Polymorphisms of Interleukin-6 and Interleukin-8 Are Not Associated with Parkinson’s Disease in Taiwan

• Published in: Brain sciences Vol. 11; no. 6; p. 768
• Main Authors: Liu, Tsai-Wei, Wu, Yih-Ru, Chen, Yi-Chun, Fung, Hon-Chung, Chen, Chiung-Mei
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 09.06.2021; MDPI
• Subjects: Age; Alzheimer's disease; Cytokines; disease association; Gender; Gene frequency; Gene polymorphism; Genes; Genetic diversity; genetic polymorphism; Genotype & phenotype; Growth factors; IL-6; IL-8; Inflammation; Interleukin 6; Interleukin 8; Movement disorders; Neurodegenerative diseases; Parkinson's disease; Pathogenesis; Polymorphism; Population; Population studies; Single-nucleotide polymorphism; Statistical analysis; Sweden; Taiwan
• ISSN: 2076-3425; 2076-3425
• DOI: 10.3390/brainsci11060768

Background: Studies have suggested that cytokines are crucial mediators in the pathogenesis of Parkinson’s disease (PD). The multifunctional cytokine interleukin (IL)-6 and its single nucleotide polymorphisms (SNPs) were found to have an impact on the development of PD. However, different studies in associations of IL-6 genetic variants with PD showed inconsistent results and it has never been explored in a Taiwanese population. Both IL-1α and IL-8 contribute to the same inflammation pathway. IL-1α genetic polymorphism has an effect on late-onset PD in Taiwan, whereas the associations of IL-8 genetic variants with PD in Taiwan remain to be investigated. Methods: This study examined the frequencies of polymorphisms within the critical promoter areas of the proinflammatory cytokine genes: IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) in Taiwanese PD patients compared with age-and gender-matched healthy subjects. Comparisons were also made in genotype and allele frequencies of IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) among different populations in previous studies. Results: In total, 1120 subjects, including 509 PD patients (female/male: 259/250) and 511 control subjects (female/male: 252/259), were recruited. We found no statistically significant differences in IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) genotypic and allelic distribution between PD and controls, even after being stratified by age at onset and gender. Conclusions: The results did not demonstrate any association of IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) with PD in a Taiwanese population. Despite the negative results, this is the first study in associations of IL-6 G-174C (rs1800795) and IL-8 A-251T (rs4073) with PD in Taiwan. The relevance of genetic variants of IL-6 G-174C (rs1800795) or IL-8 A-251T (rs4073) on PD susceptibility warrants further investigation.