PLASMA CHITOTRIOSIDASE ACTIVITY IN GAUCHER-DISEASE PATIENTS WHO HAVE BEEN TREATED EITHER BY BONE-MARROW TRANSPLANTATION OR BY ENZYME REPLACEMENT THERAPY WITH ALGLUCERASE

A marked elevation in plasma chitotriosidase (chitinase) activity has recently been observed in patients with Gaucher disease (Hollak et al 1994). It has been suggested that this phenomenon may serve as a usefu l marker for the efficacy of treatment with enzyme replacement therapy . We report our findings on the comparison of plasma chitotriosidase l evels in 8 patients treated with the modified human placental enzyme a lglucerase and 8 patients treated by allogeneic bone marrow transplant ation (BMT). Two years after transplantation the activity in the BMT p atients had fallen by over 93% and has continued to fall. Now, 5-12 ye ars post-BMT, 6 patients have normal levels of plasma chitotriosidase and 2 patients have activities slightly above the reference range. Pat ients have been treated with alglucerase for a considerably shorter ti me than the BMT patients. The chitotriosidase activities have fallen a nd are continuing to fall in 7 patients but at a slower rate than in t he BMT group. In one patient there has been no appreciable change in a ctivity over the last 6 months, which would suggest that she may be on too low a dosage.