Association of plasma levels of Protein S with disease severity in multiple sclerosis.

Background: The TAM family of receptor tyrosine kinases (TYRO3, AXL and MERTK) play important roles in modulating innate immune responses and central demyelination. The TAM receptor ligand Protein S (PROS) has also been shown to modulate innate immune cell responses.

Objectives: We assessed whether plasma levels of PROS are changed in multiple sclerosis (MS) patients and whether changes are associated with disease severity.