[Early immune reconstitution after hematopoietic stem cell transplantation]

To search for differences in early immune reconstitution after allogenic or autologous hematopoietic stem cell transplantation (HSCT).

The peripheral blood (PB) from 31 adult patients undergoing allogenic HSCT (allo-HSCT, 15 patients) or autologous HSCT (auto-HSCT, 16 patients) for the treatment of hematological malignancies and from 20 related healthy controls (HC) from December 2011 to August 2014 was used to analyze the kinetic recovery of lymphocyte subsets by means of flow cytometry during 12 months after HSCT. The T cell receptor rearrangement excision circle (TREC) levels among CD3(+) T cells were measured in the patients and HC to evaluate the thymic-dependent T cell reconstitution.

The allo- and auto-HSCT recipients did not differ significantly in CD4(+) T cells, CD8 naive T cells, effecter memory T cells (TEM), CD4 central memory T cells (TCM), mid-activated T cells and dendritic cells (DC)during the follow-up (P>0.05). But they both differed significantly from HC (P<0.05). CD8(+) T cells and NK cells reconstructed rapidly. There was no significant difference in the numbers of B cells between the allo- and auto-HSCT groups from M1 to M3 (P>0.05). B cells in both the groups were lower than those in HC (P<0.05). The recovery of B cells in auto-HSCT group was faster than in allo-HSCT group at M6 and M12 (P<0.05). The frequencies of CD4 naive T cells and later activated T cells in allo-HSCT group were significantly higher than in auto-HSCT group at M6 and M12 (P<0.05). The frequencies of CD8 TCM in auto-HSCT group were significantly higher than in allo-HSCT group at M6 and M12 (P<0.05). The TREC levels were significantly lower than in both the groups compared with the age-matched HC during the follow-up (P<0.05). No significant difference was observed between allo-HSCT and auto-HSCT groups (P>0.05).

The differences of the nature and the speed of lymphocyte reconstitution observed between the two patents groups were minor. This leads us to conclude that in allografted patients, immune reconstitution and subpopulations of peripheral blood lymphocytes are probably not related to the allogenicity of the graft, but due to the impaired thymus functions and slow differentiation of T lymphocytes in thymus.