Mismatch of minor histocompatibility antigen contributes to a graft-versus-leukemia effect rather than to acute GVHD, resulting in long-term survival after HLA-identical stem cell transplantation in Japan.

We determined the alleles of five polymorphic molecules including HA-1 and four adhesion molecules for 106 patients transplanted with HLA-identical stem cell grafts and investigated the association of mismatches as correlates of relapse and graft-versus-host disease (GVHD). All 106 recipients underwent stem cell transplantation (SCT) after myeloablative conditioning between 1985 and 2002. Risk status of disease at SCT was standard (n=63) and high (n=42). After SCT, 36, 49 and 33 developed acute GVHD, chronic GVHD and relapsed, respectively. Our patients relapsed at rates of 16.7 and 38.6% with one or more and without incompatibilities (P=0.013). The relapse rates of patients with CD62L, CD31 codon 563, CD31 codon 125, HA-1 and CD49b incompatibilities were 5.9, 11.8, 15.4, 16.0 and 33.3%, respectively. The frequency of acute GVHD did not differ regardless of incompatibilities. In standard-risk group, the accumulated relapse rates of 19 and 44 patients with and without minor histocompatibility antigen incompatibility were 22% and unexpectedly 66%, respectively (P=0.02). The probability of 12-year survival was 88% in the former and 66% in the latter patients (P=0.03). Our data suggest that incompatibility of CD62L, CD31 codon 563 and CD31 codon 125 contributes to a graft-versus-leukemia effect rather than to GVHD, resulting in prolonged survival after HLA-identical SCT.

Identification of T-cell clones showing expansion associated with graft-vs-leukemia effect on chronic myelogenous leukemia in vivo and in vitro.

Although the graft-vs-leukemia (GVL) effect induced by donor leukocyte infusion (DLI) is thought to be mediated by T cells, their features, as well as target molecules, remain unknown. To characterize T cells that mediate the GVL effect on chronic myelogenous leukemia (CML), we studied T-cell repertoire in peripheral blood (PB) of two patients treated with DLI for relapsed CML after allogeneic bone marrow transplantation. Peripheral blood mononuclear cells (PBMCs) were obtained at 2-week intervals following DLI and examined for the presence of antigen-driven T-cell proliferation using complementarity-determining region (CDR) 3 size spectratyping of T-cell receptor beta chain subfamilies. Both patients exhibited transient proliferation of a limited number of T cells at a certain point in time (day 132 for patient 1 and day 75 for patient 2) after DLI in association with a decrease in the proportion of Philadelphia chromosome (Ph)-positive cells. In patient 2, who showed expansion of a BV16(+) T cell in PB, expansion of BV16(+) T cells with a similar CDR3 motif containing QDR to that of PB was demonstrated in the bone marrow (BM) sampled on day 33 and in the buccal mucosal tissue, showing chronic graft-vs-host disease (GVHD) on day 138 after DLI. When PBMCs obtained from patient 2 in remission were cultured with cryopreserved CML cells for 2 weeks, proliferation of a BV16(+) T cell with a CDR3 motif of QIR was induced in vitro. These findings indicate that transient proliferation of a limited number of T cells detected in PB 3-5 months after DLI probably reflects the GVL response against CML cells and may serve as a marker for the appearance of the GVL effect induced by DLI.

Establishment of a CD4+ T cell clone recognizing autologous hematopoietic progenitor cells from a patient with immune-mediated aplastic anemia.

In some patients with aplastic anemia (AA), hematopoietic function is dependent on continuous administration of cyclosporine A (CyA). These AA patients may have T lymphocytes whose myelosuppressive effect is mitigated by CyA. We established a total of 29 T cell clones from the bone marrow of a CyA-dependent AA patient in relapse. Some of the CD4+ T cell clones demonstrated a specific proliferative response to irradiated autologous bone marrow cells enriched for CD34+ cells (CD34(+)-rich cells) obtained from the patient in remission. One of the T cell clones showing the best proliferative response to CD34(+)-rich cells carried the T cell receptor V beta 17 and produced interferon-gamma (IFN-gamma) only when cultured with autologous CD34(+)-rich cells. This T cell clone inhibited colony formation by colony-forming unit-granulocyte/macrophage (CFU-GM) and burst-forming unit-erythroid (BFU-E) by approximately 60% when it was cultured with autologous CD34(+)-rich cells in methylcellulose medium, although the clone did not exhibit direct cytotoxicity to the CD34(+)-rich cells. The inhibition of in vitro hematopoietic progenitor cell growth by the T cell clone was partially abrogated by the addition of CyA to the culture. These findings suggest that in some patients with CyA-dependent AA, CD4+ T cells autoreactive to hematopoietic progenitor cells exist and may play an important role in the pathogenesis of bone marrow failure.

Quality of hematologic recovery in patients with aplastic anemia following cyclosporine therapy.

To evaluate quality of hematologic recovery in aplastic anemia (AA) patients treated with cyclosporine A (CyA), we examined polymorphonuclear leukocytes (PMNCL) from 25 AA patients for clonality and glycosyl-phosphatidylinositol (GPI)-anchored membrane protein expression. Using three different X-linked gene probes, we failed to detect clonal hematopoiesis in seven CyA-responsive female patients. Clonal hematopoiesis was detected in two of six female patients refractory to CyA therapy, although one of these two patients had shown monoclonality before therapy. Flow-cytometric analysis revealed a normal expression of GPI-linked membrane proteins, including CD55, CD59, and CD16 on PMN in all patients treated with CyA, irrespective of response, except for one patient who had a small proportion of GPI-anchored membrane protein-negative cells before therapy. The proportion remained unchanged 41 months after hematologic recovery following CyA therapy. These findings suggest that successful therapy of AA with CyA may not be associated with a significant risk of developing late clonal complications, such as paroxysmal nocturnal hemoglobinuria (PNH) and myelodysplasia.

Hematologic recovery following autologous and allogeneic bone marrow transplantation.

Posttransplant hematologic recovery was compared between 9 autologous and 11 allogeneic marrow transplant patients who received similar marrow-lethal chemoradiotherapies before transplantation. Although the autotransplant patients were infused with much lower marrow doses compared with the allotransplant patients, they showed adequate hematologic recovery with acceptable risk. Regardless of marrow doses, delayed platelet recovery and failure of platelet recovery were observed in 7 patients. All of these patients experienced early transplantation-related complications before engraftment. Despite the limited number of patients, a number of myeloid progenitor cells (CFUC) infused correlated significantly with the period for recovery of polymorphonuclear cells in autologous marrow recipients while there was no significant correlation found between marrow dose and hematologic recovery in both groups of patients. Furthermore, autotransplant patients showed a characteristic recovery pattern of peripheral blood lymphocytes in an early posttransplant period, whic was not observed in allotransplant patients.

Plasma glycosyltransferase activity after ABO-incompatible bone marrow transplantation and development of an inhibitor for glycosyltransferase activity.

Plasma glycosyltransferase activities were studied in eight patients after ABO-incompatible bone marrow transplantation. The ABO red blood cell type completely changed from the recipient type to the donor type; however, preexistent plasma glycosyltransferase activities of the recipient type did not change in seven of eight patients after marrow transplantation. Weak transferase activities of the donor type were observed in all of the patients after marrow grafting. One patient with acute and chronic graft-versus-host disease produced a very potent inhibitor that was active on both A- and B-transferase activities. Because this inhibitory activity was absorbed by a protein A-coupled Sepharose column, it was strongly suggested that this inhibitory activity was mediated by an IgG antibody for a transferase.

Antigen-specific antibody responses of lymphocytes to tetanus toxoid after human marrow transplantation.

In vitro IgG anti-tetanus toxoid (IgG anti-TT) antibody produced by peripheral blood lymphocytes (PBL) from 16 normal subjects (9 marrow donors and 7 random healthy subjects) and 17 marrow graft recipients from 45-1058 days postgrafting was measured with an enzyme-linked immunosorbent assay (ELISA). PBL from 11 of 13 seropositive (anti-TT greater than or equal to 1:1024) normal subjects produced IgG anti-TT in vitro, whereas the PBL from the 3 seronegative (IgG anti-TT less than 1:1024) normal subjects did not. In our normal subjects, there was a high correlation between seropositivity and in vitro IgG anti-TT production (P = .0048, chi 2, two-tailed). PBL from only one of 13 seropositive marrow graft recipients produced in vitro IgG anti-TT antibody. B and T cell functions of 8 marrow graft recipients were assessed by coculturing their T and B cells with those from their HLA-identical marrow donors. One short-term patient and 7 long-term patients (4 with and 3 without chronic graft-versus-host disease) were studied. Recipient B cells failed to produce antibody in the presence of donor T cells in 7 of these 8 cases. However, T cells from long-term survivors provided helper activity to immune donor B cells in 7 of 9 evaluable cases. TT-specific helper T cell activity was present in most seropositive long-term recipients, and B cells from marrow recipients failed to produce specific antibody in the presence of normal donor TT-specific helper T cells. These results, TT-specific T cell helper activity, and normal circulating serum IgG anti-TT antibody levels in marrow graft recipients without postgrafting TT boosters suggest that specific immunity had been transferred from the marrow donor to the marrow recipient.

T lymphocyte reconstitution in long-term survivors after allogeneic and autologous marrow transplantation.

T cell subsets and their immune reactivities were studied in long-term survivors after bone marrow transplantation and the results of autotransplanted and allotransplanted patients were compared. These two groups of patients (4 autotransplants and 4 allotransplants) were roughly comparable in terms of their underlying diseases, pretransplant conditioning regimens, supportive care, and posttransplant sampling days for immunological studies. Significant differences were observed between autologous and allogeneic marrow recipients in the total number of OKT3-, OKT4-, OKT8-, and OKIa1 -positive cells. Similar differences were observed between transplant patients and normal controls. Decreased OKT4 cells and increased OKT8 cells resulted in inversion of the OKT4:OKT8 ratio, which was significantly lower in allotransplanted compared with autotransplanted patients, and both groups of transplant patients showed depressed responses in comparison with normal controls. In contrast, there were no significant differences in MLR reactivities between transplanted patients and normal controls. When mitogenic responses were analyzed in relation to T cell subsets, phytohemagglutinin responsiveness showed a significant correlation with OKT4:OKT8 ratios (P less than 0.01) and the proportions of cultured OKT4 cells (P less than 0.01). These observations suggest that T lymphocyte reconstitution is still incomplete or abnormal in long-term survivors regardless of the type of graft. Furthermore, abnormalities observed in these long-term survivors were characterized by an imbalance of T cell subsets that was more profound in allotransplanted than in autotransplanted patients.

Absent myocardial iodine-123-BMIPP uptake and platelet/monocyte CD36 deficiency.

UNLABELLED: Global absence of myocardial 123I-15-(p-iodophenyl)-3-(R,S)-methyl pentadecanoic acid (BMIPP) uptake is occasionally noted, and it reflects myocardial long-chain fatty acid uptake abnormality. CD36, a membrane glycoprotein expressed on platelet, monocyte and endothelial cells, may contribute to myocardial fatty acid transport, and its deficiency has been reported in a small subset of the population. We hypothesized that CD36 deficiency may be related to absent myocardial BMIPP uptake. Thus, we investigated CD36 expression of platelet/monocyte in patients with absent myocardial BMIPP uptake. METHODS: Peripheral blood of 7 patients with global absence of myocardial BMIPP uptake (3 of 7 patients in one family) and 3 control subjects were examined in flow cytometric analysis. Platelet/monocyte surface CD36 was detected by using OKM5, an anti-CD36 mouse monoclonal antibody. RESULTS: There were no apparent relationships between specific clinical symptoms and absent myocardial BMIPP uptake. None of the blood samples of the 7 patients were stained with OKM5 on the platelet/monocyte cell surface, indicating that all of these patients were Type I CD36-deficient subjects. In contrast, all the control subjects showed normal staining. CONCLUSION: The fact that rare Type I CD36 deficiency was observed in all patients with absent myocardial BMIPP uptake suggests that CD36 plays a role in the myocardial long-chain fatty acid uptake process in humans.

Enhancement of cyclosporin A-induced autologous graft-versus-host disease after peripheral blood stem cell transplantation by utilizing selected CD34(+) cells.

Although autologous graft-versus-host disease (GVHD) can be induced by administration of cyclosporin A (CsA) after peripheral blood stem cell transplantation (PBSCT), the incidence appears to be remarkably lower compared to the incidence after bone marrow transplantation. The reduced incidence of autologous GVHD after PBSCT may be attributed to peripheral regulatory cells that are transferred with the stem cell inoculum. To determine whether transplantation of CD34-selected peripheral blood stem cells (PBSCs) leads to potentiation of autologous GVHD, five patients with malignant lymphoma were transplanted with CD34-selected PBSCs, followed by administration of CsA and interferon (IFN)-gamma. Inducibility of autologous GVHD and autocytotoxic activities of peripheral blood mononuclear cells (PBMCs) after transplantation were assessed. All patients demonstrated prompt hematologic recovery. Cytotoxic activity of PBMCs against autologous lymphocytes was detectable in four of four patients analyzed during a limited period from days 14 to 34 post-transplant. An erythematous rash compatible with GVHD, confirmed by skin biopsy, developed in three of five patients. One of the three patients developed not only skin, but also gut and liver GVHD. Transplantation of the CD34-selected stem cell graft that does not accompany transfusion of regulatory cells may potentiate the inducibility of autologous GVHD by the administration of CsA and IFN-gamma.

Early recovery of host-derived hematopoiesis in marrow transplant recipients conditioned with high-dose busulfan and cyclophosphamide.

Three marrow transplant recipients with hematologic malignancies (two AML, one myelodysplastic syndrome) experienced prolonged pancytopenia after allogeneic BMT following conditioning with non-TBI regimens containing high-dose busulfan and cyclophosphamide (Bu/CY), despite the use of G-CSF. Early recovery of host-derived hematopoiesis ensued. Although neutrophil counts in these patients exceeded 500 x 10(6)/l by day 30 after transplant, these cells were of host origin. This early recovery of host-derived hematopoiesis has been observed rarely among patients conditioned with TBI-based regimens. When patients conditioned with Bu/CY show delayed hematologic recovery, mixed chimerism should be considered even in the presence of normal neutrophil recovery.

Analysis of late graft failure after allogeneic bone marrow transplantation: detection of residual host cells using amplification of variable number of tandem repeats loci.

In an attempt to gain insight into the etiology of late graft failure, we analysed the origin of bone marrow mononuclear cells (BMMC) and peripheral blood leukocytes in patients with this syndrome by taking advantage of DNA fragment length polymorphisms in variable number of tandem repeats (VNTR) loci. Amplification of the VNTR loci in DNA from BMMC using the polymerase chain reaction revealed the persistence of host cells in two of four patients studied. One of the patients, whose cultured lymphocytes inhibited in vitro growth of donor-derived hemopoietic progenitor cells, responded to immunosuppressive therapy and donor-derived hemopoiesis was restored. In the other patient, host-derived polymorphonuclear leukocytes (PMN) appeared together with donor-derived PMN from the early post-transplant period, and he proceeded to relapse with myelodysplastic syndrome. In the other two patients in whom host cells were not detectable, the marrow hypoplasia was associated with chronic graft-versus-host disease (GVHD). The hypoplasia improved significantly as the chronic GVHD improved in response to immunosuppressive therapy. We conclude that detecting minimal residual host cells by means of amplification of VNTR loci is valuable for understanding the etiology of late graft failure in marrow transplant recipients, and could prove helpful for choosing appropriate therapy for this syndrome.

Expansion and activation of minor histocompatibility antigen HY-specific T cells associated with graft-versus-leukemia response.

The immune system of females is capable of recognizing and reacting against the male-specific minor histocompatibility antigen (mHA), HY. Thus, cytotoxic T-lymphocytes (CTLs) recognizing this antigen may be useful in eradicating leukemic cells of a male patient if they can be generated in vivo or in vitro from a human leukocyte antigen (HLA)-identical female donor. The HLA-A*0201-restricted HY antigen, FIDSYICQV, is a male-specific mHA. Using HLA-A2/HY peptide tetrameric complexes, we reveal a close association between the emergence of HY peptide-specific CD8(+) T cells in peripheral blood and molecular remission of relapsed BCR/ABL(+) chronic myelogenous leukemia in lymphoid blast crisis in a patient who underwent female-to-male transplantation. Assessment of intracellular cytokine levels identified T cells that produce interferon-gamma in response to the HY peptide during the presence of HY tetramer-positive T cells. These results indicate that transplant with allogeneic HY-specific CTLs has therapeutic potential for relapsed leukemia, and that expansion of such T cells may be involved in the development of a graft-versus-leukemia response against lymphoblastic leukemia cells.

Successful treatment of Epstein-Barr virus-associated natural killer cell large granular lymphocytic leukaemia using allogeneic peripheral blood stem cell transplantation.

We report a case of natural killer cell large granular lymphocytic (NK-LGL) leukaemia successfully treated with allogeneic peripheral blood stem cell transplantation (allo-PBSCT). The peripheral blood (PB) revealed an abnormal expansion of LGL that were CD3-, CD16- and CD56+, and had natural killer activity. In situ EBER-1 hybridization of the PB mononuclear cells showed the presence of Epstein-Barr virus (EBV) in the LGL as well as in lymphocytes infiltrating the tonsils and colon. Southern blotting with an EBV-terminal repetitive sequence probe demonstrated clonal proliferation of EBV+ cells. The patient received allo-PBSCT from his HLA-matched sister with a conditioning regimen involving the use of cyclophosphamide and fractionated total body irradiation. The patient promptly recovered trilineage haematopoiesis without graft-versus-host disease, and has been in complete remission without therapy for 10 months since allo-PBSCT, suggesting that allo-PBSCT could eradicate the NK-LGL leukaemic cells.

Second allogeneic bone marrow transplantation for post-transplant leukemia relapse: results of a survey of 66 cases in 24 Japanese institutes.

To assess the consequence of second BMT (BMT2) for leukemia relapse after allogeneic BMT, we analyzed the clinical course of 66 recipients who were treated by BMT2 in Japan. Diagnoses included 29 ANLL, 27 ALL, six CML and four MDS. Durations between the first BMT (BMT1) to relapse and BMT1 to BMT2 were 13.5 +/- 13.7 months and 17.4 +/- 13.9 months, respectively. Donors for BMT2 were replaced in 11 cases. Thirty-one patients were in CR (or CP) at BMT2. Earlier deaths were observed in those who received BMT2 within 12 months after BMT1, mostly caused by regimen-related toxicity and infections. Overall leukemia-free survival rate was 28% at 2 years and 16% at 4 years. Factors influencing the poor prognosis after BMT2 were early (<6 months) relapse, early (<12 months) BMT2, not in remission at BMT2, and ALL. Intensified conditioning did not affect either remission duration or LFS. Among the 39 cases observed for more than 100 days, 18 developed chronic GVHD (cGVHD) and showed longer remission duration than those without cGVHD. Our analysis indicates that BMT2 as treatment for leukemia relapse is effective in selected cases, and exploration of pre-BMT treatment and post-BMT immunotherapy is warranted.

Administration of G-CSF to normal individuals diminishes L-selectin+ T cells in the peripheral blood that respond better to alloantigen stimulation than L-selectin- T cells.

To determine whether administration of G-CSF induces phenotypic or functional changes in T cells, we examined peripheral blood T cells from normal individuals receiving G-CSF for activation antigen and adhesion molecule expression before and after G-CSF administration. G-CSF (10 microg/kg/day) was administered subcutaneously to 14 normal individuals for 3-5 days and their PBMC were serially analyzed with monoclonal Ab (mAb) directed to HLA-DR, CD45RO, CD45RA, CD25, CD122, CD95, CD11a, CD49d, CD44 and CD62L (L-selectin) coupled with anti-CD3 mAb. Among T cells positive for these antigens, only the proportion of T cells expressing L-selectin significantly decreased from 68% to 37% after 3-day G-CSF administration. When peripheral blood CD3+ T cells obtained before and after G-CSF administration were sorted into two populations depending on the expression of L-selectin and tested for their proliferative response to allogeneic B cells, the reactivity of L-selectin- cells to alloantigen stimulation was consistently lower than that of L-selectin+ cells regardless of the exposure to G-CSF. The decrease in the relative number of L-selectin+ cells induced by G-CSF administration may contribute to the unexpectedly low incidence of severe acute GVHD after allogeneic PBSC transplantation.

Hematopoietic clone with karyotypic abnormalities of host origin after bone marrow transplantation: two case reports.

A patient with non-Hodgkin's lymphoma in remission developed a myelodysplastic syndrome (MDS) 12 years after ABMT. This patient had undergone bone marrow harvesting prior to any chemoradiotherapy. He had received the autograft following conditioning with high-dose CY and TBI. Chromosomal analysis of BM cells revealed complicated abnormalities. Similar karyotypic abnormalities in host-derived BM cells were found in another patient with AML who had received allogeneic BM following conditioning with CY plus TBI 15 months previously. These findings suggest that MDS or clonal karyotypic abnormalities following ABMT may derive from endogenous hematopoietic stem cells that survive the BMT preparative regimen.

Donor leukocyte infusion for Japanese patients with relapsed leukemia after allogeneic bone marrow transplantation: lower incidence of acute graft-versus-host disease and improved outcome.

To clarify the role of donor leukocyte infusion (DLI) in the treatment of leukemia relapsing after allo-BMT, data from 100 patients were collected from 46 facilities in Japan and analyzed with respect to the efficacy and adverse effects of donor leukocyte infusion. Complete remission was achieved in 11 of 12 (91%) patients with relapsed chronic myelogenous leukemia (CML) in chronic phase, three of 11 (27%) with CML in the acute phase, eight of 21 (38%) with acute myelogenous leukemia (AML), six of 23 (25%) with acute lymphoblastic leukemia (ALL) and five of 11 (45%) with myelodysplastic syndrome (MDS). The probability of remaining in CR at 3 years was 82% in CML patients in the chronic phase, but 0% in those with CML in the acute phase, 7% in those with AML, 0% with ALL and 33% with MDS. Acute GVHD (>/=2) developed in 31 of 89 (34%) patients with HLA-identical related donors and was fatal for seven (7%). Cytopenia developed in 21 of 94 (22%) with no associated fatalities. When the outcome of patients with CML in CP and MDS was analyzed, development of GVHD, cytopenia, or both, was associated with a higher GVL effect (15 of 16, 93%) than in those without adverse affects (one of 6, 17%). A leukocyte dose of 5 x 107/kg of recipient body weight appeared to be optimal as an initial dose of DLI. Given the relatively low incidence of acute GVHD and the similar GVL effect, DLI may be more beneficial to patients in Japan with recurrent leukemia than to those in Western countries. Bone Marrow Transplantation (2000) 26, 769-774.

Safety studies of a novel starch, pullulan: chronic toxicity in rats and bacterial mutagenicity.

This study was designed to assess the potential toxicity of pullulan, a starch-like substance produced by Aureobasidium pullulans that is proposed for use as a texturizer for meat and meat substitutes and as a flavour substrate. Sprague-Dawley rats (15/sex/group) were administered pullulan as a dietary admixture at levels of 1, 5 and 10% for a period of 62 wk. Control animals (15/sex) received untreated standard laboratory diet. The feeding study, originally intended to continue for 24 months, was terminated at 62 wk due to poor survival resulting from intercurrent pneumonia which was confirmed by histological findings. At 62 wk of treatment, all survivors were killed, complete gross post-mortem examinations were conducted on all animals, selected organs were weighed and organ/body weight and organ/brain weight ratios calculated. Mean body weights of all treated groups were comparable to controls. There were no indications of an adverse effect of pullulan on food consumption or food efficiency. At termination of the study, haematology and clinical chemistry values of treated animals were comparable to control values. There was no indication of pullulan-related toxicity in terminal organ and body weights. Macroscopic and microscopic examinations revealed no toxic lesions due to treatment. The mutagenicity of pullulan was assessed with and without metabolic activation in Salmonella typhimurium (TA100, TA1535, TA98 and TA1537). Pullulan did not increase the number of revertants per plate in any strain at any dose, including 10,000 micrograms/plate with or without metabolic activation, suggesting that it lacks mutagenic/carcinogenic potential on the basis of these results, it is concluded that pullulan lacks significant toxicological activity. The no-observed-adverse-effect level was 10% (equal to or greater than 4450 mg/kg body weight/day in males and 5080 mg/kg body weight/day in females) which would support use in various foods as a substrate for flavours.

Analysis of 55 transplantations from unrelated volunteer donors facilitated by Tokai Marrow Donor Bank.

In October, 1989, the Tokai Marrow Donor Bank (TMDB) was established through the cooperation of patients' families, the branches of blood centers of Japanese Red Cross and the hematologists' group in Tokai Area (Aichi, Shizuoka, Gifu and Mie Prefectùres) in Japan to facilitate the procurement of suitable marrow from unrelated volunteer donors for patients lacking related donors. The number of human leukocyte antigen (HLA)-A, B typed donors totaled 3,083 and the number of patients registered for donor search totaled 1,415 by June 1992, when the activities of TMDB were transferred to the newly created Japan Marrow Donor Program (JMDP), and 55 transplanations from unrelated donors facilitated by TMDD were performed.