Surface levels of platelet receptors in healthy donors, ITP patients or patients with lymphoproliferative disorders before and during treatment with ABT-263
| . | n . | Platelet count . | GPIbα geomean . | P . | CD9 geomean . | P . | GPVI geomean . | P . | αΙΙbβ3 geomean . | P . | sGPVI ng/ml . | P . |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lymphoproliferative patients | ||||||||||||
| Presample | 5 | 151 ± 43 | 271 (73) CI 165-491 | *** | 367 (188) CI 110-376 | ns | 90 (24) CI 66-290 | ** | 342 (175) CI 154-220 | ns | 23 (9) CI 5.9-15 | ns |
| + ABT-263 Day 1 | 5 | 95 ± 22 | 350 (129) CI 77-421 | ** | 329 (205) CI 75-417 | ns | 105 (40) CI 50-276 | ** | 474 (271) CI 50-380 | ns | 28 (17) CI 10-12 | ns |
| + ABT-263 Day 7 | 5 | 91 ± 30 | *226 (137) CI 199-547 | *** | 291 (191) CI 34-452 | ns | 96 (38) CI 59-285 | ** | 346 (149) CI 144-218 | ns | 16 (8) CI 5.4-15 | ns |
| ITP† patients | 7 | 35 ± 13 | 366 (187) CI 8-398 | ** | 208 (104) CI 98-486 | ** | 101 (53) CI 70-264 | ** | 399 (257) CI 102-282 | ns | 43 (10) CI 13-32 | *** |
| Healthy donors | 15 | 457 ± 114 | 599 (166) | 500 (233) | 268 (116) | 309 (172) | 21 (10) | |||||
| . | n . | Platelet count . | GPIbα geomean . | P . | CD9 geomean . | P . | GPVI geomean . | P . | αΙΙbβ3 geomean . | P . | sGPVI ng/ml . | P . |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Lymphoproliferative patients | ||||||||||||
| Presample | 5 | 151 ± 43 | 271 (73) CI 165-491 | *** | 367 (188) CI 110-376 | ns | 90 (24) CI 66-290 | ** | 342 (175) CI 154-220 | ns | 23 (9) CI 5.9-15 | ns |
| + ABT-263 Day 1 | 5 | 95 ± 22 | 350 (129) CI 77-421 | ** | 329 (205) CI 75-417 | ns | 105 (40) CI 50-276 | ** | 474 (271) CI 50-380 | ns | 28 (17) CI 10-12 | ns |
| + ABT-263 Day 7 | 5 | 91 ± 30 | *226 (137) CI 199-547 | *** | 291 (191) CI 34-452 | ns | 96 (38) CI 59-285 | ** | 346 (149) CI 144-218 | ns | 16 (8) CI 5.4-15 | ns |
| ITP† patients | 7 | 35 ± 13 | 366 (187) CI 8-398 | ** | 208 (104) CI 98-486 | ** | 101 (53) CI 70-264 | ** | 399 (257) CI 102-282 | ns | 43 (10) CI 13-32 | *** |
| Healthy donors | 15 | 457 ± 114 | 599 (166) | 500 (233) | 268 (116) | 309 (172) | 21 (10) | |||||
Citrated PRP samples were analyzed by flow cytometry in CLL patients prior to and after receipt of 100 to 150 mg ABT-263 daily. Values reported as platelet count × 103/μl, mean fluorescence intensity geomeans for the entire platelet population (standard deviation), and sGPVI levels in citrated plasma ng/ml (standard deviation). P values derived from a 2-tailed unpaired t test comparing data from healthy donors with each patient group; ns indicates no significant difference. **P < .01; ***P < .001; CI = 95% confidence intervals.
One day 7 GPIbα measurement was lost.
Seven clinically diagnosed ITP patients (6 chronic, 1 persistent) with platelet count below 50 × 103/μl on the day of blood collection. Two of the 7 were receiving 50 mg or 75 mg prednisolone, the others were not receiving medication for ITP; the autoantibody target was not determined.