Table 1.
Characteristics of Patients with Donor Chimerism by Day +100, by 1 Year, and by 2 Years
| Chimerism
|
|||
|---|---|---|---|
| Full Donor N (%) |
Graft Failure N (%) |
Mixed N (%) |
|
| Donor chimerism by day +100 (n = 95) | |||
| Number of patients | 55 | 13 | 27 |
| Median age at transplant, yr (range) | 14 (2–53) | 31 (14–57) | 11 (2–65) |
| Donor and graft type | |||
| HLA-identical sibling, bone marrow | 21 (38) | 0 | 7 (26) |
| HLA-identical sibling, peripheral blood | 18 (33) | 4 (31) | 8 (30) |
| HLA-identical sibling, cord blood | 4 (7) | 0 | 6 (22) |
| Other relative, bone marrow | 1 (2) | 0 | 0 |
| Other relative, peripheral blood | 3 (5) | 8 (62) | 3 (11) |
| Unrelated donor, bone marrow | 3 (5) | 0 | 2 (7) |
| Unrelated donor, cord blood | 5 (9) | 1 (8) | 1 (4) |
| Indication for transplantation | |||
| Stroke, acute chest syndrome, vaso-occlusive crisis | 3 (5) | 3 (23) | 2 (7) |
| Stroke, acute chest syndrome | 1 (2) | 0 | 2 (7) |
| Stroke, vaso-occlusive crisis | 3 (5) | 3 (23) | 2 (7) |
| Acute chest syndrome, vaso-occlusive crisis | 21 (38) | 3 (23) | 6 (22) |
| Stroke alone | 7 (13) | 1 (8) | 4 (15) |
| Acute chest syndrome alone | 4 (7) | 0 | 1 (4) |
| Vaso-occlusive crisis alone | 9 (16) | 2 (15) | 6 (22) |
| Not reported | 7 (13) | 1 (8) | 4 (15) |
| Transplant conditioning regimen | |||
| Myeloablative | |||
| Busulfan + cyclophosphamide | 20 (36) | 0 | 8 (30) |
| Busulfan + fludarabine | 4 (7) | 0 | 0 |
| Busulfan + cyclophosphamide + fludarabine | 0 | 0 | 2 (7) |
| Reduced intensity | |||
| Melphalan + fludarabine + alemtuzumab | 7 (13) | 1 (8) | 4 (15) |
| Melphalan + fludarabine | 1 (2) | 0 | 1 (4) |
| Total body irradiation (200 cGy) + fludarabine + alemtuzumab | 1 (2) | 0 | 1 (4) |
| Total body irradiation (300/400 cGy) + alemtuzumab | 21 (38) | 12 (92) | 11 (41) |
| Cyclophosphamide + alemtuzumab | 1 (2) | 0 | 0 |
| Year of transplant | |||
| 1994–2005 | 11 (20) | 0 | 4 (15) |
| 2006–2013 | 44 (80) | 13 (100) | 23 (85) |
| Donor Chimerism at 1 Year (n = 91)* | |||
| Number of patients | 52 | 10 | 29 |
| Median age at transplant, yr (range) | 14 (2–53) | 28 (14–57) | 11 (2–65) |
| Type of donor | |||
| HLA-identical sibling, bone marrow | 15 (29) | 0 | 13 (45) |
| HLA-identical sibling, peripheral blood | 18 (35) | 2 (20) | 7 (24) |
| HLA-identical sibling, cord blood | 6 (12) | 0 | 4 (14) |
| Other relative, bone marrow | 1 (2) | 0 | 0 |
| Other relative, peripheral blood | 2 (4) | 7 (70) | 4 (14) |
| Unrelated, bone marrow | 4 (8) | 0 | 1 (3) |
| Unrelated, cord blood | 6 (12) | 1 (10) | 0 |
| Indication for HCT | |||
| Stroke, acute chest syndrome, vaso-occlusive crisis | 3 (6) | 2 (20) | 2 (7) |
| Stroke, acute chest syndrome | 1 (2) | 0 | 2 (7) |
| Stroke, vaso-occlusive crisis | 3 (6) | 2 (20) | 2 (7) |
| Acute chest syndrome, vaso-occlusive crisis | 17 (33) | 3 (30) | 9 (31) |
| Stroke alone | 7 (13) | 1 (10) | 4 (14) |
| Acute chest syndrome alone | 2 (4) | 0 | 3 (10) |
| Vaso-occlusive crisis alone | 11 (21) | 2 (20) | 4 (14) |
| Not reported | 8 (15) | 0 | 3 (10) |
| Conditioning regimens | |||
| Myeloablative | |||
| Busulfan + cyclophosphamide | 15 (29) | 0 | 13 (45) |
| Busulfan + fludarabine | 3 (6) | 0 | 1 (3) |
| Busulfan + cyclophosphamide + fludarabine | 2 (4) | 0 | 0 |
| Reduced intensity | |||
| Melphalan + fludarabine + alemtuzumab | 10 (19) | 1 (10) | 1 (3) |
| Melphalan + fludarabine | 1 (2) | 0 | 1 (3) |
| Total body irradiation (200 cGy) + fludarabine + alemtuzumab | 1 (2) | 0 | 1 (3) |
| Total body irradiation (300/400 cGy) + alemtuzumab | 20 (38) | 9 (90) | 11 (38) |
| Cyclophosphamide + alemtuzumab | 0 | 0 | 1 (3) |
| Year of transplant | |||
| 1994–2005 | 7 (2) | 0 | 7 (24) |
| 2006–2013 | 45 (98) | 10 (100) | 22 (76) |
| Donor chimerism at 2 years (n = 76)† | |||
| Number of patients | 43 | 10 | 23 |
| Median age at transplant, yr (range) | 14 (2–53) | 28 (14–57) | 14 (2–65) |
| Type of donor | |||
| HLA-identical sibling, bone marrow | 11 (26) | 0 | 11 (48) |
| HLA-identical sibling, peripheral blood | 17 (40) | 2 (20) | 7 (30) |
| HLA-identical sibling, cord blood | 5 (12) | 0 | 2 (9) |
| Other relative, peripheral blood | 0 | 7 (70) | 3 (13) |
| Unrelated, bone marrow | 4 (9) | 0 | 0 |
| Unrelated, cord blood | 6 (14) | 1 (10) | 0 |
| Indication for HCT | |||
| Stroke, acute chest syndrome, vaso-occlusive crisis | 2 (5) | 2 (20) | 3 (13) |
| Stroke, acute chest syndrome | 3 (7) | 0 | 0 |
| Stroke, vaso-occlusive crisis | 1 (2) | 2 (20) | 2 (9) |
| Acute chest syndrome, vaso-occlusive crisis | 14 (33) | 3 (30) | 7 (30) |
| Stroke alone | 5 (12) | 1 (10) | 4 (17) |
| Acute chest syndrome alone | 2 (5) | 0 | 2 (9) |
| Vaso-occlusive crisis alone | 10 (23) | 2 (20) | 2 (9) |
| Not reported | 6 (14) | 0 | 3 (13) |
| Conditioning regimens | |||
| Myeloablative | |||
| Busulfan + cyclophosphamide | 12 (28) | 0 | 10 (43) |
| Busulfan + fludarabine | 2 (5) | 0 | 1 (4) |
| Busulfan + cyclophosphamide + fludarabine | 2 (5) | 0 | 0 |
| Reduced intensity | |||
| Melphalan + fludarabine + alemtuzumab | 8 (19) | 1 (10) | 0 |
| Melphalan + fludarabine | 2 (5) | 0 | 0 |
| Total body irradiation (200 cGy) + fludarabine + alemtuzumab | 0 | 0 | 1 (4) |
| Total body irradiation (300/400 cGy) + alemtuzumab | 17 (40) | 9 (90) | 10 (43) |
| Cyclophosphamide + alemtuzumab | 0 | 0 | 1 (4) |
| Year of transplant | |||
| 1994–2005 | 5 (11) | 0 | 4 (17) |
| 2006–2013 | 38 (88) | 10 (100) | 19 (82) |
Values are number of patients with percents in parentheses unless otherwise defined.
Four patients were censored between day +100 and 1 year: 2 patients with primary graft failure died, 1 patient with primary graft failure received a second transplant 7 months after first transplant, and 1 patient with mixed chimerism received a second transplant for graft failure 11 months after first transplant.
Fifteen patients were censored between 1 and 2 years: 1 patient with full donor chimerism died at 14 months; 1 patient with full donor chimerism received a second transplant 14 months after first transplant for secondary graft failure; 4 patients with full chimerism at 1 year did not have chimerism test at 2 years but HbS level was <50%, RBC transfusion independent, and asymptomatic; 5 patients with mixed chimerism at 1 year did not have chimerism test at 2 years, but HbS level was <50%, RBC transfusion independent, and asymptomatic; and 4 patients with mixed chimerism were not followed beyond 1 year.