Th17 cells are a highly pro-inflammatory T-helper cell subset characterised by the expression of IL17. They have been implicated in a variety of allergic and autoimmune conditions. T-regulatory (Treg) cells, a subset of CD4 cells which express Foxp3, CD25, IL10 and TGFβ, can suppress the activity of Th17 cells. In this study, we show that the circulating levels of Th17 and Treg cells in peripheral blood are correlated; furthermore, the expression of the pro-inflammatory cytokine IL17 and the anti-inflammatory cytokine IL10 by CD4 cells are also correlated. However, we found no clear correlation between cerebrospinal fluid (CSF) IL10 and IL17 cytokine levels in MS, approaching a negative correlation at the time of relapse, and an overall negative correlation between CSF IL17 and TGFβ levels, suggesting a lack of central regulation of pro:anti-inflammatory balance in this demyelinating condition.