APPARENT REACTIVATION OF A RED-CELL ALLOANTIBODY IN A HEALTHY INDIVIDUAL AFTER G-CSF ADMINISTRATION

Granulocyte-colony stimulating factor (G-CSF) has been successfully ad ministered to healthy subjects to mobilize peripheral blood stem cells (PBSC) for allogeneic transplantation. Adverse events are moderate. W e report the first case of apparent reactivation of an alloantibody to a blood cell antigen (Jk(a)) after G-CSF administration to a healthy subject and its transmission to the PBSC transplant recipient; no conc omitant reactivation of other alloantibodies was detected. This case r aises questions on the effect of G-CSF on the immune system and its sa fety in healthy individuals.