Ten patients (pts) with acute ITP presented to our institution between January and December, 1996. All were Rh+, direct coombs negative and received Anti-D (Winrho-SD) given as a single intravenous push dose of 50mcg/kg. The mean initial platelet count (plt) was 5.2 (x109/1) ± 3.9 (mean± SD). The mean dose of Anti-D was 47.9 mcg/kg. Mean time to plt > 20,000 was 23.8 hrs ± 14.4 (median 15.5 hrs, range 11.5-49 hrs). The average drop in hemoglobin was 1.27 gm/dl ± 0.7. Mean post-anti-D peak plt was 255 (x109/1) ± 214, occurring at a median of 8 days post-treatment. Three of ten pts required retreatment for plt < 20,000. One received an initial dose of 35 mcg/kg and was retreated 16 days later. Retreatment was necessary at 8 and 65 days post-anti-D in the 2 other pts. Two pts had complaints of headache at 2-3 hours post-infusion, one also vomited twice. Our data compare favorably to the historical responses seen with intravenous gammaglobulin (IVIG)(24-48hr response time) and are superior to those of Blanchette et al (Lancet 344:703, 1994) who used 25 mcg/kg/day of Anti-D for 2 doses. The dose of Anti-D at 50 mcg/kg as a single infusion is well tolerated, with a quick response time and a prolonged effect. With a median response time of 15.5 hrs and only 3 pts needing retreatment, Anti-D appears to be a safe and less costly alternative to IVIG for the initial treatment of acute ITP.
