Median no. of months from ITP diagnosis to enrollment (range)
Median age at enrollment, y (range)
Off treatment (n 5 12) On treatment (n 5 7) Splenectomy (n 5 8)
4 (1-11) 2 (1-11) 2 (2-10)
29.5 (21-63) 29 (18-56) 25 (20-61)
BLOOD, 15 MARCH 2002 VOLUME 99, NUMBER 6
Table 1. Summary of patient characteristics at enrollment
*Number of patients in each outcome group receiving these treatments prior to enrollment.
AVOIDANCE OF SPLENECTOMY WITH ANTI-D IN ITP
Gender (F, M)
8, 4 6, 1 7, 1
10 7 8
9 4 3
2 1 1
after stopping treatment. The platelet counts for those off treatment with counts below 100 3 109/L (100 000/mL) are shown in Figure 3B (also beginning the month after stopping treatment); their counts appear to be stable.
Group B. The 7 patients still receiving treatment were enrolled a median of 2 months (range 1-11 months) from diagnosis and have been followed since study initiation for a median of 25 months (range 10-37 months). Three patients still receive IV anti-D. These 3 received a median of 0.42 infusions (range 0.42-0.58 infusions) per month during the first 12 months of the study and significantly less frequent (median 0.27 infusions [range 0.11-0.32]) infusions per month during the 9- to 22-month additional follow-up period (P 5 .037). Two patients stopped responding to IV anti-D within the first 4 months of the study. One received IVIG for 20 months and is now maintaining counts above 60 3 109/L (60 000/mL)
following a course of rituximab (patient no. 18). The other has a count of 105 3 109/L (105 000/mL) on 7.5 mg prednisone a day (no. 20). Two patients received medication for other medical conditions. One developed systemic lupus erythematosus 20 months after starting the study and received prednisone for symptoms other than her platelet count (no. 17). The other was infused 3 times with 400 mg/kg IVIG while pregnant to prevent fetal loss (no. 19) and then received IV anti-D once immediately prior to delivery.
Group C. The 8 patients who underwent splenectomy were enrolled a median of 4 months (range 2-10 months) from diagnosis and have been followed for a median of 27.5 months (range 6-39 months). Four were early nonresponders to anti-D and underwent splenectomy a median of 3.5 month (range 2-7 months) from starting the study. Four were continually responsive to anti-D but decided to undergo splenectomy a median of 27 months (range 9-36 months) from starting the study. Follow-up platelet counts are available from 2 to 10 months after splenectomy (median 3 months) in these patients. Six (75%) of the 8 had counts above 150 3 109/L (150 000/mL) after splenectomy without other therapy.
Biologic variables and acute response to IV anti-D
There was no correlation between glycocalicin levels, sCD16 levels, initial MCV or initial hemoglobin level, and platelet response to treatment or hemoglobin change after treatment. There was also no relationship between the number of D sites on the red cell as estimated by CDE typing and the day 7 platelet response or hemoglobin decrease following anti-D.
Comparisons between the outcome groups
Comparisons between the groups are shown in Table 2. The 12 patients in the “off treatment” category had significantly higher platelet counts at study entry than the 8 patients who underwent splenectomy (P , .05). Eleven of the 12 “off treatment” patients had platelet counts at least 14 3 109/L (14 000/mL) at study entry, compared with only 2 of the 8 patients who underwent splenec- tomy. Furthermore, all of the 8 patients who were unresponsive to anti-D within the first few months had platelet counts below 14 3 109/L (14 000/mL) at study entry.
There was no significant difference in pretreatment glycocalicin or sCD16 levels between the long-term outcome groups, possibly because the numbers in each group were small. There was no significant predictive value of initial MCV, initial hemoglobin, or
No. of patients
Median initial platelet count (range)
Median platelet increment after first infusion* (range)
Median duration of first infusion† (range)
Off treatment On treatment Splenectomy
12 7 8
19.5‡ (4-29) 12 (5-26) 9‡ (4-21)
106.5 (6-366) 126 (8-440) 47 (3-273)
28 (10-45.62) 21 (11.15-56.75) 19.5 (15.5-42.5)
Table 2. Comparison of pretreatment and peritreatment varables in each outcome group
Figure 3. Platelet counts. (A) The platelet counts for the 6 patients who have been off treatment for more than 6 months and have platelet counts at least 100 3 109/L (100 000/mL) at their last recorded count. The x-axis is time in months, and the y-axis is the platelet count. The counts are plotted beginning with the month after their last treatment. (B) The platelet count for the 6 patients who have been off treatment for more than 6 months with platelet counts below 100 3 109/L (100 000/mL) at their last follow-up count. The x-axis is time in months, and the y-axis is the platelet count. The counts are plotted beginning with the month after their last treatment.
*Platelet count day 7 2 day 0 3 109/L.
Days between infusions no. 1 and 2.
P , .05 MWU.