Optimal stem cell source for allogeneic stem cell transplantation for hematological malignancies

Table 1 Comparison of bone marrow, peripheral blood stem cell and cord blood

	BM	PBSC	CB
Typical time frame from initiation of search to transplantation	3-6 mo	3-6 mo	2-4 wk
Usual volume	500-2000 mL	50-300 mL	25-150 mL
Adverse effects for donor	Risks of wound infection, bleeding, general anesthesia, etc.	Risks of bleeding, infection, thrombosis, hypotension, electrolyte disturbance, etc.	No
Minimal cell dose for transplant	Total nucleated cell: 2 x 108/kg	Total CD34+ cell: 2 x 106/kg	Total nucleated cell: 2.5 x 107/kg
Red blood cell content	High	Low	Low
Possibility to give additional stem cell dose	Possible	Possible	Impossible
Exposure to dimethyl sulfoxide	No if fresh	No if fresh	Yes
HLA matching requirement	More stringent (7-8 out of 8 matched)	More stringent (7-8 out of 8 matched)	Less stringent (4-6 out of 6 matched)
Speed of neutrophil engraftment	About 3 wk	About 2 wk	About 4 wk
Speed of immune reconstitution	Faster	Faster	Slower
Risk of graft-versus-host disease	Medium	Highest	Lowest
Risk of post-transplant infections	Lower	Lower	Higher
Risk of latent virus transmission	Higher	Higher	Lower
Possibility of CMV transmission	Higher as most donors are CMV seropositive	Higher as most donors are CMV seropositive	Lower as most CB units do not harbor CMV
Risk of relapse for high risk patients	Higher	Lower	Higher

PBSC: Peripheral blood stem cell; HLA: Human leukocyte antigen; BM: Bone marrow; CB: Cord blood; CMV: Cytomegalovirus.

Table 2 Randomized controlled trials comparing bone marrow and peripheral blood stem cell for matched related donor transplant

Ref.	No.ofpatients	Age of patients (yr)	Underlying diseases	Conditioning	Overall survival (BM vs PBSC)	Disease-free survival (BM vs PBSC)	Relapse (BM vs PBSC)	Transplant-related mortality (BM vs PBSC)	Acute graft-versus host disease (BM vs PBSC)	Chronic graft-versus host disease (BM vs PBSC)	Median time of neutrophil engraftment (d) (BM vs PBSC)	Median time of platelet engraftment (d) (BM vs PBSC)
[23,29]	56	7-59	Acute leukemias, CML, MDS, MM, NHL	Myeloablative1	48% vs 56%2 (2000 d)	50 vs 60%2 (2000 d)	NA	NA	23% vs 26%2 (grades 2-4)	61% vs 77%2 (extensive cGVHD)	18 vs 15a	18 vs 12b
[9]	39	22-51	Acute leukemias, CML, CLL, MDS, MM, NHL	Myeloablative1	63% vs 70%2 (2 yr)	NA	37% vs 0%a (2 yr)	32% vs 35%2	58% vs 68%2 (grades 1-4)	40% vs 44%2 (All cGVHD)	23 vs 17.5b	18 vs 11d
[25]	61	15-62	Acute leukemias, CML, MDS, PMF	Bu/Cy	73% vs 80%2 (4 yr)	55% vs 80%2 (4 yr)	30% vs 3%2	10% vs 17%2	10% vs 21%2 (grades 2-4)	27% vs 56%2 (All cGVHD)	23 vs 17d	21 vs 13d
[10,19]	101	Mean 37	Acute leukemias, CML	Myeloablative1	65% vs 67%2 (2 yr)	66% vs 67%2 (2 yr)	15% vs 6%2	21% vs 25%2	42% vs 44%2 (grades 2-4)	36% vs 65%b (All cGVHD) 17% vs 44%b (extensive cGVHD)	21 vs 153	21 vs 13d
[15-18]	329	19-58	Acute leukemias, CML, MDS	Myeloablative1	65% vs 65%2 (2 yr) 65% vs 58%2 (3 yr) 57% vs 49%2 (10 yr)	60% vs 56%2 (3 yr) 46% vs 42%2 (10 yr)	24% vs 20%2 (10 yr)	32% vs 24%2	42% vs 44%a (grades 2-4)	56% vs 74%b (All cGVHD) 19% vs 36%b (extensive cGVHD)	15 vs 12d	20 vs 15d
[12,13,20]	172	12-55	Acute leukemias, CML, CLL, MDS, MM, lymphomas	Myeloablative1	54% vs 66%2 (2 yr) 52% vs 55%2 (10 yr)	45% vs 65%a (2 yr) 40% vs 50%a (10 yr)	25% vs 14%a (2 yr) 32% vs 20%a (10 yr)	30% vs 21%2	57% vs 64%2 (grades 2-4)	52% vs 63%2 (extensive cGVHD)	21 vs 16d	19 vs 13d
[11]	227	19-64	AML, CML, MDS	Bu/Cy	60% vs 68%a (30 mo)	NA	9% vs 9%2	32% vs 21%2	44% vs 44%2 (grades 2-4)	69% vs 85%2 (All cGVHD) 30% vs 40%2 (extensive cGVHD)	23 vs 19d	22 vs 16d
[30]	110	15-62	Acute leukemias, MDS, MM, lymphomas	Myeloablative1	60% vs 34%a (4 yr)	NA	13% vs 18%2	28% vs 41%2	37% vs 52%2 (grades 2-4)	45% vs 61%2 (All cGVHD) 16% vs 28%2 (extensive cGVHD)	20 vs 15d	38 vs 25d
[14]	72	18-61	CML	Myeloablative1	72% vs 81%2 (3 yr)	65% vs 81%2 (3 yr)	15% vs 0%a (3 yr)	20% vs 19%2	49% vs 55%2 (grades 2-4)	50% vs 59%2 (extensive cGVHD)	22 vs 17a	21 vs 142

¹Different conditioning regimens;

²Not statistically significant;

^aP < 0.05,

^bP < 0.01,

^dP < 0.01. GVHD: Graft-versus-host disease; PBSC: Peripheral blood stem cell; HLA: Human leukocyte antigen; BM: Bone marrow; CML: Chronic myeloid leukemia; MDS: Myelodysplastic syndrome; MM: Multiple myeloma; NHL: Non-Hodgkin lymphoma; PMF: Primary myelofibrosis; AML: Acute myeloid leukemia; CLL: Chronic lymphocytic leukemia; Bu/Cy: Busulfan and cyclophosphamide; NA: Not available.