Background: Dysregulated levels of interleukin-1 (IL-1) were observed in patients with multiple sclerosis (MS). Previous studies have provided conflicting evidence implicating the IL-1 gene polymorphisms in MS risk.
Methods: A meta-analysis of 16 case-control studies involving 3,482 cases and 3,528 controls was conducted to evaluate this association.
Results: No association was found between the IL-1α -889 (rs1800587), IL-1α +4,845 (rs17561), IL-1β -511 (rs16944), IL-1β +3,953 (rs1143634), IL-1ra variable number tandem repeat (VNTR) polymorphisms and MS risk. However, in subgroup analyses for the IL-1ra VNTR polymorphism, we found that individuals carrying the 2 allele had a 32 % increased risk for bout-onset MS (relapsing remitting and secondary progressive MS) when compared to the LL homozygotes (OR = 1.32, 95 % CI = 1.06-1.66, P (z) = 0.014).
Conclusion: Common variants in the IL-1 region are not associated with MS risk but our data suggest that the IL-1ra VNTR polymorphism might be associated with bout-onset MS subtype.