Figure 2

VP-1 stimulated IFN-γ and TNF-α cytokine-producing CD8+ T lymphocytes in Multiple Sclerosis patients undergoing natalizumab. Results obtained over a 24 months period are shown; grey dots indicate subject in whom virus activation in blood was not detected (JCV NEG); black dots indicate individuals in whom JCV DNA was detected in blood (JCV POS). Error bars depict first and third quartiles and median values are indicated. Statistical significance is presented.