In vitro analysis of volume-reduced washed platelet concentrates stored in bicarbonated Ringer's solution containing less than 5% residual plasma.

BACKGROUND AND OBJECTIVES: Volume-reduced washed platelet (PLT) concentrates (PCs) can prevent circulatory overload and allergic reactions in patients undergoing PLT transfusions. For these reasons, they are in demand for paediatric settings and for patients at risk of circulatory overload. Here, we evaluated the quality of volume-reduced washed PCs stored for 5 days in a novel acetate-free PLT additive solution (PAS) containing glucose and bicarbonate (BRS-A) with <5% residual plasma protein. MATERIALS AND METHODS: PCs from two apheresis donations were mixed and divided equally into control and test units. For the test unit (volume-reduced washed PCs), PLTs were washed and stored in 90 ml BRS-A with <5% plasma protein. PLTs in the control unit were stored in 200 ml 100% plasma without any washing manipulations. The in vitro properties of PLTs in both units were compared over a 5-day storage period. RESULTS: The procedure for volume-reduced washed PCs effectively removed >98% plasma protein in 100% plasma PCs and yielded an approximately twofold lower mean volume (91 ml) compared to that observed with the control units. Immediately after washing, the mean PLT concentration of the test units was 20·5 × 10(11) /l, twofold higher than that of the control units. The pH (37°C) levels in the test unit remained above 7·0 for 5 days. Glucose consumption and lactate production rates of the test units on days 1-3 were higher than those of the control units, leading to glucose exhaustion in the test unit by Day 3. Hypotonic shock responses and CD62P and CD42b expression levels in both units were comparable during 5-day storage. CONCLUSION: Considering the pH buffering capacity of BRS-A, a 90-ml volume may be acceptable for maintaining the in vitro quality of washed PLTs for at least 2 days.

Washing of platelets can be fully automated using a closed-system cell processor and BRS-A platelet additive solution.

This study evaluated the in vitro properties of platelets (PLTs) washed with BRS-A additive solution in the Haemonetics ACP215 automated processing system. Two washing modes, 'manually/automatically adding ACD-A to BRS before/during the washing process', represented the control and test groups, respectively. Outcomes were compared over 7 days of storage (n = 7, for both). PLT recovery following washing processing (26-27 min) was 86·2 ± 1·7% and 86·0 ± 2·2% and plasma protein removal was 98·8 ± 0·3% and 99·0 ± 0·2% in the control and test groups, respectively (not significant). Both groups exhibited comparable in vitro properties.

Structure and function of Cas-L, a 105-kD Crk-associated substrate-related protein that is involved in beta 1 integrin-mediated signaling in lymphocytes.

Integrin/ligand binding evokes tyrosine phosphorylation of various proteins. We reported previously that a 105 kD protein (pp105) was tyrosine phosphorylated by the engagement of beta 1 integrins in T lymphocytes. We show here that pp105 is a novel p130Cas (Crk-associated substrate)-related protein. Deduced amino acid sequence revealed that pp105 contains conserved motifs with p130Cas, and both pp105 and p130Cas bind to focal adhesion kinase (pp125FAK) and Crk. However, pp105 has a clearly distinct structure from p130Cas, and pp105 is preferentially expressed in lymphocytes, whereas p130Cas is expressed in adherent cells. With these findings, we designate pp105 as Cas-L, lymphocyte-type Cas. Furthermore, we demonstrate that integrin/ligand binding results in the recruitment of Crk, Nck, and SHPTP2 to pp105. These findings further define the roles of pp105/Cas-L and pp125FAK in the integrin-mediated signaling pathways.

Expression of either the TCL1 oncogene, or transcripts from its homologue MTCP1/c6.1B, in leukaemic and non-leukaemic T cells from ataxia telangiectasia patients.

Patients with the recessively inherited disorder ataxia telangiectasia (A-T) have a high level of specific chromosome translocations which can be easily observed in peripheral T cells and show a greatly increased predisposition to leukaemia/lymphoma, mainly of T cell origin. Some translocation cells proliferate into a large clone and may develop into T cell prolymphocytic leukaemia (T-PLL). By the time of diagnosis of T-PLL, the clone contains many more genetic changes in the form of additional translocations. T-PLL is also seen in non-A-T individuals where expression of either TCL1 (at 14q32) or the c6.1B/MTCP1 A1 transcript (at-Xq28) has been demonstrated in just a few instances. We show here, that expression of TCL1 occurs in leukaemic T cells from A-T patients with chromosome 14 rearrangements. Expression of TCL1 also occurs in the preleukaemic clone cells of A-T patients containing the primary translocation alone. Some expression of TCL1 could also be detected in randomly selected A-T patients without large cytogenetic clones and without any evidence of leukaemic change. We also show that expression of the B1 transcript from a second gene, MTCP1, occurred at a relatively high level only in two T-PLL tumours from A-T patients with t(X;14) translocations whereas the MTCP1/A1 transcript is much more widely expressed in both tumour and non tumour cells of A-T and non-A-T individuals.

Functional and molecular characteristics of acute lymphoblastic leukemia cells with a mature T-cell phenotype from a patient with ataxia telangiectasia.

A 12-year-old male patient with ataxia telangiectasia developed an acute lymphoblastic leukemia of T-cell phenotype. The lymphoblasts showed uniform surface expression of CD3, CD7, CD8, and T-cell receptor (TCR) alpha/beta chains, positive immunofluorescent staining of terminal deoxynucleotidyl transferase, complex cytogenetic aberrations including t(14;14) (q11;q32) and unique rearrangements of TCR beta and gamma chain genes, indicating the clonal expansion of leukemic cells. CD25 expression could be readily induced on the leukemic cells by mitogenic stimulation, followed by CD71 expression, but interleukin-2 production and subsequent proliferation in response to mitogens were subnormal.

Cell surface c-kit receptors in human leukemia cell lines and pediatric leukemia: selective preservation of c-kit expression on megakaryoblastic cell lines during adaptation to in vitro culture.

We produced a monoclonal antibody MTK1 which recognized c-kit protein. Using MTK1, 31 leukemia cell lines and 76 leukemia blasts from pediatric patients were analyzed for expression of the c-kit receptor by flow cytometry. The c-kit receptor was detectable on four of four cell lines assigned to the megakaryo/erythromegakaryoblastic lineage and on one of seven cell lines of myeloid lineage. C-kit expression was not seen on any of 20 cell lines of erythroid and lymphoid lineages. Furthermore, c-kit was expressed on 16 of 24 nonlymphoid blasts without platelet surface antigens (67%) and on six of eight non-lymphoid blasts with platelet surface antigens (75%), but was not detectable on 44 lymphoid blasts from pediatric leukemia patients. In these cases CD34 was expressed on 26 of 32 myeloid blasts (81%) and on 27 of 44 lymphoid blasts (61%). The findings indicate a dominant expression of the c-kit receptor on established cell lines assigned to the megakaryo/erythromegakaryoblastic lineage, though a high percentage of leukemic myeloblasts also expressed the c-kit receptor on their surface.

bcr/abl mRNA in leukemic blasts of an unusual patient with acute lymphoblastic leukemia followed after 5-year remission by chronic myelogenous leukemia in blast crisis.

A 13-year-old boy without any previous illness was diagnosed as suffering from acute lymphoblastic leukemia (ALL). After a period of apparent complete remission until 17 years of age, the presence of Ph1 positive cells in bone marrow was demonstrated by karyotype analysis. This finding suggested chronic myelogenous leukemia (CML) because of the absence of blastic changes in bone marrow but mild leukocytosis with basophilia at that time. Six months later he had a relapse (blast crisis) with the appearance of peroxidase negative lymphoid blasts and myeloid surface markers. To make differential diagnosis, leukemia blasts at onset and relapse were examined for rearrangement of immunoglobulin JH gene and bcr/abl fusion mRNA, and were found to have the same JH gene rearrangement pattern and the same bcr/abl mRNA of bcr exon 2/abl exon 2. These results indicate an unusual case of CML which appeared in blast crisis at onset, followed by a long-term remission.

Establishment and characterization of a novel human immature megakaryoblastic leukemia cell line, M-MOK, dependent on fibroblasts for its viability.

A novel fibroblast-dependent human immature megakaryoblastic leukemia cell line (M-MOK) was established from the bone marrow of a girl with acute megakaryoblastic leukemia, and its growth was determined to be completely dependent on the presence of human embryonic lung-derived fibroblasts, HEL-O. Adhesive interaction between M-MOK and HEL-O was crucial for viability; once HEL-O was removed from the culture, mortality was total within a few days. On HEL-O cells, M-MOK could be passaged for more than 2 years. With regard to surface marker profile, the established cells were positive for CD11a, CD13, CD18, CD33, CD34, CD41b, CD42b, CD54, and c-kit antigens, but negative for HLA class II antigen and glycophorin. Histochemically, the cells were negative for myeloperoxidase, nonspecific esterase, and naphthol ASD chloroacetate esterase staining. Electron-microscope examination revealed the cells to be negative for platelet peroxidase (PPO). After induction of differentiation by a phorbol ester, however, the cells were demonstrated to be positive for PPO with a morphological change to megakaryocytes. From these results, M-MOK was considered to represent an immature cell line of megakaryocyte lineage. Studies of the mechanisms sustaining the HEL-O-dependent continuous in vitro growth of M-MOK cells revealed the following results: (1) M-MOK could grow even when separated from HEL-O by a nucleopore membrane; (2) conditioned medium (CM) from HEL-O supported the growth of M-MOK for more than 1 month without feeder cells; (3) the growth of M-MOK on HEL-O or CM supplement was nearly entirely inhibited by anti-GM-CSF (1 microgram/mL); (4) GM-CSF mRNA was detected in HEL-O cells; and (5) HEL-O was found to secrete GM-CSF into the culture medium. Taken together, the growth of M-MOK might therefore be driven by a soluble factor, that is, GM-CSF secreted from HEL-O cells. The presence of HEL-O, however, inhibited anti-GM-CSF-induced M-MOK death. Co-culture of M-MOK and HEL-O cells thus offers a useful experimental model for analysis of interactions between hematopoietic stem cells and stromal cells.

Flow cytometric determination of intracytoplasmic Wiskott-Aldrich syndrome protein in peripheral blood lymphocyte subpopulations.

We have produced a novel monoclonal antibody (mAb) directed against Wiskott-Aldrich syndrome protein (WASP) by immunizing mice with the recombinant protein. The mAb designated 5A5 is highly specific to WASP and suitable for Western blot analysis and immunoprecipitation. A flow cytometric assay using the 5A5 mAb identifies expression of intracytoplasmic WASP in lymphocytes from normal individuals. Double staining analysis with cell surface CD3, CD19, and CD56, and intracytoplasmic molecules revealed WASP expression in each subpopulation. With regard to WASP expression in patients with Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT), peripheral blood mononuclear cells (PBMCs) from nine patients and Epstein-Barr virus-transformed B-lymphoblastoid cell lines from seven patients examined did not show WASP expression by flow cytometric analysis. These results were confirmed by Western blot analysis. We conclude that WASP expression in lymphocyte subpopulations from patients with WAS and XLT can be more precisely evaluated by flow cytometry as compared with Western blot analysis. This flow cytometry method is important as a supplement to Western blots, but even more important as an alternative and powerful assay that can contribute to research on WASP as well as diagnosis in a clinical setting.

Monoclonal antibody directed to human T-cell malignancy antigen.

A murine monoclonal antibody (B2D) against a cultured pre-T acute lymphoblastic leukemia (ALL) cell line THP-6 has been produced. The antibody reacted with seven out of eight cultured T-ALL cell lines and with leukemic cells from three out of four T-ALL/lymphoma patients. The antibody did not react with normal T and B lymphocytes, monocytes, granulocytes, platelets, erythrocytes, bone marrow lymphoid-like precursor cells, thymocytes and other acute and chronic leukemic cells of non-T cell origin. Furthermore, B2D did not react with phytohemagglutinin-activated T cells nor with concanavalin A-activated T cells. The molecules immunoprecipitated with B2D had molecular weights of 50-55 kD. Thus, B2D seems to be highly specific for T-cell malignancies. These results show that B2D defines one of human leukemia antigens which are expressed on the cell surface of T-ALL cells. Monoclonal antibody B2D may be useful for the subclassification of T-ALL cells and has therapeutic potential for a certain type of T-ALL.

Characterization of a precursor T-cell line (THP-6) with rearranged T-cell receptor beta chain gene.

A previously established human leukemia cell line, designated THP-6, was further characterized with respect to cell surface antigen expression and immunoglobulin(Ig) and T-cell receptor(TCR) gene status. THP-6 cells were positive for CD7 and CD5 antigens and terminal deoxynucleotidyl transferase, but negative for CD2, CD1, CD4, CD8, CD10, cytoplasmic and surface CD3 and HLA-DR antigens, suggesting a precursor T-cell line. Analysis of Ig and TCR beta chain genes revealed that THP-6 had a rearranged TCR beta chain gene and a germline Ig gene. These results, in agreement with its phenotype, confirmed that THP-6 was of the T-cell lineage.

A human CD4- CD8- T-cell receptor alpha beta + T leukemic cell line undergoing phytohemagglutinin-induced apoptosis.

A human CD4- CD8- alpha beta T-cell receptor (TCR alpha beta)+ T leukemic cell line, L-KAW, was established from the peripheral blood of a 6-year-old male patient with T-cell acute lymphoblastic leukemia. Its phenotype was found to be CD7+CD2+CD3+CD4-CD8- TCR alpha beta +. The cell line proved susceptible to killing by exposure to a mitogenic concentration of phytohemagglutinin (PHA) within several hours, with biochemical analyses demonstrating extensive degradation of DNA to oligonucleosomal bands characteristic of apoptosis. Chromatin condensation and cell shrinkage features of apoptotic cells could also be clearly identified under the electron microscope. The apoptosis-related Fas antigen was expressed on L-KAW cells and DNA fragmentation was induced by incubation with anti-Fas monoclonal antibody. The c-myc mRNA levels declined within 15 min to 3 h after the addition of PHA. These results suggest that L-KAW cells are specifically sensitive to induction of apoptosis in response to PHA without preactivation. They may, therefore, be considered an analog of activated T-cells and prove useful as a model system for characterizing biochemical and molecular mechanisms underlying the process of this type of cell death.

Alterations of the p53, p21, p16, p15 and RAS genes in childhood T-cell acute lymphoblastic leukemia.

We investigated the alterations of the p53, p21, p16, p15 and RAS genes in childhood T-cell acute lymphoblastic leukemia (T-ALL) and T-ALL cell lines by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and direct sequencing. Mutations of the p53 gene were found in three of 57 (5%) patients at diagnosis, one of 14 (7%) patients at relapse and in 12 of 18 (67%) cell lines. In these 12 cell lines, four had more than two mutations of the p53 gene. The p53 mutations were found in four of five cell lines whose original fresh leukemic cells were simultaneously examined original fresh leukemic cells. However, only one of the four fresh leukemic cells had the same mutation. All patients with p53 mutations in the course of disease died. Mutations of the p21 gene were not identified in 71 fresh samples and in 18 cell lines. N-RAS mutations were found in two of 57 (4%) fresh T-ALL patients at diagnosis, and four of 18 cell lines (22%), whereas no mutations were detected in any samples at relapse. Alterations of the p16 gene were found in 18 of 47 (38%) patients at diagnosis and in seven of 14 (50%) at relapse. These differences were not statistically significant. There were no differences in the frequency of alteration of the p16 and p15 genes between event-free patients and the remaining patients. Furthermore, we found the methylation of p16 gene in three of seven patients lacking homozygous deletions, suggesting higher frequency of p16 inactivation than previous reports in T-ALL. Interestingly, we found that one allele is inactivated by methylation and another allele had nonsense mutation in one cell line (KOPT-KI), resulting in loss of protein expression of p16. This type of p16 inactivation has not been so far reported in leukemia. We conclude that, (1) p53 mutations are infrequent at diagnosis but tend to be associated with poor clinical outcome; (2) RAS and p21 mutations may not be involved in the pathogenesis of T-ALL; (3) not only frequent alterations of p16 and p15 genes but also methylation of p16 gene are involved in initiating the leukemogenesis of T-ALLs, and (4) these 5 genes are independently involved in T-ALL.

Successful treatment of steroid-resistant severe acute GVHD with 24-h continuous infusion of FK506.

We report our findings in two cases of steroid-resistant severe acute GVHD after allogeneic BMT successfully treated with FK506 (tacrolimus). An 18-year-old female (patient 1) who underwent BMT from an HLA-identical sibling for ALL in first CR, developed generalized erythema and profuse watery diarrhea, which progressed to acute GVHD of grade III severity, resistant to steroid control. After continuous 24-h administration of FK506, the diarrhea improved within 10 days. Patient 2, a 9-year-old girl with AML who underwent unrelated BMT, had skin, gut and liver lesions of acute GVHD grade IV, which did not respond to high-dose steroid therapy. They were controlled, however, by continuous intravenous infusion of FK506. Both patients are still surviving after more than 1 year without any acute GVHD sequelae or signs of chronic illness. The adverse effects of FK506 were mild and tolerable in both cases. Comparison of our findings with those in the literature suggests that it is important to give FK506 at plasma concentrations as high as 25-35 ng/ml by continuous intravenous infusion for extended periods to control steroid-resistant severe acute GVHD.

Bilateral pneumothoraces with multiple bullae in a patient with asymptomatic bronchiolitis obliterans 10 years after bone marrow transplantation.

A 16-year-old boy developed bronchiolitis obliterans (BO) 10 years after BMT for myelodysplastic syndrome. Although the patient complained of almost no dyspnea on exertion, he had mild hypercapnea with a markedly reduced forced expiratory volume of 0.32 l. Chest X-rays showed occasional bilateral minimal pneumothoraces, which is in accordance with the existence of multiple small bullae found on the pleural surface at video-assisted thoracic surgery. Histologic examination of the biopsied lung revealed BO. This case indicates that BO in adolescence following BMT and possible chronic GVHD may be masked because of lung immaturity at BMT, and BO after BMT may be associated with multiple pleural bullae.

Successful umbilical cord blood transplantation from an unrelated donor for a patient with Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis.

We report a case of a 5-year-old girl with EBV-associated hemophagocytic lymphohistiocytosis (EBV-HLH) who underwent cord blood (CB) stem cell transplantation (CBSCT) from an unrelated donor. The patient presented with persistent high-grade fever and hepatosplenomegaly. Because the disease was refractory to immunochemotherapy according to the HLH94 protocol, she received 2.0 x 10(7) CB nucleated cells/kg body weight (BW) after conditioning with BU/CY/etoposide. No acute GVHD developed, using FK506 for prophylaxis. The neutrophil count reached >0.5 x 10(9)/l by day 21 and the platelet count reached >50 x 10(9)/l by day 84. The patient recovered well with sequelae of neurological deficits more than 10 months after receiving CBSCT, without showing evidence of HLH or chronic GVHD. Real-time PCR proved applicable for estimation of the EBV load in PBMC of the patient. We conclude that CBSCT may be indicated for some cases of refractory EBV-HLH, who have no HLA-matched siblings and are therefore dependent on unrelated marrow donors.

Identification of human GATA-2 gene distal IS exon and its expression in hematopoietic stem cell fractions.

Transcription factor GATA-2 is essential for the proper function of hematopoietic stem cells and progenitors. Two first exons/promoters have been found in the mouse GATA-2 gene, and a distal IS promoter shows activity specific to hematopoietic progenitors and neural tissues. To ascertain whether the two-promoter system is also utilized in the human GATA-2 gene, we isolated and analyzed a P1 phage clone containing this gene. The nucleotide sequence of the human GATA-2 gene 5' flanking region was determined over 10 kbp, and a human IS exon was identified in the locus through sequence comparison analysis with that of the mouse GATA-2 IS exon. RNA blotting and reverse-transcribed PCR analyses identified a transcript that starts from the IS exon in human leukemia-derived cell lines. The IS-originated transcript was also identified in CD34-positive bone marrow and cord blood mononuclear cells, which are recognized as clinically important hematopoietic stem cell-enriched fractions. Phylogenic comparison of the human and mouse GATA-2 gene sequences revealed several regions in the locus that exhibit high sequence similarity. These results demonstrate that the GATA-2 gene regulatory machinery is conserved among vertebrates. The fact that the human IS promoter is active in the hematopoietic stem cell/progenitor fraction may be an important clue for the design of a vector system that can specifically express various genes in hematopoietic stem cells and progenitors.