Table 3.

Donor stem cell sources in PID HSCT.

Donor source	HSC content	Access to donor	Engraftment time	Rate of GVHD	Rate of TRM	Advantages	Disadvantages	Other
MRD	3–5 ×10∧6 CD34+ cells/kg or 300–500 ×10∧6 TNC/kg	Rapid	Short	Low	Low	Chance to obtain more cells from donor if needed	<30% patients have MRD available, risk of disease-carrier status	Considered standard approach, primary graft source in most pediatric HSCT
MUD		Slow	Short	Increased	Low		HLA mismatches impact outcome	Probability to find compatible donor between 50 and 80%
TCRαβ/CD19- depleted haploidentical donor		Rapid	Short	Low	Low		High rate of viral infections, high laboratory expertise required, risk of disease-carrier status	Increased access to family donors
Cord blood unit	0.3–0.5 ×10∧6 CD34+ cells/kg	Rapid	Long	Low	Increased	Increased donor pool for ethnic minorities	Longer immune reconstitution, limited amount of available CD34+ cells, high rate of viral infections, unable to go back to donor for more cells	Ideal in smaller children where adequate HSC dose could be achieved

MRD, matched related donor; MUD, matched unrelated donor; TCR, T cell receptor; TNC, total nucleated cells; GVHD, graft versus host disease; TRM, transplant related mortality; HLA, human leukocyte antigen; HSCT, hematopoietic stem cell transplantation; HSC, hematopoietic stem cell.