Higher baseline IL-8 was associated with conversion from radiologically and clinically isolated syndrome to definitive multiple sclerosis in one study,37 and subsequent relapses and gadolinium enhancing lesions in another study.36 It has also been linked to worse prognosis in traumatic brain injury.38 IL-8 is tightly connected to CXCL1 and in this study, both were increased in both RRMS and PMS to a similar degree. This evidence concerns the gene CXCL8 and premenstrual tension.