Platelet activation in patients with systemic scleroderma--pattern and significance.

UNLABELLED: The vasooclusive features of scleroderma are attributed to the vessel wall anomalies, while platelet's intervention is less studied. AIM: platelet activation markers (PAM) pattern and significance in systemic sclerosis. DESIGN: 20 scleroderma patients with severe Raynaud phenomenon, under aspirin treatment, were evaluated by quantitative flow-cytometry for PAM (P-selectin, GPIIbIIIa, CD40L) in correlation with scleroderma activity and severity, systemic endothelial dysfunction (flow-mediated vasodilatation), systemic inflammation (serum CRP and IL-6) and cold-provocation test. Associated autoantibodies (ANCA, antiTPO, anticardiolipin, antiplatelet, antimitochondrial antibodies) were evaluated in relation to IL-6. RESULTS: PAM were expressed in 11 (55%) cases: P-selectin in 5 (45.45%), GPIIbIIIa in 1 (9.1%), combined P-selectin and GPIIbIIIa in 5 (45.45%), CD40L in 0 cases. Scleroderma patients expressing PAM had increased incidence of disease activity and severity. There was no correlation between PAM and systemic endothelial dysfunction. CRP increased in 14(70%) cases was correlated with P-selectin and GPIIbIIIa expression (r = 0.28). Normal IL6 present in 19 (90.9%) cases was correlated with lack of CD40L expression (r = 0.69) and with low autoantibodies incidence (r = 0.69 for ANCA, 0.55 for anti TPO and antiplatelet, 0.39 for anti cardiolipin, 0.45 for antimitochondrial). After cold provocation test PAM were significantly lost and were not expressed de novo. CONCLUSIONS: In systemic scleroderma platelet activation markers are correlated with disease activity and severity and increased CRP and are not correlated with systemic endothelial dysfunction or exposure to cold. Normal IL-6 was correlated with lack of CD40L expression and with low incidence of associated autoantibodies.