CXCL8 Gene Polymorphism Influence on Optic Neuritis

Introduction Optic neuritis (ON) is one of the most common diseases at any age resulting in damage and inflammation of the optic nerve. Multiple sclerosis (MS) is often the cause of this condition, but the origin of ON varies [1]. The estimated prevalence in Europe is 5/100000 per year, with women being affected more than twice as often as men. Patients are usually in their late thirties [2]. This disease is characterized by the slow destruction of the myelin covering the nerve, damage to nerve fibres and the death of retinal cells, leading to visual disturbances and loss of vision [3].Typical symptoms of ON include sudden pain with eye movements, mostly affecting one eye, usually resulting in temporary blurring or complete loss of vision usually lasting around 2 weeks. [4]. ON can be triggered by various causes, including infections like herpes simplex virus encephalitis, demyelinating diseases such as multiple sclerosis and neuromyelitis optica, inflammation (with a third of sarcoidosis patients affected), and genetic abnormalities [5]. CXCL8 is a key chemokine that attracts neutrophils, aiding in infection control and tissue repair. In the nervous system, it acts as a neuromodulator, influencing neurodevelopment, inflammation, and synaptic transmission. Additionally, CXCL8 is involved in tissue regeneration, improving blood flow after organ transplants, and aiding in wound healing [6,7]. As a key player in inflammation-related processes, dysregulated CXCL8 and its receptors have been linked to various inflammatory diseases, including multiple sclerosis (MS), HIV and cystic fibrosis [8]. Given that the mechanism behind ON is not yet fully understood, we sought to explore a potential link between ON and single nucleotide polymorphisms in the CXCL8 gene. Aim To determine the influence between optic neuritis and CXCL8 gene single nucleotide polymorphism. Methods DNA was isolated by the salting out method from the venous blood of patients with ON and healthy individuals. Genotyping of CXCL8 rs2227306 single nucleotide polymorphism was performed by real-time polymerase chain reaction (RT-PCR). Statistical data analysis was carried out using the "IBM SPSS Statistics 29.0.1.0 " program. Results There was a total of 184 participants in the research, consisted of 74 (40.2%) women and 110 (59.8%) men. The results showed that CXCL8 rs2227306 genotype (TT, TC and CC) distribution did not differ statistically significantly between ON and controls in both 28.6%, 46.4% and 25% vs. 35%, 51% and 14%, p=0.158). The T allele is seen to be more frequent in the ON group compared to the control group (81 (48.2) vs. 79 (39.5)), however no statistically results were found (p=0.093). Also, binary logistic regression analysis did not show any statistically significant results (all p>0.05). Conclusions We did not reveal a link between CXCL8 rs2227306 gene polymorphism and optic neuritis.