No evidence of association between functional polymorphisms located within IL6R and IL6ST genes and systemic sclerosis

Cellular and Molecular Diversity in Scleroderma

With the increasing armamentarium of high-throughput tools available at manageable cost, it is attractive and informative to determine the molecular underpinnings of patient heterogeneity in systemic sclerosis (SSc). Given the highly variable clinical outcomes of patients labelled with the same diagnosis, unravelling the cellular and molecular basis of disease heterogeneity will be crucial to predicting disease risk, stratifying management and ultimately informing a patient-centered precision medicine approach. Herein, we summarise the findings of the past several years in the fields of genomics, transcriptomics, and proteomics that contribute to unraveling the cellular and molecular heterogeneity of SSc. Expansion of these findings and their routine integration with quantitative analysis of histopathology and imaging studies into clinical care promise to inform a scientifically driven patient-centred personalized medicine approach to SSc in the near future.

Current status and relevance of single nucleotide polymorphisms in IL-6-/IL-12-type cytokine receptors

Cytokines control immune related events and are critically involved in a plethora of patho-physiological processes including autoimmunity and cancer development. In rare cases, single nucleotide polymorphisms (SNPs) or single nucleotide variations (SNVs) in cytokine receptors eventually cause detrimental ligand-independent, constitutive activation of signal transduction. Most SNPs have, however, no or only marginal influences on gene expression, protein stability, localization and function and thereby only slightly affecting pathogenesis probability. The SNP database (dbSNP) is an archive for a broad collection of polymorphisms in which SNPs are categorized and marked with a locus accession number "reference SNP" (rs). Here, we engineered an algorithm to directly align dbSNP information to DNA and protein sequence information to clearly illustrate a genetic SNP landscape exemplified for all tall cytokine receptors of the IL-6/IL-12 family, including IL-23R, IL-12Rβ1, IL-12Rβ2, gp130, LIFR, OSMR and WSX-1. This information was complemented by a comprehensive literature summary and structural insights of relevant disease-causing SNPs in cytokine/cytokine receptor interfaces. In summary, we present a general strategy with potential to apply to other cytokine receptor networks.

Relationship Between Interleukin-6 -174G/C Genetic Variant and Efficacy of Methotrexate Treatment in Psoriatic Arthritis Patients

Introduction

The purpose of the study was to investigate whether single-nucleotide polymorphisms (SNPs) IL-6 −174 G/C and IL-6R Asp358Ala are associated with susceptibility to psoriatic arthritis (PsA) or affect response to treatment with methotrexate (MTX).

Patients and Methods

Seventy-four patients diagnosed with PsA and qualified for MTX treatment were enrolled to the study. The control group consisted of 120 healthy individuals. Polymorphisms IL-6 −174 G/C and IL-6R Asp358Ala were genotyped using a polymerase chain reaction (PCR) amplification employing LightSNiP assays.

Results

A significant association between the IL-6 −174 CC genotype and an improved clinical outcome of MTX therapy was observed. A good response was more frequently observed among PsA patients bearing the IL-6 −174 CC genotype than patients with the GC or GG genotypes (P = 0.007). On the other hand, patients carrying the IL-6 −174 GC genotype less frequently responded to MTX treatment as compared to patients with other genotypes (P = 0.006). With respect to the IL-6R Asp358Ala SNP, there were no significant differences in genotype and allelic frequencies in relation to clinical outcome of MTX treatment. No association was found between the IL-6 −174 G/C or IL-6R Asp358Ala SNPs and PsA susceptibility.

Conclusion

Results from this study provide evidence that the IL-6 −174 G/C polymorphism might influence efficacy of MTX treatment.