Platelet aggregation assays using a CD40L-binding agent

A method of assaying platelet aggregation comprising:

• activating platelets with ADP;
• contacting the activated platelets with an anti-CD40L antibody;
• and
• contacting the activated platelets with sCD40L or anti-hFc antibody, and wherein sedimented platelets is indicative of aggregation of the platelets.

A method of determining whether a human is susceptible to clotting upon administration of a CD40L-binding moiety comprising:

• removing platelets from the human;
• contacting the platelets with a platelet activating agent;
• contacting the activated platelets with the CD40L-binding moiety;
• and
• contacting the activated platelets with a cross-linking agent, and
• determining the presence or absence of platelet aggregation, wherein 70% or greater platelet aggregation is indicative of susceptibility to clotting.

A method of determining whether a human is susceptible to clotting upon administration of an anti-CD40L antibody comprising:

• removing platelets from the human;
• activating the platelets with ADP;
• contacting the activated platelets with the anti-CD40L antibody;
• and
• contacting the activated platelets with sCD40L or anti-hFc antibody, and determining the presence or absence of platelet aggregation, wherein 70% or greater platelet aggregation is indicative of susceptibility to clotting.