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CD25(+)CD4(+) regulatory T cells suppress T cell activation and regulate multiple immune reactions in in vitro and in vivo studies. To define the regulatory function of human CD25(+)CD4(+) T cells at various stages of maturity, we investigated in detail the functional differences of CD25(+)CD4(+) T cells from thymocytes, cord blood (CB), and adult peripheral blood (APB). CB CD25(+)CD4(+) T cells displayed low-FOXP3 protein expression level and had no suppressive activity. In contrast, CD25(+)CD4(+) T cells from thymocytes or APB expressed high expression level of FOXP3 protein associated with significant suppressive activity. Although CB CD25(+)CD4(+) T cells exhibited no suppressive activity, striking suppressive activity was observed following expansion in culture associated with increased FOXP3 expression and a shift from the CD45RA(+) to the CD45RA(-) phenotype. These functional differences in CD25(+)CD4(+) T cells from Thy, CB, and APB hence suggest a pathway of maturation for Treg in the peripheral immune system.

Recently, piglets have been obtained from in vitro-produced blastocysts by using in vitro maturation systems in which oocytes have been matured in North Carolina State University (NCSU) solution supplemented with porcine follicular fluid (PFF). However, PFF is not available commercially. To prepare PFF from the ovaries required time and effort and there is substantial variation in quality among batches. Furthermore, PFF is considered a potential source of infectious agents. We evaluated another commercially available potential protein source, fetal bovine serum (FBS), for in vitro maturation, to produce embryos and piglets. Cumulus-oocyte complexes were matured in NCSU-37 with PFF or with one of four batches of FBS. The proportions of oocytes with expanded cumulus cells were lower in all FBS batch groups (P < 0.05, 15-41%) than that in the PFF group (74%). The proportions of oocytes that matured were also lower in all FBS batch groups (P < 0.05, 26-41%) than in the PFF group (73%), irrespective of cumulus expansion. However, the proportions of oocytes that underwent germinal vesicle breakdown were almost the same in all groups (76-96%). After in vitro fertilization, the rate of sperm penetration into matured oocytes was higher in the PFF group (P < 0.05, 63%) than in one batch of FBS (22%) and removal of the compacted cumulus cells after maturation did not affect fertilization status (21%). Subsequent in vitro embryo culture of the PFF and FBS groups for 6 day resulted in similar rates of blastocyst formation (17 and 19%, respectively) and similar numbers of cells per blastocyst (43 and 46 cells, respectively). When blastocysts obtained from oocytes matured with FBS were transferred into two recipients, one became pregnant and farrowed seven piglets. Transfer of blastocysts obtained from oocytes matured with PFF into two other recipients resulted in one pregnancy and production of four piglets. These data suggested that porcine in vitro maturation in NCSU-37 supplemented with FBS reduced the maturational ability of oocytes, but once oocytes have matured, they have the same ability to develop to term after in vitro fertilization and embryo transfer as those matured with PFF.

CD26 is a T-cell activation antigen that contains dipeptidyl peptidase IV activity and binds adenosine deaminase. Recent work showed that specialized membrane microdomains, also known as lipid rafts, play a key role in T-cell signaling. In this study, we investigate the role of CD26 in cord blood T-cell activation and signal transduction. We demonstrated that different expression levels of CD26 were observed between cord blood T cells (CBTCs) and peripheral blood T cells (PBTCs) and that CD26(+)CD45RA(+) CBTCs were different compared with CD26(+)CD45RA(+) PBTCs. Moreover, the comitogenic effect of CD26 was not as pronounced in CBTCs as in PBTCs. We also showed that CD26 cross-linking induced less phosphorylation of T-cell receptor-signaling molecules, lymphoid T-cell protein tyrosine kinase (Lck), zeta-associated protein 70 (ZAP-70), T-cell receptor zeta (TCRzeta), and linker for activator of T cells (LAT) in CBTCs than in PBTCs. Furthermore, CD26 molecules associated with CD45RA molecules outside lipid rafts in CBTCs. Our results suggest that strong physical linkage of CD26 with CD45RA outside lipid rafts may be responsible for the attenuation of T-cell activation signaling through CD26, which may be responsible for immature immune response and the low incidence of severe graft-versus-host disease in cord blood transplantation.

The results for 49 patients with hematologic and non malignancies who were subjected to a cord blood transplantation from HLA-mismatched unrelated donors (UCBT) are presented here. This retrospective study included 22 patients with acute lymphoblastic leukemia, 12 with acute myelogenous leukemia, one each with chronic myelogenous leukemia, refractory anemia with myelodysplastic syndrome, and juvenile myelomonocytic leukemia, three with Wistott-Aldrich syndrome, three with adrenoleukodystrophy, two with Hunter's syndrome, one each with Hurler's syndrome, purine nucleotide phosphorylase deficiency, pure red cell aplasia, and severe aplastic anemia. In malignant diseases, the Kaplan-Meier estimates for three-year overall survival (OAS) and event-free survival (EFS) were 51.9 +/- 17.8, and 51.4 +/- 17.8%, respectively. In patients with non malignant disease, the Kaplan-Meier estimates for three-year OAS and EFS were 64.2 +/- 28.8, and 37.5 +/- 29.4%, respectively. In patients with malignancy, the HLA disparity had no effect on OAS, EFS, incidence of acute graft-versus-host disease, or engraftment. On the other hand, for engraftment, the use of UCBT from HLA-mismatched unrelated donors may require a larger study in patients with non-malignant diseases.

Factors influencing the outcome for 39 children with haematological malignancy who were subjected to a cord blood transplantation (CBT) from genotypically HLA-mismatched unrelated donors were analysed. This retrospective study included 21 children with acute lymphoblastic leukaemia, 15 with acute myelogenous leukaemia and one each with chronic myelogenous leukaemia, refractory anaemia with myelodysplastic syndrome (MDS) and juvenile myelomonocytic leukaemia (JMML). Those subjected to CBT during the first or second complete remission (CR) and MDS without blasts were assigned to the standard-risk (SR) group (n = 16). Patients in third or subsequent remission, relapse or partial remission with refractory leukaemia at the time of CBT were considered to be in advanced phase, and placed in the high-risk (HR) group (n = 11). JMML and the second CR after a relapse (n = 8), or bone marrow failure after a rejection (n = 3), following haematopoietic stem cell transplantation (HSCT) in the first CR were included in the high-risk group. Kaplan-Meier estimates for neutrophil and platelet recovery were 83.7 +/- 12.2 at d 60 and 55.4 +/- 16.6% at d 100 respectively. The incidence of grades II-VI acute graft-versus-host disease was 58.5 +/- 16.8%. The Kaplan-Meier estimate for 3-year event-free survival (EFS) was 49.2 +/- 16.6. From multivariate analysis, the most important factor influencing EFS was disease status at CBT: SR patients had a 3-year EFS of 75.0 +/- 21.6%, compared with 29.6 +/- 20.6% for those with HR disease (P = 0.013, RR 4.746, 95% CI 1.382-16.298). These data confirm that HLA-mismatched, unrelated CBT is a feasible procedure to cure a significant proportion of children with leukaemia, especially if conducted in a favourable phase of the disease.

Here we report a case with precursor natural killer (NK) cell leukemia successfully treated with an unrelated cord blood transplantation. A 7-month-old Japanese boy was diagnosed to have NK cell leukemia based on the existence of abnormal cells in the bone marrow with the phenotype of CD3(-) /CD4(+) /CD7(-) /CD8(-) /CD16(-) /CD33(+) /CD34(-) /CD56(+) /HLA-DR(+) /NKB1(+) / CD94(+). The leukemic cells showed few azurophilic granules in the cytoplasm and weak cytotoxic activity. Although he presented with a huge mass occupying the bilateral paranasal sinuses and hepatosplenomegaly, he achieved complete remission by the conventional chemotherapeutic regimen for acute myelogenous leukemia, followed by an unrelated cord blood transplantation. He has remained in complete remission for 14 months posttransplant. To our knowledge, this is the youngest reported case with precursor NK cell leukemia; cord blood transplantation may thus be the treatment of choice for this disease.

We performed retrospective DNA typing of class I (A, B, Cw) and class II (DRB1, DQB1, DPB1) HLA alleles in 27 unrelated cord blood transplantation (CBT) cases donated from a single cord blood bank (Kanagawa Cord Blood Bank). The influence of HLA genotype matching on clinical outcome was evaluated. From Cox's model, we found that incompatibility of two or more HLA alleles between the donor and recipient of an unrelated CBT was suggested to be a risk factor for a worse event-free survival (EFS) (p = 0.04; RR, 4.06; 95% CI, 1.06-15.61). Furthermore, mismatches including HLA-DRB1 alleles had an adverse effect on EFS (p = 0.04; RR, 4.91; 95% CI, 1.01-24.02). For definite conclusions on the role of HLA allele typing in unrelated CBT, more accumulation of data and analysis will be required.

We describe harvest techniques for cord blood after delivery of the placenta. The umbilical vein is punctured or catheterized, and then placental/cord blood is aspirated with syringes contained anticoagulants. Other method of collection, which has been undertaken in the Cord Blood Bank of the New York Blood Center, is to drain blood into a collection-bag by gravity. The collection bags with anticoagulants are manufactured by TERUMO and BAXTER HEALTHCARE CO.

Umbilical cord-blood (CB) has been used as a source of hematopoietic stem cells in pediatric patients with sibling donors. As a result of the success with CB transplantation from sibling donors, pilot programs for the banking of unrelated donor CB were initiated in the organization of Kanagawa Cord Blood Bank, Japan in 1995. As of December 1997, unrelated donor CB was used to reconstitute hematopoiesis in seven patients aged 0.7-12.8 years, weighing 7-36 kg with high-risk leukemia (n = 5), myelodysplastic syndrome (n = 1), and immunodeficiency syndrome (n = 1). Engraftment of CB was achieved in six patients. The absolute neutrophil count reached 500/microliter in a median of 27 days; a platelet count of 20,000/microliter was reached by a median of 64 days in three patients who could be evaluated. Five patients are currently surviving. Grade I GVHD developed in three patients and grade III in one patient; no GVHD developed in three patients. Although only a small number of patients have been studied and the period of observation is too short to determine long-term survival, HLA-matched or HLA-mismatched CB from unrelated donors can provide an alternative source of hematopoietic reconstitution for clinical transplantation.

We report the case of a patient with fatal obstructive lung disease after an HLA-haploidentical sibling cord blood transplant (CBT), with severe acute GVHD. A 2-year-old girl developed expiratory air trapping gradually with acute and chronic GVHD after CBT for the treatment of ALL. Anti-CMV and immunosuppressive therapy were ineffective, and the patient died of progressive respiratory acidosis. Necropsy of the lung revealed severe bronchiolitis obliterans with cytomegalic inclusion cells in the granulation tissues of the bronchiolitis. Thus, immunologic and GVHD problems can occur even in CBT.

Allogeneic bone marrow transplantation (BMT) can cure some hematologic and solid malignancies, but its success depends on the prompt identification of a suitable donor and the avoidance of severe graft-versus-host (GVH) disease. Transplantation using hematopoietic stem cells from umbilical cord blood may overcome these problems. Over the past several years, cord blood transplantation (CBST) from siblings and unrelated donors has been performed in more than 300 patients. The probability of event-free survival was almost similar to that for BMT. This review described the recent status of CBST in USA, Europe and Japan, and the outlook for CBST.

Cord blood stem cell transplantation (CBSCT) was performed on a patient with acute promyelocytic leukemia. The patient was a boy 3 years and 8 months old, who had shown complete remission following treatment with intensive chemotherapy. However, after the final course of consolidation chemotherapy, chromosome analysis of his bone marrow aspirates revealed 46XY, t(15,17)(q22;q21), and a PML-RAR alpha fusion gene was detected by the reverse transcriptase-polymerase chain reaction test. All-trans retinoic acid diminished the chromosomal abnormality, but the PML-RAR alpha fusion gene remained. The patient was then treated with CBSCT from an HLA-matched sibling donor. The number of nucleated cells in the cord blood was 2.2 x 10(7)/kg of body weight, and that of granulocyte-macrophage colony-forming units 0.6 x 10(4)/kg. Methotrexate was given, on days 3 and 6, as prophylaxis against graft-versus-host disease (GVHD). The neutrophil count rose to above 500/microliters on day 22. The platelet count exceeded 50,000/microliters on day 48. Platelet transfusions were given 12 times after CBSCT, the last one on day 36. Grade I acute GVHD was treated with steroids. The patient was well and discharged on day 103, without symptoms or laboratory data suggestive of relapse. Following this experience we instituted a project of the Kanagawa Cord Blood Bank, which is scheduled for expansion nationwide.