinib and dasatinib have recently proven efficacy in experimental models of SSc. The potential of TKIs of the VEGF receptor (e.g., semaxinib, vatalanib, sutent, and sorafenib) and the EGF receptor (e.g., erlotinib, gefitinib, lapatinib, and canertinib) as anti-fibrotic treatments are also discussed in this review. Prior to clinical use, however, controlled trials need to address efficacy as well as tolerability of TKIs in patients with different fibrotic diseases.

B cells play a critical role for renal injury in an experimental model of systemic sclerosis (48.3)

Abstract Systemic sclerosis (SSc) is a complex autoimmune disease involving autoreactive B and T cells and excessive extracellular matrix deposition in target organs such as kidneys. We have developed a novel human collagen V (hCollV) induced autoimmune model which shares some common pathological and immunological features with Ssc. Mice immunized with hCollV have increased proteinuria, renal fibrosis, serum autoantibodies (anti- RNP, -SSA, -collagen I, II) (p&amp;lt;0.01), and renal IgG depositions by day 42. Levels of proinflammatory cytokines and chemokines associated with tissue fibrosis, such as IL-6 and MCP-1, were elevated in the sera of immunized mice when compared to controls, as were gene expression levels in the kidneys by qPCR analysis. Depletion of B cells by afucosylated anti-hCD19 antibody resulted in reduced proteinuria, tissue fibrosis, and IgG depositions in the kidneys of immunized mice, decreased cytokines and chemokines levels, and greatly declined serum autoantibodies. Therefore, our data indicated that the B cells play crucial roles in causing renal damage in the hCollV-induced systemic sclerosis model, suggesting a potential therapeutic target to benefit Ssc patients.

Autoantibody profile in the experimental model of scleroderma induced by type V human collagen

The aim of this study is to evaluate the humoral autoimmune response in the experimental model of systemic sclerosis (SSc) induced by human type V collagen (huCol V). New Zealand rabbits were immunized with huCol V in Freund's complete adjuvant (FCA) and boosted twice with 15 days intervals with huCol V in Freund's incomplete adjuvant. Control groups included animals injected only with FCA or bovine serum albumin. Bleeding was done at days 0, 30, 75 and 120. Tissue specimens were obtained for histopathological investigation. Serological analysis included detection of antibodies against huCol V and anti-topoisomerase I (Anti-Scl70) by enzyme-linked immunosorbent assay, antinuclear antibodies (ANA) by indirect immunofluorescence, and rheumatoid factor (RF) by a latex agglutination test. Target antigens were characterized by immunoblot. Histological analysis revealed extracellular matrix remodeling with fibrosis and vasculitis. Anti-Scl70 and ANA were detected as early as 30 days in all huCol V animals. The universal ANA staining pattern was Golgi-like. This serum reactivity was not abolished by previous absorption with huCol V. Characterization of the target antigen by immunoblot revealed two major protein fractions of 175,000 and 220,000 MW. Similarly to ANA, there was a gradual increase of reactivity throughout the immunization and also it was not abolished by preincubation of serum samples with huCol V. RF testing was negative in hyperimmune sera. The production of autoantibodies, including anti-Scl70, a serological marker for SSc associated with histopathological alterations, validates huCol V induced-experimental model and brings out its potential for understanding the pathophysiology of SSc.

Collagen V nasal tolerance in experimental model of systemic sclerosis

Our aim was to study skin remodeling and autoantibody production in an experimental model of scleroderma (SSc), following nasal tolerance with human type V collagen (Col V). Female New Zealand rabbits (n = 12) were immunized with two doses of 1 mg/ml of Col V in complete Freund's adjuvant and additional two boosters in incomplete Freund's adjuvant to induce SSc. After 150 days, half of these immunized rabbits were submitted to type V collagen-induced tolerance receiving a daily nasal administration of 25 mug of Col V. Control animals (n = 6) were only submitted to type V collagen-induced tolerance. Serial skin biopsies were performed on days 0, 150 and 210, and stained with H&E, Masson's trichrome and Picrosirius for morphological and morphometric analysis. Types I, III and V collagen were identified by immunofluorescence. The animals' serum samples were collected to determine anti types I, III, IV and V collagen and antinuclear antibodies (ANA). Skin biopsies from immunized animals confirmed SSc morphology as previously described, such as progressive decrease of papillary dermis, appendages atrophy, increased type I, III and V collagen deposition. Rabbits with Col V-induced nasal tolerance showed reduction of skin involvement, with significant decrease of collagen amount. Humoral immune response did not change with nasal tolerance. Collagen V nasal tolerance promotes regression of skin remodeling process in an experimental model of SSc. We suggest that nasal tolerance with type V collagen can be a promising therapeutic option to treat scleroderma patients.

Therapeutic inhibition of the complement system. Y2K update.

Activation of complement is an essential part of the mechanism of pathogenesis of a large number of human diseases; its inhibition by pharmacological means is likely to suppress disease processes in complement mediated diseases. From this point of view low molecular weight synthetic inhibitors of complement are being developed and high molecular weight natural inhibitors of human origin present in plasma or embedded in cell membrane are being purified or produced in their recombinant forms. This review is concerned with high molecular weight inhibitors, some of which are already in clinical use but may be efficacious in many other diseases in which they have not yet been tried. C1-esterase inhibitor (C1-INH) concentrate prepared from human plasma is being successfully used for the treatment of hereditary angioneurotic edema. Recently, C1-INH has been found to be consumed in severe inflammation and has been shown to exert beneficial effects in several inflammatory conditions such as human sepsis, post-operative myocardial dysfunction due to reperfusion injury, severe capillary leakage syndrome after bone marrow transplantation, reperfusion injury after lung transplantation, burn, and cytotoxicity caused by IL-2 therapy in cancer. Factor I has been used for the treatment of factor I deficiency. Recombinant soluble forms of membrane cofactor protein (MCP), and decay accelerating factor (DAF) have not yet been tried in humans but have been shown to be effective in immune complex mediate inflammation in animals. Organs of pigs transgenic for one or more of human membrane regulators of complement namely membrane cofactor protein (MCP), decay accelerating factor (DAF) or CD59, are being produced for transplantation into humans. They have been shown to be resistant to hyperacute rejection in non-human primates; acute vascular rejection is still a problem in their clinical use. It is hoped that these observations together with future developments will make xeno-transplantation in clinical practice a reality. Several recombinant variants of complement receptor 1 (CR1) have been produced. The most effective of these appears to be sCR1-SLe x, sCR1 part of which inhibits complement and carbohydrate Sle x moiety inhibits selectin mediated interactions of neutrophils and lymphocytes with endothelium. Although clinical trials of sCR1 in humans is eagerly awaited, several of the recombinant versions of sCR1 have been shown to suppress ischemia/reperfusion injury, thermal trauma, and immune complex mediated inflammation. They have also been shown to be effective in experimental models of systemic sclerosis, arthritis, myasthenia gravis, Guillain Barré syndrome and glomerulonephritis. Intravenous immunoglobulin, three of the most prominent properties of which are neutralization of autoantibody activity, suppression of autoantibody production and inhibition of complement activity, is being used in several diseases. These include autoimmune thrombocyopenic purpura, Kawasaki disease and several neurological diseases such as myasthenia gravis and Guillain Barre syndrome. In many uncontrolled small scale studies intravenous immunoglobulin has been shown to be effective in many immunological including dermatological diseases; controlled clinical trials in a large number of patients with these diseases is needed to establish the efficacy. It is hoped that in future therapeutic inhibition of complement will be one of the major approaches to combat many human diseases.

T Cells Infiltrating the Skin of Tsk2 Scleroderma-Like Mice Exhibit T Cell Receptor Bias

The T cell repertoire expressed by Tsk2 mice, a novel experimental model of systemic sclerosis, was examined to determine whether cells infiltrating the areas of involved skin exhibit a T cell receptor (TCR) bias. Reverse transcription-polymerase chain reactions (RT-PCR) were conducted using RNA extracted from lymph nodes and skin from Tsk2 mice and from normal mice, with an oligonucleotide primer library specific for the variable region of the TCR (β) chain, RT-PCR signals were observed in all lymph node cell (LNC) samples from both Tsk2 mice and control mice, with eighteen of the twenty-one Vβ types present. In contrast, cDNA extracted from areas of involved skin from Tsk2 mice exhibited a restricted pattern, with positive Vβ signals corresponding to eight T cell subtypes (Vβ1, 6, 8.1, 8.2, 10, 11, 16, and 18). Band strength analysis revealed that three Vβ subtypes dominated within this restricted pattern (Vβ8.1, 11, and 18). Moreover, this pattern of VB bias was consistent among the four skin samples from different Tsk2 mice. These data suggest that a restricted T cell population participates in the inflammatory cell infiltrate of Tsk.2 skin.