Human Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes home preferentially to and induce selective regressions of autologous EBV-induced B cell lymphoproliferations in xenografted C.B-17 scid/scid mice

C.B-17 scid/scid (severe combined immunodeficiency [SCID]) mice inoculated with peripheral blood lymphocytes from Epstein-Barr virus (EBV)-seropositive donors, or with EBV-transformed lymphoblastoid B cell lines (EBV-LCL), develop lethal human EBV+ B cell lymphoproliferative disorders (EBV-LPD) with characteristics similar to those arising in immunodeficient patients. Using this model, we examined the capacity of human effector cells to control human EBV-LPD. SCID mice received rabbit anti-asialo GM1 antiserum to abrogate endogenous natural killer-cell function. Preliminary experiments showed that adoptive transfer of peripheral blood mononuclear cells (PBMC), purified T cells, interleukin (IL) 2-activated PBMC or anti-CD3-activated T cells derived from EBV-seropositive donors did not result in improved survival of treated mice (in vivo effector/target ratio 2:1 to 1:1). In contrast, EBV-specific cytotoxic T lymphocytes (CTL), derived from EBV-seropositive donors and expanded in vitro, exhibited strong EBV-specific and HLA-restricted activity both in vitro and in vivo. SCID mice inoculated intraperitoneally with autologous but not with HLA-mismatched EBV-LCL had significantly improved survival relative to untreated mice after inoculation of EBV-specific CTL either intraperitoneally (P<0.001) or intravenously (P<0.001) (in vivo effector/target ratio 1:1). SCID mice bearing large subcutaneous EBV+ tumors and treated intravenously with 10(7) EBV-specific CTL achieved complete tumor regression. Both CTL- and CTL-plus-IL-2-treated mice survived significantly longer than untreated animals or animals treated with IL-2 alone (P = 0.0004 and P<0.02, respectively). SCID mice bearing two subcutaneous EBV+ tumors, one autologous and the other HLA mismatched to the EBV-specific CTL donor, had regression of only the autologous tumor after intravenous infusion of 10(7) EBV-specific CTL. Moreover, we could demonstrate preferential homing of PKH26-labeled EBV-specific CTL to autologous but not to HLA-mismatched EBV+ tumors as early as 24 h after intravenous adoptive transfer. Immunophenotypic analyses also demonstrated preferential infiltration of T cells into the autologous EBV+ tumor in SCID mice bearing both the autologous and either fully HLA-mismatched or genotypically related haplotype-sharing EBV+ tumors. The human T cells infiltrating EBV+ tumors were CD3+ and, predominantly, CD8+CD4-. Our results indicate that EBV-specific CTL preferentially localize to and infiltrate EBV+ tumors bearing the appropriate HLA antigens and thereafter induce targeted regressions of disease.

Administration of rabbit anti-asialo GM1 antiserum facilitates the development of human Epstein-Barr virus-induced lymphoproliferations in xenografted C.B-17 scid/scid mice

Mice with severe combined immune deficiency (C.B-17 scid/scid [SCID mice]) lack functional B and T lymphocytes and are permissive for the growth of human xenografts. However, the development of functional NK cells is not affected by the scid mutation. Mouse NK cells express the surface glycolipid asialo GM1 and are implicated in the rejection of heterotransplanted cells. In the present study, we demonstrate that SCID mice treated with rabbit anti-asialo GM anti-serum (alpha-asialo GM1), for in vivo depletion of endogenous NK cell function, develop lethal Epstein-Barr virus (EBV)-induced lymphoproliferative disorders (EBV-LPD) at lower doses od inoculated EBV-transformed lymphoblastoid B cell lines (EBV-LCL) than untreated animals. Furthermore, at any given dose of EBV-LCL inoculated, EBV-LPD developed earlier and induced lethality sooner in alpha-asialo GM1-treated animals. We also demonstrate that SCID mice treated with alpha-asialo GM1 have reduction in the number of asialo GM1-expressing splenocytes. Moreover, splenic cell suspensions derived from alpha-asialo GM1-treated SCID mice show lower cytotoxicity against the mouse NK-sensitive cell line YAC-1 and human EBV-LCL than splenocytes obtained from untreated SCID mice.

Multiple minor histocompatibility antigen-specific cytotoxic T lymphocyte clones can be generated during graft rejection after HLA-identical bone marrow transplantation

Graft rejection after T cell-depleted HLA-genotypically identical bone marrow transplantation (BMT) is probably mediated by mH antigen-specific cytotoxic T lymphocytes (CTL). We have analyzed peripheral blood mononuclear cells (PBMC) from a female bone marrow graft recipient, collected during graft rejection after a sex mismatched HLA-identical BMT. A CTL line was generated by stimulating recipient PBMC collected during graft rejection with donor PBMC and donor EBV-transformed lymphoblastoid cell lines. From this CTL line a large number of clones of different specificity and phenotype was established by limiting dilution. These clones exhibited several mH antigen specificities, restricted by HLA-B7, -B27 or -DR2 as shown by differential recognition of family members and unrelated individuals sharing potential restriction elements. The CD3+CD4+ and CD3+CD8+ bulk culture was cloned, resulting in 50 HLA-B7 restricted CD3+CD4-CD8+CTL clones, three HLA-B27 restricted CD3+CD4-CD8+CTL clones, one HLA-DR2 restricted CD3+CD4+CD8-CTL clone and two additional HLA class II restricted CD3+CD4+CD8-CTL clones with a different specificity. One representative clone of each specificity was selected for further analysis. The CTL line and the HLA-B7 restricted CD8+CTL clone, but not the HLA class II restricted CD4+ CTL clone, inhibited the growth of donor hematopoietic progenitor cells (HPC). In conclusion, these results show that graft rejection after HLA-identical BMT may be mediated by multiple CTL clones that specifically recognize one mH antigen peptide presented by different HLA molecules or different mH antigens expressed on donor cells and that CTL, but not CD4+ CTL inhibited donor HPC growth.

Selective treatment of SCID mice bearing methotrexate-transport-resistant human acute lymphoblastic leukemia tumors with trimetrexate and leucovorin protection

Impaired transport of methotrexate (MTX) is a common resistance mechanism of tumor cells to this drug. Trimetrexate (TMTX), a second-generation folate antagonist, is still active against MTX-transport-resistant cells because it enters cells by passive diffusion and does not use the reduced folate transport system for cell entry. Therefore, although leucovorin (LV) protects MTX-sensitive cells from TMTX toxicity, MTX-transport defective cells are poorly rescued by LV. Severe combined immunodeficiency mice bearing MTX-transport-resistant CCRF-CEM acute lymphoblastic leukemia tumors were treated with TMTX alone or with the combination of TMTX and LV, with tumor regressions in both groups (P < .001) and without significant toxicity. These results indicate that TMTX with LV protection may be a useful therapeutic regimen for patients with MTX-transport-defective acute lymphoblastic leukemia. Furthermore, resistance to TMTX plus LV may result in reversion to MTX sensitivity.

Adoptive immunotherapy using donor leukocytes following bone marrow transplantation for chronic myeloid leukemia: is T cell dose important in determining biological response?

We investigated the use of donor leukocytes for the treatment of Epstein-Barr virus (EBV) lymphoproliferative disease following T cell-depleted bone marrow transplantation (BMT) for chronic myeloid leukemia (CML). We wanted to determine whether donor leukocyte treatment would result in altered biological responses with respect to anti-EBV lymphoma activity, donor-host chimerism and graft-versus-leukemia (GVL) responses. Three patients with CML in cytogenetic remission received < 10(6)/kg donor leukocytes for treatment of EBV lymphoproliferative disease. Lineage specific chimerism and residual leukemia detection were assessed using sensitive PCR methodologies. Following donor leukocyte treatment 1 patient had no recurrence and the other 2 had responsive EBV lymphoma. The 2 patients who were mixed T cell chimeras before treatment, remained so after treatment. Two were BCR-ABL positive by PCR before and after treatment and both developed hematologic relapse. None of the 3 patients developed acute graft-versus-host disease (GVHD) with 1 patient developing limited chronic GVHD. These data suggest that small numbers of donor T cells can eradicate EBV lymphoproliferative disease but may not alter donor-host chimerism or mediate GVL responses.

Enrichment of peripheral blood stem cells in a primate model following administration of a single dose of rh-IL-1 beta

In a pre-clinical primate model, the effect of a single intravenous injection of rh-GM-CSF (50 micrograms/kg), rh-IL3 (20 micrograms/kg), rh-IL-1 beta (1 micrograms/kg), rh-G-CSF (50 micrograms/kg) and rh-pIXY 321 (50 micrograms/kg) on peripheral blood mononuclear cell and hematopoietic stem cell concentration was determined. The results indicated that administration of a single dose of rh-IL-1 beta increased the concentrations of hematopoietic stem cells, including CFU-GM progenitors and precursors to CFU-GM. No toxicity was noted with this procedure. None of the remaining cytokines tested caused a significant increase in the peripheral blood hematopoietic stem cell concentration when administered in this manner and only G-CSF caused an increase in peripheral blood mononuclear cell concentrations. Autologous transplantation with limiting numbers of peripheral blood mononuclear cells (1 x 10(7) cells/kg) collected either 24 or 72 h following injection of 1 microgram/kg rh-IL-1 beta conferred a survival advantage to recipients compared with controls. These results imply that a single intravenous administration of rh-IL-1 beta may increase the concentration of peripheral blood stem cells to levels sufficient for transplantation.

Granulocyte colony-stimulating factor (CSF) but not interleukin-1 (IL-1), IL-3, and granulocyte-macrophage CSF protect bone marrow progenitor cells from suppression by allosensitized cytotoxic T cells

The major immunological reactions after an allogeneic bone marrow transplantation (BMT) are graft rejection and graft-versus-host disease (GVHD). GVHD can be prevented by T-cell depletion of the allogeneic BM graft, but the beneficial effect of T-cell depletion on the incidence of GVHD is counterbalanced by a higher incidence of graft failure. One option for the prevention of graft rejection after T-cell-depleted BM grafts is the administration of cytokines. Before applying cytokines after an allogeneic BMT, we considered it desirable to learn whether cytokines would alter the susceptibility of donor BM cells to host T cells. An in vitro assay was developed to investigate the role of the cytokines interleukin-1 (IL-1), IL-3, granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage CSF (GM-CSF) on the interaction between allosensitized, cytotoxic-T cells (CTLs) and T-cell-depleted BM cells. CTLs primed against the BM donor suppressed the formation of colonies consisting of granulocytes and macrophages (colony-forming unit GM). Colony formation was not inhibited by CTLs sensitized against a third party. Accordingly, the number of colonies scored in cocultures with CTLs sensitized to third party antigens were designated as 0% inhibition. A 66% inhibition of colony formation was observed for untreated BM cells at an effector:target (E:T) ratio of 1:1. Pretreatment of the BM cells with the cytokines G-CSF, GM-CSF, IL-1, and IL-3 resulted in a 38% (P = .001), 53%, 66%, and 68% inhibition of colony formation, respectively, at E:T ratios of 1:1. G-CSF reduced the susceptibility of BM cells over a range from 4:1 to 1:16 (E:T ratios). GM-CSF had only significant influence at the lower E:T ratios (1:4 and 1:16). These in vitro data indicate that G-CSF could protect BM cells from killing by allosensitized CTLs and suggest that administration of these cytokines might potentially reduce the susceptibility of T-cell-depleted allogeneic BM grafts to host T-cell-mediated rejection.

ICAM-1 (CD54) expression on B lymphocytes is associated with their costimulatory function and can be increased by coactivation with IL-1 and IL-7

Recent studies have demonstrated that acute lymphoblastic leukemia-derived pre-B cell lines are deficient in their costimulatory function for T cell proliferation in response to the mitogen Con A and the superantigens TSST-1 and SEB. Stimulation of these pre-B cells with IL-7 increased their costimulatory function which involved the B7/CD28 pathway. In the present study, we stimulated T cells with Con A, TSST-1, and SEB in the presence of peripheral blood B lineage cells that do not constitutively express B7/BB1 on their surface and investigated whether their costimulatory function could also be enhanced by IL-7. We found that, in the presence of IL-1, stimulation with IL-7 increased the costimulatory function of B cells and their surface expression level of ICAM-1 (CD54). We then investigated whether costimulatory B cell function could be inhibited by blocking the ICAM-1/LFA-1 pathway. Addition of anti-ICAM-1 mAb to the coculture of T and B cells inhibited T cell proliferation by approximately 20%. In contrast, addition of anti-LFA-1 beta (CD18) mAb, directed against the T cell ligand of ICAM-1, inhibited T cell proliferation almost completely. To determine the role of ICAM-1 in costimulatory B cell function, we sorted B cells into ICAM-1low-and ICAM-1high-expressing populations. We found that B cells expressing high levels of surface ICAM-1 elicited significantly higher T cell responses than those with low levels, suggesting that the expression level of ICAM-1 on peripheral blood B cells correlates with their costimulatory function.

Minimal residual disease is more common in patients who have mixed T-cell chimerism after bone marrow transplantation for chronic myelogenous leukemia

Determining both lymphoid chimerism and the presence of minimal residual disease after allogeneic bone marrow transplantation (BMT) for chronic myelogenous leukemia (CML) could be helpful to the understanding of the biology of leukemic relapse in this disease. We prospectively investigated 32 patients with CML post-BMT by assessing T-cell chimerism and minimal residual disease using sensitive polymerase chain reaction (PCR) methodologies. Patients were studied between 1 and 24 months post-BMT. Thirty patients received a T-cell-depleted marrow grafts and 2 received unmanipulated marrow. All but 1 patient were conditioned with total body irradiation (TBI)+thiotepa+cyclophosphamide (Cy). The other patient received TBI+Cy as conditioning. The T cells were exclusively of donor origin in 12 of 16 patients who were tested at 1 month post-BMT, but were mixed chimeric in 11 of these patients by > or = 3 months. Once mixed T-cell chimerism was documented, no patient returned to having all donor T-cells. At a median follow-up of 12 months, minimal residual disease was present in 18 of 22 patients with mixed T-cell chimerism and in 3 of 10 patients with full donor chimerism. The actuarial molecular relapse rate at 24 months for the two groups is 91% and 33%, respectively (P < .02). The finding of BCR-ABL mRNA within the first 6 months of transplant or on two consecutive assays was highly predictive of subsequent cytogenetic or hematologic relapse (P = .032 and P < .02, respectively). Ten patients, 9 with mixed T-cell chimerism, have relapsed (4 clinical, 6 cytogenetic) at a median of 12 months post-BMT. These data suggest that mixed T-cell chimerism may be a marker for abrogation of graft-versus-leukemia activity that is thought to be pivotal in eradicating minimal residual disease after BMT for CML.

Bone marrow transplantation for thalassemia. The USA experience

PURPOSE

We have reviewed the results of bone marrow transplantation in 30 patients with thalassemia major who were treated in the United States.

PATIENTS AND METHODS

Ten patients who underwent transplantation in Seattle and 20 patients from five other U.S. centers were identified through a survey of the International Bone Marrow Transplant Registry. These transplants were performed between November 1981 and April 1992 in patients with diverse ethnic backgrounds and ranged in age from 6 months to 14 years (median 4.0 years). Twenty-seven of the 30 patients received marrow from a human leukocyte antigen (HLA)-identical sibling or other family member, one patient received HLA-matched marrow from an unrelated donor, and two patients were given haploidentical but HLA-mismatched marrow from a related donor. Cytoreductive (preparative) therapy varied among institutions and pretransplant risk categories. In general, patients were given busulfan (12-24 mg/kg) or dimethylmyleran (5 mg/kg) in combination with cyclophosphamide (120-240 mg/kg). A subset of patients were given total body irradiation (TBI) at a dose of 720 cGy followed by cyclophosphamide (120 mg/kg).

RESULTS

Sixteen of 27 patients (59%) who received marrow from an HLA-identical family member are event-free survivors, with a duration of follow-up ranging from 2 months to > 10 years after transplantation. Six of these 27 patients (22%) had recurrence of thalassemia and five (19%) died. The estimated actuarial rate of thalassemia recurrence was 24% and the rate of event-free survival was 57%. Only one of the three patients who received marrow from HLA-nonidentical or unrelated donors survives event-free. Liver biopsies were not routinely performed before transplant. Thus, classification of patients into Lucarelli risk groups was not possible. A modified risk classification was devised by using liver size and iron status assessed by the regularity of chelation and the serum ferritin level. With use of this classification, there was no significant difference in event-free survival between transplant risk groups.

CONCLUSIONS

The findings observed in this small series of patients confirms that thalassemia can be cured with bone marrow transplantation. Although most patients are event-free survivors, a significant number experienced recurrence of their disease. A cooperative multicenter trial of U.S. transplant centers may be necessary to evaluate the use of marrow transplantation for thalassemia and to determine optimal treatment.

IL-7 induces surface expression of B7/BB1 on pre-B cells and an associated increase in their costimulatory effects on T cell proliferation

Treatment with IL-7 of NALM-6 pre-B cells, but not of EBV-LCL, Daudi, HeLa, or K562 cells resulted in enhanced costimulatory activity for TSST-1-induced T cell proliferation. The effect of IL-7 on the costimulatory function of NALM-6 cells was dose-dependent, could be inhibited by a neutralizing anti-IL-7 mAb, and resulted in the need of less costimulatory cells, or less superantigen, to obtain proper T cell proliferation. Addition of anti-IL-7 mAb to the coculture of superantigen-stimulated T cells with IL-7-pretreated NALM-6 cells did not alter the T cell responses obtained without addition of this antibody. These findings suggest that a possible costimulation of T cells by surface-bound IL-7 on pretreated NALM-6 cells did not contribute to the enhanced costimulatory function observed. Rather, these studies implicate IL-7-induced alterations of the NALM-6 cells themselves as the basis for the enhanced costimulatory activity observed. The most remarkable phenotypic differences between efficient costimulatory B lineage cells and deficient pre-B cells are a lower expression of ICAM-1 (CD54) and a lack of expression of the costimulatory B cell activation antigen B7/BB1. Upon activation with IL-7, the expression of ICAM-1 was increased, and the expression of B7/BB1 antigens was induced. The increased T cell responses in the presence of IL-7-treated NALM-6 cells could be inhibited by addition of anti-BB1 mAb. These results suggest that B7/BB1-negative pre-B cells may acquire the surface expression of B7/BB1 upon stimulation with IL-7, a process which is associated with increased costimulatory function for T cell proliferation.

Dyshematopoiesis in combined immune deficiency with congenital neutropenia

This report describes a patient with combined immune deficiency associated with congenital neutropenia (CID/CN) and reports a partial characterization of his hematopoietic abnormalities. The CID/CN syndrome described is characterized by neutropenia and by deficiencies in B-lymphoid and T-lymphoid cell number and function. Red cell and platelet counts were normal. In vitro assays indicate that the myeloid lineage was developmentally arrested at the level of the committed monocyte/granulocyte progenitor (CFU-GM), while precursors to the CFU-GM progenitor were normal. In vitro studies showed that the defect in myeloid development was not corrected with G-CSF or GM-CSF. However, combinations of cytokines present in conditioned media from the T-cell lines MO or C5MJ, or defined multiple cytokine combinations containing IL-1, IL-3, GM-CSF, kit ligand, IL-6, and IL-9, restored myelopoiesis in-vitro. In contrast, C5MJ-conditioned media did not correct deficiencies in immune function in the patient's lymphocytes and accessory cells. No abnormalities in the production of G-CSF, GM-CSF, M-CSF, or IL-1 from the patient could be identified to account for the defects in myelopoiesis orimmune function.

Treatment of Diamond-Blackfan anemia with recombinant human interleukin-3

This report describes the response of eighteen Diamond-Blackfan anemia (DBA) patients to recombinant human interleukin-3 (rhIL-3). rhIL-3 was administered subcutaneously once daily on an escalating dose schedule (0.5 to 10 micrograms/kg/d). The rhIL-3 dose was escalated every 21 days until erythroid response was attained, grade III or IV nonhematologic toxicity was observed, or the maximum rhIL-3 dose was reached. Four patients experienced clinically significant erythroid responses. Two of the responders were steroid-dependent and transfusion-independent, while two were steroid-independent and transfusion-dependent. Baseline clinical or laboratory parameters, in particular in vitro bone marrow erythroid progenitor assays, were not useful in predicting rhIL-3 response. rhIL-3 administered at 5 to 10 micrograms/kg/d was associated with an increase in total white blood cell count, secondary to increases in neutrophils, eosinophils, and lymphocytes. Patients experienced a dose-dependent elevation in absolute eosinophils across the entire dose range. Two of the responding patients remain on maintenance rhIL-3, without diminution of effect at 244 and 370 + days. rhIL-3 was discontinued in the other two responders, because of the development of deep venous thrombi.

Transfer of the ADA gene into bone marrow cells and peripheral blood lymphocytes for the treatment of patients affected by ADA-deficient SCID

Severe combined immunodeficiency (SCID) caused by deficiency of the enzyme adenosine deaminase (ADA) is the first genetic disorder considered for human somatic cell gene therapy. ADA-SCID patients can be cured by HLA-matched sibling donor bone marrow transplantation. Alternative transplantation strategies as well as enzyme replacement are being tested in those patients who do not have a suitable matched sibling donor. Some ADA-SCID patients may not be candidates for cytoablation due to infectious damage to the lung or liver, or may have a milder phenotype that does not justify the risks associated with haploidentical bone marrow transplantation. Replacement therapy with PEG-ADA has resulted in improvement in growth, a variable increase in the number of peripheral blood lymphocytes, and a decrease in the incidence of severe infections. Another approach to the treatment of severe genetic diseases is now represented by somatic cell gene therapy. We and others have conducted experiments in vitro and in vivo that have documented that T-lymphocytes are suitable vehicles for gene transfer. Although the pluripotent stem cell remains the ideal target cell for somatic cell gene therapy of disorders of the hematopoietic system, the use of T-lymphocytes as gene therapy vehicles is specifically indicated for ADA-deficient patients where they represent the affected cells. Furthermore, the selective engraftment of T-cells only, following bone marrow transplantation, has resulted in reconstitution of cellular and humoral immunity. A model for the functional analysis in vivo of the human immune system has been utilized for the preclinical evaluation of this approach.(ABSTRACT TRUNCATED AT 250 WORDS)

Successful treatment of Diamond-Blackfan anemia with interleukin 3

This report describes the response of 18 Diamond-Blackfan anemia (DBA) patients to recombinant human interleukin 3 (rhIL-3). rhIL-3 was administered s.c. once daily on an escalating dose schedule (0.5-10 micrograms/kg/day). The rhIL-3 dose was escalated every 21 days until erythroid response was attained, grade III or IV nonhematologic toxicity was observed, or the maximal rhIL-3 dose was reached. Four patients experienced clinically significant erythroid responses. Two of the responders were steroid-dependent and transfusion-independent, while two were steroid-independent and transfusion-dependent. Baseline clinical or laboratory parameters, in particular in vitro bone marrow erythroid progenitor assays, were not useful in predicting rhIL-3 response. Two of the responding patients remain on maintenance rhIL-3 without diminution of effect at 490 and 855+ days. rhIL-3 was discontinued in the other two responders because of the development of deep venous thrombi.

Dissection of the function of HLA class II and costimulation in B cell-mediated and toxic shock syndrome toxin-1-induced T cell proliferation

In this study we have demonstrated that costimulation for TSST-1-induced T cell proliferation is provided by HLA class II negative accessory B cells. In addition, TSST-1 binding to these HLA class II negative accessory B cells could not be detected by immunocytofluorescence, or in a system in which T cell proliferation depended on TSST-1 pretreated HLA class II negative B cells. These findings suggest that accessory signals can be supplied by B cells that are not involved in the activation of T cells via Ag-HLA/TCR-CD3 complex interaction: TCR ligation by a TSST-1/HLA complex and costimulation need not be delivered by the same cell. In the presence of HLA class II negative B cells, T cell proliferation in response to TSST-1 could be achieved despite addition of a mAb that can block HLA class II binding sites for TSST-1. These findings suggest the possibility that TSST-1 may directly ligate TCR. In the presence of anti-BB1-treated HLA class II negative accessory cells, TSST-1-induced T cell proliferation was inhibited by over 50% indicating the involvement of the BB1/CD28 pathway. The leukemic pre-B cell lines NALM-6, and BLIN-1, both of which express surface HLA class II Ag, but not the costimulatory B cell activation Ag BB1, were deficient in their accessory function for T cell proliferation in response to the superantigen TSST-1 and the mitogen Con A.

Dissection of the function of HLA class II and costimulation in B cell-mediated and toxic shock syndrome toxin-1-induced T cell proliferation

In this study we have demonstrated that costimulation for TSST-1-induced T cell proliferation is provided by HLA class II negative accessory B cells. In addition, TSST-1 binding to these HLA class II negative accessory B cells could not be detected by immunocytofluorescence, or in a system in which T cell proliferation depended on TSST-1 pretreated HLA class II negative B cells. These findings suggest that accessory signals can be supplied by B cells that are not involved in the activation of T cells via Ag-HLA/TCR-CD3 complex interaction: TCR ligation by a TSST-1/HLA complex and costimulation need not be delivered by the same cell. In the presence of HLA class II negative B cells, T cell proliferation in response to TSST-1 could be achieved despite addition of a mAb that can block HLA class II binding sites for TSST-1. These findings suggest the possibility that TSST-1 may directly ligate TCR. In the presence of anti-BB1-treated HLA class II negative accessory cells, TSST-1-induced T cell proliferation was inhibited by over 50% indicating the involvement of the BB1/CD28 pathway. The leukemic pre-B cell lines NALM-6, and BLIN-1, both of which express surface HLA class II Ag, but not the costimulatory B cell activation Ag BB1, were deficient in their accessory function for T cell proliferation in response to the superantigen TSST-1 and the mitogen Con A.

Effect of stem cell factor on in vitro erythropoiesis in patients with bone marrow failure syndromes

Stem cell factor (SCF) enhances normal hematopoiesis. We examined its effect in vitro on bone marrow and blood progenitors from patients with inherited bone marrow failure syndromes, including 17 patients each with Diamond-Blackfan anemia (DBA) and Fanconi's anemia (FA), 3 with dyskeratosis congenita (DC), and 1 each with amegakaryocytic thrombocytopenia (amega) and transient erythroblastopenia of childhood (TEC). Mononuclear cells were cultured with erythropoietin (Ep) alone or combined with SCF or other factors. SCF increased the growth of erythroid progenitors in cultures from 50% of normal controls, 90% of DBA, 70% of FA, 30% of DC, and the amega and TEC patients; normal numbers were reached in 25% of DBA studies. Improved in vitro erythropoiesis with SCF in all types of inherited marrow failure syndromes does not suggest a common defect involving kit or SCF, but implies that SCF may be helpful in the treatment of hematopoietic defects of varied etiologies.

Myeloid and lymphoid chimerism after T-cell-depleted bone marrow transplantation: evaluation of conditioning regimens using the polymerase chain reaction to amplify human minisatellite regions of genomic DNA

Determining both myeloid and lymphoid chimerism after T-cell-depleted allogeneic bone marrow transplantation (BMT) could be helpful in the understanding of the biology of engraftment and could provide a rational method of assessing the ability of different conditioning regimens to promote engraftment. We prospectively investigated the role of different pretransplant conditioning regimens in 29 leukemic patients post-BMT by assessing myeloid and T-cell chimerism using a rapid and sensitive polymerase chain reaction (PCR) method. Minisatellites are hypervariable regions of DNA consisting of tandem repeats of a core nucleotide sequence, and allelic polymorphism results from differences in the number of the repeats. We used this variation to distinguish between donor and recipient cells post-BMT. Seventeen patients (9 sibling and 8 unrelated donors) received conditioning with hyperfractionated total body irradiation (TBI), thiotepa, and cyclophosphamide (Cy). Of the other 12 patients (all sibling donors), 11 received TBI plus Cy plus another agent: VP16, carboplatinum, or AZQ. One patient received TBI plus thiotepa plus VP16. All but one of the patients studied received marrow from HLA-identical donors. PCR analysis confirmed donor lymphoid engraftment within 8 days of transplant in six of six patients studied. All granulocyte DNA was of donor origin within the first 4 weeks of transplant, regardless of the conditioning regimen. The day +28 T cells were exclusively of donor origin in 14 of 17 patients who received TBI plus thiotepa plus Cy, but were mixed chimeric in 10 of 12 patients who received other conditioning regimens (P < .001). Early graft rejection was seen in one unrelated transplant recipient conditioned with TBI plus thiotepa plus Cy. Late graft failure was observed in 3 of 12 patients with mixed T-cell chimerism and in none of 16 patients with full donor chimerism at day +28. However, 5 of 16 patients who had complete T-cell chimerism at day +28 developed acute graft-versus-host disease (GVHD), whereas no patient with mixed chimerism had acute GVHD. Our results indicate that minisatellite PCR is a rapid and sensitive method for assessing chimerism post-BMT, that the donor T cells are important for consistent durable engraftment, and that TBI plus thiotepa plus Cy may be superior to the other regimens studied in inducing full donor chimerism. Larger numbers and longer follow-up are necessary to confirm these data and also to assess the relationship between complete donor T-cell chimerism and leukemia-free survival.

Marrow transplantation for thrombocytopenia-absent radii syndrome

A two-year-old girl with thrombocytopenia-absent radii syndrome underwent transplantation of allogeneic bone marrow from her histocompatible sibling to correct her persistently low platelet count. Six years after transplantation, she has durable engraftment of allogeneic marrow and a normal platelet count that will allow her to undergo necessary corrective orthopedic procedures.

Clonal analysis of myelodysplastic syndrome: monosomy 7 is expressed in the myeloid lineage, but not in the lymphoid lineage as detected by fluorescent in situ hybridization

Conflicting results have been published on whether or not myelodysplastic syndromes (MDS) affect all cell lineages. Involvement of myeloid and erythroid cell lineages has been regularly observed, but it remains controversial whether the different lymphoid cell lineages are involved. In this study of eight patients with MDS associated with monosomy 7, fluorescent in situ hybridization (FISH) was used to enumerate the chromosomes 7 in interphase cells. With the probe D7Z1, the rate of false-positive detection of monosomy 7 was 3% +/- 2% in normal cells. T- and B-cell lines were established from eight patients with MDS and monosomy 7. As determined by FISH in interphase cells, 1.9% (0% to 3%) of the cells in the B-cell lines showed one fluorescent spot and 1.1% (0% to 2.9%) of the cells in the T-cell lines. These values do not differ from normal values. However, the possibility that normal cells were selected when the T- and B-cell lines were established could not be excluded. Therefore, peripheral blood cells were obtained, separated according to surface markers specific for lymphoid and myeloid cell lineage with a cell sorter, and analyzed for the expression of monosomy 7 by FISH. Antibodies recognizing T cells (CD3), B cells (CD20), natural killer (NK) cells (CD57), monocytes and granulocytes (low and high expression of CD11b antigen), and myeloid progenitors (CD33) were used to separate cells. The expression of monosomy 7 in the T cells, NK cells, and B cells did not differ from control values. These results in the lymphoid subpopulations are in stark contrast with the observations in the myeloid populations; the percentage of cells with monosomy 7 ranged from 9% to 78% (controls: 6% +/- 2%) in cells with low CD11b expression, 20% to 89% in cells with a high expression of the CD11b antigen (controls: 7% +/- 3%), and 23% to 91% in the CD33 positive cells (controls: 5% +/- 3%). The results of this study suggest that monosomy 7 does not usually affect lymphoid subpopulations but is restricted to committed progenitor cells with the capacity to differentiate into mature myeloid cells.

Marrow transplantation from human leukocyte antigen-identical or haploidentical donors for correction of Wiskott-Aldrich syndrome

Since 1979, a total of 17 patients with Wiskott-Aldrich syndrome have undergone allogeneic bone marrow transplantation at Memorial Sloan-Kettering Cancer Center. Eleven patients received marrow from either human leukocyte antigen (HLA) genotypically identical siblings (nine patients) or an HLA phenotypically identical parent (two patients). Six patients received marrow grafts from HLA-disparate parents. Cytoreduction was accomplished with busulfan and cyclophosphamide for the HLA-identical recipients and total-body irradiation followed by high-dose cytarabine therapy in the mismatched recipients. All 11 recipients of HLA-identical marrow had successful grafts, and 10 of 11 are alive and well 28 to 145 months after transplantation. One patient died 10 months after transplantation of chronic graft-versus-host disease and interstitial pneumonitis caused by cytomegalovirus. Only one of the six mismatched graft recipients survives, 52+ months after transplantation; the other patients have died of extensive chronic graft-versus-host disease (one patient), lymphoma (three patients), or progressive pancytopenia accompanying Candida sepsis (one patient). Thus bone marrow transplantation represents the treatment of choice in patients with Wiskott-Aldrich syndrome who have an HLA-identical donor. However, our approach for patients lacking a histocompatible family donor requires modifications to overcome allogeneic resistance and decrease the posttransplantation immunoincompetence in these patients.

High-dose melphalan with 6-hydroxydopamine-purged autologous bone marrow transplantation for poor-risk neuroblastoma

Long-term results are presented of 28 patients who were diagnosed with neuroblastoma at more than 12 months of age and who received melphalan 180 mg/m2 (n = 6) or 240 mg/m2 (n = 22) to consolidate remissions of Stage IV disease or to control refractory disease. Twenty-four patients also received dianhydrogalactitol 180 to 240 mg/m2, and 11 received total body irradiation 450 to 600 cGy. Autologous bone marrow transplantation (ABMT) was performed with marrow that was unpurged (n = 2) or purged ex vivo (n = 26) with 6-hydroxydopamine (6-OHDA) 20 micrograms/ml plus ascorbate 200 micrograms/ml. The median time to an absolute neutrophil count of 500/microliters was 21 days and to self-sustaining platelet counts more than 20,000/microliters, 28 days. One patient required infusion of unpurged reserve marrow. Two groups of patients underwent ABMT: (1) 17 patients (Group I) who were in first remission a median of 7 months after diagnosis; and (2) 11 patients (Group II) who had refractory disease or were in second remission. For Group I, event-free survival was 29% at 12 months and 6% at 24 months post-ABMT. All Group II patients died of disease or ABMT-related toxicity. Overall, of the 28 patients, one is a long-term relapse-free survivor; five died of ABMT-related toxicity; ten patients with tumors present at ABMT had progressive disease within 6 months of ABMT; and 12 patients with no measurable disease at ABMT relapsed 4 to 32 months (median, 12) post-ABMT. Among the latter, six relapses involved the primary site, and six were restricted to distant sites. These results--in accord with the long-term outcome in other series--suggest that for neuroblastoma high-dose melphalan cannot be relied on to ablate residual disease or to salvage patients with refractory tumors. In addition, the pattern of relapse in several patients could be explained by infusion of incompletely purged autografts; this would support recent laboratory evidence that 6-OHDA/ascorbate is a suboptimal purging method.