Assessment of immune reconstitution status in recipients of a successful hematopoietic stem cell transplant from peripheral blood after reduced intensity conditioning.

OBJECTIVE: To document immune reconstitution status after hematopoietic stem cell transplantation (HSCT) for malignant hematologic diseases.

METHODS: Hematology patients who received a reduced intensity conditioning (RIC) were followed after successful allogeneic or autologous HSCT. Patients had at least 100days post-transplant. T, B and NK cells in peripheral blood (PB), and CD34+, CD133+ progenitor cells in bone marrow (BM) and peripheral blood (PB) were determined by flow cytometry.

RESULTS: Twenty-seven HSCT recipients, 19 allogeneic and 8 autologous, were studied at a median 155 (100-721) days post-transplant. In the whole group the median value of CD34+ cells was 1.03% in the bone marrow and 0.04% in PB, whereas values for CD133+ cells were 0.39% and 0.13%, respectively, without statistical differences between autologous and allogeneic recipients. Significantly more B cells (CD3-/CD56-/CD19+) were found in the autologous compared to the allogeneic group, 12.6 vs. 5.01, p=0.04. An increased number of CD8+ lymphocytes with a 0.63 CD4:CD8 relationship was documented in PB.

CONCLUSION: In clinically recovered autologous and allogeneic HSCT recipients BM and PB CD34+/CD133+ hematoprogenitor homeostasis is maintained within normal ranges, with better B-cell reconstitution in the autologous group.