TNFRSF9 and stroke disorder: The results showed a correlation of the surface expression of CD137 on CD4+ T cells and levels of plasma sCD137 with NIHSS (r = 0.7167, P < 0.0001 and r = 0.7119, P = 0.0137) and infarct volume (r = 0.6207, P = 0.0006 and r = 0.7072, P < 0.0001) in stroke patients.