Table 1.

Demographic and baseline characteristics

	DC		SC
Characteristic	n	%	n	%
Total	13	100.0	3	100
Sex, male	4	30.8	2	66
Age at enrollment, y
2-11	6	46.2	0	0
12-17	7	53.8	3	100
Primary race, Black	13	100.0	3	100
Sickle cell or thalassemia disease type			—	—
HbSS	13	100.0	2	66
HbSS/β0 thalassemia	—	—	1	33
CMV seropositive	7	53.8	2	66
Performance status
100	6	46.2	2	66
90	3	23.1	0	0
80	4	30.8	0	0
70	0	—	1	33
Three or more painful events in the past 2 y	6	46.2	2	66
ACS (≥2 episodes in the past 2 y)	2	15.4	1	33
Neurologic event	4	30.8	1	33
Abnormal MRI/MRA results	5	38.5	1	33
Long-term PRBC transfusions	8	61.5	1	33
Hydroxyurea use before enrollment	10	76.9	2	66
Conditioning regimen A	3	23.0	—	—
(−35 to −10 hydroxyurea, 30 mg/kg per d orally; −9 to −6 busulfan 1 mg/kg per dose, IV every 6 h × 16 doses; −5 to −2 cyclophosphamide 50 mg/kg per d × 4 doses; and −3 to −1 eATG 30 mg/kg per d × 3 doses)
Conditioning regimen B *	10	77.0	2	66
(−35 to −15 hydroxyurea 30 mg/kg/day orally; −14 to −10 fludarabine 35 mg/m2 IV daily × 5 days; −9 to −6 busulfan 1 mg/kg/dose IV every 6 h × 16 doses; and −5 to −2 cyclophosphamide 50 mg/kg per day × 4 doses)
Conditioning regimen B (modified)*	—	—	1	—
(−12 to −10 eATG 30 mg/kg per day)

ACS, acute chest syndrome; MRA, magnetic resonance angiography; MRI, magnetic resonance imaging; PRBC, packed red blood cell; TCD, transcranial Doppler ultrasound.

^*The last patient in the SC cohort received additional eATG 30 mg/kg per day on days −12 to −10.