Allelic combinations of immune-response genes as possible composite markers of IFN-β efficacy in multiple sclerosis patients

CCR5 Δ32 and CTLA-4 +49 A/G Gene Polymorphisms and Interferon-β Treatment Response in Croatian and Slovenian Multiple Sclerosis Patients

The aim of the present study was to investigate the impact of CCR5 Δ32 and CTLA-4 polymorphisms on the response to IFN-β treatment in our cohort of MS patients from Croatia and Slovenia. Genomic DNA was obtained from 295 MS patients (230 female; 65 male) classified as responders (n = 173) and non-responders (n = 122) based on clinical criteria for treatment efficacy. Genotyping was performed via PCR/PCR-RFLP. No significant differences in the genotype/allele frequencies of CCR5Δ32 and CTLA-4 +49 A/G were detected between male responders and non-responders. A significantly higher prevalence (p = 0.039) of the CTLA-4 +49 AA genotype was found in female responders (42.1%) compared to non-responders (28.9%). Using multiple forward regression analysis, the CTLA-4 +49 AA genotype significantly predicted a positive response to IFN-β therapy in females (p = 0.011) and contributed to 4.5% of response variability. Furthermore, the combined presence of the CCR5Δ32 wtwt/CTLA-4 +49 AA genotype significantly predicted a positive response to treatment in females (p = 0.025). The age at disease onset, pretreatment relapse rate, and baseline EDSS score were not reliable predictors of treatment response in MS patients. Our results indicate that the presence of the CCR5Δ32 polymorphism was not associated with the response to IFN-β treatment, whereas the CTLA-4 +49 polymorphism showed a positive correlation with an optimal response in female patients.

Genetic variations in the PSMA6 and PSMC6 proteasome genes are associated with multiple sclerosis and response to interferon-β therapy in Latvians

Several polymorphisms in genes related to the ubiquitin-proteasome system exhibit an association with pathogenesis and prognosis of various human autoimmune diseases. Our previous study reported the association between multiple sclerosis (MS) and the PSMA3-rs2348071 polymorphism in the Latvian population. The current study aimed to evaluate the PSMA6 and PSMC6 genetic variations, their interaction between each other and with the rs2348071, on the susceptibility to MS risk and response to therapy in the Latvian population. PSMA6-rs2277460, -rs1048990 and PSMC6-rs2295826, -rs2295827 were genotyped in the MS case/control study and analysed in terms of genotype-protein correlation network. The possible association with the disease and alleles, single- and multi-locus genotypes and haplotypes of the studied loci was assessed. Response to therapy was evaluated in terms of 'no evidence of disease activity'. To the best of our knowledge, the present study was the first to report that single- and multi-loci variations in the PSMA6, PSMC6 and PSMA3 proteasome genes may have contributed to the risk of MS in the Latvian population. The results of the current study suggested a potential for the PSMA6-rs1048990 to be an independent marker for the prognosis of interferon-β therapy response. The genotype-phenotype network presented in the current study provided a new insight into the pathogenesis of MS and perspectives for future pharmaceutical interventions.

Pharmacogenomics of Multiple Sclerosis: A Systematic Review

Background: Over the past two decades, various novel disease-modifying drugs for multiple sclerosis (MS) have been approved. However, there is high variability in the patient response to the available medications, which is hypothesized to be partly attributed to genetics. Objectives: To conduct a systematic review of the current literature on the pharmacogenomics of MS therapy. Methods: A systematic literature search was conducted using PubMed/MEDLINE database searching for articles investigating a role of genetic variation in response to disease-modifying MS treatments, published in the English language up to October 9th, 2018. PRISMA guidelines for systematic reviews were applied. Studies were included if they investigated response or nonresponse to MS treatment defined as relapse rate, by expanded disability status scale score or based on magnetic resonance imaging. The following data were extracted: first author's last name, year of publication, PMID number, sample size, ethnicity of patients, method, genes, and polymorphisms tested, outcome, significant associations with corresponding P-values and confidence intervals, response criteria, and duration of the follow-up period. Results: Overall, 48 articles published up to October 2018, evaluating response to interferon-beta, glatiramer acetate, mitoxantrone, and natalizumab, met our inclusion criteria and were included in this review. Among those, we identified 42 (87.5%) candidate gene studies and 6 (12.5%) genome-wide association studies. Existing pharmacogenomic evidence is mainly based on the results of individual studies, or on results of multiple studies, which often lack consistency. In recent years, hypothesis-free approaches identified novel candidate genes that remain to be validated. Various study designs, including the definition of clinical response, duration of the follow-up period, and methodology as well as moderate sample sizes, likely contributed to discordances between studies. However, some of the significant associations were identified in the same genes, or in the genes involved in the same biological pathways. Conclusions: At the moment, there is no available clinically actionable pharmacogenomic biomarker that would enable more personalized treatment of MS. More large-scale studies with uniform design are needed to identify novel and validate existing pharmacogenomics findings. Furthermore, studies investigating associations between rare variants and treatment response in MS patients, using next-generation sequencing technologies are warranted.

Efficacy of Synthetic Peptide Corresponding to the ACTH-Like Sequence of Human Immunoglobulin G1 in Experimental Autoimmune Encephalomyelitis

Peptide immunocortin sequence corresponds to the amino acid residues 11-20 of the variable part of human immunoglobulin G1 (IgG1) heavy chain. Since immunocortin was shown previously to inhibit phagocytosis in peritoneal macrophages and ConA-induced T-lymphocytes proliferation in culture, we suggested that immunocortin administering may be of use for patients with self-immune syndrome. Immunocortin in concentration 10 μM inhibited proliferation of both antigen (myelin)-induced and ConA-induced LN lymphocytes isolated from the lymph nodes of Dark Agouti (DA) rats immunized with chorda shear. The biological trials of the synthetic immunocortin were carried out on the DA rats with induced experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. These in vivo experiments have shown that intraperitoneal injections of immunocortin in a daily dosage 100 μg per animal reduced symptoms of EAE in DA rats.

Pharmacogenetic Biomarkers to Predict Treatment Response in Multiple Sclerosis: Current and Future Perspectives

Disease-modifying therapies (DMTs) have significantly advanced the treatment of relapsing multiple sclerosis (MS), decreasing the frequency of relapses, disability, and magnetic resonance imaging lesion formation. However, patients' responses to and tolerability of DMTs vary considerably, creating an unmet need for biomarkers to identify likely responders and/or those who may have treatment-limiting adverse reactions. Most studies in MS have focused on the identification of pharmacogenetic markers, using either the candidate-gene approach, which requires prior knowledge of the genetic marker and its role in the target disease, or genome-wide association, which examines multiple genetic variants, typically single nucleotide polymorphisms (SNPs). Both approaches have implicated numerous alleles and SNPs in response to selected MS DMTs. None have been validated for use in clinical practice. This review covers pharmacogenetic markers in clinical practice in other diseases and then reviews the current status of MS DMT markers (interferon β, glatiramer acetate, and mitoxantrone). For a complex disease such as MS, multiple biomarkers may need to be evaluated simultaneously to identify potential responders. Efforts to identify relevant biomarkers are underway and will need to be expanded to all MS DMTs. These will require extensive validation in large patient groups before they can be used in clinical practice.

HLA genes as modifiers of response to IFN-β-1a therapy in relapsing-remitting multiple sclerosis

AIMS

This study investigated the influence of HLA class-I and -II genes in the response to IFN-β in relapsing-remitting multiple sclerosis (MS) patients.

PATIENTS & METHODS

In this cohort, 231 relapsing-remitting MS patients who are classified into IFN-β responders (n = 146) and nonresponders (n = 85) and 180 ethnic-matched healthy controls were analyzed. Clinical outcome of IFN-β therapy particularly Expanded Disability Status Scale scores were evaluated in relation to HLA-A, -B and -DRB1 alleles and haplotypes.

RESULTS

Increased frequencies of HLA-DRB1*04 allele and HLA-A*03-B*44-DRB1*04 haplotype, and decreased frequency of HLA-B*15 were associated with better response to IFN-β treatment.

CONCLUSION

The possibility of genetic screening particularly HLA typing prior to starting IFN-β therapy for MS may permit the identification of likely responders or nonresponders.

Comparative pharmacogenetics of multiple sclerosis: IFN-β versus glatiramer acetate

Various diseases require the selection of preferable treatment out of available alternatives. Multiple sclerosis (MS), an autoimmune inflammatory/neurodegenerative disease of the CNS, requires long-term medication with either specific disease-modifying therapy (DMT) - IFN-β or glatiramer acetate (GA) - which remain the only first-line DMTs in all countries. A significant share of MS patients are resistant to treatment with one or the other DMT; therefore, the earliest choice of preferable DMT is of particular importance. A number of conventional pharmacogenetic studies performed up to the present day have identified the treatment-sensitive genetic biomarkers that might be specific for the particular drug; however, the suitable biomarkers for selection of one or another first-line DMT are remained to be found. Comparative pharmacogenetic analysis may allow the identification of the discriminative genetic biomarkers, which may be more informative for an a priori DMT choice than those found in conventional pharmacogenetic studies. The search for discriminative markers of preferable first-line DMT, which differ in carriage between IFN-β responders and GA responders as well as between IFN-β nonresponders and GA nonresponders, has been performed in 253 IFN-β-treated MS patients and 285 GA-treated MS patients. A bioinformatics algorithm for identification of composite biomarkers (allelic sets) was applied on a unified set of immune-response genes, which are relevant for IFN-β and/or GA modes of action, and identical clinical criteria of treatment response. We found the range of discriminative markers, which include polymorphic variants of CCR5, IFNAR1, TGFB1, DRB1 or CTLA4 genes, in different combinations. Every allelic set includes the CCR5 genetic variant, which probably suggests its crucial role in the modulation of the DMT response. Special attention should be given to the (CCR5*d+ IFNAR1*G) discriminative combination, which clearly points towards IFN-β treatment choice for carriers of this combination. As a whole the comparative approach provides an option for the identification of prognostic composite biomarkers for a preferable medication among available alternatives.