Fumiko Tsuchida

The Kinetics of Immune Reconstitution after Cord Blood Transplantation and Selected cd34+ Stem Cell Transplantation in Children: Comparison with Bone Marrow Transplantation

The present study compares immune reconstitution after allogeneic cord blood transplantation (CBT) and CD34+ stem cell transplantation (CD34-SCT) with that after bone marrow transplantation (BMT). Eighty-eight children who underwent CBT (20 patients), BMT (58), and CD34-SCT (10) were enrolled, and lymphocytes and T-, B-, and natural killer—lymphocyte subsets were monitored for more than 5 years after transplantation. CBT recipients showed significant increases in (1) total lymphocyte counts (P < .001), (2) CD4+/CD8+ cell ratios (P < .01), (3) CD4+ and CD4+CD45RA+ cells (P < .001), (4) CD8+CD11b+ cells (P < .001), and (5) CD19+ and CD19+CD5+ cells (P < .0001) and marked decreases in the frequencies of CD8+ and CD8+CD11b- cells (P < .0001). CD34-SCT recipients showed lower lymphocyte counts in the first 6 months and an emergence of lymphocyte and CD4+CD45RA+ cells at approximately 9 months and 1 year. Both CBT and CD34-SCT recipients showed increased frequencies of CD56+ cells at 1 month (CD34-SCT versus BMT, P < .001) but decreased frequencies after 6 months (CBT versus BMT, P < .001). Lymphoproliferative responses to exogenous interleukin 2 were constantly lower in CBT and CD34-SCT recipients than in BMT recipients.These results suggest that the delay in immune reconstitution after CBT in the early phase was mainly qualitative and related to the immaturity of cells, whereas the delay in CD34-SCT was mainly quantitative in the first several months. Int J Hematol. 2003;77:399-407.

Association between HLA-DPB1 matching and 1-year rejection-free graft survival in high-risk corneal transplantation

We analyzed the effect of matching for HLA class II alleles on corneal graft outcome in a single-center, retrospective study from January 1991 through April 1996. The study involved 81 transplant recipients at high and low risk of corneal graft rejection, who were typed by the polymerase chain reaction-restriction fragment length polymorphism method and who completed at least 1-year of follow-up. The DRB1, DQB1, and DPB1 alleles were analyzed together and transplant recipients were subdivided into groups with matching (one to four alleles matched in the high risk or one to five alleles matched in the low risk) and without matching (no allele matched) for HLA class II. A significantly higher rate of 1-year rejection-free graft survival was revealed in high-risk transplant recipients with matching, compared with those without matching (P=0.0238). We have shown that matching for at least one HLA class II allele was actually beneficial in high-risk transplants. An analysis of matching for each allele separately, detected that only HLA-DPB1 matching was significantly associated with a higher rate of 1-year rejection-free graft survival in high-risk transplant recipients with matching (one or two alleles matched) compared with those without matching (no allele matched) (P=0.0139). In particular, matching for one DPB1 allele was significantly beneficial compared with no matching (P=0.0140). There was no significant effect of HLA-DRB1 and -DQB1 matching (P=0.3177 and P=0.2878, respectively). Furthermore, a strong association between DPB1 matching and 1-year rejection-free graft survival was observed in DRB1-incompatible high-risk transplant recipients (P=0.0308). Nevertheless, no significant effect of DPB1 matching was detected in DQB1-incompatible transplant recipients. Our findings indicate that HLA class II DNA typing is clinically relevant for corneal transplant recipients and that especially HLA-DPB1 matching has a beneficial effect in high-risk corneal transplantation.

Proliferative Response by Stimulation of DP-Transfectants

DP antigens are products of the HLA-D region (class II antigens) along with DR and DQ. They were first defined by the primed lymphocyte typing (PLT) system (1–3). Whereas alloantisera exist against DR and DQ, no single DP specific alloantiserum has yet been discovered (4). The role of HLA-DP in transplantation immunology has not been defined. By introducing DP gene clones into cell lines, the resultant transfectant cells will allow the expression of DP antigens and hence enable their study. Using such transfectant cells as stimulator cells, the T-cell proliferative response was measured. In this study, it was observed that DP transfectant cells could generate a T-cell response.

PLT Analysis of D Region Complexity by Cloned Cells: A New Non-DP Antigen

The HLA-D region is very complex. HLA-D specificity is not identical to DR. It is not known whether the difference in HLA-D of cells with the same DR can be supposed to be due to one antigen determinant. To resolve the problem, PLT clones were used. From the MLC of cells with the same DR, DQ, DP antigens but with different D antigens, Dwl5-specific PLT clones and a Dw4-specific clone were established.