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D Stroncek

Publications and source records attributed to D Stroncek.

At least 37 records · Page 2Linked to original sources
PubMed1997

Allogeneic blood stem cell transplantation: considerations for donors.

Allogeneic transplantation of cytokine-mobilized peripheral blood stem cells (PBSCs) is now being increasingly performed, but safety considerations for hematologically normal PBSC donors have not been fully addressed. Progenitors are generally mobilized for collection from normal donors using recombinant human granulocyte colony-stimulating factor (rhG-CSF). Although the short-term safety profile of rhG-CSF seems acceptable, experience remains limited and its optimal dose and schedule have not been defined. Minimal data exist regarding long-term safety of rhG-CSF, primarily derived from experience in patients with chronic neutropenia or cancer. An "ad hoc" workshop was recently convened among a group of investigators actively involved in the field of allogeneic stem cell transplantation to discuss the safety issues pertaining to normal PBSC donors. There was agreement on the following points: (1) On the basis of available data, it appears that rhG-CSF treatment and PBSC collection have an acceptable short-term safety profile in normal donors. However, the need for continued safety monitoring was recognized. (2) rhG-CSF doses up to 10 microg/kg/d show a consistent dose-response relationship with the mobilization (and collection) of CD34+ progenitor cells, and this dose is acceptable for routine clinical use. Whether higher doses are superior (or cost effective) remains to be determined, and they may produce more severe side effects. The potential risks of marked leukocytosis (arbitrarily defined as a leukocyte count of more than 70 x 10(9)/L) have been a concern, and rhG-CSF dose reduction is performed by many centers to maintain leukocyte counts below this level. (3) Transient post donation cytopenias, involving granulocytes, lymphocytes, and platelets, may occur and are at least partly related to the leukapheresis procedure. These are generally asymptomatic and self-limited; follow-up blood counts are not necessarily required. Reinfusion of autologous platelet-rich plasma should be considered for donors with expected postdonation thrombocytopenia (platelet count < 80 to 100 x 10(9)/L). (4) Donors should meet the eligibility criteria which apply to donors of apheresis platelets, with the exception that pediatric donors may also be considered. Any deviation from these criteria should have supporting documentation. There is insufficient information at this time to clearly establish definite contraindications for PBSC collection in a hematologically normal donor. Potential contraindications include the presence of inflammatory, autoimmune, or rheumatologic disorders, as well as atherosclerotic or cerebrovascular disease. (5) The creation of an International PBSC Donor Registry is desirable to facilitate monitoring the long-term effects of the procedure. Individual institutions or donor centers are encouraged to establish their own PBSC donor follow-up system, preferably with a standardized approach to data collection.

Adult↗
PubMed1997

Primitive long-term culture initiating cells (LTC-ICs) in granulocyte colony-stimulating factor mobilized peripheral blood progenitor cells have similar potential for ex vivo expansion as primitive LTC-ICs in steady state bone marrow.

We have recently shown that more than 90% of long-term culture initiating cells (LTC-IC) mobilized in the peripheral blood (PB) of normal individuals express HLA-DR and CD38 antigens and can sustain hematopoiesis for only 5 weeks. However, 10% of LTC-IC in mobilized PB are CD34+ HLA-DR- and CD34+ CD38- and can sustain hematopoiesis for at least 8 weeks. We now examine the ex vivo expansion potential of CD34+ HLA-DR+ cells (rich in mature LTC-IC) and CD34+ HLA-DR- cells (rich in primitive LTC-IC) in granulocyte colony-stimulating factor (G-CSF) mobilized PB progenitor cells (PBPC). Cells were cultured in contact with M2-10B4 cells (contact) or in transwells above M2-10B4 (noncontact) without and with interleukin-3 (IL-3) and macrophage inflammatory protein (MIP-1alpha) for 2 and 5 weeks. Progeny were evaluated for the presence of colony-forming cells (CFC) and LTC-IC. When CD34+ HLA-DR+ PB cells were cultured in contact cultures without cytokines, a threefold expansion of CFC was seen at 2 weeks, but an 80% decrease in CFC was seen at week 5. Further, the recovery of LTC-IC at week 2 was only 17% and 1% at week 5. This confirms our previous observation that although CD34+ HLA-DR+ mobilized PB cells can initiate long-term cultures, they are relatively mature and cannot sustain long-term hematopoiesis. In contrast, when CD34+ HLA-DR- mobilized PB cells were cultured in contact cultures without cytokines, CFC expansion persisted until week 5 and 49% and 11% of LTC-IC were recovered at week 2 and 5, respectively. As we have shown for steady state bone marrow (BM) progenitors, recovery of LTC-IC was threefold higher when CD34+ HLA-DR- PBPC were cultured in noncontact rather than contact cultures, and improved further when IL-3 and MIP-1alpha were added to noncontact cultures (96 +/- 2% maintained at week 5). We conclude that although G-CSF mobilizes a large population of "mature" CD34+ HLA-DR+ LTC-IC with a limited proliferative capacity, primitive CD34+ HLA-DR- LTC-IC present in mobilized PB have similar characteristics as LTC-IC from steady state BM: (1) they can be maintained in noncontact cultures containing IL-3 and MIP-1alpha for at least 5 weeks; (2) they are subject to the same proliferation inhibitory influences of contact with stroma. Since the absolute number of primitive LTC-IC (week 8 LTC-IC) per mL of G-CSF mobilized PB is similar to that per mL of steady state BM, these studies further confirm that G-CSF mobilized PBPC may have similar long-term repopulating abilities as steady state BM.

Antigens, CD34↗
PubMed1997

Characterization of a new alloantigen (SH) on the human neutrophil Fc gamma receptor IIIb.

Polymorphic structures of the neutrophil Fc gamma receptor IIIb (Fc gamma RIIIb) result in alloantibody formation that causes alloimmune neonatal neutropenia and transfusion reactions. Alloantigens located on Fc gamma RIIIb include the antigens NA1 and NA2. In four cases of alloimmune neonatal neutropenia, granulocyte-specific alloantibodies directed against a thus far unknown antigen were detected by granulocyte agglutination and immunofluorescence tests in the maternal sera. By the use of the monoclonal antibody-specific immobilization of granulocyte antigens (MAIGA) assay, the new antigen, termed SH, was located on the Fc gamma RIIIb. Nucleotide sequence analysis of the Fc gamma RIIIb coding region from a SH(+) individual showed a single-base C-->A mutation at position 266, which results in an Ala78Asp amino acid substitution. A family study confirmed that this nucleotide difference is inherited, and corresponds to the SH phenotype. Serologic typing of 309 randomly selected individuals showed an antigen frequency of 5% in the white population. The same frequency was found by genotyping, for which a technique based on polymerase chain reaction (PCR) using sequence-specific primers (PCR-SSP) was developed. Typing of all SH(+) individuals for NA1 and NA2, and PCR-restriction fragment length polymorphism analysis of the NA-specific PCR products from five SH(+) individuals using the SH-specific endonuclease SfaN 1 showed that SH antigen is very probably the result of an additional mutational event in the NA2 form of the Fc gamma RIIIB gene. Immunochemical studies also demonstrated that the SH determinants reside on the 65- to 80-kD NA2 isoform of the Fc gamma RIIIb. Our findings show the existence of an additional polymorphism of the Fc gamma RIIIb, which can result in alloantibody formation causing alloimmune neonatal neutropenia.

Adult↗
PubMed1997

Retroviral transduction of peripheral blood leukocytes in a hollow-fiber bioreactor.

BACKGROUND: Peripheral blood white cells (leukocytes) (PBLs) have been used as effective targets for genetic manipulation by transduction with retroviruses in open systems. A semi-closed hollow-fiber bioreactor was tested for culturing and transducing lymphocytes. STUDY DESIGN AND METHODS: PBLs were isolated from five healthy donors, and 5 x 10(7) cells were cultured in hollow-fiber bioreactors for 4 days after stimulation with anti-CD3 in medium containing 200 units per mL of recombinant interleukin 2. Transduction with retroviral vector containing the gene for iduronate-2-sulfatase and G 418 resistance, L2SN, was performed daily on Days 4, 5, 6, and 7, and the cells were expanded for an additional 3 days. RESULTS: PBLs from three donors were harvested from the bioreactor after transduction and expansion, and 4.5 x 10(9), 7.0 x 10(9), and 2.9 x 10(9) cells were recovered, representing 90-, 136-, and 58-fold expansions. The transduction frequency of L2SN was 10, 5, and 1 percent, respectively. For additional expansion of PBLs, in two cases the bioreactor was reinoculated with 5 x 10(7) cells, which were expanded again for 16 and 8 days, respectively, yielding 1.4 x 10(9) and 3.1 x 10(9) cells, which reflected an additional 28- and 62-fold expansion of cells. PBLs from two other donors were transduced and expanded in the bioreactor, and then 0.8 mg per mL of G 418 was added to the medium in an attempt to enrich the transduced population. Although 2.5 and 10 percent of the cells were transduced, cell death and absence of expansion in the presence of G 418 resulted in final cell lots with viabilities of only 4 and 8 percent. In all cases, the harvested cells tested negative in bacterial and fungal cultures. CONCLUSION: Hollow-fiber bioreactors are an efficient and effective system for the retroviral transduction and expansion of PBLs for clinical gene therapy.

Bioreactors↗
PubMed1996

Phenotypic and functional characterization of long-term culture-initiating cells present in peripheral blood progenitor collections of normal donors treated with granulocyte colony-stimulating factor.

Granulocyte colony-stimulating factor (G-CSF) mobilized peripheral blood progenitor cells (PBPC) have successfully been used as stem cells for both autologous and allogeneic transplants. However, little is known concerning the absolute number and phenotype of primitive progenitors, such as long-term culture-initiating cells (LTC-IC) in mobilized PBPC. The aim of our study was to evaluate the capacity of G-CSF to mobilize LTC-IC in the PB of normal individuals and to evaluate the phenotypic and functional characteristics of G-CSF mobilized LTC-IC. G-CSF was administered to 29 healthy volunteers at 7.5 micrograms or 10 micrograms/kg/d subcutaneously (SC) for 5 consecutive days and PBPC were harvested on day 6. Mobilization with G-CSF increased the absolute number of week 5 LTC-IC in PB 60-fold, while the number of CD34+ cells and committed colony forming cells (CFC) was increased sevenfold to 12-fold. The frequency of CFC and week 5 LTC-IC in CD34+ cells selected by fluorescence-activated cell sorter (FACS) from mobilized PBPC was 2 +/- 0.3-fold and 9 +/- 2.2-fold higher respectively than in CD34+ cells selected from unmobilized PBMNC. CFC were enriched in the CD34+ CD38+ and CD34+ HLA-DR+ populations. The absolute number of LTC-IC present in CD34+ CD38- and CD34+ HLA-DR- cells selected by FACS from either mobilized PBPC, unmobilized PBMNC or steady state bone marrow (BM) was similar (0.5% to 2%). In contrast to unmobilized PBMNC or steady state BM CD34+ CD38+ and CD34+ HLA-DR+ cells, which contain less than 0.1% LTC-IC, CD34+ CD38+ and CD34+ HLA-DR+ cells sorted from mobilized PBPC contained 0.5% to 5% of cells capable of sustaining hematopoiesis in long-term cultures for 5 weeks. However, 90% to 95% of LTC-IC present in mobilized CD34+ CD38+ and CD34+ HLA-DR+ cells were not able to sustain hematopoiesis for 8 weeks, while 30% of CD34+ CD38- and CD34+ HLA-DR- LTC-IC present in mobilized PBPC could sustain hematopoiesis for at least 8 weeks. This suggests that the majority of CD34+ CD38+ and CD34+ HLA-DR+ week 5 LTC-IC represent progenitors at an intermediate state of differentiation. We conclude that G-CSF effectively mobilizes LTC-IC in the blood of normal individuals. Although a fraction of these cells has functional characteristics similar to those of steady state PBMNC or BM LTC-IC, more than 85% of mobilized PBPC LTC-IC are CD34+ CD38+ and CD34+ HLA-DR+, capable of sustaining hematopoiesis for 5 weeks, but not for 8 weeks. The functional and phenotypic characterization of primitive and more mature populations of LTC-IC in mobilized PBPC should prove extremely useful in future studies examining the role of these progenitors in engraftment following transplantation.

ADP-ribosyl Cyclase↗
PubMed1996

Molecular characterization of antigenic polymorphisms (Ond(a) and Mart(a)) of the beta 2 family recognized by human leukocyte alloantisera.

We show that the previously described alloantisera Ond and Mart, which recognize the alloantigens Ond(a) and Mart(a), react with polymorphic variants of alpha L and alpha M subunits of the beta 2 integrin family (CD11a and CD11b molecules). This was shown by testing the alloantisera in a monoclonal antibody-specific immobilization of leukocyte antigens, immunoprecipitation, and immunofluorescence assay against cells from normal donors and from patients with leukocyte adhesion deficiency (beta 2 intergrin deficient). To elucidate the molecular basis of the Ond(a) and Mart(a) alloantigens, RNA was isolated from mononuclear leukocytes derived from individuals of known serologic phenotype. Reverse transcriptase-polymerase chain reaction (RT-PCR) was performed to amplify the entire coding region of the alpha L and alpha M mRNAs. The Ond(a) antigen was found to be due to a G2466C substitution in the DNA coding for the alpha L subunit, which predicts an Arg766Thr amino-acid polymorphism. The Mart(a) antigen was also found to be due to a single nucleotide substitution (G302A) in the DNA coding for the alpha M subunit, which predicts an Arg61His amino acid polymorphism. Using allele-specific restriction enzyme analysis, the association between point mutations and phenotypes was confirmed. The localization of these alloantigens on integrin molecules further illustrates the polymorphic nature of this class of proteins. Whether the polymorphisms influence the adhesive capacity of the leukocyte integrins remains to be investigated.

Alleles↗
PubMed1995

Immune mediated agranulocytosis and anemia associated with thymoma.

Thymoma has been associated with a variety of autoimmune disorders. We report a case of agranulocytosis and anemia in a 68-year-old woman with a spindle cell thymoma. She was unresponsive to treatment with antibiotics, granulocyte-colony stimulating factor (G-CSF), prednisone, and high-dose intravenous immunoglobulin. Serial bone marrow examinations on this therapy showed progression from a cellular marrow with mild myeloid and erythroid hyperplasia and lymphocytosis, to granulocyte aplasia and severe erythroid hypoplasia. Her serum contained granulocyte-specific antibodies and inhibited the growth in culture of her own marrow cells and marrow cells from a normal donor. An IgG fraction from her serum also inhibited the growth of marrow cells. Although the patient's spindle cell thymoma was surgically removed, she remained neutropenic. She was treated with six plasma exchanges followed by 1,000 milligrams of intravenous cyclophosphamide 2 days after the final plasma exchange and daily G-CSF. Three weeks later her peripheral blood showed marked leukocytosis with pronounced neutrophilia and a left shift. Although her agranulocytosis resolved, she died of fungal sepsis. This case demonstrates that aggressive plasma exchange and immunosuppressive therapy may benefit patients with agranulocytosis associated with thymoma.

Aged↗
PubMed1994

The changing activities of a regional marrow donor program.

BACKGROUND: A regional marrow donor program was established in 1982. Following the establishment of the National Marrow Donor Program (NMDP) in 1987, the activities of this regional program changed. STUDY DESIGN AND METHODS: To better understand the changes that occurred in the regional marrow donor program, its donor recruitment and marrow collection activities through 1991 were studied retrospectively. Data analyzed included the total number of potential donors, the number and types of potential donors recruited each year, the number of searches performed, the number of samples collected for HLA-DR typing and mixed lymphocyte culture testing, and the number of transplants in both programs from 1987 through 1991. Statistical analysis was performed by using chi-square. RESULTS: Initially, only persons who donated platelets by apheresis were enrolled into the program. In 1986, the regional program's first drive to recruit people who were not apheresis donors occurred. The number of such drives increased each year, and in 1991, 12 drives occurred, which resulted in the recruitment of 1313 potential marrow donors. From 1987 to 1991, the number of potential donors in the regional program grew from 3252 to 9146, but the proportion of apheresis donors in the program decreased. In 1987, 91.9 percent of marrow donors at the regional center had been apheresis donors, but in 1991, 41.7 percent had been apheresis donors. The number of marrows donated at the regional center increased from 11 in 1987 to 29 in 1989, but then fell to 24 per year in 1990 and 1991. The decrease in the number of donations at the regional program was due to the rapid growth in the NMDP file of potential marrow donors and the selection of donors whose HLA antigens were more compatible with those of the transplant recipients. In 1989, the regional program contained 4.6 percent of all HLA-A,B-typed and 11.2 percent of all HLA-A,B,DR-typed potential donors in the NMDP and collected 15.3 percent of all marrows. However, in 1991, the regional program contained 2.0 percent of HLA-A,B-typed donors and 4.1 percent of HLA-A,B,DR-typed donors and collected 5.3 percent of marrows. In 1987, 18 percent of the people who donated marrow at the regional center were phenotypically HLA-A,B,DR identical with the recipient, but in 1991, 92 percent of donor-recipient pairs were phenotypically HLA-A,B,DR identical. CONCLUSION: Recruitment activities became an increasingly larger part of the Regional Marrow Donor Program's activities. Increasing the size of the file of potential donors was necessary to maintain a constant number of donations. Persons who were not regular blood donors were an important part of the marrow donor program.

Blood Donors↗
PubMed1994

Proposed policies and procedures for the establishment of a cord blood bank.

To carry out cord blood transplants from allogeneic unrelated donors, cord blood stem cell banks must be established. This report proposed the policies and procedures that can be used to establish cord blood banks. The areas covered include donor consent and suitability criteria; infectious and genetic disease testing; collection, processing, and preservation of the cord blood; retention of specimens for special testing; confidentiality; documentation and record keeping; establishment of a quality control program; and related regulatory issues. There are no technologic impediments to establishing cord blood banks. Agreement on some standard policies and procedures would facilitate exchange of cord blood stem cells among transplant centers and should increase the number of transplants that can be done.

Blood↗
PubMed1994

Idiopathic thrombocytopenia and neutropenia in childhood.

PURPOSE: Between 1975 and 1990, 13 patients seen at The Hospital for Sick Children, Toronto, Ontario, were noted to have concurrent idiopathic thrombocytopenia and neutropenia (ITN; platelet count < 150 x 10(9)/L; absolute neutrophil count < 1.5 x 10(9)/L). These patients all had normal marrow function and no evidence of systemic disease. PATIENTS AND METHODS: A detailed chart review was performed to define the clinical and laboratory features of these patients. RESULTS: Although this was a heterogeneous group of patients, they shared several common characteristics. The disease followed a chronic course with thrombocytopenia or neutropenia or both that persisted or recurred over the entire period of follow-up in all patients (18 months to 15 years). The disease was associated with splenomegaly in eight patients and lymphadenopathy in nine patients. Boys were affected more frequently than were girls (ratio 11:2). Thrombocytopenia improved temporarily during treatment with corticosteroids, i.v. immunoglobulin G, RhoGAM, and a variety of immunosuppressive agents; however, neutropenia tended to be much more resistant to these therapies. Splenectomy was ineffective in two children in whom the procedure was performed. Platelet of and neutrophil antibodies or both were detected in five of six patients who were tested, suggesting an autoimmune cause for the cytopenias. CONCLUSIONS: These findings suggest that ITN in childhood is distinct from immune thrombocytopenic purpura, particularly in terms of its chronicity and poor response to therapy.

Adolescent↗
PubMed1993

The National Marrow Donor Program.

As the number of successful marrow transplants has increased, the lack of HLA-identical sibling donors for 60 to 70 percent of transplant candidates has become a serious problem. Pilot studies established that marrow transplantation between phenotypically HLA-identical, unrelated individuals can be accomplished successfully. Therefore, the National Marrow Donor Program was established to develop a large file of volunteer marrow donors and to serve as a center for the coordination of the donor search and donor-recipient matching processes. By November 1991, 63 months after the program was established, 457,205 potential marrow donors typed for HLA-A and -B antigens had agreed to be listed in the marrow donor registry. A donor search had been initiated for 8481 patients. At least one potential donor matched for at least three of the four HLA-A and -B antigens was located for 99.8 percent of patients. Among the 3156 searches that were completed, 940 (29.8%) resulted in a transplant. The median time in which to locate a matched donor, complete all predonation evaluations, and obtain donor consent was 208 days. The most common diagnosis in patients who underwent transplantation was chronic myelogenous leukemia (42.0%). When this analysis was completed in November 1991, the National Marrow Donor Program was operating a national network of 99 donor centers and 53 transplant centers. The donor file was increasing rapidly, and a follow-up system was in place to determine the effects of donation on the donors and the outcome in the patients who underwent transplantation. This national network of donor and transplant centers exists and is now facilitating unrelated-donor marrow transplants. The National Marrow Donor Program made it possible to locate donors for many patients in need of a transplant and helped to determine the role of unrelated-donor marrow transplants in the treatment of many diseases.

Blood Component Removal↗
PubMed1992

Selection of platelets for refractory patients by HLA matching and prospective crossmatching.

A multi-site clinical study compared platelets chosen for refractory patients by prospective platelet crossmatching using stored donor platelets and HLA-based selection. Seventy-three patients who were refractory to random-donor platelets received two plateletpheresis components, one chosen by HLA-based criteria and the other by crossmatching. Patients were carefully evaluated to exclude nonimmune factors that could adversely affect transfusion results. Each of the five study sites used a crossmatch procedure with which it had experience. Results from this study indicate the following: 1) The overall rate of successful transfusion was similar when an HLA-based method of donor selection that includes all grades of matching and mismatching was compared to a crossmatch-based method of donor selection. 2) HLA-based selection that restricts recipients to grade A and BU matches was superior to a selection method based upon crossmatching alone. Donor selection based on HLA matching (grades A or BU) was also superior to selection based on any degree of HLA mismatching (grades BX, C, or D). 3) Selection of donors based on HLA-cross-reactive groups (defined by in vitro serologic crossreactivity) was no more successful than that based on grade C and D mismatches and was no more successful than selection by crossmatching alone. 4) Lymphocytotoxic and platelet antibodies were not detected in many of the enrolled patients, even though patients demonstrating nonimmune factors were eliminated from the study. It can be concluded that HLA-compatible (grades A and BU) platelets provide optimal support for refractory patients, but that crossmatch-selected platelets are acceptable as an alternative component.

Adult↗
PubMed1989

Attitudes and physical condition of unrelated bone marrow donors immediately after donation.

Annually, over 3000 bone marrow transplants are performed worldwide involving HLA-identical sibling donors. However, only 30 percent of those patients who need a bone marrow transplant have a matched sibling donor. Programs have been developed to provide volunteer unrelated bone marrow donors for patients without sibling donors. Because bone marrow donation requires a high level of altruism, especially on the part of a donor unrelated to the patient, it is important to determine the effect of donation on the donor. Serious medical complications during the collection of marrow from related donors have been reported only rarely, but there have been no reports on the psychosocial and physical effects of the bone marrow donation process on volunteer unrelated bone marrow donors. The first 20 unrelated volunteers who donated bone marrow through the authors' volunteer bone marrow donor program were surveyed. They suffered no serious emotional or physical aftereffects. Seventeen of 20 donors reported that making the decision to donate was easy, and 16 reported making the decision to donate right away. Nine of 20 donors, however, stated that a friend or family member discouraged them from donating. All 20 donors thought that they were well prepared for the donation process. Four donors thought that the donation process required more time than they expected, but four donors thought the reverse. One person thought the process was more painful than they expected; however, 12 found the process to be less painful than expected.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

The National Marrow Donor Program: how it works, accomplishments to date.

As the use of bone marrow transplantation increases, the lack of a suitable matched sibling donor for approximately 60% of patients is a growing problem. Recently, marrow transplantation has been done successfully using HLA-matched unrelated donors. In an effort to provide more donors, the National Marrow Donor Program (NMDP) was established. It involves 50 blood banks and 20 marrow transplant centers throughout the United States. More than 20,000 HLA-typed apheresis donors from these blood banks have agreed to be listed in the NMDP registry. A preliminary search for donors has been carried out for 1,116 patients. Donors suitably matched for HLA-A and B antigens were located for 99% of the patients.

Bone Marrow Transplantation↗
PubMed1987

Granulocyte oxygen radicals as potential suppressors of hemopoiesis: potentiating roles of lactoferrin and elastase; inhibitory role of oxygen radical scavengers.

In vitro studies suggest intact endothelial cells and their released growth factors are required for optimal growth and differentiation of hematopoietic cells in culture. Conversely, processes that damage endothelium might, therefore, suppress hematopoiesis. We have studied mechanisms by which stimulated inflammatory cells, particularly granulocytes, damage endothelium and suggest these studies may provide new insights into the hematopoietic suppression of inflammatory diseases. We demonstrate that the granulocyte lysosomal constituent, lactoferrin, which has independently been shown to inhibit in-vitro hematopoiesis, may act by amplifying granulocyte-mediated toxic oxidant damage to endothelium. Its deleterious effects are twofold: 1) it releases iron that catalyses the Haber-Weiss reaction, thereby producing highly toxic hydroxyl radicals; and 2) its highly positive charge facilitates its absorption to target membranes that traffics oxygen-radical damage directly to endothelium. In addition, we demonstrate that another granulocyte lysosomal component, elastase, also perturbs endothelium--not so much by direct lytic effect, but by proteolysing matrix proteins that serve to attach endothelium to its substratum. Thus, elastase promotes endothelial lift-off. Plasma alpha-1-antiproteinase, a potent antielastase, should be protective, but is inactivated by the same granulocyte oxidants that directly lyse endothelial cells. However, antielastase activity can be preserved by antioxidants and a novel, innocuous one--methionine--is described. It is oxidized as a surrogate for the critical-site methionine of alpha-1-proteinase inhibitor, preserving in the process antielastase activity. Our results suggest that strategies to reduce production of inflammatory cell toxic oxygen radicals with reagents such as antilactoferrin antibody or iron chelators might be useful adjuncts in maintaining in vitro hematopoiesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Antioxidants↗
PubMedDate not supplied

Frequency of human leukocyte antigen-A 24 alleles in patients with melanoma determined by human leukocyte antigen-A sequence-based typing.

The analysis of immune responses of patients with melanoma has led to the identification of melanoma-associated antigens targeted by T cells. Cytotoxic T lymphocytes recognize peptides from melanoma-associated antigens presented on the cancer cell surface in the context of HLA class I molecules. Immunodominant melanoma-associated antigen epitopes are being evaluated for their ability to immunize patients with advanced melanoma. However, these vaccination efforts are limited by the extensive polymorphism of the HLA class I heavy chain, which occurs in functional domains of the molecule. Patients with melanoma with the HLA-A-24 phenotype were recruited for vaccination with the peptide AFLPWHRLF from the melanoma-associated antigen tyrosinase. This peptide is recognized in association with HLA-A*2402. The HLA-A24 family includes at least 15 alleles whose frequency and ability to present the same peptide are unknown. The distribution of HLA-A24 alleles was studied in a melanoma population for the practical purpose of identifying patients suitable for vaccination with HLA-A*2402 epitopes. An HLA-A locus-specific polymerase chain reaction method followed by sequencing was developed to determine the HLA-A alleles in genomic DNA. HLA-A 24 was also typed in healthy persons of various ethnic backgrounds to further explore the HLA-A24 family. In white persons, the HLA-A*2402 allele was most common (in 85% of white persons and in 97% of the patients with melanoma). Fewer persons carried the HLA-A*2403 allele (13% in all samples, 3% in melanoma patients). Finally, two new alleles, HLA-A*2422 and HLA-A*24 null, were identified. These results suggest that vaccination with HLA-A*2402-associated epitopes has the potential for broad use in this patient population.

Alleles↗