Early identification of interferon-beta responders by ex vivo testing in patients with multiple sclerosis

Pharmacogenomic update on multiple sclerosis: a focus on actual and new therapeutic strategies

Multiple sclerosis (MS) is an inflammatory and demyelinating disease of central nervous system comprising several subtypes. Pharmacological treatment involves only few drugs. Among these, interferon beta (IFN-β) and glatiramer acetate were the most used. Although evidence supports the efficacy of these agents in treating MS symptoms, actual studies allowed to introduce new innovative drugs in clinical practice. Applying pharmacogenetic approach to MS, IFN-β and several other immune pathways were abundantly investigated. Numerous reports identified some promising therapy markers but only few markers have emerged as clinically useful. This may be partially due to differences in clinical and methodological criteria in the studies. Indeed, responder and non-responder definitions lack standardized clinical definition. The goal of this review is to treat advances in research on the pharmacogenetic markers of MS drugs and to highlight possible correlations between type of responses and genetic profile, with regard to clinical and methodological discrepancies in the studies.

Immune response during interferon beta-1b treatment in patients with multiple sclerosis who experienced relapses and those who were relapse-free in the START study

We measured immune markers in subjects with multiple sclerosis (MS) treated with IFNβ-1b for 12 months. IL-17 levels were significantly higher at Month 6 (p=0.036) in relapsing subjects while BDNF levels were significantly higher at Month 3 (p=0.028) in relapse-free subjects. Change from baseline in IL-4 levels inversely correlated with disability score whereas change from baseline in IL-10/IFN-gamma ratio inversely correlated with occurrence of relapses. CXCR3+CD8+ T-cells tended to be higher but declined with treatment in relapse-free compared with relapsing subjects. Findings show the potential of cytokine and neurotrophic factors as biomarkers of clinical response to IFNβ-1b.

Excessive biologic response to IFNβ is associated with poor treatment response in patients with multiple sclerosis

BACKGROUND

Interferon-beta (IFNβ) is used to inhibit disease activity in multiple sclerosis (MS), but its mechanisms of action are incompletely understood, individual treatment response varies, and biological markers predicting response to treatment have yet to be identified.

METHODS

The relationship between the molecular response to IFNβ and treatment response was determined in 85 patients using a longitudinal design in which treatment effect was categorized by brain magnetic resonance imaging as good (n = 70) or poor response (n = 15). Molecular response was quantified using a customized cDNA macroarray assay for 166 IFN-regulated genes (IRGs).

RESULTS

The molecular response to IFNβ differed significantly between patients in the pattern and number of regulated genes. The molecular response was strikingly stable for individuals for as long as 24 months, however, suggesting an individual 'IFN response fingerprint'. Unexpectedly, patients with poor response showed an exaggerated molecular response. IRG induction ratios demonstrated an exaggerated molecular response at both the first and 6-month IFNβ injections.

CONCLUSION

MS patients exhibit individually unique but temporally stable biological responses to IFNβ. Poor treatment response is not explained by the duration of biological effects or the specific genes induced. Rather, individuals with poor treatment response have a generally exaggerated biological response to type 1 IFN injections. We hypothesize that the molecular response to type I IFN identifies a pathogenetically distinct subset of MS patients whose disease is driven in part by innate immunity. The findings suggest a strategy for biologically based, rational use of IFNβ for individual MS patients.

Effects of interferon-beta therapy on innate and adaptive immune responses to the human endogenous retroviruses HERV-H and HERV-W, cytokine production, and the lectin complement activation pathway in multiple sclerosis

The effects of treatment of multiple sclerosis patients with IFN-beta on elements in the innate and adaptive immune response were analysed in a longitudinal study. We demonstrate significant decreases in anti-Envelope antibody reactivity for the two closely related Gammaretroviral human endogenous retroviruses (HERVs), HERV-H and HERV-W, as a consequence of IFN-beta therapy, closely linked to efficacy of therapy/low disease activity. We also show strong indications of a protective effect of high levels of two components in the innate pathogen-associated molecular pattern recognition: mannan-binding lectin (MBL), and MBL-associated serine protease 3 (MASP-3). Serum levels of typical Th1- and Th2-related, MS-relevant cytokines were also monitored. Overall both Th1- and Th2-associated cytokines were modestly, albeit significantly up-regulated, notably IL-2 and TNF-alpha (MS patients with inactive disease), as well as IL-4 and, to some extent IL-10 (no increase in IL-10 for MS patients with active disease (non-responders)). We found no overall changes in Th1/Th2 ratios. Our results support that HERV-H/HERV-W and the antiviral immune response may play a role in MS development, and that these HERVs have potential as biomarkers for disease activity.

Interferon-beta treatment in multiple sclerosis attenuates inflammatory gene expression through inducible activity of the phosphatase SHP-1

Interferon-beta is a current treatment for multiple sclerosis (MS). Interferon-beta is thought to exert its therapeutic effects on MS by down-modulating the immune response by multiple potential pathways. Here, we document that treatment of MS patients with interferon beta-1a (Rebif) results in a significant increase in the levels and function of the protein tyrosine phosphatase SHP-1 in PBMCs. SHP-1 is a crucial negative regulator of cytokine signaling, inflammatory gene expression, and CNS demyelination as evidenced in mice deficient in SHP-1. In order to examine the functional significance of SHP-1 induction in MS PBMCs, we analyzed the activity of proinflammatory signaling molecules STAT1, STAT6, and NF-kappaB, which are known SHP-1 targets. Interferon-beta treatment in vivo resulted in decreased NF-kappaB and STAT6 activation and increased STAT1 activation. Further analysis in vitro showed that cultured PBMCs of MS patients and normal subjects had a significant SHP-1 induction following interferon-beta treatment that correlated with decreased NF-kappaB and STAT6 activation. Most importantly, experimental depletion of SHP-1 in cultured PBMCs abolished the anti-inflammatory effects of interferon-beta treatment, indicating that SHP-1 is a predominant mediator of interferon-beta activity. In conclusion, interferon-beta treatment upregulates SHP-1 expression resulting in decreased transcription factor activation and inflammatory gene expression important in MS pathogenesis.

A single nucleotide polymorphism in Tyk2 controls susceptibility to experimental allergic encephalomyelitis

Genes controlling immunopathologic diseases of differing etiopathology may also influence susceptibility to autoimmune disease. B10.D1-H2(q)/SgJ mice with a 2538 G-->A missense mutation in the tyrosine kinase-2 gene (Tyk2) are susceptible to Toxoplasma gondii yet resistant to autoimmune arthritis, unlike the wild-type B10.Q/Ai substrain. To understand whether Tyk2 is also important in a second autoimmune model, experimental allergic encephalomyelitis (EAE) was induced in B10.D1-H2(q)/SgJ (Tyk2(A)) and B10.Q/Ai (Tyk2(G)) mice with the myelin oligodendrocyte glycoprotein peptide 79-96. B10.D1-H2(q)/SgJ mice were resistant to EAE whereas B10.Q/Ai mice were susceptible, and a single copy of the Tyk2(G) allele conferred EAE susceptibility in F(1) hybrids. Furthermore, EAE resistance in B10.D1-H2(q)/SgJ mice was overridden when pertussis toxin (PTX) was used to mimic the effects of environmental factors derived from infectious agents. Numerous cytokines and chemokines were increased when PTX was included in the immunization protocol. However, only RANTES, IL-6, and IFN-gamma increased significantly with both genetic compensation and PTX treatment. These data indicate that Tyk2 is a shared autoimmune disease susceptibility gene whose genetic contribution to disease susceptibility can be modified by environmental factors. Single nucleotide polymorphisms like the one that distinguishes Tyk2 alleles are of considerable significance given the potential role of gene-by-environment interactions in autoimmune disease susceptibility.

Current approaches to the identification and management of breakthrough disease in patients with multiple sclerosis

Disease-modifying drugs (DMDs) for relapsing-remitting multiple sclerosis (RRMS) are only partly effective -- breakthrough disease commonly occurs despite treatment. Breakthrough disease is predictive of continued disease activity and a poor prognosis. Availability of several DMDs offers the possibility of tailoring treatment to individual patients with RRMS and altering treatment in patients with breakthrough disease. However, no biological or imaging markers have been validated to guide initial treatment, markers of individual responsiveness to DMDs are scarce, and there is no class 1 evidence to guide alternative therapy in patients with breakthrough disease. In this Review, we discuss proposed strategies to monitor patients with RRMS being treated with DMDs, outline approaches to identifying therapeutic response in individual patients, review MRI and biological markers of treatment response, and summarise the role of antibodies in biological therapies. We also outline possible strategies for the management of patients with breakthrough disease and highlight areas in which research is needed.

Therapeutic potential of IL-27 in multiple sclerosis?

BACKGROUND

Multiple sclerosis (MS) is a debilitating neurological disease, characterized by inflammatory demyelination and axonal degeneration in the CNS. Currently approved therapies are partially effective, however safer and more effective treatments are needed.

OBJECTIVE/METHODS

To assess the therapeutic potential of the heterodimeric cytokine, IL-27 in MS, based on the current literature.

RESULTS/CONCLUSIONS

IL-27 exerts profound anti-inflammatory effects in several infectious and experimental autoimmune models. In particular, suppressive effects on helper T cells, which are implicated in the pathogenesis of MS, suggest that IL-27 may be therapeutically relevant in MS. However, while exciting discoveries have been made, further work is required particularly in human health and disease, to understand the diverse roles of IL-27 and its therapeutic potential.