Case report: induction of immune tolerance to factor VIII inhibitor after a major operation.

INTRODUCTION We report a successful case of immune tolerance to factor VIII (FVIII) inhibitor after a major operation. An attempt was made to induce immune tolerance with inhibitor in a haemophilia A patient, who was required to undergo an above-knee amputation. We opted to give high-dose FVIII infusion with no immunosuppression. OUTCOME The highest preoperative FVIII inhibitor level was 5 BU and the peak postoperative FVIII inhibitor level was 1.5 BU demonstrated on Day 9 post operation. High-dose FVIII support was provided during the perioperative period and continued with a low maintenance dose to achieve a FVIII level of 30% to 40%. The requirement of high-dose FVIII lasted from day 6 to 23 post operation and this was tailed down to a maintenance dose over the next 37 days. There were only 2 episodes of mild oozing from the wound at around Day 9, which coincided with the peak postoperative FVIII inhibitor level. Both bleeding episodes were arrested adequately by administering a single dose of FEIBA during each episode. Immune tolerance was demonstrated after around 3 months and a follow-up period of 233 days showed no recurrence of FVIII inhibitor with the normalisation of FVIII half-life study. CONCLUSION After immune tolerance, the patient suffered fewer episodes of joint haemorrhage and required a lower amount of FVIII infusion as well. The cost may be high initially but the longterm cost-effectiveness has to be carefully evaluated.