A method for identifying an inhibitor of endothelial protein C receptor (EPCR) function in an autoimmune disease, wherein said autoimmune disease is selected from the group consisting of antiphospholipid syndrome (APS), primary Sjögren syndrome, rheumatoid arthritis, systemic lupus erythematosus, and lupus nephritis, the method comprising:
- i) providing a biological sample comprising an EPCR protein,
- ii) contacting a potential inhibitor with said sample,
- iii) adding LBPA to the sample,
- iv) testing binding of LBPA to said EPCR protein in the presence of said potential inhibitor, and
- iv) identifying said potential inhibitor based on said LBPA-binding as tested.