Summary
Baseline studies of 111indium oxine labelled platelet life-span, platelet α-granule release products, β-thromboglobulin
(βTG) and platelet factor 4 (PF4), and factor VIII related activities were performed
on 9 asymptomatic patients with sickle cell disease, who were subsequently randomised
in a prospective double-blind trial of ticlopidine (250 mg. b. d.) or placebo for
one month and the investigations repeated. Control studies indicated that 5 of the
9 patients had shortened platelet survivals: mean βTG (50.8 ng/ ml) and PF4 (19.5
ng/ml), factor VIII: C (283.4 i. u./dl) and factor VIIIR: AG (168.7 u/dl) levels were
raised. Ticlopidine treatment did not significantly improve platelet life-span or
factor VIII levels, though it was associated with reduced values of βTG and PF4. One
patient taking ticlopidine developed an infarctive sickle crisis. Although ticlopidine
blocked platelet activation, this alone did not improve platelet survival or prevent
sickle crisis: in view of evidence of platelet activation in sickle cell disease,
however, a longer trial of prophylactic antiplatelet drugs might be warranted.
Keywords
Sickle cell disease - Platelet survival - Ticlopidine - β-thromboglobulin - Platelet
factor 4
