Plasma Concentrations of Platelet-Specific Proteins Correlated With Platelet Survival

Relationships between 51Cr platelet survival and plasma concentrations of β-thromboglobulin (βTG) and platelet factor 4 (PF4) were analyzed in 91 studies of patients with coronary artery disease. βTG was significantly correlated with platelet life-span, turnover, and the number of hits in the multiple hit model. PF4 was significantly correlated with life-span and turnover. The most significant relationship involving platelet-specific protein concentrations and life-span estimates was between βTG and life-span estimated using the multiple hit model (r = –0.39, p < 0.001). There was a high correlation between βTG and PF4 (r = 0.62, p 0.001), and no improvement could be obtained by combining the measurements of the two proteins in any regression with life-span or turnover. The results indicate that the patients with the shortest platelet survival time in this group tended to have the highest plasma concentrations of βTG and PF4 and thus probably increased in vivo release of βTG and PF4. They strengthen the claim that these platelet-specific proteins may be indicators of platelet involvement in disease.