Transient suppression of hematopoietic colony formation from cytokine
mobilized PBSC was observed in a patient following local radiation the
rapy for lymphoma. This effect was seen 2 weeks after completion of ra
diation and reversed by 6 weeks. The patient successfully engrafted af
ter myeloablative chemotherapy with harvested PBSC. This report docume
nts the first reported case of suppression of PBSC colony formation fo
llowing radiation and we speculate that this finding may be due to an
abscopal effect.