2003; baxter - Supplements - Haematologica

88A. Huth-Kühne et al.were regenerated by protein elution with glycinebuffer at p.H. 2.8, followed by washing cycles withphosphate-buffered saline and 9 g/L isotonic sodiumchloride solution. An adsorption-desorptionautomate system (ADA system, Baxter) was used tocontrol the flow of plasma and regenerating solutionsto the IA columns. After passing through thecolumns, the plasma and separated blood cellswere re-infused into the patient.AssaysClotting assays were performed with citratedplasma on an Amax Coagulometer (Amelung,Lemgo-Lieme, Germany). FVIII:C activity wasdetermined with a one-step clotting assay using ahuman FVIII:C deficient (Haemophilia A) plasma(Immuno, Austria) and a Dapttin reagent(Immuno, Austria) (normal range 0.7-1.1U/mL). Activated partial thromboplastin time(APTT) was determined using a Dapttin reagentconsisting of kaolin and sulphatide as surface activatorsand a blend of highly purified phospholipids(Immuno, Austria) (normal range 32-42seconds). FVIII:C inhibitory activity was quantifiedby the Bethesda assay. 29 The inhibitor titre wasexpressed as the reciprocal of the patient plasmadilution, which yielded 50% of the residual FVIII:Cactivity in the test system.ResultsBetween December 1997 and November 2000eight patients with autoantibodies to FVIII:C werereferred to the MHMP. All patients were transferredto our hospital because of severe bleedingcomplications. The median age of patients was 73years (range 60-82) with a gender distribution of5 males and 3 females. Six of the 8 patientsshowed an associated underlying medical condition.3 patients were taking immunosuppressivedrugs due to their underlying disease (Table 1).Maximum inhibitor titres, inhibitor titres andFVIII:C levels prior to IA are shown in Table 2. Theeffect of the immunomodulatory treatment oninhibitor titres and FVIII:C activity in 2 patients isshown in Figures 1A and 1B. After a median of 3.5adsorptions, patients FVIII:C levels increased to>30%, while the inhibitor was no longerdetectable in plasma. CR in all patients requiredcontinuous FVIII replacement for a median of 19days and 16 adsorptions. (Table 3). In contrast toother therapeutic strategies, CR in all patients wasachieved in less than 3 weeks in median.Therapywas well tolerated by all patients without severeside effects. To date, after a median follow-up periodof 47 months (range 8-52 months), 7/8patients continue to be in remission.One patientdied due to a plasmocytoma, which had been inremission at the time of the diagnosis of acquiredhemophilia.DiscussionTreatment of patients with FVIII or FIX autoantibodiesstill represents a major challenge. Thehemorrhagic manifestations in these patients aremore dramatic and often life-threatening as comparedto bleeds associated with inhibitory alloantibodies.In most cases, immediate intervention tocontrol the acute bleeding is necessary and anychoice of therapeutic modality should be based onan algorithm which considers primarily the clinicalpresentation and severity of bleeding. Therapeuticdecisions should not be based only on theinhibitor level, because the Bethesda-assay is lesspredictive of FVIII recovery in patients withacquired hemophilia and often underestimates thein vivo potency of type II inhibitors. 7,8 For themanagement of acute bleeds treatment optionsconsist of high-dose FVIII (plasma-derived orrecombinant), porcine FVIII depending on crossactivity,or administration of plasma-derivedbypassing agents, including PCCs and APCCs.A new treatment option to bypass the inhibitorand achieve hemostasis, is the administration ofrFVIIa, 11,12 which has been reported to be clinicallyeffective and safe in patients with congenitalhemophilia and inhibitors and in patients withacquired hemophilia. In healthy individuals FXactivation on the surface of activated plateletsand the resulting necessary burst of thrombin generationis ensured by the Tenase complex consistingof FIX and FVIII. If one part of this complex ismissing or compromised by autoantibodies, thenecessary amount of thrombin is not generated.Administration of rFVIIa in supraphysiologicaldoses activates FX on the surface of activatedplatelets attached to the injured vessel wall providingthe necessary amount of thrombin. 30 Comparedto conventional bypassing products, whichare known to cause systemic activation of coagulationand thromboembolism, 31-33 the risk ofthrombotic complications seems to be very lowafter administration of rFVIIa. Because of its modeof action, rFVIIa has much less thrombogenicpotential and although administered in supraphysiologicaldoses, to date only few side effectshave been reported. 34 There is no anamnesticresponse and it has been shown to be very effectiveirrespective of the inhibitor titer. 12 Clear disadvantagesare the high costs when applied asbolus infusion with a current recommended doseof 90–120 mg/kg every 2 hours and the lack ofany specific laboratory control other than FVII levels.Adequate hemostatic levels still remain to beestablished. Administration by continuous infusionis a new approach and may reduce FVIIarequirement up to 50%. 35,36Concerning permanent inhibitor eliminationthe most successful treatment to date is theadministration of immunosuppressive and cytotoxicagents. 1,37 Due to their myelosuppressiveeffects, the currently available cytotoxic agentsmay lead to severe side effects. Neutropenia andsubsequent life-threatening infection have beenreported, 20 even after a single treatment, 38 andmay contribute to death. 39FVIII autoantibodies may also be responsive toimmune-modulating strategies, including IVIGwith varying response rates 22 and IA. A newhaematologica vol. 88(supplement n. 12):september 2003