Adult Stem Cell Treatment of Scleroderma
Alan Tyndall; Daniel E. Furst

Curr Opin Rheumatol.  2007;19(6):604-610.  ?2007 Lippincott Williams & Wilkins
Posted 11/06/2007

Abstract and Introduction

Abstract

Purpose of review: Provides an update of hematopoietic stem cell transplantation for systemic sclerosis from phase I/II studies and prospective randomized phase III trials, and introduces the concept of mesenchymal stem cells as potential therapy for autoimmune disease.
Recent findings: Around 170 transplanted systemic sclerosis patients are registered in Europe. Most received autologous, peripheral blood derived hematopoietic stem cell transplantation. Treatment-related mortality has fallen to 2.5% in the controlled trials compared with 12.5% in the first report in 2002. Over one-third of patients have experienced sustained remission. Two prospective randomized phase III studies are active: the Autologous Stem cell Transplantation International Scleroderma (ASTIS) trial in Europe and the Scleroderma Cyclophosphamide Or Transplant (SCOT) trial in the USA. Both have similar selection criteria, endpoint and control arms, but the SCOT trial uses radiation and less cyclophosphamide. So far, no unexpected toxicity has occurred. Reports produced in the past 12 months show reduction of skin collagen and reversal of microvascular remodelling, years after transplant. Bone marrow-derived mesenchymal stem cells from systemic sclerosis patients show in-vitro immunomodulatory properties equal to healthy controls.
Summary: Hematopoietic stem cell transplantation is currently being tested in prospective randomized controlled trials and appears to 'reset' autoimmunity in systemic sclerosis. Mesenchymal stem cells may have an immunomodulatory role in autoimmune disease.

Introduction

Immunosuppressive agents such as cyclophosphamide have long been used to treat autoimmune disease, but the dose is often limited by bone marrow suppression. Ten years ago several groups considered adopting the oncological approach of myeloablative therapy followed by haematological 'rescue' using either autologous or allogeneic hematopoietic stem cells to treat severe, therapy-resistant autoimmune disease. The concept was supported by animal model data,[1] suggesting tolerance induction in a rat arthritis model and cases of patients receiving an hematopoietic stem cell transplantation (HSCT) for conventional indications and in whom a coincidental autoimmune disease was improved or eradicated.[2]

After several international meetings,[3,4] consensus guidelines were developed and the first published case of a patient receiving an HSCT as treatment for an autoimmune disease alone was published in October 1996.[5] Since then, over 1000 patients have been transplanted for autoimmune disease, the majority within the context of phase I/II trials and more recently within phase III prospective randomized studies.

In the European Group for Blood and Marrow Transplantation (EBMT) and European League Against Rheumatism (EULAR) database, 136 systemic sclerosis (SSc) patients are registered.

Results of Phase I/II Studies

All studies have used autologous hematopoietic stem cells.

Autologous Hematopoietic Stem Cell Transplantation

The first 65 transplanted patients reported to the EBMT/EULAR database showed an improvement of 25% or more in the skin score (measured by the modified Rodnan method) in 70% of the patients, with a transplant-related mortality (TRM) of 12.5%.[6] Several protocols were used, mostly either cyclophosphamide based (4 g/m2 cyclophosphamide mobilization and cyclophosphamide 200 mg/kg body weight conditioning) or radiation (8 Gy/cyclophosphamide 120 mg/kg body weight). With further patient recruitment and longer term follow up, the TRM of the EBMT-registered patients fell, considered to be related to more careful patient selection and appropriate changes in the treatment regimens. Lung function tended to stabilize and renal function generally remained stable, but some factors were identified as potentially hazardous for HSCT (see below). A long-term follow up of this cohort showed an overall TRM of 8.5%, no further transplant-related deaths and trend to durable remissions (Fig. 1).[7] Within controlled trials, the TRM has thus far been 2.5%. For this subset of SSc there is so far no proven disease-modifying therapy capable of controlling the disease.

     

Between 1997 and early 2005, 34 early, poor prognosis SSc patients enrolled in a pilot North American study. After an early protocol in eight patients (which had probable radiation-related toxicity) was modified, the next 25 patients underwent conditioning with 800 cGy total body irradiation (with lung shielding to 200 cGy), 120 mg/kg cyclophosphamide and 90 mg/kg equine ATG. After a median follow up of 4 years, an approximately 70% improvement in skin and 55% improvement in function were noted (P < 0.0001). Transplant-related mortality occurred in five patients [two from pulmonary toxicity before protocol modification - none have died of pulmonary toxicity since - one of Epstein-Barr virus-associated posttransplantation lymphoproliferative disorder, one with myelodysplastic syndrome, and one of multiorgan failure (15%)].[8,9]

Patient Selection

Initially, most groups followed the consensus guidelines of 'life or organ threatening autoimmune disease refractory to conventional therapy and with sufficient reversible pathology to allow a decent quality of life after cessation of inflammation'. Such SSc patients have a 50% 5-year survival[10] and were therefore considered suitable candidates for such an aggressive treatment. The phase I/II experience showed that particular clinical features are associated with potential toxicity, for example patients with a mean pulmonary artery pressure above 50 mmHg by right heart catheterization tended not to tolerate neutropenic fever well due to circulatory compromise, and advanced cardiac or pulmonary disease was prone to deteriorate. This is due to a combination of direct organ toxicity, for example cyclophosphamide cardiac toxicity, and the hyperhydration required during mobilization and conditioning.

Cardiac assessment and monitoring is particularly important in HSCT for SSc,[11??] since subclinical myocardial involvement is more frequent than suspected[12] and fatal ventricular tachyarrhythmia may occur. In general, it is thought that an ejection fraction above 40% is necessary to cope with a doubling of cardiac output over several days, as may occur with sepsis-associated pyrexia, and sufficient diastolic reserve to tolerate a 30% expansion of intravascular volume typically seen in hyperhydration. This is analogous to the reserve required to survive pregnancy.[11??] SSc as well as amyloidosis are both conditions associated with diastolic dysfunction and which may be treated with HSCT.

All patients with SSc who are potential HSCT candidates should undergo screening consisting of a standard 12-lead ECG, 24 h Holter monitor and, if coronary artery disease is suspected, coronary artery angiography or pulmonary hypertension, and right heart catheter exam. In addition, echocardiography should always be performed, and if the results suggest pulmonary artery hypertension, a right heart catheter study is required. This should include measuring the pulmonary capillary wedge pressure, which reflects the left ventricular function and should be less than 15 mmHg. This procedure may need to be repeated prior to conditioning in the European protocol in which cyclophosphamide is used during mobilization, as the patient may experience a deterioration after taking this drug. Based on one experience,[11??] an implantable defibrillating device is suggested if nonsustained ventricular arrhythmias are present, since antiarrhythmic drugs are considered as adjunct therapy and will not prevent sudden cardiac death on their own.

Thoracic high-resolution computer tomography (HRCT) should be performed to assess interstitial lung disease, with a 'ground glass' pattern suggesting active alveolitis.[13] In addition, HRCT excludes unsuspected pulmonary emboli as the cause of pulmonary artery hypertension. This is particularly relevant if significant pulmonary artery hypertension is present, and in fact, most patients are anticoagulated for this reason.

The routine use of angiotensin converting enzyme (ACE) inhibitors during the transplant period has been subject to debate, but several reports of acute renovascular crises in patients not taking these agents have prompted some groups to routinely use them. In the Autologous Stem cell Transplantation International Scleroderma (ASTIS) trial it is mandatory during the treatment period and generally continued indefinitely afterwards. In the Scleroderma Cyclophosphamide Or Transplant (SCOT) trial, ACE inhibitors are required during the 2 months when steroids are utilized. The combination of hyperhydration and pulses of glucocorticosteroids during the ATG infusion may increase the risk of scleroderma renal crisis.

Outcome From Phase I/II Studies

There are now significant numbers of SSc patients followed for 10 years in which major regression of skin thickening has occurred as well as stabilization of lung function. All groups have noted that the first positive impact on disease is often improved quality of life and scleroderma health assessment questionnaires, which include parameters such as physical function, vitality and fatigue. Studies of immune reconstitution have been few, with one study up to 1 year following transplant confirming the known prolonged impairment of the na?e T-cell compartment with no significant difference between responders and nonresponders. A similar study in multiple sclerosis patients in remission 2 years following transplant showed a rejuvenation of the T-cell repertoire, with no relapse.[14] This indicates that the clinical benefit is not simply dependent on prolonged immunosuppression through lymphopenia.

Similar data are evolving concerning morphological changes induced by HSCT. One group has reported remodelling and reduction of skin collagen following autologous HSCT in eight of 10 patients[15??] and another following both autologous and allogeneic HSCT.[9,16] Several reports of improvement of nail fold capillaroscopy changes following autologous HSCT indicate a more profound impact on tissue and matrix function than simply transient antiinflammatory and immunosuppressive effects (M. Matucci-Cerinic, personal communication).

Prospective Randomized Trials

Figures 2 and 3 outline two ongoing studies: the ASTIS trial in Europe[17,18] and the SCOT trial in the USA. Both trials are similar in their selection criteria, primary outcome and control arms, but differ in the transplant regimen. ASTIS uses cyclophosphamide 200 mg/kg body weight and rabbit ATG, SCOT uses cyclophosphamide 120 mg/kg body weight, equine ATG and radiation 800 cGy (with shielding of the lungs to 200 cGy and renal shielding as well). The positive effect of cyclophosphamide alone (the control arm) on SSc was established in randomized placebo-controlled trials after initiation of both studies[19,20], confirming clinical practice and experience. Thus all patients in both trials receive active treatment.     

ASTIS is run under the auspices of the EBMT and EULAR and started randomizing 5 years ago. As of May 2007, 92 patients have been randomized, 44 to transplant and 48 to control. So far, no unexpected toxicity has been observed with one 'probable' transplant-related death occurring due to progressive cardiac failure. The independent safety committee adjudicated that no protocol violation had occurred and that there is no reason to change the protocol. It is planned to include a total of 120 patients.

The 226-patient SCOT trial is supported by the National Institutes of Health/National Institute of Arthritis and Musculoskeletal and Skin Diseases and is currently recruiting. Twenty six patients have been randomized and 17 patients are undergoing testing for qualification. Thus far, there has been no mortality and there is no unexpected toxicity.

Both studies include extensive mechanistic studies relating to immune reconstitution, skin biopsy immunohistology, collagen and vascular remodelling, broncheoalveolar lavage cellular components and high-resolution computed tomography lung changes. An extensive biobank of serum, DNA and skin biopsy will facilitate further mechanistic studies, in particular, relating objective biomarkers to disease activity.

Allogeneic Hematopoietic Stem Cell Transplantation

Less is known about this more toxic treatment option, personal communication (GvHD) being a known complication. Three cases are reported, all receiving a reduced intensity nonmyeloablative HSCT.[16,21] In two, a successful response was seen and in a third, TRM occurred at about 1 year from complications relating to acute GvHD. A multidisciplinary consensus group recently published guidelines for allogeneic HSCT in autoimmune disease in general.[22]

Mesenchymal Stem Cells

MSCs are multipotent cells capable of differentiating in vitro and in vivo to different MSC lineages, including adipose tissue, bone, cartilage and myelosupportive stroma.[23-26] MSCs are found in bone marrow, skeletal muscle, adipose tissue, synovial membranes and other connective tissues of human adults.[27-30] Although controversy exists as to how best to identify MSCs, they seem best defined by using a combination of phenotypic markers and functional properties. Controversy still exists over the in-vivo phenotype of MSCs: however, ex-vivo expanded MSCs do not express the hematopoietic markers CD14, CD34, CD45 and major histocompatibility (MHC) class II.[26,31] In addition to their multipotentiality, they can be identified as cells that stain positive for CD73, CD90 and CD105, and by flow cytometry.[25,26,31-33]

In vitro, MSCs have vast proliferative potential, can clonally regenerate, and can give rise to differentiated progeny. They also exhibit antiproliferative and antiinflammatory properties in vitro and in vivo, making them candidates for treatment of acute inflammatory autoimmune disease.[34??] Regardless of whether or not MSCs are true stem cells, the clinical benefit from MSCs may not require sustained engraftment of large numbers of cells. It is possible that the therapeutic benefit is due to MSCs homing to inflamed tissue and the release of local cytokines and growth factors resulting in a local antiproliferative and immunomodulatory effects.

MSCs were originally thought to be immunoprivileged, in that they did not induce lymphocyte proliferation when cocultured with allogeneic lymphocytes and were not targets for CD8+ cytotoxic lymphocytes or KIR-ligand mismatched natural killer (NK) cells.[35-38] Recent data, however, suggest that in a nonimmunosuppressed host, allogeneic MSCs will be eliminated[39] and that allogeneic MSCs under some circumstances may be targeted by NK cells.[40]

In-vitro results indicate that MSCs possess immunosuppressive properties. Rodent, baboon and human MSCs suppress T and B-cell lymphocyte proliferation in mixed lymphocyte cultures or when induced by mitogens and antibodies, in a dose-dependent fashion.[35,37,38,41-45] The suppression is MHC independent and in human cell cultures, the magnitude of suppression is not significantly reduced when the MSCs are separated from the lymphocytes in transwells, indicating that cell-cell contact is not required.[35,38,46] The mechanisms underlying the immunosuppressive effect remain to be clarified. Various factors produced by MSCs, including hepatocyte growth factor, transforming growth factor-β1,[38] prostaglandin E2,[47] indoleamine 2,3-deoxygenase[48] and inducible nitric oxide synthetase[49] have been implicated as responsible for reduced lymphocyte proliferation. Clearly, a major antiproliferative mechanism in lymphocytes is arrest of the cell cycle in G0/G1.[45]

An immunosuppressive effect of MSC in vivo was first suggested in a baboon model, in which infusion of ex-vivo expanded donor or third-party MSCs delayed the time to rejection of histoincompatible skin grafts.[43] MSCs also downregulate bleomycin-induced lung inflammation and fibrosis in murine models, if given early (but not late) after the induction.[50] A similar effect was seen in a murine hepatic fibrosis model (carbon tetrachloride induced) using a MSC line bearing the fetal liver kinase-1 marker.[51] Tissue protective effects of MSCs were also seen in a rat kidney model of ischaemia/reperfusion injury in which syngeneic MSCs but not fibroblasts were used.[52]

Autologous bone marrow-derived MSCs have been shown to be highly antiproliferative to activated T cells from normal individuals and autoimmune (rheumatoid arthritis, SSc, Sjoegrens, systemic lupus erythematosus) patients,[53??] and in SSc patients these MSCs were normal with respect to proliferation, clonogenicity and differentiation.[54]

Animal Models of Autoimmunity

In the two experimental autoimmune encephalomyelitis murine models both clinical and histological improvement occurred. The responses were dependant on the timing of MSC treatment - the earlier the better - and the effects were reversed with interleukin-2 treatment, indicating that anergy rather than apoptosis had occurred.[55,56] In a murine model of arthritis, however, collagen-induced arthritis was not improved by the addition of MSCs and the in-vitro immunosuppressive effects were reversed by the addition of tumor necrosis factor-α. MSCs were not found in the joints.[57] A second murine arthritis model, however, showed a positive outcome.[58]

Mesenchymal Stem Cells and Human Experience

Ex-vivo-expanded allogeneic MSCs have been infused in several phase I studies.[59-63] No adverse events during or after MSC infusion have been observed and no ectopic tissue formation has been noted. After infusion, MSCs remain in the circulation for no more than an hour.[62] Although durable stromal cell chimerism has been difficult to establish, low levels of engrafted MSCs have been detected in several tissues.[60,63,64]

Infusion of haploidentical MSCs to a patient with steroid-resistant severe acute GvHD of the gut and liver promptly improved liver values and intestinal function.[65] Upon discontinuation of cyclosporine, acute GvHD recurred but was still responsive to a second MSC infusion. Lymphocytes from the patient, when investigated on multiple occasions after MSC infusion, continued to proliferate against lymphocytes derived from the haploidentical MSC donor in coculture experiments. This suggests an immunosuppressive effect of MSCs in vivo, rather than a development of tolerance.

The EBMT is currently planning protocols for prevention and treatment of acute GvHD using MSCs, through the Developmental Sub-Committee (W. Fibbe, K. Le Blanc, personal communication).

Conclusion

In conclusion, HSCT for SSc has advanced to the stage of two international prospective randomized controlled trials which should determine if this aggressive form of therapy may 'reset' an autoaggressive immune system and benefit patients with severe, poor prognosis SSC. During the past several years the potential use of MSCs as immunomodulating agents is being explored (e.g. in the acute GvHD setting in which a positive effect seems possible with little or no acute toxicity). Preliminary results suggest that bone marrow-derived MSCs from SSc patients exhibit effective in-vitro antiproliferative effects on lymphocytes.

References

Papers of particular interest, published within the annual period of review, have been highlighted as:
? of special interest
?? of outstanding interest

  1. van Bekkum DW. Stem cell transplantation for autoimmune disorders: preclinical experiments. Best Pract Res Clin Haematol 2004; 17:201-222.
  2. Marmont AM. Stem cell transplantation for autoimmune disorders: coincidental autoimmune disease in patients transplanted for conventional indications. Best Pract Res Clin Haematol 2004; 17:223-232.
  3. Tyndall A, Gratwohl A. Blood and marrow stem cell transplants in auto-immune disease: a consensus report written on behalf of the European League against Rheumatism (EULAR) and the European Group for Blood and Marrow Transplantation (EBMT). Bone Marrow Transplant 1997; 19:643-645.
  4. Sullivan KM, Furst DE. The evolving role of blood and marrow transplantation for the treatment of autoimmune diseases. J Rheumatol Suppl 1997; 48:1-4.
  5. Tamm M, Gratwohl A, Tichelli A, et al. Autologous haemopoietic stem cell transplantation in a patient with severe pulmonary hypertension complicating connective tissue disease. Ann Rheum Dis 1996; 55:779-780.
  6. Binks M, Passweg JR, Furst D, et al. Phase I/II trial of autologous stem cell transplantation in systemic sclerosis: procedure related mortality and impact on skin disease. Ann Rheum Dis 2001; 60:577-584.
  7. Farge D, Passweg J, van Laar JM, et al. Autologous stem cell transplantation in the treatment of systemic sclerosis: report from the EBMT/EULAR Registry. Ann Rheum Dis 2004; 63:974-981.
  8. McSweeney PA, Nash RA, Sullivan KM, et al. High-dose immunosuppressive therapy for severe systemic sclerosis: initial outcomes. Blood 2002; 100:1602-1610.
  9. Nash RA, McSweeney PA, Crofford LJ, et al. High-dose immunosuppressive therapy and autologous hematopoietic cell transplantation for severe systemic sclerosis: long-term follow-up of the U.S. multicenter pilot study. Blood 2007; 23 April [Epub ahead of print].
  10. Bryan C, Knight C, Black CM, Silman AJ. Prediction of five-year survival following presentation with scleroderma: development of a simple model using three disease factors at first visit. Arthritis Rheum 1999; 42:2660-2665.
  11. ?? Coghlan JG, Handler CE, Kottaridis PD. Cardiac assessment of patients for haematopoietic stem cell transplantation. Best Pract Res Clin Haematol 2007; 20:247-263. Excellent summary of cardiac aspects of HSCT risk/benefit assessment.
  12. Ferri C, Giuggioli D, Sebastiani M, et al. Heart involvement and systemic sclerosis. Lupus 2005; 14:702-707.
  13. Desai SR, Veeraraghavan S, Hansell DM, et al. CT features of lung disease in patients with systemic sclerosis: comparison with idiopathic pulmonary fibrosis and nonspecific interstitial pneumonia. Radiology 2004; 232:560-567.
  14. Muraro PA, Douek DC, Packer A, et al. Thymic output generates a new and diverse TCR repertoire after autologous stem cell transplantation in multiple sclerosis patients. J Exp Med 2005; 201:805-816.
  15. ?? Verrecchia F, Laboureau J, Verola O, et al. Skin involvement in scleroderma: where histological and clinical scores meet. Rheumatology (Oxford) 2007; 46:833-841. Evidence of remodelling of collagen after HSCT.
  16. Nash RA, McSweeney PA, Nelson JL, et al. Allogeneic marrow transplantation in patients with severe systemic sclerosis: resolution of dermal fibrosis. Arthritis Rheum 2006; 54:1982-1986.
  17. van Laar JM, Farge D, Tyndall A. Autologous Stem Cell Transplantation International Scleroderma (ASTIS) trial: hope on the horizon for patients with severe systemic sclerosis. Ann Rheum Dis 2005; 64:1515.
  18. van Laar JM, Tyndall A. Adult stem cells in the treatment of autoimmune diseases. Rheumatology (Oxford) 2006; 45:1187-1193.
  19. Hoyles RK, Ellis RW, Wellsbury J, et al. A multicenter, prospective, randomized, double-blind, placebo-controlled trial of corticosteroids and intravenous cyclophosphamide followed by oral azathioprine for the treatment of pulmonary fibrosis in scleroderma. Arthritis Rheum 2006; 54:3962-3970.
  20. Tashkin DP, Elashoff R, Clements PJ, et al. Cyclophosphamide versus placebo in scleroderma lung disease. N Engl J Med 2006; 354:2655-2666.
  21. Khorshid O, Hosing C, Bibawi S, et al. Nonmyeloablative stem cell transplant in a patient with advanced systemic sclerosis and systemic lupus erythematosus. J Rheumatol 2004; 31:2513-2516.
  22. Griffith LM, Pavletic SZ, Tyndall A, et al. Target populations in allogeneic hematopoietic cell transplantation for autoimmune diseases - a workshop accompanying: cellular therapy for treatment of autoimmune diseases, basic science and clinical studies, including new developments in hematopoietic and mesenchymal stem cell therapy. Biol Blood Marrow Transplant 2006; 12:688-690.
  23. Friedenstein AJ, Petrakova KV, Kurolesova AI, Frolova GP. Heterotopic of bone marrow: analysis of precursor cells for osteogenic and hematopoietic tissues. Transplantation 1968; 6:230-247.
  24. Haynesworth SE, Goshima J, Goldberg VM, Caplan AI. Characterization of cells with osteogenic potential from human marrow. Bone 1992; 13:81-88.
  25. Prockop DJ. Marrow stromal cells as stem cells for nonhematopoietic tissues. Science 1997; 276:71-74.
  26. Pittenger MF, Mackay AM, Beck SC, et al. Multilineage potential of adult human mesenchymal stem cells. Science 1999; 284:143-147.
  27. Friedenstein AJ, Deriglasova UF, Kulagina NN, et al. Precursors for fibroblasts in different populations of hematopoietic cells as detected by the in vitro colony assay method. Exp Hematol 1974; 2:83-92.
  28. Nakahara H, Dennis JE, Bruder SP, et al. In vitro differentiation of bone and hypertrophic cartilage from periosteal-derived cells. Exp Cell Res 1991; 195:492-503.
  29. Sampath TK, Nathanson MA, Reddi AH. In vitro transformation of mesenchymal cells derived from embryonic muscle into cartilage in response to extracellular matrix components of bone. Proc Natl Acad Sci USA 1984; 81:3419-3423.
  30. Jones EA, Kinsey SE, English A, et al. Isolation and characterization of bone marrow multipotential mesenchymal progenitor cells. Arthritis Rheum 2002; 46:3349-3360.
  31. Deans RJ, Moseley AB. Mesenchymal stem cells: biology and potential clinical uses. Exp Hematol 2000; 28:875-884.
  32. Barry F, Boynton R, Murphy M, et al. The SH-3 and SH-4 antibodies recognize distinct epitopes on CD73 from human mesenchymal stem cells. Biochem Biophys Res Commun 2001; 289:519-524.
  33. Barry FP, Boynton RE, Haynesworth S, et al. The monoclonal antibody SH-2, raised against human mesenchymal stem cells, recognizes an epitope on endoglin (CD105). Biochem Biophys Res Commun 1999; 265:134-139.
  34. ?? Tyndall A, LeBlanc K. Stem cells and rheumatology: update on adult stem cell therapy in autoimmune diseases. Arthritis Rheum 2006; 55:521-525.
  35. Tse WT, Pendleton JD, Beyer WM, et al. Suppression of allogeneic T-cell proliferation by human marrow stromal cells: implications in transplantation. Transplantation 2003; 75:389-397.
  36. Le Blanc K, Tammik C, Rosendahl K, et al. HLA expression and immunologic properties of differentiated and undifferentiated mesenchymal stem cells. Exp Hematol 2003; 31:890-896.
  37. Klyushnenkova E, Mosca JD, Zernetkina V, et al. T cell responses to allogeneic human mesenchymal stem cells: immunogenicity, tolerance, and suppression. J Biomed Sci 2005; 12:47-57.
  38. Di Nicola M, Carlo-Stella C, Magni M, et al. Human bone marrow stromal cells suppress T-lymphocyte proliferation induced by cellular or nonspecific mitogenic stimuli. Blood 2002; 99:3838-3843.
  39. Nauta AJ, Westerhuis G, Kruisselbrink AB, et al. Donor-derived mesenchymal stem cells are immunogenic in an allogeneic host and stimulate donor graft rejection in a nonmyeloablative setting. Blood 2006; 108:2114-2120.
  40. Sotiropoulou PA, Perez SA, Gritzapis AD, et al. Interactions between human mesenchymal stem cells and natural killer cells. Stem Cells 2006; 24:74-85.
  41. Le Blanc K, Tammik L, Sundberg B, et al. Mesenchymal stem cells inhibit and stimulate mixed lymphocyte cultures and mitogenic responses independently of the major histocompatibility complex. Scand J Immunol 2003; 57:11-20.
  42. Krampera M, Glennie S, Dyson J, et al. Bone marrow mesenchymal stem cells inhibit the response of naive and memory antigen-specific T cells to their cognate peptide. Blood 2003; 101:3722-3729.
  43. Bartholomew A, Sturgeon C, Siatskas M, et al. Mesenchymal stem cells suppress lymphocyte proliferation in vitro and prolong skin graft survival in vivo. Exp Hematol 2002; 30:42-48.
  44. Corcione A, Benvenuto F, Ferretti E, et al. Human mesenchymal stem cells modulate B cell functions. Blood 2006; 107:367-372.
  45. Glennie S, Soeiro I, Dyson PJ, et al. Bone marrow mesenchymal stem cells induce division arrest anergy of activated T cells. Blood 2005; 105:2821-2827.
  46. Rasmusson I, Ringden O, Sundberg B, Le Blanc K. Mesenchymal stem cells inhibit the formation of cytotoxic T lymphocytes, but not activated cytotoxic T lymphocytes or natural killer cells. Transplantation 2003; 76:1208-1213.
  47. Aggarwal S, Pittenger MF. Human mesenchymal stem cells modulate allogeneic immune cell responses. Blood 2005; 105:1815-1822.
  48. Meisel R, Zibert A, Laryea M, et al. Human bone marrow stromal cells inhibit allogeneic T-cell responses by indoleamine 2,3-dioxygenase-mediated tryptophan degradation. Blood 2004; 103:4619-4621.
  49. Sato K, Ozaki K, Oh I, et al. Nitric oxide plays a critical role in suppression of T cell proliferation by mesenchymal stem cells. Blood 2007; 109:228-234.
  50. Ortiz LA, Gambelli F, McBride C, et al. Mesenchymal stem cell engraftment in lung is enhanced in response to bleomycin exposure and ameliorates its fibrotic effects. Proc Natl Acad Sci USA 2003; 100:8407-8411.
  51. Fang B, Shi M, Liao L, et al. Systemic infusion of FLK1(+) mesenchymal stem cells ameliorate carbon tetrachloride-induced liver fibrosis in mice. Transplantation 2004; 78:83-88.
  52. Togel F, Hu Z, Weiss K, et al. Administered mesenchymal stem cells protect against ischemic acute renal failure through differentiation-independent mechanisms. Am J Physiol Renal Physiol 2005; 289:F31-F42.
  53. ?? Bocelli-Tyndall C, Bracci L, Spagnoli G, et al. Bone marrow mesenchymal stromal cells (BM-MSCs) from healthy donors and auto-immune disease patients reduce the proliferation of autologous- and allogeneic-stimulated lymphocytes in vitro. Rheumatology (Oxford) 2007; 46:403-408. First evidence that autologous MSCs from autoimmune disease patients have effective antiproliferative properties.
  54. Vonk MC, Marjanovic Z, van den Hoogen FH, et al. Long-term follow-up results after autologous haematopoietic stem cell transplantation for severe systemic sclerosis. Ann Rhem Dis 2007; 25 May [Epub ahead of print].
  55. Zhang J, Li Y, Chen J, et al. Human bone marrow stromal cell treatment improves neurological functional recovery in EAE mice. Exp Neurol 2005; 195:16-26.
  56. Zappia E, Casazza S, Pedemonte E, et al. Mesenchymal stem cells ameliorate experimental autoimmune encephalomyelitis inducing T-cell anergy. Blood 2005; 106:1755-1761.
  57. Djouad F, Fritz V, Apparailly F, et al. Reversal of the immunosuppressive properties of mesenchymal stem cells by tumor necrosis factor alpha in collagen-induced arthritis. Arthritis Rheum 2005; 52:1595-1603.
  58. Augello A, Tasso R, Negrini SM, et al. Cell therapy using allogeneic bone marrow mesenchymal stem cells prevents tissue damage in collagen-induced arthritis. Arthritis Rheum 2007; 56:1175-1186.
  59. Lazarus HM, Haynesworth SE, Gerson SL, et al. Ex vivo expansion and subsequent infusion of human bone marrow-derived stromal progenitor cells (mesenchymal progenitor cells): implications for therapeutic use. Bone Marrow Transplant 1995; 16:557-564.
  60. Lazarus HM, Koc ON, Devine SM, et al. Cotransplantation of HLA-identical sibling culture-expanded mesenchymal stem cells and hematopoietic stem cells in hematologic malignancy patients. Biol Blood Marrow Transplant 2005; 11:389-398.
  61. Koc ON, Day J, Nieder M, et al. Allogeneic mesenchymal stem cell infusion for treatment of metachromatic leukodystrophy (MLD) and Hurler syndrome (MPS-IH). Bone Marrow Transplant 2002; 30:215-222.
  62. Koc ON, Gerson SL, Cooper BW, et al. Rapid hematopoietic recovery after coinfusion of autologous-blood stem cells and culture-expanded marrow mesenchymal stem cells in advanced breast cancer patients receiving high-dose chemotherapy. J Clin Oncol 2000; 18:307-316.
  63. Horwitz EM, Gordon PL, Koo WK, et al. Isolated allogeneic bone marrow-derived mesenchymal cells engraft and stimulate growth in children with osteogenesis imperfecta: implications for cell therapy of bone. Proc Natl Acad Sci USA 2002; 99:8932-8937.
  64. Fouillard L, Bensidhoum M, Bories D, et al. Engraftment of allogeneic mesenchymal stem cells in the bone marrow of a patient with severe idiopathic aplastic anemia improves stroma. Leukemia 2003; 17:474-476.
  65. Le Blanc K, Rasmusson I, Sundberg B, et al. Treatment of severe acute graft-versus-host disease with third party haploidentical mesenchymal stem cells. Lancet 2004; 363:1439-1441.

Acknowledgements

We would like to thank AMGEN and Genzyme for unrestricted research grants and EULAR and the Horton Foundation, Switzerland for part financial support for the ASTIS study. In addition, the SCOT trial is supported by the NIH/NIAMS. Our gratitude also extends to Prof. Jakob Passweg and Dr Chiara Bocelli-Tyndall for gathering the data for the phase I/II studies and Prof. Jakop van Laar and Prof. Dominique Farge for an update on the ASTIS study and the EBMT registry.

Abbreviation Notes

ASTIS = Autologous Stem cell Transplantation International Scleroderma; EBMT = European Group for Blood and Marrow Transplantation; EULAR = European League Against Rheumatism; GvHD = graft versus host disease; HSCT = hematopoietic stem cell transplantation; MSC = mesenchymal stem cell; SCOT = Scleroderma Cyclophosphamide Or Transplant; SSc = systemic sclerosis; TRM = transplant-related mortality

Reprint Address

Correspondence to Alan Tyndall, Department of Rheumatology Felix Platter Spital, Burgfelderstrasse 101, 4012 Basel, Switzerland Tel: +41 61 326 4003; fax: +41 61 3264010; e-mail: alan.tyndall@fps-basel.ch
Alan Tyndalla and Daniel E. Furstb

aDepartment of Rheumatology, University of Basel, Switzerland
bDepartment of Rheumatology, Geffen School of Medicine at the University of California in Los Angeles, USA