Increased P-selectin plasma levels in patients with thrombotic thrombocytopenic purpura.
BACKGROUND
Thrombotic thrombocytopenic purpura (TTP) is a rare vascular disorder of unknown etiology. There is evidence to support the hypothesis that platelets and endothelium play a pivotal pathogenetic role. Immunological assays for plasma thrombomodulin and P-selectin levels have recently been made available and they allow simple evaluation of endothelial damage and endothelial/platelet activation, respectively. In this study, we measured the plasma levels of thrombomodulin, P-selectin and von Willebrand factor in 9 TTP patients during active disease and at the time of complete remission (CR).


METHODS
Thrombomodulin, P-selectin and von Willebrand factor were measured by enzyme immunoassay.


RESULTS
Mean thrombomodulin and von Willebrand factor plasma values were always within the normal range. P-selectin plasma levels, both in the active phase of the disease and in CR (median 312 and 185 ng/mL, respectively), were significantly higher than in normal controls (mean 96 +/- 35 ng/mL, mean 88 ng/mL; p < 0.05). However, the mean value of P-selectin in CR (median 185 ng/mL) was significantly lower than that observed at diagnosis (p < 0.05). In addition, an inverse relationship between P-selectin plasma levels and platelet count (r = -0.526; p = 0.03) was observed.


CONCLUSIONS
These findings suggest that activation of platelets and/or endothelium may play a relevant role in the pathogenesis of TTP.
Vianelli
N
N
Hematology Institute "Seràgnoli", University of Bologna, Italy.
Catani
L
L
Gugliotta
L
L
Nocentini
F
F
Baravelli
S
S
Lancellotti
G
G
Tura
S
S
D000328:Adult; D001792:Blood Platelets / Q000502:physiology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019007:P-Selectin / Q000097:blood*; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood* / Q000628:therapy; D012074:Remission Induction
D019007:P-Selectin