TABLE 2.
Likelihood of rituximab response by clinical and laboratory characteristics
|
Clinical/Laboratory characteristic n (%) or median (range) |
Na (N = 64) |
Rituximab responder (n = 36) |
Rituximab nonresponder (n = 28) |
P value Fisher’s exact or Wilcoxon rank‐sum |
|---|---|---|---|---|
| Sex | ||||
| Male | 25 | 16 (64) | 9 (36) | .44 |
| Female | 39 | 20 (51) | 19 (49) | |
| Age | ||||
| <18 y at first rituximab | 24 | 14 (58) | 10 (42) | >.99 |
| ≥18 y at first rituximab | 40 | 22 (55) | 18 (45) | |
| Type of ITP | ||||
| Primary ITP | 43 | 23 (53) | 20 (47) | .60 |
| Secondary ITP | 21 | 13 (62) | 8 (38) | |
| Phase of ITP at time of rituximab | ||||
| Newly diagnosed, <3 mo | 11 | 8 (73) | 3 (27) | .18 |
| Persistent, 3‐12 mo | 14 | 5 (36) | 9 (64) | |
| Chronic, >12 mo | 39 | 23 (59) | 16 (41) | |
| Number of different treatments given prior to rituximab | 3 (1‐7) | 2 (1‐6) | 3 (1‐7) | .13 |
| Complete IVIG response | 18 | 8 (44) | 10 (56) | .23 |
| Complete corticosteroid response | 29 | 18 (62) | 11 (38) | .79 |
| ANA obtained | 32 | 20 (62) | 12 (38) | .45 |
| ANA positive, ≥1:80 | 19 | 10 (53) | 9 (47) | .79 |
| DAT obtained | 51 | 28 (55) | 23 (45) | .76 |
| DAT positive | 8 | 4 (50) | 4 (50) | .72 |
| IgG level obtained | 54 | 31 (57) | 23 (43) | >.74 |
| Hypergammaglobulinemiaa | 4 | 2 (50) | 2 (50) | >.99 |
| Hypogammaglobulinemiab | 13 | 7 (54) | 6 (46) | >.99 |
| IgA level obtained | 54 | 30 (56) | 24 (44) | >.99 |
| Low IgA levelc | 11 | 7 (64) | 4 (36) | .74 |
| B‐cell lymphocyte subsets obtained | 28 | 16 (57) | 12 (43) | >.99 |
| Low B‐cell (CD19) numberd | 7 | 4 (57) | 3 (43) | .65 |
Abbreviations: ANA, antinuclear antibody; DAT, direct antiglobulin test; ITP, immune thrombocytopenia; IVIG, intravenous immunoglobulin.
Lab values correspond to the earliest available result chronologically.
a
Hypergammaglobulinemia: IgG level >2000 mg/dL.
b
Hypogammaglobulinemia: IgG level<600 mg/dL.
c
Low IgA level: <7 mg/dL.
d
Low B‐cell number: absolute CD19 < 110 cells/µL.