Phenotype of lymphocyte subsets after autologous peripheral blood stem cell transplantation

The expression of CD45RA(+) and CD45RO(+) isoforms on T cells and the recovery of B lymphocytes and NK cells after autologous peripheral blood stem cell transplantation (PBSCT) were studied during the early period following transplantation. The same panel of monoclonal antibodies was used to analyze the lymphocyte subsets after allogeneic bone marrow transplantation (allo-BMT) and in cord blood. The CD4(+) subsets regenerated differently from the CD8(+) isoforms and the CD4(+)CD45RA(+) subset appears to be the only thymus-dependent regenerating population post-transplantation. Since the CD8(+) CD45RA(+) and CD8(+) CD45RO(+) isoforms recovered to normal levels within a month after PBSCT and within 3 months after allo-BMT, there seems to be no thymic influence on the regeneration of the immature CD8(+)CD45RA(+) subset. The regeneration of the CD4(+) cells was markedly delayed, but was faster in the PBSCT recipients, mainly because of the faster recovery of the mature CD4(+) CD45RO(+) subset. The pattern of surface antigens on T lymphocytes after transplantation did not resemble the antigen pattern on cord blood cells. The CD19(+) CD20(+) cells recovered earlier in the PBSCT group and remained compromised after allo-BMT during the time studied. The faster B lymphocyte regeneration correlates with the faster reconstitution of the mature CD4(+)CD45RO(+) cells. The pattern of antigens CD38(+), HLA-DR(+), CD10(+) on B lymphocytes of the recovery phase resembled the pattern on B cells of cord blood lymphocytes. The NK cells were not deficient at any time post-transplant in both groups.