Background Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating disease of the central nervous system, characterized by recurrent relapses of inflammation that cause mild to severe disability. Exposure to airborne particulate matter (PM) has been associated with acute increases in systemic inflammatory responses and neuroinflammation. In the present study, we hypothesize that exposure to PM < 10 µm in diameter (PM10) might increase the occurrence of MS-related hospitalizations. Methods We obtained daily concentrations of PM10 from 53 monitoring sites covering the study area and we identified 8287 MS-related hospitalization through hospital admission-discharge records of the Lombardy region, Italy, between 2001 and 2009. We used a Poisson regression analysis to investigate the association between exposure to PM10 and risk of hospitalization. Results A higher RR of hospital admission for MS relapse was associated with exposure to PM10 at different time intervals. The maximum effect of PM10 on MS hospitalization was found for exposure between days 0 and 7: Hospital admission for MS increased 42% (95%CI 1.39–1.45) on the days preceded by one week with PM10 levels in the highest quartile. The p-value for trend across quartiles was < 0.001. Conclusions These data support the hypothesis that air pollution may have a role in determining MS occurrence and relapses. Our findings could open new avenues for determining the pathogenic mechanisms of MS and potentially be applied to other autoimmune diseases.

BackgroundMultiple sclerosis (MS) is a complex disorder of the central nervous system whose cause is currently unknown. Evidence is increasing that DNA methylation alterations could be involved in inflammatory and neurodegenerative diseases and could contribute to MS pathogenesis. Repetitive elements Alu, LINE-1 and SAT-α, are widely known as estimators of global DNA methylation. We investigated Alu, LINE-1 and SAT-α methylation levels to evaluate their difference in a case–control setup and their role as a marker of disability.ResultsWe obtained blood samples from 51 MS patients and 137 healthy volunteers matched by gender, age and smoking. Methylation was assessed using bisulfite-PCR-pyrosequencing. For all participants, medical history, physical and neurological examinations and screening laboratory tests were collected. All repetitive elements were hypermethylated in MS patients compared to healthy controls. A lower Expanded Disability Status Scale (EDSS) score was associated with a lower levels of LINE-1 methylation for ‘EDSS = 1.0’ and ‘1.5 ≤ EDSS ≤ 2.5’ compared to an EDSS higher than 3, while Alu was associated with a higher level of methylation in these groups: ‘EDSS = 1.0’ and ‘1.5 ≤ EDSS ≤ 2.5’.ConclusionsMS patients exhibit an hypermethylation in repetitive elements compared to healthy controls. Alu and LINE-1 were associated with degree of EDSS score. Forthcoming studies focusing on epigenetics and the multifactorial pathogenetic mechanism of MS could elucidate these links further.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-016-0395-0) contains supplementary material, which is available to authorized users.

MDC/CCL22 has been detected in the brain of mice with experimental autoimmune encephalomyelitis. MDC/CCL22 cerebrospinal fluid levels were evaluated in 56 patients with multiple sclerosis (MS) and in 17 controls. No significant differences were found, even when stratifying patients according to the disease subtype. Stratifying by gender, significantly increased MDC/CCL22 levels were observed in female patients when compared with female controls and male patients (109.03 versus 98.54 and 99.37 pg/mL, P = 0.034 and 0.018, respectively). Therefore, MDC/CCL22 is likely to play a role in the development of MS in females only, possibly influencing the intracerebral recruitment of Th2 cells, which produce anti-inflammatory cytokines.