Haematologica 2004;89: supplement no. 8 - Supplements ...

46Oral CommunicationsCO-051DESMOPRESSIN SUBCUTANEOUS ADMINISTRATION IMPROVESPLATELET RESPONSE IN VIVO TO PLATELET-ACTIVATINGFACTOR, SOLUBLE P-SELECTIN RELEASE AND CAUSES A RISEIN INTERLEUKIN-6 PLASMA LEVELS IN HAEMOPHILIA A ANDVON WILLEBRAND DISEASE TYPE IMusso R, Cultrera D,* Chiarenza A,* Cipolla N,Burgio N, D'Arpa S, Giustolisi R*Haemophilia and Thrombosis Regional ReferenceCenter, *Dept. of Haematology, University ofCatania, ItalyIt has been reported that elevated plasma plateletactivatingfactor (PAF) concentrations are significantlyhigher in children with haemophilia A (HA)and Von Willebrand disease (VWD) than in healthychildren (Kavakli K. Thromb Haemost 1999; 81). It alsobeen also postulated that increased cellular PAFactivity may be an adaptative response by the organismin order to prevent hemorrhages and assist primaryhaemostasis (Kavakli K. Haemophilia 2001; 7).In conjunction with Von Willebrand Factor (VWF),the adhesion molecule P-selectin, stored in endothelialWeibel-Palade bodies and platelet α-granulemembrane, is suggested to regulate platelet biologyin VWD. In addition, it has been shown desmopressinto cause a rise in plasma interleukin-6 (IL-6) levels,which correlates with an increase of VWF and FactorVIII (FVIII:C)(Newby. Thromb Haemost 2000; 84).We here report that in vitro PAF at different concentrationinduced a marked increase of platelet aggregation(PA) in mild HA patients (n=14) and in VWDtype 1 subjects known to be responders to thedesmopressin (n=14, 6 males and 8 females). PA wasperformed in platelet-rich plasma (PRP) at250,000/mL cells count by using the Aggrecoder PA3210 in presence of subcritical (0.2 mM) and optimal(1 mM) concentrations of PAF acether (C18:0). PAwas performed before and 1 h after subcutaneousdesmopressin (Emosint. Sclavo) injection (0.4 mg/Kg).aPTT, FVIII:C, VW:Ag, RiCof, soluble P-selectin andIL-6 (ELISA method) were also measured. As expected,all FVIII complex plasma activities were significantly(p