Table 1.

Demographic, clinical, and treatment data for the patient cohort

Entire cohort (N = 124)RTX (N = 60)No RTX (N = 64)
Study site, n (%)
 Harvard Consortium91 (73)46 (77)45 (70)
 University of Washington17 (14)9 (15)8 (13)
 Boston Medical Center16 (13)5 (8)11 (17)
Type of presentation, n (%)
 First-time104 (84)50 (83)54 (84)
 Presenting in relapse20 (16)10 (17)10 (16)
Sex, n (%)
 Male38 (31)18 (30)20 (31)
 Female86 (69)42 (70)44 (69)
Age, median (IQR), y42 (31-52)41 (31-52)43 (31-53)
ABO blood group, n (%)
 Group O64 (52)31 (52)33 (52)
 Non-group O58 (47)27 (45)31 (48)
 Unknown2 (1)2 (3)0 (0)
Ethnicity, n (%)
 White67 (54)34 (57)33 (52)
 Nonwhite52 (42)24 (40)28 (44)
 Unknown5 (4)2 (3)3 (5)
Laboratory values, median (IQR)
 ADAMTS13 activity, %*0 (0-0)0 (0-0)0 (0-0)
 ADAMTS13 inhibitor, BU1.4 (0.7-2.0)1.4 (0.8-2.0)1.4 (0.6-2.0)
 Hemoglobin, g/dL8.9 (7.3-10.1)8.6 (7.1-9.6)9.4 (7.4-10.8)
 Platelets, ×109/L16 (10-22)15 (10-20)17 (11-24)
 Lactate dehydrogenase, U/L1090 (742-1402)1089 (734-1504)1090 (782-1329)
 Cr, mg/dL1.0 (0.8-1.4)1.0 (0.7-1.3)1.1 (0.9-1.6)
 Total bilirubin, mg/dL2.3 (1.5-3.1)2.4 (1.5-3.1)2.3 (1.5-3.1)
 Reticulocyte, %4.6 (2.9-8.3)6.2 (3.7-9.9)3.6 (2.6-6.4)
 Day 4 platelets, ×109/L131 (68-181)111 (49-160)159 (107-216)
 Days to platelet normalization5 (4-8)6 (4-15.3)4 (3.5-6)
Treatment
 No. (%) treated with TPE120 (97)60 (100)60 (94)
  Median (IQR) TPE procedures15 (8-23)22 (14-29)9 (6-15)
 No. (%) treated with steroids113 (91)58 (97)56 (88)
 No. (%) treated with second-line drug8 (6.5)8 (13)0 (0)
 Median (IQR) hospital stay, d12 (8-20)18 (11-27)9 (7-14)
  • * An undetectable ADAMTS13 activity level was recorded as 0%.

  • Five patients were given cyclophosphamide, 2 were given bortezomib (1 in combination with tacrolimus), and 1 patient was given vincristine.