Natural alpha interferon in multiple sclerosis: results of three preliminary series

The Role of Interferon-α in Neurodegenerative Diseases: A Systematic Review

BACKGROUND

Neurodegenerative diseases (NDs) impose significant financial and healthcare burden on populations all over the world. The prevalence and incidence of NDs have been observed to increase dramatically with age. Hence, the number of reported cases is projected to increase in the future, as life spans continues to rise. Despite this, there is limited effective treatment against most NDs. Interferons (IFNs), a family of cytokines, have been suggested as a promising therapeutic target for NDs, particularly IFN-α, which governs various pathological pathways in different NDs.

OBJECTIVE

This systematic review aimed to critically appraise the currently available literature on the pathological role of IFN-α in neurodegeneration/NDs.

METHODS

Three databases, Scopus, PubMed, and Ovid Medline, were utilized for the literature search.

RESULTS

A total of 77 journal articles were selected for critical evaluation, based on the inclusion and exclusion criteria. The studies selected and elucidated in this current systematic review have showed that IFN-α may play a deleterious role in neurodegenerative diseases through its strong association with the inflammatory processes resulting in mainly neurocognitive impairments. IFN-α may be displaying its neurotoxic function via various mechanisms such as abnormal calcium mineralization, activation of STAT1-dependent mechanisms, and increased quinolinic acid production.

CONCLUSION

The exact role IFN-α in these neurodegenerative diseases have yet to be determine due to a lack in more recent evidence, thereby creating a variability in the role of IFN-α. Future investigations should thus be conducted, so that the role played by IFN-α in neurodegenerative diseases could be delineated.

Treatment of Experimental Autoimmune Encephalomyelitis by Sustained Delivery of Low-Dose IFN-α

Multiple sclerosis (MS) is a chronic autoimmune disease with no curative treatment. The immune regulatory properties of type I IFNs have led to the approval of IFN-β for the treatment of relapsing-remitting MS. However, there is still an unmet need to improve the tolerability and efficacy of this therapy. In this work, we evaluated the sustained delivery of IFN-α1, either alone or fused to apolipoprotein A-1 by means of an adeno-associated viral (AAV) system in the mouse model of myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis. These in vivo experiments demonstrated the prophylactic and therapeutic efficacy of the AAV-IFN-α or AAV-IFN-α fused to apolipoprotein A-1 vectors in experimental autoimmune encephalomyelitis, even at low doses devoid of hematological or neurologic toxicity. The sustained delivery of such low-dose IFN-α resulted in immunomodulatory effects, consisting of proinflammatory monocyte and T regulatory cell expansion. Moreover, encephalitogenic T lymphocytes from IFN-α-treated mice re-exposed to the myelin oligodendrocyte glycoprotein peptide in vitro showed a reduced proliferative response and cytokine (IL-17A and IFN-γ) production, in addition to upregulation of immunosuppressive molecules, such as IL-10, IDO, or PD-1. In conclusion, the results of the present work support the potential of sustained delivery of low-dose IFN-α for the treatment of MS and likely other T cell-dependent chronic autoimmune disorders.

How type I interferons work in multiple sclerosis and other diseases: some unexpected mechanisms

Type I interferons (IFNs) are important in innate and adaptive immunity. They are used to treat virus infections, cancer, and multiple sclerosis (MS). There are 5 type I IFN families in humans-IFN-α with 13 subtypes, plus IFN-β, ɛ, κ, and ω. Because their receptor binding affinities vary, these IFNs have different gene induction profiles and quite variable therapeutic effects. IFN-α subtypes may each be specific for certain viruses, but can be neurotoxic. IFN-β induces IFN-α, plus has additional direct effects on target cells. IFN-β was the first therapy approved that could change the course of MS. It has broader specificity than IFN-α, enhances cognition in MS, and may be neuroprotective and can potentially enhance fertility in women. Priming the IFN signaling system with an injection of IFN-β can enhance subnormal type I IFN signals in MS. Many other commonly used drugs and vitamins may potentiate clinical benefits of IFN-β.

Type I IFN-mediated regulation of IL-1 production in inflammatory disorders

Although contributing to inflammatory responses and to the development of certain autoimmune pathologies, type I interferons (IFNs) are used for the treatment of viral, malignant, and even inflammatory diseases. Interleukin-1 (IL-1) is a strongly pyrogenic cytokine and its importance in the development of several inflammatory diseases is clearly established. While the therapeutic use of IL-1 blocking agents is particularly successful in the treatment of innate-driven inflammatory disorders, IFN treatment has mostly been appreciated in the management of multiple sclerosis. Interestingly, type I IFNs exert multifaceted immunomodulatory effects, including the reduction of IL-1 production, an outcome that could contribute to its efficacy in the treatment of inflammatory diseases. In this review, we summarize the current knowledge on IL-1 and IFN effects in different inflammatory disorders, the influence of IFNs on IL-1 production, and discuss possible therapeutic avenues based on these observations.

Multiple sclerosis associated with interferon-alpha therapy for chronic myelogenous leukemia

We report a chronic myelogenous leukemia (CML) patient in chronic phase (CP) who developed multiple sclerosis (MS) in association with interferon-alpha (IFN-alpha) administration. In our patient, recombinant IFN-alpha2b therapy induced hematologically complete and cytogenetically major partial response for CML first, and sequential central nervous system dysfunction evolved, which subsided shortly after the cessation of its administration. Restarting IFN-alpha therapy by changing to a natural type of IFN-alpha resulted in rapid exacerbation of MS. The patient's neurological symptoms progressed gradually, but partial hematologic response persisted without any IFN-alpha derivatives or anti-cancer agents until a matched unrelated donor transplant procedure was performed. Myeloablative therapy led to lasting stable state of MS and finally to complete cytogenetic remission of CML. This patient's presenting clinical course and laboratory data suggest that both exertion of anti-leukemic activity and autoimmune process of MS might be mediated by mutual mechanisms, such as enhancement of specific cellular immunity induced by IFN-alpha.

Recent developments in drug therapy for multiple sclerosis

Symptomatic treatment of multiple sclerosis (MS) includes a diverse range of drugs intended to relieve the specific symptoms with which a patient may present at a particular point in the progression of the disease. These drugs, not specifically designed for the treatment of MS, may include antispastic agents (e.g. baclofen), drugs to reduce tremor (e.g. clonazepam), anticholinergics (e.g. oxybutynin) which relieve urinary symptoms, anti-epileptics (e.g. carbamazepine) to control neuralgia, stimulants to reduce fatigue (e.g. amantadine), and antidepressants (e.g. fluoxetine) to treat depression. The treatment of acute relapses or exacerbations is dominated by corticosteroids such as methylprednisolone. The most active area of current investigation is the development of drugs which will inhibit the progression of the disease process itself, and in this category the beta- and alpha-interferons are the most effective drugs currently available, although many new treatments are currently in trials, including immunoglobulin, copolymer-1. bovine myelin, T-cell receptor (TCR) peptide vaccines, platelet activating factor (PAF) antagonists, matrix metallo-proteinase inhibitors, campath-1, and insulin-like growth factor (IGF).

Failure of treatment with Linomide or oral myelin tolerization to ameliorate demyelination in a viral model of multiple sclerosis

Both Linomide (quinoline-3-carboxamide) and tolerization with self-antigens have been demonstrated to successfully ameliorate demyelinating disease in experimental autoimmune encephalomyelitis (EAE). Based on the autoimmune hypothesis of multiple sclerosis (MS), both agents have been tested in clinical trials but have been found to be toxic or not efficacious. We investigated the efficacy of these immunomodulators in an alternative experimental model of MS, a virus-induced demyelinating disease. Oral administration of Linomide to Theiler's virus-infected mice beginning either at time of infection or at day 15 post-infection (p.i.) resulted in an increased percentage of spinal cord quadrants with demyelination. Administration of Linomide beginning at day 15 p.i. increased lesion size as compared to infected control-treated mice. Treatment with 80 mg kg(-1) day(-1) of Linomide beginning at the time of infection significantly increased the number of Theiler's murine encephalomyelitis virus (TMEV)-positive cells mm(-2) of spinal cord white matter. There were no differences in the amount of remyelination between mice treated with Linomide or water. However, chronically infected mice treated with Linomide had severely reduced spontaneous vertical activity as measured using a activity wheel. Oral tolerization of mice with mouse or bovine myelin had no effect on virus-induced demyelination or virus antigen expression. The contrasting results obtained between the TMEV model and the autoimmune model of demyelination do not support recent reports suggesting that the underlying mechanism of demyelination in the Theiler's model is autoimmune.