Study on bacteria contamination during the collection, processing and storage of umbilical cord blood / 国际儿科学杂志

ObjectiveTo evaluate bacteria contamination during collection,processing and storage of cord blood to gain insight into contamination mechanism and direct prevention.MethodsFresh cord blood was separated by hydroxyethyl starch (HES) to harvest nucleated cells.The bacteria contamination was tested by culturing 10 ml plasma-red cells with BacT/ALERT 3D-480 automatic blood culture system.Total 87 positive samples were further identified for bacteria species.Ninety six cord blood nucleated cells concentrate with bacteria positive stored in liquid nitrogen(LN2) for 6-7 years were thawed at 37 C and re-cultured for bacteria analysis.ResultsWe collected 19 062 umbilical cord blood.Among them,336 was bacteria positive ( contamination rate 1.8 ％ ).Eighty-seven positive samples were further investigated with facultative bacteria 58 (66.7 ％ ),aerobic 38(43.7％ ) and anaerobic 17( 19.5％ ),Gram- negative accounted for 68％ while positive 32％.The most frequent bacteria were Escherichia coli ( 25.3％ ),Streptacoccus intermediate ( 14.9％ ) and Chromobacteria violaceum(9.2％ ).Ninety-six nucleated cells concentrate with bacteria positive were cryopreserved at liquid nitrogen for researching.Of them,83 samples( 86％ ) showed positive of bacteria culture after deep-low temperature storage for 6-7 years.ConclusionsBacteria contamination rate of the cord blood collection,processing and storage in 2000 ～ 2007 was 1.8％.Stored in liquid nitrogen for 6-7 years,the viability of bacteria was 86％.The aseptic procedures of cord blood collection in delivery room should be intensified.The bacteria re-culture following thawing of cord blood cells is necessary before clinical transfusion.

Relationship between HLA-DRB1 alleles and idopathic thrombocytopenic purpura in children / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the relationship between HLA-DRB1 alleles and idiopathic thrombocytopenic purpura (ITP) in children.</p><p><b>METHODS</b>PCR-SSO was used to identify DRB1 alleles of 42 children with ITP. Among them, anti-GPIIb/IIIa and anti-GPIb/IX autoantibody were detected in 36 cases by modified monoclonal antibody specific immobilization of platelet antigens (MAIPA).</p><p><b>RESULTS</b>(1) Compared with healthy controls, HLA-DRB1 * 17 was significantly increased (relative risk = 2.76, P < 0.05, etiologic factor = 0.106 4) and HLA-DRB1 * 1202 decreased (relative risk = 0.20, P < 0.025, prophylactic factor = 0.761 6) in children with ITP. (2) In comparison with patients with good response to steroids and IgG therapy, HLA-DRB1 * 11 was significantly increased (P < 0.025) in patients with a poor response, furthermore, most (5/6) of HLA-DRB1 * 11-positive patients were female teen-ager. (3) Twenty-seven patients (75%) had anti-GPIIb/IIIa and seventeen (47.22%) had anti-GPIb/IX autoantibodies, the positivity rates of both anti-GPIIb/IIIa (P = 0.02) and anti-GPIb/IX (P = 0.01) were associated with HLA-DRB1 * 02. However, the pos./itivity rates of autoantibodies between refractory and non-refractory patients showed no significant difference.</p><p><b>CONCLUSION</b>(1) The DRB1 * 17 seems to predict susceptibility to ITP in children, while DRB1 * 1202 appears to be protective to against ITP. (2) The DRB1 * 11 plays an important role in resistance to steroid and IgG therapy in children with ITP. (3) It seems that the response to the antigenic epitope of GPIIb/IIIa and GPIb/IX is restricted by DRB1 * 02, while the presence of the autoantibodies couldn't predict prognosis. Our preliminary findings indicate that genetic factors influence the clinical course of ITP, but its exact mechanism needs to be further investigated.</p>

Effects of HLA disparity of two umbilical cord blood units on human engraftment in SCID mice / 中华血液学杂志

<p><b>OBJECTIVE</b>To evaluate the feasibility and characteristics of human engraftment in HLA disparate cord blood transplantation.</p><p><b>METHODS</b>Two human HLA-haploidentical or HLA-mismatched cord blood units were transplanted into sublethally irradiated severe combined immunodeficiency (SCID) mice. The characteristics of engraftment, hematopoietic and immunological reconstitution between the two groups were compared.</p><p><b>RESULTS</b>Two mixed cord blood units can engraft in SCID mice with donor-recipient chimerism and reconstitute hematopoiesis and immunological functions. No unfavorable factors had been observed. Only one of the two cord blood units which had higher colony forming ability in vitro could engraft in most SCID mice as shown by HLA-DQB(1) gene detection. Two HLA-haploidentical cord blood units were simultaneously engrafted in 3 SCID mice.</p><p><b>CONCLUSION</b>Double HLA-haploidentical or HLA-mismatched cord blood can engraft in SCID mice and reconstitute hematopoietic and immunological functions. HLA disparity has no significant effect on survival and engrafting rate. However, in less HLA disparity group, two cord blood units were prone to engraft simultaneously.</p>

Study on the relations between HLA-DRB1 alleles and idiopathic thrombocytopenic purpura in children / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To gain an insight into the relations between human leukocyte antigen-DRB1 (HLA-DRB1) alleles and idiopathic thrombocytopenic purpura (ITP) in children.</p><p><b>METHODS</b>Polymerase chain reaction-sequence specific oligonucleotide (PCR-SSO) was used to identify DRB1 alleles of 42 children with ITP. Among them, 36 were identified for anti-GPIIb/IIIa and anti-GPIb/Ix autoantibody by modified monoclonal antibody specific immobilization of platelet antigens.</p><p><b>RESULTS</b>Compared with health controls, the frequency of HLA-DRB1*17 significantly increased (P<0.05, relative risk=2.76, etiologic factor=0.1064) and the frequency of HLA-DRB1*1202 significantly decreased (P<0.025, relative risk=0.20, prophylactic factor=0.7616) in children with ITP. In comparison with patients of good response to steroids and IVIgG therapy, the frequency of HLA DRB1*11 significantly increased (Chi-square=6.091, P<0.025) in patients with a poor response, furthermore, the most of HLA-DRB1*11 positive patients were female teen-agers. Twenty-seven patients (75%) had anti GPIIb/IIIa and seventeen (47.22%) had anti_GPIb/Ix autoantibodies. The positivities of both anti_GP IIb/IIIa (P=0.02) and anti-GPIb/Ix (P=0.01) were associated with HLA-D RB1*02. However, the positivity of autoantibodies between refractory and non-refractory patients showed no significant difference.</p><p><b>CONCLUSION</b>The allele of HLA-DRB1*17 seems to predict susceptibility of ITP in children, while HLA-DRB1*1202 appears to be protective to ITP. The allele of HLA DRB1*11 plays an important role in resistance to steroid and IgG therapy in children with ITP. It seems that the response to the antigenic epitope of GPIIb/IIIa and GPIb/Ix is restricted by HLA-DRB1*02, while the presence of the antibodies could not predict prognosis. In conclusion, the above preliminary findings indicate that genetic factors influence the clinical course of ITP, but the exact mechanism needs to be investigated further.</p>

Origin and Regulation of Hematopoietic Stem Cells During Embryonic Ontogeny / 中国实验血液学杂志

Stem cells of various tissues including hematopoietic tissue in the body are derived from embryonic stem cells (ESC). There exists intricated gene regulation during ESC development and its differentiation into hematopoietic stem cells (HSC). In embryo hematopoiesis development, there are two kinds of hematopoietic types, primitive hematopoiesis and definitive hematopoiesis. The theory of the yolk sac of primitive hematopoiesis is well accepted, while the initial site of definitive hematopoiesis still exists controversy. In present opinion, there are at least two independent sites associated with definitive hematopoiesis, those are, yolk sac and para-aortic splanchnopleura (PAS)/aorta-gonad mesonephros (AGM). Study on the hematopoiesis and its regulation during embryonic ontogeny will benefit not only to the dicovery of the mechanism of some blood disorders, but as well to gene therapy and HSC engineering.

Vascular endothelial growth factor promotes hematopoietic differentiation from mouse embryonic stem cells / 中国病理生理杂志

AIM: To study the effect of vascular endothelial growth factor(VEGF) on hematopoietic differentiation from mouse embryonic stem cells(ESC) in vitro.METHODS: ES-D3 was allowed to grow on mouse fetal fibroblast feeder layer,and then was developed into embryoid bodies(EB).EB cells were transferred into medium supplemented with different concentration of VEGF and VEGF+SCF for 1 week.Six groups,including.VEGF 5 ?g/L,VEGF 10 ?g/L,VEGF 20 ?g/L, VEGF 5 ?g/L+SCF,VEGF 10 ?g/L+SCF and VEGF 20 ?g/L+SCF,were designed.The group of spontaneous differentiation without cytokine(s) was used as control.Hematopoietic transcription factor GATA-2 and early hematopoietic differentiation genes(c-kit and ?-H1) were detected by RT-PCR.The content of CD34~+ cells in each group were measured by flow cytometry.The cells derived from ESC were incubated in semisolid methycellulose cultures.The numbers of total colony-forming units in culture(CFU-C) were counted by reverse microscope.RESULTS: ES-D3 grew and formed EB at day 4.VEGF had a stimulatory effect as a single factor on the expression of genes associated with early hematopoietic differentiation(GATA-2,c-kit and ?-H1),the generation of CD34~+ cells and CFU-C in EB.The effects of VEGF+SCF were the most potent in the experimental groups according to the percent of CD34~+ cells and the numbers of hematopoietic colonies.The most highest inducing efficacy was achieved in VEGF 20 ?g/L or VEGF 10 ?g/L combined with SCF.CONCLUSION: VEGF promotes the differentiation of ESC into hematopoietic cells in vitro.The strongest effect was achieved when VEGF was combined with SCF.

Characteristics of hematopoietic and immunologic reconstitution following co-transplantation of two umbilical cord blood units in SCID mice / 中华器官移植杂志

Objective To evaluate characteristics of hematopoietic and immunologic reconstitution in mixed cord blood transplantation. Methods Single, 2 human HLA-haploidentical or HLA-mismatched cord blood units were transplanted into sublethally irradiated severe combined immunodeficiency (SCID) mice, respectively. The characteristics of engraftment, multilineage hematopoiesis and immunologic reconstitution among the three guoups were compared. Results Single or 2 cord blood units could engraft SCID mice and reconstitute human hematopoiesis and immunologic functions. No significant differences in engrafting rate were observed. Cord blood cells were apt to differentiate into NK cells and B lymphocytes. One or 2 cord blood units could be implanted in SCID mice simultaneously as shown by HLA-DQB1 gene detection. The cord blood containing more hematopoietic progenitor cells and higher colony forming potentiality was apt to engraft. Moreover, in less HLA disparity group, 2 cord blood units were prone to engraft simultaneously. Conclusions Co-transplantation of two cord blood units can reconstitute hematopoietic and immunologic functions in SCID mice. However, imbalance in multilineage differentiation existed.

A Transfusion-Associated GVHD / 中国输血杂志

A case of the 12-year-old female patient with first relapsed acute lymphoblastic leukemia was reported. During the induction chemotherapy, the patient, transfused with whole blood and granulocytes, developed diarrhea and generalized macular rash. The skin biopsy showed some changes compatible with graft versushost disease (GVHD). Therefore, the related literature was reviewed, and the clinical features of transfusionassociated GVHD and the measures for its prevention and treatment were succinctly introduced.