In a previous study, we found that total body irradiation (TBI) was essential to induce acute graft-versus-host disease (GVHD) after allogeneic H-2-incompatible splenocyte (SP) transplantation in SCID mice. SCID mice (H-2d) conditioned with cyclophosphamide and transplanted intravenously (IV) with 5 x 10(7) C57BL/6 (H-2b) SP developed chronic GVHD within 3 months posttransplant without any evidence of preceding acute GVHD. In this study, SCID mice were conditioned with 4 Gy TBI or non-TBI regimens, either BuCy2 (busulfan 4 mg/kg/d + cyclophosphamide 100 mg/kg/d for 2 days) or Cy5 (cyclophosphamide 100 mg/kg/d for 5 days), and then transplanted IV with 5 x 10(7) SP. The TBI-conditioned mice were further divided into tree transplant groups: (1) TBI and SP administered the same day (TBI + D0 SP), (2) SP administered 4 days post-TBI (TBI + D4 SP), and (3) SP administered 7 days post-TBI (TBI + D7 SP). The severity of GVHD was compared among these groups by clinical and histologic grading. Twenty- eight of 28 mice treated with TBI + D0 SP died of acute GVHD, with overwhelming diarrhea by day 15 posttransplantation. Sixteen mice treated with either TBI + D4 SP or TBI + D7 SP developed acute GVHD, but none of them died of this disorder during 30 days posttransplantation. The mice conditioned with non-TBI regimens developed chronic GVHD within 3 months without showing any detectable signs of acute GVHD. Serum and in situ colonic cytokines were determined by enzyme-linked immunosorbent assay and immunohistology respectively. TBI itself significantly increased both serum and colonic tumor necrosis factor-alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha), and IL-6 when compared with non-TBI regimens and normal controls. TNF-alpha appeared in the serum and colon 4 hours post-TBI and peaked in 24 hours, followed by increasing IL-1 alpha and then IL-6 levels. TNF-alpha and IL-1 alpha decreased rapidly within 3 to 5 days post-TBI if no allogeneic cells were transplanted. Histoincompatible transplantation augmented cytokine release, which remained elevated on day 10 in these animals. Mice treated with TBI + D0 SP developed the most severe acute GVHD and had the highest levels of TNF-alpha, IL-1 alpha, and IL-6. The BuCy2-conditioned mice had the lowest cytokine levels and developed no acute GVHD. When the mice transplanted with TBI + D0 SP were treated immediately with recombinant soluble human TNF receptor (rhuTNFR:Fc) 100 micrograms/d intraperitoneally and for the subsequent 15 days acute GVHD mortality was significantly reduced from 100% to 50% (P < .001).

Summary:Haploidentical donors are available for most patients who need allografts but do not have matched donors. However, GVHD, rejection, delayed immune reconstitution, and infections have been significant barriers. We designed a haploidentical BMT protocol focusing on prevention of GVHD and rejection. A total of 53 leukemic patients underwent haploidentical G-CSF-primed BMT without ex vivo T-cell depletion. GVHD prophylaxis consisted of antithymocyte globulin, cyclosporine, methotrexate, and mycophenolate mofetil. In all, 38 patients (the CD25 group) received additional anti-CD25 monoclonal antibody basiliximab. The results were compared to 15 patients who did not receive basiliximab. All patients achieved trilineage engraftment with full-donor chimerism. The incidence of acute II-IV GVHD was 11% in the CD25 group vs 33% in the control group (P ¼ 0.046). The overall incidence of extensive chronic GVHD was 15%. T, B, and NK cells recovered within 12 months post transplant. The disease-free survival at 2 years was 53% with a median follow-up of 31 months. In conclusion, G-CSF primed haploidentical BMT along with sequential immunosuppressive agents as described here deserves further study.

Summary:Based on our encouraging results of G-CSF-primed HLA-matched related marrow transplants for high-risk leukemia, we extended the study from matched related to haploidentical transplants using G-CSF primed marrow and sequential immunosuppressants to prevent both graft-versus-host disease (GVHD) and host-versusgraft rejection (HVGR). Fifteen high-risk leukemia patients, who needed urgent transplantation but lacked an HLA-matched donor, underwent G-CSF-primed haploidentical marrow transplantation without ex vivo T cell depletion. Donors were given G-CSF (Lenograstim) at 3-4 g/kg/day for 7 days prior to marrow harvest. GVHD and HVGR prophylaxis were combined in the sequential usage of cyclosporin A, methotrexate, anti-thymocyte globulin and mycophenolate mofetil. All patients established sustained trilineage engraftment at a median of 19 days and 21 days for neutrophil and platelets respectively. G-CSF priming significantly increased CD34 + and CFU-GM cells, reduced total lymphocytes and reversed the CD4 + /CD8 + ratio in the donor marrow. The incidence of grade II-IV acute GVHD was 33.3%. Nine patients survived more than a year with a Karnofsky performance status of 100%. Estimated overall disease-free survival at 2 years was 60 ؎ 7%. In conclusion, using G-CSF priming marrow grafts along with sequential immunosuppressants provided an excellent alternative for the treatment of high-risk hematological malignancy in patients who lack matched donors.

In a previous study, we found that total body irradiation (TBI) was essential to induce acute graft-versus-host disease (GVHD) after allogeneic H-2-incompatible splenocyte (SP) transplantation in SCID mice. SCID mice (H-2d) conditioned with cyclophosphamide and transplanted intravenously (IV) with 5 x 10(7) C57BL/6 (H-2b) SP developed chronic GVHD within 3 months posttransplant without any evidence of preceding acute GVHD. In this study, SCID mice were conditioned with 4 Gy TBI or non-TBI regimens, either BuCy2 (busulfan 4 mg/kg/d + cyclophosphamide 100 mg/kg/d for 2 days) or Cy5 (cyclophosphamide 100 mg/kg/d for 5 days), and then transplanted IV with 5 x 10(7) SP. The TBI-conditioned mice were further divided into tree transplant groups: (1) TBI and SP administered the same day (TBI + D0 SP), (2) SP administered 4 days post-TBI (TBI + D4 SP), and (3) SP administered 7 days post-TBI (TBI + D7 SP). The severity of GVHD was compared among these groups by clinical and histologic grading. Twenty- eight of 28 mice treated with TBI + D0 SP died of acute GVHD, with overwhelming diarrhea by day 15 posttransplantation. Sixteen mice treated with either TBI + D4 SP or TBI + D7 SP developed acute GVHD, but none of them died of this disorder during 30 days posttransplantation. The mice conditioned with non-TBI regimens developed chronic GVHD within 3 months without showing any detectable signs of acute GVHD. Serum and in situ colonic cytokines were determined by enzyme-linked immunosorbent assay and immunohistology respectively. TBI itself significantly increased both serum and colonic tumor necrosis factor-alpha (TNF-alpha), interleukin-1 alpha (IL-1 alpha), and IL-6 when compared with non-TBI regimens and normal controls. TNF-alpha appeared in the serum and colon 4 hours post-TBI and peaked in 24 hours, followed by increasing IL-1 alpha and then IL-6 levels. TNF-alpha and IL-1 alpha decreased rapidly within 3 to 5 days post-TBI if no allogeneic cells were transplanted. Histoincompatible transplantation augmented cytokine release, which remained elevated on day 10 in these animals. Mice treated with TBI + D0 SP developed the most severe acute GVHD and had the highest levels of TNF-alpha, IL-1 alpha, and IL-6. The BuCy2-conditioned mice had the lowest cytokine levels and developed no acute GVHD. When the mice transplanted with TBI + D0 SP were treated immediately with recombinant soluble human TNF receptor (rhuTNFR:Fc) 100 micrograms/d intraperitoneally and for the subsequent 15 days acute GVHD mortality was significantly reduced from 100% to 50% (P < .001).