[Platelet function and high-dose methotrexate treatment with citrovorum factor rescue]

Bleeding symptoms complicating HDMTX and CFR therapy have been reported, Thrombocytopenia and disturbed plasmatic coagulation could not explain all bleeding episodes. Platelet function had not been investigated in HDMTX and CFR treatment so far. In vitro tests showed a dose-dependent inhibition of platelet aggregation post incubation with MTX. Platelet factor 3 availability was decreased as well. Ex vivo investigations in 10 children undergoing HDMTX and CFR treatment (6 or 12 g/m2) showed impaired platelet factor 3 release whereas aggregation tests were normal. No severe platelet function disturbances could be seen under HDMTX with CFR treatment. However, platelet function should be tested in cases of unexplained bleeding tendency under HDMTX/CFR treatment, since the impairment of platelet function observed in vitro might become relevant in the individual condition.