Table 1.

Differences between conventional bone marrow and organ transplantation

Bone Marrow	Feature	Organ
Yes	Recipient cytoablationa	No
Critical	MHC compatibility	Not critical
GVHD	Principal complication	Rejection
Common	Drug free state	Rare
Tolerance	Term for success	‘Acceptance’b

Abbreviations: GVHD, graft-versus-host disease; MHC, major histocompatibility complex.

^aAll differences derive from this therapeutic step which in effect establishes an unopposed CVH reaction in the bone marrow recipient whose countervailing immune reaction is eliminated.

^bOr ‘operational tolerance’.