Selective depletion of alloreactive donor T cells leads to elimination of graft-versus-host reactivity and stimulates graft-versus-leukaemia/myeloma effect.

Graft-versus-host disease is a severe complication of allogeneic stem cell transplantation. The major role is played by alloreactive donor T-cell clones leading to host tissue damage. Selective depletion is a strategy to eliminate host-reactive donor T cells from haematopoietic stem cell allografts to prevent graft-versus-host disease while conserving useful donor immune functions. We have used irradiated peripheral blood mononuclear cells from cancer patients and healthy donor cells as responder cells in primary mixed leukocyte reaction. To prepare graft-versus leukaemia/myeloma-specific T cells, alloreactive T cells in primary mixed leukocyte reaction were depleted with anti-CD25 immunotoxin. The remaining T cells had insignificant alloreactivity in secondary mixed leukocyte reaction. Then, allodepleted donor T cells were repeatedly stimulated using purified leukaemia/tumour cells from the same cancer patient. Leukaemia/tumour-reactive donor T cells were purified using cell sorter on the basis of CD4 and CD8 activation. Their specificity was tested in nonradioactive cytotoxicity test. We performed 22 reactions (15 samples with leukemic and 7 samples with multiple myeloma cells). Selective depletion of alloreactive donor T cells with anti-CD25 immunotoxin led to significant depletion (99.2-100 %, median 99.7%). The effect of donor T cells was well preserved, while the graft-versus-host reactivation of donor cells was negligible, even after repeated stimulation with patient's non-tumour cells. Thus, it is possible to selectively deplete donor alloreactive T cells with anti-CD25 immunotoxin. In the cases of leukaemia patients, a strong graft-versus-leukaemia reactivity was noticed in allodepleted donor T cells; in myeloma patients, graft-versus-myeloma reactivity was less significant.

Generation of myeloma-specific T cells using dendritic cells loaded with MUC1- and hTERT- drived nonapeptides or myeloma cell apoptotic bodies.

Dendritic cells are able to induce anti-tumor immune responses by presenting tumor-specific antigens to T-lymphocytes. Various tumor-associated antigens have been studied in multiple myeloma in an effort to find a strong antigen capable of generating clinically meaningful responses in vaccinated patients. The aim of our study was to generate myeloma-specific cytotoxic T lymphocytes in vitro using dendritic cells loaded with peptide antigens or apoptotic bodies. Peripheral blood mononuclear cells from HLA-A2+ healthy donors were used for isolation and culture of dendritic cells (DCs) and T lymphocytes. DCs were loaded with hTERT- and MUC1-derived nonapeptides or apoptotic bodies from myeloma cells. Repeated stimulation of T lymphocytes led to their activation characterized by interferon-gamma production. Activated T lymphocytes were separated immunomagnetically and expanded in vitro. Specific cytotoxicity of the expanded T lymphocytes was tested against a myeloma cell line. There was evidence of cytotoxicity for all three types of antigens used for T lymphocyte priming and expansion. No statistically significant differences were observed in T lymphocyte cytotoxicity for any of the antigens. We present a method for the priming and expansion of myeloma-specific T lymphocytes using dendritic cells loaded with different types of tumor antigens. Cytotoxic T lymphocytes and/or activated dendritic cells generated by the described methods can be applied for cellular immunotherapy against multiple myeloma and other malignancies.

[Selective depletion of alloreactive T cells and study of anti-tumor activity of specific T cell clones in patients with leukemia]. / Selektivní deplece aloreaktivních T lymfocytu a studium protinádorové aktivity specifických klonu T lymfocytu u pacientu s leuikémií.

BACKGROUND: Graft-versus-host disease (GVHD) is a severe complication of allogeneic transplantation of hematopoietic stem cells. Donor T cells play a major role in GVHD leading to the host tissue damage, mainly the skin, liver, and gastrointestinal tract. A selective depletion using an anti-CD25 immunotoxin can eliminate harmful alloreactive T cells while preserving other donor T cells with antileukemic and antiinfectious reactivity. PATIENTS AND METHODS: We performed 15 mixed lymphocyte reactions with clinical specimens from 12 patients with various types of leukemia (7x AML, 3x ALL, 1x CML, 1x CLL) and PBMC from 15 healthy volunteers from Transfusive station FN Brno Bohunice. RESULTS: In our experiments we have demonstrated, that antileukemic (GVL) effect of donor, especially CD4+ T cells was well preserved (7.46%), while unfavourable alloreactive (GVH) reaction of donor T cells was completely removed. The graft-versus-host (GVH) reactivation of donor cells was negligible ever after repeated stimulation with irradiated patient's PBMC. CONCLUSION: We have shown that anti-CD25 immunotoxin (IT), RFT5-SMPT-dgA, launched against alpha chain for human interleukin 2 (IL-2), led to long-term selective depletion of alloreactive donor T cell clones while their antileukemic activity was well preserved. Base on our results the clinical phase I/II study was designed. This study was initiated in year 2007 in three clinical centers in Czech Republic.

[Allogenic transplantation of hematopoietic stem cells in the treatment of children with high-risk acute leukemia]. / Alogenní transplantace kmenových bunek krvetvorby v lécbe detí s vysoce rizikovou akutní leukémií.

BACKGROUND: Most children with acute lymphoblastic leukemia (ALL) and increasing number of children with acute myelogenous leukemia (AML) are currently cured with conventional chemotherapy. Despite of this success there is a subset of patients with high-risk features at diagnosis who are predisposed to a very high risk of relapse. Relapse of AML and early bone marrow relapse of ALL can not be cured by conventional chemotherapy. Allogeneic hematopoietic stem cell transplantation (HSCT) is therapeutic option in these children with very high-risk acute leukemia. METHODS AND RESULTS: Between XI/1989-XII/1996 33 children with acute leukemia (ALL: 22, AML: 11) underwent an allogeneic HSCT from HLA identical related donors (HLA-identical sibling: 30, twin: 1, other HLA-identical relative: 2) at the 2nd Dept. of Pediatrics, University Hospital Motol. Median age of our group was 9 years (1.5-19 y.), boys (n = 23) clearly dominated over the girls (n = 10). The resource of stem cells was bone marrow in 31 children, bone marrow and peripheral blood progenitor cells (PBPC) and PBPC in one child respectively. Myeloablative conditioning regimen varied, consisting of total body irradiation and chemotherapy in 21 children and chemotherapy in 12 children. HSCT was performed in first complete remission of acute leukemia in 9 children (AML: 7, ALL: 2), in second remission in 14 children (AML: 2, ALL: 12), in third remission in 4 children (ALL: 4). Six children underwent HSCT in first partial remission (n = 1) and in second (n = 4) or third (n = 1) chemoresistant relapse. Seven (21%) children died due to post-transplant complications. Nine (28%) children suffered from clinically significant acute graft-versus-host reaction (GVH) and 15% (4/27) children who survived 100 days post-transplant suffered from chronic GVH disease. Relapse of leukemia was diagnosed in 39% (12/31) children. Fourteen (42%) children are alive and well in continuous remission with median follow-up 42 months. CONCLUSIONS: Allogeneic HSCT can cure children with very high-risk acute leukemia in the situations where conventional chemotherapy fails. Relapse of leukemia and GVH reaction are most important causes of post-transplant morbidity and mortality.

[Analysis of HLA class I molecules using isoelectric focusing. Its application in selection of bone marrow donors]. / Analýza molekul HLA-I. trídy metodou izoelektricke fokuzace. Vyuzití pri výberu dárce kostní drene.

BACKGROUND: Differences between HLA proteins class I are assessed by serological typing using HLA allo-antisera. This method suffices for the assessment of HLA signs in allogenic transplantations of bone marrow in genotypically identical siblings. However, it does not suffice in the selection of donors from the wider family of a related or not related donor from the register of voluntary bone marrow donors. In order to assess the polymorphism of the HLA-class I not detected by serological typing other more sensitive techniques are introduced. In the authors department one-dimensional isoelectric focusing was introduced as an auxiliary method for evaluation of identity of molecules in HLA-class I between bone marrow recipient and donor. METHOD AND RESULTS: The authors introduced the method of one-dimensional isoelectric focusing which uses for detection of molecules of HLA-class I a polyclonal antibody against heavy chains of HLA molecules class I and a secondary antibody labelled by alkaline phosphatase. Forty-one pairs of bone marrow donors and recipient were examined. In six instances, i.e. in almost 15%, the authors detected by isoelectric focusing disagreement in HLA molecules class I. The authors present three interesting pairs of donors and recipients where isoelectric focusing helped with the selection of a suitable bone marrow donor. CONCLUSIONS: The isoelectric focusing is at present another method which helps to reveal differences in HLA class I molecules. When methods of DNA analysis are introduced to recognize alleles of the HLA-I class, correlation with serologically and biochemically assessed variants wil be an essential guide in the evaluation of the final typing of HLA molecules class I.

[Donor selection for allogenic bone marrow transplantation from 1991 to 1995. (The Prague Center for Bone Marrow Transplantation)]. / Výber dárcu pro alogenní transplantaci kostní drene v letech 1991-1995 (Prazské centrum transplantace kostní drene).

BACKGROUND: The prerequisite of successful transplantation of haematopoietic stem cells is to find a suitable, i.e. HLA matched bone marrow donor. In the submitted paper the authors give an account of the strategy of selection of bone marrow donors, as practised by the Prague transplantation group. METHODS AND RESULTS: In 1991 to 1995 (end of first quarter) the authors sought suitable bone marrow donors for 421 patients where an allogenic bone marrow transplantation was indicated. During that period 95 transplantations were performed (22.5% of all indicated cases), incl. 82 from siblings (86.3%) of the implemented allogenic bone marrow transplantations). A HLA matched donor from the wider family circle was selected for 15 donors, transplantation were performed in 6 patients (6.4% of the implemented allogenic bone marrow transplantations). An unrelated bone marrow donor was sought for 41 patients as no donor was found in the wider family. Transplantation was implemented in 7 of these patients (7.3% of the implemented transplantations. CONCLUSIONS: With the increasing experience of our transplantation centre, no doubt, the ratio of other than sibling transplantations of bone marrow will increase. At present it accounts for 13.7%. The task of our HLA group must be selection of donors matched as well as possible with the recipient according to all available tests of tissue compatibility - from the wider family circle as well as from the register of unrelated donors.

The search for HLA-compatible bone marrow donors. Procedure currently used in the Institute of Hematology and Blood Transfusion, Prague.

The search for compatible donors is based on the HLA types of donors and recipients. HLA-A, -B and -DRB1 antigens or alleles must be unequivocally typed in donors and recipients. The typing of HLA-DQB, -DPB and -C gene products is also useful to characterize the HLA phenotype, but it is not absolutely necessary in the donor selection. The standard serological methods using alloantisera and one-dimensional isoelectric focusing are used for the typing of HLA class I antigens. Recently, DNA analysis of class I alleles has been introduced. In HLA class II typing the serological analysis was generally replaced by DNA analysis. In addition to typing techniques that determine the individual HLA alleles or HLA gene products, the cellular matching techniques are used in the selection procedure (mixed lymphocyte culture, cytotoxic T lymphocyte precursor frequency assay, and IL-2-producing helper T lymphocyte precursor frequency assay). The cellular matching techniques determine the compatibility in the regions of HLA comprising several HLA loci; some of them may detect minor histocompatibility (non-HLA) gene disparities as well.

Frequency analysis of cytotoxic T lymphocyte precursors in search for donors in bone marrow transplantation.

The usefulness of cytotoxic T lymphocytes precursors (CTLp) frequency analysis in the search for donors in bone marrow transplantation was studied. The frequency of anti-recipient CTLp was approached by limiting dilution assay in HLA matched unrelated, HLA partially matched related and HLA genotypically identical donors. The majority of patients examined were affected with different hematological malignancies. Alloreactive CTLp recognizing non-HLA gene products were not detected in pretransplant examination of two pairs of HLA identical siblings. However, an increased incidence of allospecific CTLp was identified in HLA matched MLC negative unrelated pairs. Thus, CTLp assay allowed to uncover the residual Class I incompatibilities that remained hidden in standard serotyping. In two matched unrelated pairs with high pretransplant CTLp frequency the severe acute graft-versus-host disease (GVHD) developed after bone marrow transplantation. Examination of other relatives in patients lacking an HLA identical sibling showed the importance of Class I incompatibility for CTLp generation as well. The lack of correlation between CTLp frequency and HLA-D disparity could suggest that Class II antigens do not participate in CTLp induction. With one exception we had good correlation between MLC and DNA analysis of Class II antigens demonstrating that MLC gives interpretable results even in unrelated pairs. Our results demonstrate the significance of CTLp frequency assay in detection of residual Class I incompatibilities in matched unrelated pairs and in assessment of Class I compatibility in related pairs. For that it should be used in the final selection of BMT donors.

[A registry of potential bone marrow donors]. / Registr potencionálních dárcu kostní drene.

Transplantation of bone marrow is relatively successful treatment in some haematological diseases. The most suitable donor of bone marrow is a HLA genotypic identical sibling; however, roughly only 30% of patients have a suitable related donor. In order to find a HLA identical non-related donor for a maximum number of patients it is necessary to create as extensive registers as possible of potential bone marrow donors. The authors mention the possibility to obtain these donors from the ranks of regular blood donors and they mention the advantages of obtaining a register from this group of subjects.

Different selectivities of oxidants during oxidation of methionine residues in the alpha-1-proteinase inhibitor.

Oxidation of the reactive site methionine (Met) in alpha-1-proteinase inhibitor (alpha-1-PI) to methionine sulfoxide (Met(O] is known to cause depletion of its elastase inhibitory activity. To estimate the selectivity of different oxidants in converting Met to Met(O) in alpha-1-PI, we measured the molar ratio Met(O)/alpha-1-PI at total inactivation. This ratio was determined to be 1.2 for both the myeloperoxidase/H2O2/chloride system and the related compound NH2Cl. With taurine monochloramine, another myeloperoxidase-related oxidant, 1.05 mol Met(O) were generated per mol alpha-1-PI during inactivation. These oxidants attack preferentially one Met residue in alpha-1-PI, which is identical with Met 358, as concluded from the parallelism of loss of elastase inhibitory activity and oxidation of Met. A similar high specificity for Met oxidation was determined for the xanthine oxidase-derived oxidants. In contrast, the ratio found for ozone and m-chloroperoxybenzoic acid was 6.0 and 5.0, respectively, indicating oxidation of additional Met residues besides the relative site Met in alpha-1-PI, i.e. unselective action of these oxidants. Further studies were performed on the efficiency of oxidants for total depletion of the elastase inhibitory capacity of alpha-1-PI. Ozone and m-chloroperoxybenzoic acid were 10-fold less effective and the superoxide anion/hydroxyl radicals were 30-50-fold less effective to inactivate the elastase inhibitory activity as compared to the myeloperoxidase-derived oxidants. The myeloperoxidase-related oxidants are discussed as important regulators of alpha-1-PI activity in vivo.

Nucleoli of lymphocytes in the peripheral blood of patients with gastric cancer and gastric ulcer.

Nucleoli in lymphocytes were investigated in the peripheral blood of patients with gastric cancer and gastric ulcer. The number of "active lymphocytes" (lymphocytes with compact nucleoli or nucleoli with nucleolonemata as functionally dominant nucleoli) was increased in the peripheral blood of patients with gastric cancer as well as gastric ulcer. In contrast, the number of "resting lymphocytes" (lymphocytes with ring shaped nucleoli as functionally dominant nucleoli which under proper conditions can be stimulated with respect to the blastic transformation) was decreased in the peripheral blood of patients with gastric cancer. The decrease of these lymphocytes in number in the peripheral blood of patients suffering of gastric cancer might represent one of factors responsible for the spread of the malignant process.

Nucleoli of lymphocytes in the peripheral blood of patients with bronchogenic lung and gastrointestinal cancer.

Patients suffering from bronchogenic and gastrointestinal cancer without, as well as with metastases, were investigated to provide more information on the number of morphology of lymphocytes in their peripheral blood particularly in respect to the frequency of various nucleolar types in these cells. The decreased number of lymphocytes in the peripheral blood of the cancer patients was due to the decline of lymphocytes with ringshaped nucleoli representing resting cells which can be stimulated in respect to the RNA synthesis and blastic transformation. The decreased number of such cells was apparently more pronounced in the peripheral blood of the patients suffering from gastrointestinal cancer with metastases. The increased frequency of lymphocytes with compact nucleoli or nucleoli with nucleolonemas representing immature or stimulated cells was noted in most patients suffering from bronchogenic cancer without, and with metastases in lymph nodes, as well as in some patients with gastrointestinal cancer and, without metastases. On the contrary, the decreased number of these cells was observed in the peripheral blood of patients suffering from gastrointestinal cancer with metastases. All these changes provide further information on the changes of the lymphocytes in the peripheral blood of the patients suffering from malignant disease. The possible interpretation of these changes presented in the discussion is in accordance with the present conception on the relationship between the malignant growth and lymphocytes.

The effects of combined administration of cytembena and cyclophosphamide on the blood count and morphology of nucleoli in peripheral-blood lymphocytes in patients with malignant tumors.

In patients with malignant tumors, changes in the blood count and morphological changes in the nucleoli in peripheral-blood lymphocytes were studied during treatment with Cytembena, Cyclophosphamide, or combinations of both drugs. After administration of Cyclophosphamide (400 mg i.v. daily for 10 days, then 100 mg orally daily), the counts of leukocytes, especially of neutrophils, sank (by 40% maximally), and the erythrocyte count and the haemoglobin content in blood sank moderately. In peripheral-blood lymphocytes, the proportion of ring-shaped nucleoli (stimulable to synthesis of RNA) reversibly sank, and the proportion of micronucleoli (nonstimulable) rose. After administration of Cytembena (400 mg i.v. daily for 10 days, then 200 mg i.m. at intervals of 2--4 days), neither the leukocyte counts nor the relative percentages of lymphocytic nucleoli signigicantly changed; the mean corpuscular haemoglobin content (MCH) transitorily increased (by 10 percent max.). In the group receiving combined cytostatics (Cytembena 400 mg i.v. daily for 10 days, then 200 mg i.m. at intervals of 2--4 days plus Cyclophosphamide 50 mg orally daily), the erythrocyte count and the haemoglobin content in blood sank moderately. In the population of peripheral-blood lymphocytes in this group, there sank the absolute counts of lymphocytes with ring-shaped nucleoli (by 44% max.) and those with micronucleoli (by 33% max.).

Peripheral blood lymphocyte nucleoli of rats with Yoshida ascitic sarcoma and the effect of cyclophosphamide.

Changes in the leucocytes, lymphocytes and peripheral blood lymphocyte nucleoli of Yoshida ascitic sarcoma bearing rats untreated and treated with cyclophosphamide were studied. In the course of the growth of Yoshida ascitic sarcoma lymphocytes with "active" nucleoli (compact nucleoli and nucleoli with nucleolonemas) first increased and then, in the terminal stage of the disease, decreased in number. The number of lymphocytes with ring-shaped nucleoli ("reversibly inactive") and micronucleoli was rising throughout the disease. The increase in numbers of micronucleoli in the lymphocytes produced increased values of nucleolar coefficient. After administration of cyclophosphamide to rats with transplanted tumour the number of lymphocytes with both "active" and "reversibly inactive" nucleoli decreased and the number of lymphocytes with micronucleoli increased. The increase in the proportion of micronucleoli also led to increased values of nucleolar coefficient. After cessation of cyclophosphamide treatment and when the signs of the neoplastic disease had disappeared, the changes observed in the white blood cell picture returned to the values before sarcoma transplantation.