Human nonspecific killer cells

The NK and K-cell activity of human leukocytes was investigated as compared with those cells of the K 562 cell line and murine cells covered by xenoantibodies in Graffi erythroblast leukaemia by means of the 51Cr release test. NK and K-cells could be identified in the blood and bone-marrow. However, they could not be identified in the thymus, lymph-nodes, and tonsils. Attempts of cell fraction with the blood of healthy donors revealed that the K-cells must be attributed to non-T-lymphocytes. NK-cells may be found in the fraction of non-T-lymphocytes as well as in that of T-lymphocytes. Killer cell activity tests in children with acute leukaemia resulted in leukaemia cells having NK and K-cell activity only in very rare cases. ALL patients in remission had strongly lowered NK-cell values under chemotherapy. In comparison to that, chemotherapy had no influence on K-cell activity. On the one hand, NK-cell activities were induced in mixed cultures of allogenous lymphocytes of the blood and, on the other hand, in cells of lymph-nodes. Attempts of fractionation, investigations for determining the influence of chemotherapy and attempts of inducing killer cell activity in vitro lead to the conclusion that NK and K-cells may be regarded as similar cell populations, being, however, not identical.     

Analysis of cytotoxic effector cell function in patients with leukemia or aplastic anemia before and after marrow transplantation

Cytotoxic effector cells mediating natural killing (NK), antibody-dependent cellular cytotoxicity (ADCC), and lectin-dependent cellular cytotoxicity (LDCC) were studied in patients with leukemia or aplastic anemia before and/or after marrow transplantation. Before transplantation, about one-third to one-half of the patients were deficient in cytotoxic activity. In patients with leukemia, this was most likely due to large numbers of circulating blast cells diluting or replacing the effector cells. In patients with aplastic anemia there was an apparent absence of the effector cells in a proportion of the patients. After marrow transplantation, cytotoxic activity in all three systems returned to normal rapidly, by 30 days, and remained so through 100 days. However, about 20% of patients studied beyond 1 year were deficient in these functions. There were no significant associations between cytotoxic activity and important clinical parameters including infections, graft-vs-host disease, and recurrence of leukemia. Our findings do not support an immunosurveillance role for NK against leukemia after marrow transplantation. Furthermore, they point out the need for new in vitro approaches for meaningful monitoring of marrow transplant patients. Finally, our results showed a significant discordance between NK, ADCC, and LDCC activities in these immunologically perturbed individuals, indicating that either different cell populations or different cellular mechanisms are involved in these cytotoxic functions.     

Monosomy 7 in donor cell-derived leukemia after bone marrow transplantation for severe aplastic anemia: Report of a new case and review of the literature

Monosomy 7 arises as a recurrent chromosome aberration in donor cell leukemia after hematopoietic stem cell transplantation. We report a new case of donor cell leukemia with monosomy 7 following HLA-identical allogenic bone marrow transplantation for severe aplastic anemia (SAA). The male patient received a bone marrow graft from his sister, and monosomy 7 was detected only in the XX donor cells, 34 months after transplantation. The patient’s bone marrow microenvironment may have played a role in the leukemic transformation of the donor hematopoietic cells.     

Treatment of severe aplastic anaemia with antilymphocyte globulin or bone-marrow transplantation.

Fifty-three patients with severe aplastic anaemia were admitted to this hospital between January 1976 and June 1980, of whom three arrived in terminal condition and died before treatment for their basic disease could be given. Thus 50 patients were treated and evaluated in a prospective study according to one protocol. Eighteen patients with an HLA-identical sibling underwent bone-marrow transplantation with the aim of achieving haematopoietic chimerism. Thirty-two patients without an HLA-identical sibling were given antilymphocyte globulin with or without an infusion of HLA-haplotype-identical marrow. All these 32 patients received low-dose androgens after the procedure. In the first group eight patients (44%) survived. In the two other groups, 22 patients survived (69%), of whom 20 were completely self-sustaining (63%). Engraftment and graft-versus-host disease did not occur in the group who received antilymphocyte globulin and haploidentical marrow, and the haematopoietic reconstitutions in these patients were all autologous. These results confirm the efficacy of antilymphocyte globulin in the treatment of severe aplastic anaemia and show that such treatment is at least as good as bone-marrow transplantation. Its mechanism of action remains unknown, but most patients with aplastic anaemia have a pool of haematopoietic stem cells able to repopulate the marrow after this type of treatment.     

The value of cell cultures in leukemias, aplastic anemias and bone marrow transplantations

In a survey different methods of culture are represented for the purpose of identifying and quantifying haemopoietic stem cells (CFU-GEMM, CFU-GM, CFU-E/BFU-E) in human bone-marrow or peripheral blood respectively. On the basis of findings from international medical literature their validity is explained in the diagnostics and prognosis of some haematological diseases, such as acute and chronic myeloic leukemia, aplastic anemia, preleukemia. Special attention is given to their significance within bone-marrow transplantation. Their importance in evaluating transplantations after their preceding in-vitro manipulation as to the separation of rest tumour and T-cells is particularly referred to.     

Karyotype and in vitro-response to GM-CSF. Analysis of bone marrow cultures in leukemia, myelodysplasia and aplastic anemia

The influence of GM-CSF on bone marrow cultures from 13 patients with aplastic anemia, MDS and acute leukemia was studied in a short-term suspension culture system. In each case combined cytogenetic and proliferation analyses were performed with respect to the question, whether chromosome aberrations play a role in the in vitro response to GM-CSF and in order to search for stimulating effects on malignant cells. The responsiveness was compared of aplastic and myelodysplastic cultures on the one hand and of leukemic cells on the other. Our results show that myelodysplastic and aplastic cells display a tendency for reduced susceptibility to GM-CSF as compared to healthy controls, while in leukemic bone marrow the response to the growth factor was significantly enhanced, indicating a leukemia-specific response pattern. In the majority of leukemias analyzed, the presence of cytogenetically abnormal cells in cultures with excessive response to GM-CSF can be taken as a proof for stimulation of malignant cells. The significance of these findings for pathogenesis and prognosis in aplastic anemia, myelodysplasia and leukemia is discussed.     

Marrow transplantation for severe aplastic anemia associated with exposure to quinacrine

Severe aplastic anemia developed in a patient after administration of quinacrine for treatment of discoid lupus erythematosus. Marrow transplantation was performed from an HLA genotypically identical sister after conditioning with cyclophosphamide. Quinacrine which was accumulated in the patient tissues did not interfere with engraftment, suggesting that the drug has no direct cytotoxic effect on hematopoietic stem cells. This study extends our previous observation that severe aplastic anemia acquired after exposure to drugs or toxins can be cured by marrow transplantation.     

Growth and growth hormone in children after bone marrow transplantation

Growth and growth hormone (GH) were investigated every year in 24 children after allogeneic bone marrow transplantation (BMT) for severe aplastic anemia (SAA) or leukemia. Conditioning included total body irradiation (TBI) in all cases of leukemia. The young leukemic children grew poorly. At 4 years after BMT, the mean standard deviation score for attained height had decreased from 0 to -1.73. GH deficiency was diagnosed with provocation tests. Three years after BMT, 10/18 children had a subnormal response. Ten children were further investigated with 24-hour GH profiles. Children with SAA had normal growth and GH levels. TBI seemed to be the major factor responsible for impaired growth.     

The release of interleukin-2 (IL-2) and colony stimulating activity (CSA) in aplastic anemia patients: opposite behaviour with improvement of bone marrow function

Peripheral blood cells from patients with aplastic anemia were tested for their ability to release interleukin-2 (IL-2) and colony stimulating activity (CSA) before treatment. IL-2 release--as measured in the mouse thymocyte assay--was abnormally high in 18/34, and abnormally low in 10/34 patients. "Low" release was due to simultaneous release of thymocyte inhibitors. In 18 patients who achieved self-sustaining hemopoiesis after high dose immunosuppressive therapy, excess IL-2 release decreased to low levels (p less than 0.001), and the release of inhibitors disappeared. In contrast, the release of CSA by patient cells--which did not correlate with peripheral blood monocyte counts--either remained high or increased to excessively high values in 24/24 patients tested before and after successful immunosuppressive treatment. Patients with stable hemopoietic grafts after bone marrow transplantation for aplastic anemia, did not release excess CSA. It is concluded that IL-2 and CSA play opposite roles in aplastic anemia. High IL-2 release seems associated with disease activity, whereas high CSA-release appears to reflect a repair mechanism.     

Bone marrow transplantation for leukemia and aplastic anemia: management of ABO incompatibility.

Between February 1971 and October 1980, 34 patients with leukemia or aplastic anemia received bone marrow transplants from HLA-identical siblings whose lymphocytes did not react in a mixed leukocyte culture. The donors of 10 patients were ABO-incompatible, and for five pairs the ABO incompatibility was major. Plasma exchanges followed by a red blood cell exchange transfusion reduced the anti-A titres to 1:4 or less in these patients. The ABO incompatibility had no adverse effect on the results of marrow transplantation. Twenty-two patients, including 16 of the 20 who received their transplant after Jan. 1, 1980, are still living. Seven of the 15 patients with acute leukemia have survived 89 to 466 days, and 4 of the 6 with chronic myelogenous leukemia (CML) have survived 117 to 545 days. Of the 13 patients with aplastic anemia, 11 are alive up to 8 years after transplantation. Marrow transplantation, when possible, is the treatment of choice for young patients with acute leukemia in remission and for patients with aplastic anemia. Marrow transplantation may also prove to be effective in patients with CML.     

Effect on natural killer and antibody-dependent cellular cytotoxicity of adjuvant cytotoxic chemotherapy including melphalan in breast cancer

Natural killer (NK) cell activity and antibody-dependent (K) cell activity were studied sequentially in 30 patients with early node-positive breast cancer entered into an adjuvant chemotherapy trial. The drugs used were melphalan, and melphalan with methotrexate, given for 12 months. Estimations were made 3-monthly during chemotherapy, and then at 15 and 24 months to assess recovery. Mean values for NK-cell activity during chemotherapy were significantly lower than the mean pre-chemotherapy baseline value at all time-points from 3 to 15 months, but there was recovery by 24 months. Mean values for K-cell activity during chemotherapy did not appear to differ from the mean pre-chemotherapy value, but variability in individual values was high. Over a 4-year follow-up period, a comparison of 16 patients who did not develop recurrent breast cancer with 14 who did showed that NK-cell activity was significantly lower in the latter group 12 months after the start of chemotherapy.     

Nonspecific suppressor cells in patients with chronic graft-vs-host disease after marrow grafting.

Forty-four human long-term survivors after marrow transplantation for aplastic anemia or hematologic malignancy were studied for the presence of circulating nonspecific suppressor cells. Twenty-two of the patients were healthy and 22 had mild to moderately severe chronic graft-vs-host disease (GVHD). Patient mononuclear cells (of donor origin) were tested for their ability to suppress the responses of lymphocytes obtained from the respective marrow donors to alloantigens in mixed leukocyte culture (MLC) and/or to concanavalin A (Con A). Tests were carried out between 199 and 2393 (median 376) days after transplantation. Cells from only 1 of 22 patients without chronic GVHD showed suppression of donor cell blastogeneis responses. In contrast, cells from 11 of 22 patients with chronic GVHD showed more than 30% suppression of donor cell responses in MLC and/or to Con A. The finding of suppressor cells was not related to the time of testing after grafting nor to immmunosuppressive therapy. Nonspecific suppressor activity was abrogated by irradiation with 1600 rads in vitro in five of six cases tested. Nonspecific suppressor cells may be one explanation for the severe combined immunodeficiency and the recurrent infectious complications characteristic of patients with chronic GVHD.     

Antibody-dependent cellular cytotoxicity (AAZZ) against leukemia cells--K-cell activity of human leukocytes

The activity of human leukocytes from the peripheral blood (PB) and bone-marrow (BM) to take the function as K-cells in the antibody dependent cellular cytotoxicity (ADCC) was tested in a 51Cr-test against mouse leukaemic cells and ALL cells covered with specific heterologous antibodies. Mononuclear PB-leukocytes and granulocytes of healthy donors and patients with leukemia and lymphoma in remission lysed murine and human leukaemic cells in the presence of specific antibodies. There was no lowering of K-cell activity of mononuclear PB-leukocytes of patients with leukaemia and lymphoma in remission under chemotherapy as compared with healthy donors and patients in remission without chemotherapy. There was a good correlation between the percentage of K-cell active mononuclear leukocytes in PB and BM. Attempts of fractionation with peripheral blood leukocytes of healthy donors resulted in the non-adherent mononuclear PB-leukocytes (lymphocytes) and granulocytes being effector cells in ADCC. To a high degree K-cell active lymphocytes could be identified in the non-B-fraction and only slightly in the fraction forming E rosettes.     

Cellular interactions in marrow-grafted patients. I. Impairment of cell-mediated lympholysis associated with graft-vs-host disease and the effect of interleukin 2

Forty patients with hematologic malignancy or aplastic anemia were given allogeneic marrow after conditioning with high-dose cyclophosphamide alone or in combination with total body irradiation. Between 28 and 3857 days after transplantation, their peripheral blood mononuclear leukocytes were tested for reactivity in indirect cell-mediated lympholysis against normal leukocytes from unrelated individuals, and the results were compared to those with cells from their healthy marrow donors. An impairment of cell-mediated lympholysis was found with cells from most patients with acute and chronic graft-vs-host disease (GVHD) whereas cells from most short-term and long-term patients without GVHD had cell-mediated lympholysis reactivity comparable to that of cells from the marrow donors. When interleukin 2 was added to the mixed leukocyte cultures during the sensitization phase, the impaired cell-mediated immunity of cells from most short-term patients with acute GVHD, but not that of cells from most patients with chronic GHVD, could be restored to normal levels. These results suggest the impairment of cell-mediated immunity seen in cells of short-term patients with acute GVHD is attributable to helper cell defects or to ineffective communication between antigen-presenting cells and helper T cells. The impairment in cell-mediated immunity seen in patients with chronic GVHD, however, may reside on the effector cells (or their precursors) or may be due to the presence of suppressor cell activity.     

Bone marrow transplantation in Canada.

Bone marrow transplantation is an established form of therapy for aplastic anemia and severe combined immunodeficiency. It is also a therapeutic option for acute leukemia in remission. Unfortunately, compatible donors are not available for most patients who could benefit from it. Further refinement of the techniques involved may make it suitable for more patients. Graft rejection, recurrent leukemia, graft-versus-host disease and interstitial pneumonia continue to be the main unsolved complications of bone marrow transplantation, but recent advances have decreased their frequency and severity. Most of the complications of allogeneic bone marrow transplantation may be eliminated with the use of autologous stem cells. For further refinement bone marrow transplantation should continue to be performed in large centres that combine treatment with research.     

Characterization of HNK-1+ (Leu-7) human lymphocytes: III. Interferon effects on spontaneous cytotoxicity and phenotypic expression of lymphocyte subpopulations delineated by the monoclonal HNK-1 antibody

Interferon (IFN) augments the cytotoxic function of natural killer (NK) and killer (K) cells. We have previously shown that all NK- and K-cell function resides in the HNK-1⁺ population of granular lymphocytes. The present experiments demonstrated that IFN significantly augmented the efficiency of purified HNK-1⁺ cells to perform both NK- and K-cell function. In contrast, HNK-1^? cells could not lyse target cells even in the presence of IFN. IFN did not generate new HNK-1⁺ cells from the pool of HNK-1^? cells. We then examined the possibility that IFN might induce the maturation of immature NK cells previously defined as having an HNK⁺T3⁺ phenotype and a paucity of cytoplasmic granules. However, no changes were observed either in the proportion of HNK-1⁺ cells expressing the T3 antigen or in the number of granules within each HNK-1⁺ cell even after an 18-hr incubation with IFN. While fresh HNK-1^? cells lack NK-cell function, they can acquire NK-like activity without expressing the HNK-1 antigen after incubation with either alloantigens or mitogens. When incubated further with IFN, these alloantigen- or PHA-activated HNK-1^? cells with NK-like activity demonstrated relatively little augmentation of their cytotoxicity. It is concluded that interferon exerts its influence on restricted subpopulations of cells, primarily HNK-1⁺ cells. Its mechanism appears to concern the cytotoxic event rather than influencing cellular maturation.     

Reversal of aplastic anaemia secondary to systemic lupus erythematosus by high-dose intravenous cyclophosphamide

Aplastic anaemia is rare as a primary feature of systemic lupus erythematosus and is more commonly a complication of treatment with cytotoxic drugs. Three years after starting treatment for systemic lupus erythematosus a 22-year-old woman developed bone-marrow depression. Azathioprine was thought to be responsible and was withdrawn. The aplastic anaemia worsened despite treatment with prednisolone. In view of clinical and serological evidence of lupus disease activity the patient was given high-dose intravenous cyclophosphamide and the aplastic anaemia responded in a sustained manner.In such cases of continued disease activity high-dose immunosuppressive agents may prove effective.     

Structure of neuromuscular junctions and differentiation of striated muscle fibers in mdx mice after bone-marrow stem cell therapy

Mdx mice are an experimental model of Duchenne muscular dystrophy caused by mutations in the dystrophin gene. Repeated cycles of muscle degeneration-regeneration are common for mdx mice. Disrupted neuromuscular junctions also characterize mdx mice. The structure of mdx mice neuromuscular junctions and the differentiation of striated muscle fibers were investigated 4, 8, 16, and 24 weeks after transplantation of C57BL/6 Lin(−) bone-marrow stem cells. We found that the death of striated muscle fibers decreased 4 weeks after the transplantation of bone-marrow stem cells. Accumulation of muscle fibers without centrally located nuclei began in 8 weeks and dystrophin synthesis increased in 16–24 weeks after the bone-marrow stem cells transplantation. On the longitudinal sections of quadriceps muscle of mdx mice 4 weeks after transplantation, we observed a reduced quantity of acetylcholine receptor clusters and an increase in their area in neuromuscular junctions. Sixteen weeks after the transplantation, the total area of neuromuscular junctions increased due to an enlarged number of acethylcholine receptors and their extended area. The single intramuscular transplantation of C57BL/6 Lin(−) bone-marrow stem cells induces the differentiation of mdx mice striated muscle fibers and improves the structure of neuromuscular junctions.     

Complement-dependent hematopoietic inhibitors in the sera of patients with aplastic anemia and paroxysmal nocturnal hemoglobinuria

The sera of 14 out of 48 patients with aplastic anemia and four out of nine patients with paroxysmal nocturnal hemoglobinuria (PNH) contained complement-dependent hematopoietic inhibitory activity against allogeneic marrow progenitor cells. Some sera with hematopoietic inhibitory activity, however, demonstrated no effect on autologous marrow progenitor cells. Hematopoietic inhibitory activity was absorbed by pooled, packed platelets. Serum hematopoietic inhibitory activity was present in both IgM and IgG fractions. These data suggested that serum hematopoietic inhibitors are alloantibodies and might be associated with graft rejection in the transplanted marrow of patients with aplastic anemia and PNH.     

Interleukin-15 enhances natural killer cell cytotoxicity in patients with acute myeloid leukemia by upregulating the activating NK cell receptors

Interleukin-15 (IL-15) has a major role in NK-cell homeostasis. Modulation of the relative frequency and expression intensity of the NK-cell receptors by IL-15 may increase NK cell-mediated cytotoxicity in cancer patients. We investigated the receptor repertoire and measured NK-cell activity in newly diagnosed AML patients and evaluated the ex vivo effects of IL-15. The expression of the activating NK cell receptors was significantly decreased in the AML patients compared to that in NK cells of healthy donors. When NK cells obtained from AML patients were cultured with IL-15, expression of the activating receptors was significantly upregulated compared to pre-culture levels. Concomitantly, cytotoxic activity of NK cells against autologous leukemic blasts increased following IL-15 stimulation. This IL-15 induced increase in activity was blocked by neutralizing antibodies specific for the NK cell activating receptors. These pre-clinical data support the future use of IL-15 for NK cell- based therapies for AML patients.