A preliminary analysis of the balance between Th1 and Th2 cells after CD34+ cell-selected autologous PBSC transplantation

Background CD34(+) cell-selected autologous PBSC transplantation (CD34(+) APBSCT) is a procedure used for the treatment of patients with malignant disease that is intended to eliminate residual tumor cells from autologous grafts. However, frequent infectious complications after CD34(+) APBSCT can occur. A delay of recovery of the absolute number of CD4(+) T cells after transplantation was reported to be one disadvantageous factor. As data on T-cell function after CD34(+) APBSCT are scanty, we analyzed changes in T-helper cell 1 (Th1) and T-helper cell 2 (Th2) after CD34(+) APBSCT to evaluate immune reconstitution. Methods Twelve patients underwent APBSCT (CD34(+) APBSCT group, n = 4, and unselected APBSCT, n = 8). Peripheral blood (PB) samples were obtained at 2, 4, 8, 12 and 16 weeks after the transplantation. The dynamics of the Th1 and Th2 were analyzed at a single-cell level, using flow cytometry. Results In the CD34(+) APBSCT group, not only the absolute count of CD4(+) T cells but also the proportion of Th1 cells in CD4(+) T cells and the ratio of Th1 to Th2 after transplantation were significantly decreased at 2 and 4 weeks after transplantation compared with findings in the unselected APBSCT group. Discussion We suggest that higher rates of infectious complications after CD34(+) APBSCT may be due to the inability of residual T cells from the CD34(+) cell selection to generate mature T cells that function adequately against infection. Although further study would be required, our preliminary data provide some information on the immune reconstitution after CD34(+) APBSCT and differentiation of T lymphocytes into Th1 and Th2 in vivo.