Platelets are the main type of blood cell involved in the formation of blood clots that cause
heart attacks. The investigators give antiplatelet drugs (aspirin, for example) to reduce the
risk of another clot forming in the future and causing another heart attack. Platelets are
known to have a role in inflammation and infection as well as clotting. In a recent large
clinical trial, known as the PLATO study, it was also shown that patients treated with a new
antiplatelet medication (ticagrelor) developed fewer lung infections, as well as fewer heart
attacks, compared to the current standard treatment (clopidogrel). The investigators would
therefore like to investigate the reasons behind this and look at the effect of these
medications on immune response. This may help us develop new drugs that have a better effect
on immune response. The investigators are planning a clinical trial that investigates the
effect of these medications on the immune response of healthy volunteers aged 18 to 65.
Only volunteers with no significant past medical history and not taking any medications will
be included.
Thirty volunteers will receive either a normal dose of ticagrelor or clopidogrel or no
antiplatelet medication for 1 week.
They will then attend the Sheffield Clinical Research Facility where their immune response
will be stimulated using a safe, well established method. The investigators will do this with
an injection of a low dose of endotoxin, which is part of the surface coating of some
bacteria and has been used extensively in similar studies, in over a thousand volunteers over
the past 20 years to investigate immune response. It is known to cause temporary flu-like
symptoms that last approximately 68 hours. The investigators will take measurements of
inflammatory markers, white blood cell function and platelet function and compare the effect
of ticagrelor and clopidogrel on this immune response.