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Biomedical subjects

N Flomenberg

Publications and source records attributed to N Flomenberg.

At least 37 records · Page 2Linked to original sources
PubMed1994

Hyperfractionated total lymphoid irradiation and cyclophosphamide for preparation of previously transfused patients undergoing HLA-identical marrow transplantation for severe aplastic anemia.

PURPOSE: To assess the immunosuppressive capacity of hyperfractionated total lymphoid irradiation and cyclophosphamide for transplantation of unmodified allogeneic marrow in sensitized aplastic anemia patients. METHODS AND MATERIALS: From February 1983 to September 1990, 23 multiply transfused aplastic anemia patients underwent unmodified bone marrow transplantation from HLA genotypically identical sibling donors following preparation with 6 Gy hyperfractionated total lymphoid irradiation and 160 mg/kg cyclophosphamide. Graft-versus-host disease prophylaxis included steroids in one patient, methotrexate in four, cyclosporine in seven, and methotrexate/cyclosporine in 12. There were 17 males and 6 females with a median age of 13 (range: 2.5-32). RESULTS: One patient died early before engraftment of bacterial sepsis. Twenty-two patients were evaluable for engraftment. Three experienced graft failure including one primary, and two late graft failures associated with cyclosporine withdrawal. Acute graft-versus-host disease occurred in 7/22 (> or = grade II in 6), and chronic graft-versus-host disease in 3/17 patients. Except for a patient who received total body irradiation for a second transplant, no patient in this series developed interstitial pneumonia. Fifteen patients are alive with follow-up of 38-125 months (median 68). The overall actuarial survival at 5 years is 69%, at 8 years it is 60%, with one late death. The survival of adult patients was similar to that of younger patients (> or = 16 years old: 63%, < 16 years old: 55%). The development of acute graft-versus-host disease adversely influenced survival (88% with Grade 0-I, 17% with grade II-IV; p = 0.002). No hypothyroidism or secondary malignancies have been documented in this series. CONCLUSION: Pretransplant immunosuppression with 6 Gy of hyperfractionated total lymphoid irradiation and 160 mg/kg CY reduces but does not eliminate the incidence of graft failure in sensitized aplastic anemia patients. The dose and the mode of administration of total lymphoid irradiation in this trial may be associated with a lower incidence of late side effects. Survival is comparable to that obtained using preparative regimens without radiation.

Adolescent↗
PubMed1994

Circulating T cell repertoire complexity in normal individuals and bone marrow recipients analyzed by CDR3 size spectratyping. Correlation with immune status.

The analysis of the T cell repertoires involved in local or systemic immune responses is beginning to play an important role in many clinical situations. These include autoimmunity, response to viral or bacterial superantigens, alloimmunity including allograft rejection, and tumor immunity. Here we analyze circulating T cell repertoires by determining TCR beta-chain gene complexity using a modification of V beta family-specific PCR. This approach, called CDR3 size spectratyping, uses the size heterogeneity of the CDR3 as a further source of specificity in TCR analysis. It has been used here to analyze the complexity and stability of circulating T cell repertoires in normal adults, including bone marrow donors, and bone marrow transplant recipients. Normal spectratypes are both complex and stable. The repertoire complexity of marrow recipients correlates with their state of immune function. Contractions and gaps in repertoires are revealed in individuals suffering from recurrent infections associated with T cell impairment. Spectratype analysis is applicable to other studies of specific repertoire skewing such as may be associated with immunodeficiency or found at sites of immune activity.

Adult↗
PubMed1993

Transcriptional diversity at the duplicated human CD8 beta loci.

In order to understand the structural organization of the human CD8 beta locus, genomic clones containing CD8 beta sequences were isolated and analyzed. Physical linkage of these clones with the CD8 alpha locus using pulsed-field electrophoresis revealed a duplication of the CD8 beta locus. CD8B-1 lies 35 kb upstream from the CD8 alpha locus and contains eight exons, including four alternatively spliced cytoplasmic exons. The CD8B-2 gene contains six exons and is at present unlinked to CD8B-1. Analysis of sequences upstream to the leader exon of the CD8B-1 and CD8B-2 genes revealed a GC-rich promoter which lacks canonical "CCAAT" and "TATA" motifs, but which has sites for multiple transcriptional activators and three additional elements which are conserved in the murine CD8 beta promoter. Seven unique CD8 beta cDNA isoforms were isolated and characterized, which derive from alternative splicing of the transmembrane and/or cytoplasmic exons. Three cDNA are membrane spanning, while the remaining four isoforms lack a transmembrane region and are potentially secreted. These transcripts are differentially expressed in the thymus and in the periphery. Transfection experiments in murine fibroblasts confirmed that the membrane CD8 beta isoforms could be expressed as heterodimers with the CD8 alpha chain. The regulated expression of multiple CD8 beta cytoplasmic isoforms and their potential role in T lymphocyte signal transduction is discussed.

Alternative Splicing↗
PubMed1993

Human herpesvirus-6 (HHV-6) infection in allogeneic bone marrow transplant recipients: evidence of a marrow-suppressive role for HHV-6 in vivo.

Sixteen adults were studied for the first 100 days after allogeneic bone marrow transplant to assess the pathogenic role of human herpesvirus-6 (HHV-6) infection in patients with unexplained febrile illnesses. HHV-6 was directly isolated from the blood of 6 patients. Analysis of the clinical courses of these 16 patients revealed otherwise unexplained posttransplant marrow suppression in 5 patients. Idiopathic marrow suppression occurred more frequently in patients with concurrent HHV-6 viremia (4/6) than in those from whom HHV-6 was not isolated from peripheral blood (1/10, P < .05). An etiologic role for the virus was also supported by isolation of HHV-6 from the bone marrow of all 4 patients at the time of marrow suppression and by in vitro colony-forming unit (cfu) assays that demonstrated that HHV-6 could inhibit cfu-granulocyte-macrophage and burst-forming unit-erythroid growth from human bone marrow. By restriction enzyme mapping, all clinical isolates were type B, suggesting that bone marrow transplant recipients may be preferentially infected with and reactivate this HHV-6 subtype. This study implicates HHV-6 as a novel cause of bone marrow suppression in marrow transplant recipients.

Adult↗
PubMed1992

Heterogeneous immunophenotype of granular lymphocyte expansions: differential expression of the CD8 alpha and CD8 beta chains.

In this study, we have evaluated 14 large granular lymphocyte (LGL) expansions, 11 of which were CD8+. Analysis of the membrane expression of the alpha and beta chains of the CD8 antigen, using specific monoclonal antibodies (MoAbs), has shown that LGL expansions with the CD3+, CD4+, CD8+, CD57+ T-cell receptor (TcR) alpha beta phenotype bear the CD8 alpha/alpha isoform, while the CD3+, CD4-, CD8+, CD57+ TcR alpha beta samples were positive for both the CD8 alpha and CD8 beta chains. These data were confirmed also by messenger RNA analysis. One additional case, with a peculiar phenotype (CD3-, CD2-, CD4-, CD8+, CD57-) and a germline configuration of the TcR beta and gamma chain genes, expressed only the CD8 alpha chain. After additional phenotypic analysis with a wider panel of MoAbs, it was found that the beta chain of the interleukin-2 receptor was constitutively expressed on the majority of the samples tested, and that most of the monoclonal samples coexpressed CD45RA/R0 antigens. Using MoAbs directed against the variable regions of the TcR beta chain, we could show a preferential V beta region restriction in the CD8+ monoclonal cases. This more extensive characterization of CD8+ LGL expansions has further documented the marked heterogeneity within this rare condition and allowed a better phenotypic dissection between the monoclonal and polyclonal cases.

Adult↗
PubMed1992

T-cell-depleted allogeneic bone marrow transplantation in adults with acute nonlymphocytic leukemia in first remission.

We prospectively evaluated the efficacy of T-cell-depleted bone marrow transplantation (BMT) in adults with de novo acute nonlymphocytic leukemia (ANLL) in first complete remission (CR), with regard to relapse-free survival and incidence of graft-versus-host disease (GvHD). Thirty-one patients older than 16 years (range, 16.5 to 43.2) received T-cell-depleted grafts for this purpose from related HLA/MLC-compatible donors. Twelve of the patients were older than 30 years at the time of transplantation. Patients were prepared with hyperfractionated total body irradiation (HFTBI; 1,375 to 1,500 cGy) and high-dose cyclophosphamide (120 mg/kg). T cells were removed from the marrow grafts by a two-step soybean lectin agglutination and sheep red blood cell (sRBC)-rosette procedure, achieving a 2.5- to 3-log depletion of clonable T lymphocytes. No additional prophylaxis against GvHD was administered. The median age at transplantation was 28.8 years; the median interval from diagnosis to transplantation was 3.8 months, and from CR was 2.7 months. Seventy-four percent received consolidation after remission induction therapy. The product-limit estimate of disease-free survival (DFS) at 3 years is 45% (95% confidence interval [CI], 24% to 66%), and the cause-specific probability of relapse is 13%. The median follow-up of the survivors is 72 months (range, 34.5 to 95.6). Median time to achieve a sustained absolute neutrophil count of 500 or greater was 16 days, and to maintain an untransfused platelet count of 20,000 or greater was 20 days. Five patients suffered immune-mediated graft rejection. Three patients developed grade I to II acute GvHD limited to the skin, which resolved promptly with brief courses of systemic steroids. None of the patients has developed clinically apparent chronic GvHD or a secondary lymphoproliferative disorder, and no patient is receiving immunosuppressive therapy. T-cell-depleted BMT by the method reported here is a favorable option as postremission therapy for adults with de novo ANLL in first remission who have an HLA/MLC-compatible related donor, and it is not associated with an increased risk of relapse posttransplant.

Adolescent↗
PubMed1992

Cytotoxic and proliferative allospecific T-cell clones contain perforin and mediate anti-CD3-induced cytotoxicity.

Some in vitro-generated allospecific T-cell clones can kill target cells bearing specific antigen, whereas others can only proliferate in response to that antigen. The mechanism of target lysis by clones that exhibit antigen-specific cytotoxicity is thought to involve the exocytosis of lytic granules, which contain the pore-forming protein perforin. Here, CD4+, CD8+, and CD4-8- T-cell clones, positive for CD3 and the alpha/beta T-cell receptor, were tested for their ability to lyse the mouse-anti-human CD3 hybridoma OKT3; this hybridoma has been shown to trigger the cytolytic mechanism in cytotoxic T cells regardless of their clonal specificity. We found that all in vitro-generated allospecific T-cell clones can efficiently lyse the OKT3 targets whether or not they can kill alloantigen-bearing lymphoblastoid B-cell line targets. Furthermore, all tested clones contained perforin. The OKT3 hybridoma was not lysed by perforin-negative, CD3+ leukemic T-cell lines or by CD3- NK clones. Thus, the presence of perforin in T-cell clones correlated with their ability to lyse OKT3 targets, but not with their ability to lyse alloantigen-bearing targets. These results demonstrate that T-cell clones that are nonlytic when activated by specific antigen nevertheless contain a complete lytic mechanism and also support the proposed central role in perforin in that mechanism.

Animals↗
PubMed1992

Interferon-alpha, zidovudine, and granulocyte-macrophage colony-stimulating factor: a phase I AIDS Clinical Trials Group study in patients with Kaposi's sarcoma associated with AIDS.

PURPOSE: To increase the hematologic tolerance of interferon-alpha (IFN alpha) and zidovudine combination therapy by the addition of granulocyte-macrophage colony-stimulating factor (GM-CSF), and to evaluate the safety, tolerance, and potential efficacy of the combination in patients with Kaposi's sarcoma and AIDS. PATIENTS AND METHODS: Seventeen patients with Kaposi's sarcoma associated with AIDS received zidovudine 200 mg orally every 4 hours and GM-CSF 5 micrograms/kg/d subcutaneously. Successive cohorts received IFN-alpha 2b at a daily subcutaneous dose of 5, 10, or 20 million units. The dose of GM-CSF was titrated to maintain the neutrophil count between 1 and 5 x 10(9) cells/L. Doses of all three drugs were reduced, as required, for nonhematologic toxicities. RESULTS: GM-CSF induced leukocytosis in all patients. On average, a dose of 1.25 micrograms/kg/d was sufficient to maintain the neutrophil count within the desired range. The combination of 20 million units of IFN-alpha with zidovudine and GM-CSF induced dose-limiting toxicity in four of six patients. The major side effects were constitutional symptoms, which included malaise, anorexia, fatigue, fever, and were dose-limiting in three patients. Severe anemia and/or thrombocytopenia developed in three patients. Seven patients (41%; 95% confidence interval [CI], 18% to 64%) showed objective tumor regression that persisted for a median of 51 weeks. A rapid decrease in free-serum p24 antigen levels was observed in seven patients who had measurable levels at baseline; the mean time required to isolate human immunodeficiency virus (HIV-1) from peripheral-blood cells was increased by 7 days. The number and percentage of CD4-positive lymphocytes showed no significant change. CONCLUSIONS: GM-CSF prevents neutropenia induced by the IFN-alpha and zidovudine combination and induced no adverse effects on immune function or HIV activity. However, nonhematologic toxicity precluded a major increase in the maximum-tolerated doses of IFN-alpha and zidovudine.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Cord blood transplants: potential utility and potential limitations.

Cord blood has been utilized successfully for the hematopoietic reconstitution of children with lethal disorders of hematopoiesis, as an alternative to marrow derived stem cells. The majority of the transplants performed to date have utilized umbilical cord blood from HLA-identical siblings, however, much of the interest in this modality is due to its potential as a source of readily available unrelated stem cells. Cord blood offers intriguing theoretical advantages over the use of unrelated bone marrow, but additionally suffers from several limitations as well. This review is intended to highlight a number of these issues, rather than to serve as a detailed review of the clinical experience with cord blood transplantation to date.

Blood Transfusion↗
PubMed1991

Generation of anti-human CD8 beta-specific antibodies using transfectants expressing mixed-species CD8 heterodimers.

The CD8 glycoprotein is a lymphocyte differentiation antigen comprised of two distinct polypeptide chains, alpha and beta, which have the capacity to form homodimeric (CD8 alpha/alpha) or heterodimeric (CD8 alpha/beta) cell surface complexes. The majority of monoclonal antibodies which recognize the human CD8 antigen react with the CD8 alpha chain, while a single mAb, referred to as T8/2T8-5H7 (or 2ST8-5H7), has been identified which binds to the CD8 alpha/beta heterodimer. In order to generate antibodies specific for CD8 beta, murine fibroblast transfectants were constructed which express the human CD8 beta chain in combination with either the human CD8 alpha chain or the murine CD8 alpha homologue, the Lyt-2 molecule. These transfectants were used to raise polyclonal heteroantisera in mice. Transfectants expressing human CD8 alpha/beta heterodimers induced moderate anti-CD8 alpha titers, but were weakly effective in generating anti-CD8 beta titers, despite high level cell surface expression of this protein. In contrast, transfectants expressing mixed-species CD8 heterodimers (murine CD8 alpha and human CD8 beta) induced high anti-CD8 beta titers in immunized mice. Following fusion of splenocytes from mice immunized with mixed-species CD8 transfectants, the mAb 5F2 was isolated which specifically recognizes the human CD8 beta chain. Unlike T8/2T8-5H7, the mAb 5F2 can bind the CD8 beta chain irrespective of its pairing partner, and can immunoprecipitate the CD8 beta protein from cells transfected with the CD8 beta gene in the absence of the human or mouse CD8 alpha gene product. Anti-CD8 beta antibodies should help elucidate the extent of biochemical heterogeneity of the CD8 beta protein, and will also be useful in defining the role of the CD8 beta protein in thymocyte and lymphocyte development, recognition and activation.

Animals↗
PubMed1991

Relationship and prognostic value of endogenous interferon-alpha, beta 2-microglobulin, and neopterin serum levels in patients with Kaposi sarcoma and AIDS.

We investigated whether elevated serum levels of beta 2-microglobulin and neopterin were related to the abnormal in vivo production of interferon described in patients with human immunodeficiency virus (HIV) infection, and whether these factors might add to measurements of CD4+ T cells in predicting survival and tumor regression in patients with Kaposi sarcoma associated with AIDS. beta 2-Microglobulin and neopterin levels were strongly correlated (r = 0.82), and were each significantly higher in patients with detectable serum interferon-alpha activity. Inverse correlations were observed between prognosis and levels of these serum products. Prediction by CD4+ T-cell count of tumor regression after treatment with interferon-alpha and zidovudine was improved by each of two factors: (a) the presence or absence of endogenous interferon-alpha activity, and (b) a combined variable reflecting relative levels of the interferon-inducible products, beta 2-microglobulin and neopterin. The level of beta 2-microglobulin was the single best predictor of survival. When beta 2-microglobulin was not considered, the endogenous interferon-alpha variable was the best predictor of survival, and the prediction was enhanced by addition of the combined variable, or the neopterin value alone. We conclude that serologic markers, which directly or indirectly reflect activation of the endogenous interferon system, may be valuable adjuncts to CD4+ T-cell counts in assessing prognosis and selecting and evaluating treatments for patients with Kaposi sarcoma and AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1990

B-cell differentiation following autologous, conventional, or T-cell depleted bone marrow transplantation: a recapitulation of normal B-cell ontogeny.

The circulating lymphocytes of 88 consecutive patients following autologous, conventional, or T-cell depleted bone marrow transplantation were serially analyzed for B-cell surface antigen expression and function. In the majority of patients, except for those who developed chronic graft-versus-host disease, the number of circulating CD20+ B cell normalized by the fourth posttransplant month. The earliest detectable B cells normally expressed HLA-DR, CD19, surface immunoglobulin (slg), CD21, Leu-8, and lacked expression of CD10 (CALLA). In addition, the circulating B cells expressed CD1c, CD38, CD5, and CD23 for the first year following transplant, antigens that are normally expressed on a small percentage of circulating B cells in normal adults, but highly expressed on cord blood B cells. Similar to cord blood B cells, patient B cells isolated during the first year following transplant, proliferated normally to Staphylococcus aureus Cowan strain I (SAC), and produced IgM, but minimal or no IgG when stimulated with pokeweed mitogen and SAC, unlike normal adult B cells that produce both. The similar phenotype and function of posttransplant and cord blood B cells, and their similar rate of decline in patients and normal children adds further evidence to support the hypothesis that B-cell differentiation posttransplant is recapitulating normal B-cell ontogeny.

Adult↗
PubMed1990

Interferon-alpha with zidovudine: safety, tolerance, and clinical and virologic effects in patients with Kaposi sarcoma associated with the acquired immunodeficiency syndrome (AIDS)

OBJECTIVE: To evaluate safety, tolerance, and potential efficacy of interferon-alpha and zidovudine combination therapy in patients with Kaposi sarcoma and the acquired immunodeficiency syndrome (AIDS). DESIGN: Open, phase-I study with randomization between two preparations of interferon-alpha. SETTING: Outpatient clinic of a cancer research center. PATIENTS: Forty-three patients with Kaposi sarcoma associated with AIDS. INTERVENTIONS: Patients were treated with interferon-alpha, 4.5, 9, or 18 million U/d, and zidovudine, 100 or 200 mg orally every 4 hours. MEASUREMENTS AND MAIN RESULTS: Neutropenia was the major dose-limiting toxicity. Fatigue, liver enzyme elevation, anemia, and thrombocytopenia were dose-limiting in some patients. Maximum tolerated dosages for interferon-alpha 2a with zidovudine, respectively, were 4.5 million U/d with 200 mg every 4 hours or 18 million U/d with 100 mg every 4 hours. An interferon-alpha n1 [corrected] dosage of 9 million U/d with zidovudine dosages of either 100 or 200 mg every 4 hours induced dose-limiting toxicity in most patients. Of 37 evaluable patients, 17 (46%; 95% CI, 30% to 62%) showed complete or partial tumor regression. Antitumor effects occurred more frequently in patients with baseline CD4 counts above 200 x 10(6) cells/L (65%) than in patients with lower baseline counts (30%, P = 0.05). Effects on CD4 cells were related to both initial CD4 count and interferon dose. Increased skin test reactivity and decreased serum human immunodeficiency virus (HIV) p24 antigen and virus recovery from blood cells were seen. CONCLUSIONS: Combined therapy with interferon-alpha and zidovudine can be safely administered to patients with AIDS and Kaposi sarcoma. The observed effects on tumor growth, HIV replication, and immune function support further studies of the combination in patients at various stages of HIV infection.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Absence of interleukin 2 production in a severe combined immunodeficiency disease syndrome with T cells.

We have characterized a child with a severe combined immunodeficiency disease syndrome with increased numbers, but a normal distribution, of CD3+ T cells. This patient's immunological defect appears to be attributable to a selective deficiency in T cell production of IL-2, which may reflect a subtle abnormality in the IL-2 gene locus or a defect in a regulatory factor necessary for IL-2 transcription. The increased numbers of phenotypically normal T cells in this patient suggest that alternative pathways of T cell development exist in man or that IL-2 production intra- and extrathymically is controlled via distinct regulatory mechanisms.

Antigens, CD↗
PubMed1990

Both ongoing suppression and clonal elimination contribute to graft-host tolerance after transplantation of HLA mismatched T cell-depleted marrow for severe combined immunodeficiency.

Lymphocytes from children with severe combined immunodeficiency who had been immunologically reconstituted with haploidentical T cell-depleted bone marrow were analyzed with regard to their immunologic recognition of donor, host, or third party alloantigens. When compared with freshly isolated donor lymphocytes, the engrafted donor cells exhibited markedly reduced to absent responses toward host Ag in primary or secondary MLC and cell-mediated lympholysis assays. However, under limiting dilution conditions, cytotoxic responses to host Ag could be demonstrated, indicating that small numbers of host reactive cells were present, although down-regulated at high responder cell doses. These results are consistent with prior observations in limiting dilution cultures that indicate that cells with the potential to lyse autologous target cells exist in the peripheral blood of all normal individuals. The number of host reactive cells present in these patients is significantly less than that present in cells isolated directly from the marrow donors, and is also less than the number of autocytotoxic cells normally seen in peripheral blood. Together, these observations indicate that two mechanisms contribute to donor host tolerance in these patients. The majority of host reactive cells appear to have undergone clonal deletion or inactivation, whereas the small residual host-reactive population appears to be under ongoing immunoregulatory control.

Bone Marrow Transplantation↗