Stem cell therapy for autoimmune disease: overview of concepts from the Snowbird 2002 tolerance and tissue regeneration meeting

Acquisition and Cure of Autoimmune Disease Following Allogeneic Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation (HSCT) can either cause or eliminate autoimmune disease. Here, we report two cases. One was a 33-year-old woman with myelodysplastic syndrome (refractory anemia) who received bone marrow transplantation from her human leukocyte antigen (HLA)-identical sister who had a history of Graves disease. Antithyroid antibodies, including antimicrosomal antibody and antithyroglobulin antibody, appeared 4 months after transplantation. Clinical hyperthyroidism appeared 7 months after transplantation, and a hypothyroid state was noted 2 months later. The other case was a 50-year-old woman with Sjgrens syndrome and hypothyroidism who was diagnosed with peripheral T cell non-Hodgkins lymphoma. She received allogeneic peripheral blood stem cell transplantation (PBSCT) from her histocompatible sister owing to only partial response to traditional chemotherapy. Cure of lymphoma and remission of Sjgrens syndrome was noted 4 years after PBSCT. These two illustrative cases, one of acquisition of hyperthyroidism and the other of remission of Sjgrens syndrome after transplantation, highlights that HSCT can induce adoptive autoimmune disease or cure coincidental autoimmune disease. Donor selection and attentive monitoring is required in such circumstances.

A phase I-II trial of autologous peripheral blood stem cell transplantation in the treatment of refractory autoimmune disease

OBJECTIVES

To carry out a phase I-II trial to elucidate the feasibility and efficacy of high dose cyclophosphamide (CY) supported by autologous peripheral blood stem cell transplantation (PBSCT) in the treatment of severe and refractory autoimmune disease (AD).

METHODS

Peripheral blood stem cells (PBSCs) were mobilised during haematological recovery after relatively high dose CY (2 g/m2) for 2 days, followed by administration of granulocyte colony stimulating factor. After collecting PBSCs--more than 2x10(6) CD34+ cells/kg--by apheresis, CD34+ cells were immunologically selected and cryopreserved. Eight patients were enrolled--five had systemic sclerosis (SSc) alone, one had SSc with systemic lupus erythematosus, one amyopathic dermatomyositis (ADM), and one Wegener's granulomatosis (WG). All of the patients were treated with high dose CY (50 mg/kg) for 4 days and autologous PBSCT.

RESULTS

Haematopoietic reconstitution was rapid and sustained. Toxicity due to the regimen included various infections such as pneumonia, sepsis, cystitis, herpes zoster, and acute heart failure. However, there was no treatment related mortality. Encouraging results were obtained after autologous PBSCT. Sclerosis of the skin was markedly improved in all of the patients with SSc. Interstitial pneumonia (IP), evaluated by PaO2, serum KL-6 levels, and pulmonary high resolution computed tomography, improved significantly. In a patient with ADM, severe and progressive IP also improved markedly. In a patient with WG, the size of the left orbital granuloma decreased substantially, resulting in reduction of the exophthalmos.

CONCLUSIONS

These observations suggest that high dose CY with autologous PBSCT is feasible and may be effective in the treatment of severe and refractory AD.

Impact of human leucocyte antigen mismatch on graft-versus-host disease and graft failure after reduced intensity conditioning allogeneic haematopoietic stem cell transplantation from related donors

The impact of human leucocyte antigen (HLA) incompatibility between donor and recipient on graft-versus-host disease (GVHD) and graft failure after reduced-intensity conditioning stem cell transplantation (RICT) remains to be elucidated. We retrospectively analysed outcome in 341 patients who underwent RICT from related donors for haematological malignancies. The overall cumulative incidence of grade II-IV acute GVHD (aGVHD) was 40% for all subjects; 39% in recipients with HLA-matched donors, 44% in those with one-locus-mismatched donors, and 50% in those with two- to three-loci-mismatched donors. In a Cox regression model adjusted for potential confounders, the tendency for grade II-IV aGVHD (P=0.01), chronic GVHD (cGVHD) (P=0.05) and graft failure (P=0.033) increased with HLA disparity. Use of peripheral blood grafts instead of marrow was a risk factor for cGVHD. Use of antithymocyte globulin was associated with reduced aGVHD and cGVHD. Overall survival (OS) in recipients of two- to three-loci-mismatched RICT at 2 years (18%) was significantly worse than that in patients who received one-locus-mismatched RICT (51%) and HLA-matched RICT (48%) (P<0.0001). A two- to three-loci mismatch was identified as an independent risk factor for OS (P<0.001), but there was no significant difference in OS between HLA-matched and one-locus-mismatched RICT. HLA incompatibility between the donor and recipient is an important risk factor for graft failure, aGVHD, cGVHD and OS after RICT. RICT from a one-locus-mismatched donor may represent an effective alternative approach in patients with high-risk malignancies who lack HLA-matched related donors.

Rituximab in autoimmune diseases

Modern treatments of autoimmune diseases are based on immunological therapies. Rituximab induces a targeted B-cell depletion in the aim of eradicating autoreactive clones in various autoimmune disorders. Several studies are being undertaken and preliminary reports are very encouraging. The mechanism of action is not evident, but appears to be connected with the lowering of autoantibody levels, in the diseases where relevant antibody titres are relievable. Most of the patients treated were affected by idiopathic thrombocytopenic purpura (ITP) and autoimmune haemolytic anaemia, but also very rare diseases like acquired haemophilia are reported. Best results are described in autoimmune haemolytic anaemia, in many others there is clear evidence for efficacy; in all the diseases the number of complete or partial remission, though temporary, is much greater than 50%. Side effects are rarely reported, and immunosuppression is not a great problem. The persistence of clinical improvement for more than 1 year after B-lymphocyte repopulation supports the hypothesis of a stochastic generation of pathogenic B-cell subsets. Other studies and controlled trials are required to establish when and which patients are to be treated, and find the opportunity of the association of others drugs.