Linda M. Muul

A progress report on the treatment of 157 patients with advanced cancer using lymphokine-activated killer cells and interleukin-2 or high-dose interleukin-2 alone.

We studied the effects of adoptive immunotherapy with lymphokine-activated killer (LAK) cells plus interleukin-2 or therapy with high-dose interleukin-2 alone in 157 patients with metastatic cancer for whom standard therapy had proved ineffective or no standard effective treatment was available. One hundred eight patients were treated with 127 courses of LAK cells plus interleukin-2, and 49 patients were treated with 53 courses of high-dose interleukin-2 alone. Of 106 evaluable patients receiving LAK cells plus interleukin-2, 8 had complete responses, 15 had partial responses, and 10 had minor responses. The median duration of response was 10 months among those with complete responses and 6 months among those with partial responses; the patient with the longest complete response was still in remission 22 months after treatment. Of 46 evaluable patients treated with high-dose interleukin-2 alone, 1 had a complete response (remission greater than 4 months), 5 had partial responses (2, greater than 3, greater than 5, 7, and greater than 11 months), and 1 had a minor response. Seven of the total of nine complete responses still remain in remission. Hypotension, weight gain, oliguria, and elevation of bilirubin and creatinine levels were common, but these side effects resolved promptly after interleukin-2 administration was stopped. There have been four treatment-related deaths among these 157 patients. This immunotherapeutic approach can result in marked tumor regression in some patients for whom no other effective therapy is available at present. Determining its ultimate role in cancer therapy awaits further attempts to increase the therapeutic efficacy of treatment and decrease its toxicity and complexity.

Observations on the systemic administration of autologous lymphokine-activated killer cells and recombinant interleukin-2 to patients with metastatic cancer

We describe here the preliminary results of the systemic administration of autologous lymphokine-activated killer (LAK) cells and the recombinant-derived lymphokine interleukin-2 to patients with advanced cancer. This regimen was based on animal models in which the systemic administration of LAK cells plus interleukin-2 mediated the regression of established pulmonary and hepatic metastases from a variety of murine tumors in several strains of mice. We treated 25 patients with metastatic cancer in whom standard therapy had failed. Patients received both 1.8 to 18.4 X 10(10) autologous LAK cells, generated from lymphocytes obtained through multiple leukaphereses, and up to 90 doses of interleukin-2. Objective regression of cancer (more than 50 per cent of volume) was observed in 11 of the 25 patients: complete tumor regression occurred in one patient with metastatic melanoma and has been sustained for up to 10 months after therapy, and partial responses occurred in nine patients with pulmonary or hepatic metastases from melanoma, colon cancer, or renal-cell cancer and in one patient with a primary unresectable lung adenocarcinoma. Severe fluid retention was the major side effect of therapy, although all side effects resolved after interleukin-2 administration was stopped. Further development of this approach and additional patient follow-up are required before conclusions about its therapeutic value can be drawn.

Isolated allogeneic bone marrow-derived mesenchymal cells engraft and stimulate growth in children with osteogenesis imperfecta: Implications for cell therapy of bone

Treatment with isolated allogeneic mesenchymal cells has the potential to enhance the therapeutic effects of conventional bone marrow transplantation in patients with genetic disorders affecting mesenchymal tissues, including bone, cartilage, and muscle. To demonstrate the feasibility of mesenchymal cell therapy and to gain insight into the transplant biology of these cells, we used gene-marked, donor marrow-derived mesenchymal cells to treat six children who had undergone standard bone marrow transplantation for severe osteogenesis imperfecta. Each child received two infusions of the allogeneic cells. Five of six patients showed engraftment in one or more sites, including bone, skin, and marrow stroma, and had an acceleration of growth velocity during the first 6 mo postinfusion. This improvement ranged from 60% to 94% (median, 70%) of the predicted median values for age- and sex-matched unaffected children, compared with 0% to 40% (median, 20%) over the 6 mo immediately preceding the infusions. There was no clinically significant toxicity except for an urticarial rash in one patient just after the second infusion. Failure to detect engraftment of cells expressing the neomycin phosphotransferase marker gene suggested the potential for immune attack against therapeutic cells expressing a foreign protein. Thus, allogeneic mesenchymal cells offer feasible posttransplantation therapy for osteogenesis imperfecta and likely other disorders originating in mesenchymal precursors.

T Lymphocyte-Directed Gene Therapy for ADA− SCID: Initial Trial Results After 4 Years

In 1990, a clinical trial was started using retroviral-mediated transfer of the adenosine deaminase (ADA) gene into the T cells of two children with severe combined immunodeficiency (ADA− SCID). The number of blood T cells normalized as did many cellular and humoral immune responses. Gene treatment ended after 2 years, but integrated vector and ADA gene expression in T cells persisted. Although many components remain to be perfected, it is concluded here that gene therapy can be a safe and effective addition to treatment for some patients with this severe immunodeficiency disease.

Signaling by IL-12 and IL-23 and the immunoregulatory roles of STAT4

Summary:  Produced in response to a variety of pathogenic organisms, interleukin (IL)‐12 and IL‐23 are key immunoregulatory cytokines that coordinate innate and adaptive immune responses. These dimeric cytokines share a subunit, designated p40, and bind to a common receptor chain, IL‐12Rβ1. The receptor for IL‐12 is composed of IL‐12Rβ1 and IL‐12Rβ2, whereas IL‐23 binds to a receptor composed of IL‐12Rβ1 and IL‐23R. Both cytokines activate the Janus kinases Tyk2 and Jak2, the transcription factor signal transducer and activator of transcription 4 (STAT4), as well as other STATs. A major action of IL‐12 is to promote the differentiation of naïve CD4+ T cells into T‐helper (Th) 1 cells, which produce interferon (IFN)‐γ, and deficiency of IL‐12, IL‐12R subunits or STAT4 is similar in many respects. In contrast, IL‐23 promotes end‐stage inflammation. Targeting IL‐12, IL‐23, and their downstream signaling elements would therefore be logical strategies for the treatment of immune‐mediated diseases.

Expansion of human tumor infiltrating lymphocytes for use in immunotherapy trials

The potential utility of tumor-infiltrating lymphocytes (TIL) in the adoptive immunotherapy of human tumors has been suggested by murine experiments showing these cells to be 50-100 times more powerful than LAK cells in treating advanced metastatic disease. A method for the large-scale expansion of human TIL for the use of these cells in clinical trials is described in this report. TIL were successfully expanded on an experimental scale from 24 of 25 consecutive human tumors, including six melanomas, ten sarcomas, and eight adenocarcinomas. Tumors were digested enzymatically to yield single cell suspensions which were cultured in RPMI 1640 medium with 10% human serum and 1000 U/ml recombinant interleukin-2. Lymphocytes constituted from 3% to 74% of single cell tumor suspensions, and expanded from 2.9-fold to 9.1 X 10(8)-fold over a culture period ranging from 14 to 100 days. Nine of 24 TIL cultures lysed fresh autologous tumor targets in 4 h chromium release assays. Cell surface phenotyping identified cultured TIL as activated cytotoxic/suppressor T cells. Subsequently, large-scale expansion of TIL was successful in generating more than 10(10) lymphocytes in five of eight consecutive cases. Clinical trials employing the adoptive transfer of expanded TIL to patients with metastatic disease have begun.

Characterization of a suppressor-cell leukemia. Evidence for the requirement of an interaction of two T cells in the development of human suppressor effector cells.

To characterize the suppressor activity of neoplastic T cells from a child with acute lymphoblastic leukemia and hypogammaglobulinemia, we applied an in vitro assay that determines the capacity of pokeweed-mitogen-stimulated lymphocytes to mature into immunoglobulin-secreting cells. The geometric mean synthesis by peripheral blood lymphocytes from 12 normal persons was 3200 ng for IgM, 2447 ng for IgG and 1825 for IgA (2 X 10(6) cells per 12 days in culture). The patients leukemic cells produced no detectable immunoglobulin and depressed the immunoglobulin production of normal lymphocytes by 85 to 100 per cent in co-culture experiments. However, suppression was observed only when co-operating normal T cells were present. Prior irradiation of either the leukemic T cells or the co-operating normal T cells nullified the suppressor effect. Therefore, an interaction between at least two different T-cell subsets may be required for the generation of suppressor effector T cells in man.

Immune Response to Fetal Calf Serum by Two Adenosine Deaminase-Deficient Patients After T Cell Gene Therapy

The first approved clinical gene therapy trial for adenosine deaminase (ADA) deficiency employed autologous T cells grown in fetal calf serum (FCS)-supplemented medium and transduced with a retroviral vector (LASN) also produced in the presence of FCS. Ten years after their enrollment, both patients have circulating T cells containing vector DNA. However, whereas approximately 20% of the circulating T cells from patient 1 are still vector positive, less than 1% of patient 2s T cells have detectable vector. This difference appears to be not only a function of the original transduction efficiency and cell expansion capability in vitro, but also of the immune response that patient 2 developed to FCS components during the course of her treatment. In this study, serum samples from each patient were tested for antibodies to FCS by enzyme-linked immunosorbent assay and anti-FCS responses were demonstrated in both patients. Analysis of immunoglobulin classes revealed comparable levels of IgA and IgM anti-FCS titers. Patient 2, however, had significantly higher IgG responses to FCS than did patient 1. Investigation of the development of anti-FCS responses by IgG subclasses indicated that there was a different pattern in the development of IgG immunity to FCS between the two patients. In addition, significant antibody response to bovine lipoprotein was detected in patient 2, but not in patient 1 or in control samples. These findings suggest that the unique immune response mounted by patient 2 may have influenced the outcome of the gene transfer treatments in this patient.

Large scale production of human lymphokine activated killer cells for use in adoptive immunotherapy.

Immunotherapy utilizing the adoptive transfer of lymphokine activated killer (LAK) cells in conjunction with recombinant interleukin 2 (RIL-2) is capable of reducing established metastatic cancer in a variety of animal tumor models. A major difficulty in the application of these efforts to the treatment of human cancer has been the activation in vitro of up to 2 X 10(11) human peripheral blood lymphocytes obtained by repeated leukaphereses. We have thus developed optimal and simplified techniques for the generation of human LAK cells for use in clinical trials. We have found that 1.5 X 10(9) lymphocytes separated on Ficoll-Hypaque gradients and incubated in 1000 ml of culture medium in a 2.3 liter roller bottle with 1000-1500 U of RIL-2 per ml, generated LAK cells capable of killing fresh human tumor cells in a 4 h chromium release assay. The culture medium used was RPMI 1640 with 2 mM glutamine, 2% heat-inactivated human AB serum, 50 micrograms/ml streptomycin and gentamicin and 50 U/ml penicillin. This technique allows activation of sufficient numbers of cells in a research laboratory setting to conduct human clinical trials. The administration of LAK cells generated in this fashion can mediate the regression of human tumors when administered in conjunction with IL-2.

Tpl2 kinase regulates T cell interferon-γ production and host resistance to Toxoplasma gondii

Tpl2 (Tumor progression locus 2), also known as Cot/MAP3K8, is a hematopoietically expressed serine-threonine kinase. Tpl2 is known to have critical functions in innate immunity in regulating tumor necrosis factor–α, Toll-like receptor, and G protein–coupled receptor signaling; however, our understanding of its physiological role in T cells is limited. We investigated the potential roles of Tpl2 in T cells and found that it was induced by interleukin-12 in human and mouse T cells in a Stat4-dependent manner. Deficiency of Tpl2 was associated with impaired interferon (IFN)-γ production. Accordingly, Tpl2−/− mice had impaired host defense against Toxoplasma gondii with reduced parasite clearance and decreased IFN-γ production. Furthermore, reconstitution of Rag2−/− mice with Tpl2-deficient T cells followed by T. gondii infection recapitulated the IFN-γ defect seen in the Tpl2-deficient mice, confirming a T cell–intrinsic defect. CD4+ T cells isolated from Tpl2−/− mice showed poor induction of T-bet and failure to up-regulate Stat4 protein, which is associated with impaired TCR-dependent extracellular signal-regulated kinase activation. These data underscore the role of Tpl2 as a regulator of T helper cell lineage decisions and demonstrate that Tpl2 has an important functional role in the regulation of Th1 responses.