[Platelet function study in primary Raynaud's phenomenon and Raynaud's phenomenon associated with scleroderma].

We evaluated platelet function in 59 patients with Raynaud's phenomenon (RP): 24 had primary RP (PRP) and in 35 RP was associated with diffuse scleroderma (DS). In the group with PRP there were 10 males and 14 females, with a mean age of 43 +/- 12 years and a time of evolution of 5 +/- 5 years. In the group with RP associated with DS there were 31 females and 4 males with a mean age of 53 +/- 12 years and a time of evolution of 9 +/- 7 years. The control group consisted of 20 healthy individuals (14 males and 6 females with a mean age of 40 +/- 12 years). In all patients and controls beta-thromboglobulin (BTG) and platelet factor 4 (PF4) levels were measured in plasma, and platelet aggregation was evaluated in the presence of adenosine diphosphate (ADP), collagen and arachidonic acid. The patients with RP associated with DS had BTG and PF4 higher than those with PRP and controls (p less than 0.02). The BTG/PF4 ratio was also significantly greater in patients with DS (p less than 0.005). The platelets from patients with DS had a greater aggregation with ADP (1 microM and 0.5 microM) than those from PRP (p less than 0.03). We concluded that patients with RP associated with DS had in vivo activation and a greater aggregation of platelets, in contrast with the absence of these findings in the group with PRP and in controls.