Hematopoietic stem cell transplantation in multiple sclerosis

[Current concepts on intrathecal humoral immune response and diagnostic importance of oligoclonal immunoglobulins in multiple sclerosis]

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system of probable autoimmune origin. In this review of literature, the authors present a constantly broadening list of potential antigens, including myelin and non-myelin structures, that cause the autoimmune reaction. Determination of antibodies to any antigen has not sufficient specificity and sensitivity for the use in routine laboratory practice. Oligoclonal immunoglobulins determined with isoelectric focusing (IEF) technique are currently considered as the main immunological MS markers. The sensitivity and specificity of IEF are 90 and 86%, respectively. The authors have considered the additional markers such as oligoclonal IgM and MRZ-response.

[The role and place of high-dose immunosuppressive therapy and autologous transplantation of hematopoietic stem cells for autoimmune diseases]

AIM

To determine the possible boundaries of high-dose immunosuppressive therapy and autologous hematopoietic stem cell transplantation (HDIT-autoHSCT) for autoimmune diseases (AUDs), such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and multiple sclerosis (MS).

SUBJECTS AND METHODS

A long-term trial was conducted at one center to evaluate the efficiency and safety of HDIT-autoHSCT in patients with AUDs. The previous standard therapy was noted to be resistant or lowly effective. The age of 10 patients with systemic connective tissue diseases was 27.6±2.8 years; the pre-HDIT-autoHSCT disease duration was 5.9±1.3 years; the median posttransplantation follow-up was 39.3 months. The age of 49 patients with MS reached 34.9±1.33 years; the pretransplantation disease duration was 8.4±0.69 years; the median post-HDIT-autoHSCT follow-up was 42 months. The efficiency of transplantation was evaluated on the basis of clinical findings, by using scales, laboratory tests, and magnetic resonance imaging. Pretransplantation conditioning was carried out according to the protocols: a) BEAM + antilymphocyte globulin (ALG); b) fludarabine + melphalan + ALG. No fatal outcomes due to a transplant procedure were observed.

RESULTS

Overall 5-year survival after transplantation was 80% for systemic connective tissue diseases and 95% for MS; 5-year progression-free survival rates were 30% in the RA and SLE groups and 45% in the MS group. HDIT-autoHSCT turned out safe and reduced the activity of the process and further disease progression for a long period of time, as confirmed by regression of clinical symptoms and/or status stabilization in 9 patients with SLE or RA and in all patients with MS.

CONCLUSION

The favorable factors associated with the results of transplantation are age younger than 35 years in collagenoses with their short-term duration and moderate signs; age younger than 40 years in MS with a disease duration of less than 10 years and expanded disability status scale scores of not more than 6.5. Of importance are functional system scores, duration of first remission, and an index of disease progression in different types of MS.

Immune mechanisms underlying the beneficial effects of autologous hematopoietic stem cell transplantation in multiple sclerosis

A recent phase I/II clinical trial drew serious attention to the therapeutic potential of autologous hematopoietic stem cell transplantation (AHSCT) in multiple sclerosis. However, questions were raised as to whether these beneficial effects should be attributed to the newly reconstituted immune system per se, or to the lymphoablative conditioning regimen-induced immunosuppression, given that T-cell depleting combinational drug therapies were used in the study. We discuss here the possibility that both AHSCT and T-cell depleting therapies may re-program alternatively the immune system, and why transplantation of CD34+ hematopoietic stem cells may offer AHSCT a possible advantage regarding long-term remission.

Mesenchymal stem cells for the treatment of neurodegenerative disease

Mesenchymal stem cells/marrow stromal cells (MSCs) present a promising tool for cell therapy, and are currently being tested in US FDA-approved clinical trials for myocardial infarction, stroke, meniscus injury, limb ischemia, graft-versus-host disease and autoimmune disorders. They have been extensively tested and proven effective in preclinical studies for these and many other disorders. There is currently a great deal of interest in the use of MSCs to treat neurodegenerative diseases, in particular for those that are fatal and difficult to treat, such as Huntington's disease and amyotrophic lateral sclerosis. Proposed regenerative approaches to neurological diseases using MSCs include cell therapies in which cells are delivered via intracerebral or intrathecal injection. Upon transplantation into the brain, MSCs promote endogenous neuronal growth, decrease apoptosis, reduce levels of free radicals, encourage synaptic connection from damaged neurons and regulate inflammation, primarily through paracrine actions. MSCs transplanted into the brain have been demonstrated to promote functional recovery by producing trophic factors that induce survival and regeneration of host neurons. Therapies will capitalize on the innate trophic support from MSCs or on augmented growth factor support, such as delivering brain-derived neurotrophic factor or glial-derived neurotrophic factor into the brain to support injured neurons, using genetically engineered MSCs as the delivery vehicles. Clinical trials for MSC injection into the CNS to treat traumatic brain injury and stroke are currently ongoing. The current data in support of applying MSC-based cellular therapies to the treatment of neurodegenerative disorders are discussed.