Selected CD34 blood cell allografts for older patients: low transplant-related mortality, graft failure and acute GvHD.

Background: Early transplant mortality is related to acute GvHD, which this study in older patients (40 to 60 years) decreased by reducing the graft T-cell number while maintaining a high CD34 cell number--by positive CD34 cell selection. Potential increased risk of relapse is addressed by giving donor leucocyte infusion (DLI) post-transplant.

Methods: CD34 cells selected by Isolex devices from leukophereses obtained from Filgrastim-treated matched sibling donors were transplanted and DLI given later if there was no GvHD.

Results: Selection of CD34 cells achieved a median of 5.2 million cells/kg, with minimum target for transplantation achieved in 17 of 21 donors. Median CD3 cell number was 0.24 million/kg. Engraftment was rapid and graft failure rare. Transplant-related mortality was low (6% at 3 months). Acute GvHD of >or=Grade 2 occurred in only two patients (12.5%). DLI were given to only six patients who had resolved Grade 1 or no GvHD. Eight of the 17 patients relapsed, including three of the six who had DLI. Extensive chronic GvHD developed in six of 12 evaluable patients, two of these had received DLI. Seven of the 17 patients (41%) are alive at median follow-up of 56 months.

Conclusion: CD34 selection allows transplantation of high numbers of CD34 cells with low CD3 cell count, reducing early mortality in patients 40-60 years old because of rapid hemopoietic reconstitution and low acute GvHD incidence. Administration of DLI was often precluded by low-grade acute GvHD.