MMP9 and viral infectious disease: In a totally unrelated condition such as pyramidal syndrome or progressive weakness and stiffness of the lower limbs due to tropical spastic paraparesis and viral infection (inflammation), TIMP-2, TIMP-3, and TIMP-4 levels were increased compared with healthy controls, while TIMP-1 was only increased in the presence of inflammation, and MMP-3 and MMP-9 levels were significantly increased in the presence or absence of inflammation [47].