Infusion Of Lymphokine-activated Killer Cells Research Articles

A Combination Therapy of Gemcitabine With Immunotherapy for Patients With Inoperable Locally Advanced Pancreatic Cancer

Dendritic cell (DC) therapy frequently induces a measurable immune response. However clinical responses are seen in a minority of patients, presumably due to insufficient expansion of antigen-specific cytotoxic T lymphocytes (CTLs) capable of eradicating tumor cells. To increase therapeutic efficacy of DC-based vaccination, we have undertaken the first clinical trial involving a combination therapy of gemcitabine (GEM) with immunotherapy for patients with inoperable locally advanced pancreatic cancer. Patients (n = 5) received the treatment course, which consisted of intravenous GEM administration at 1000 mg/m (day 1) and the endoscopic ultrasound-guided fine-needle injection of OK432-pulsed DCs into a tumor, followed by intravenous infusion of lymphokine-activated killer cells stimulated with anti-CD3 monoclonal antibody (CD3-LAKs) (day 4), at 2-week intervals. No serious treatment-related adverse events were observed during the study period. Three of the 5 patients demonstrated effective responses to this clinical trial; 1 had partial remission and 2 had long stable disease more than 6 months. In the patient with partial remission, it has been shown that DC-based vaccination combined with GEM administration induces tumor antigen-specific CTLs. This combined therapy was considered to be synergistically effective and may have a role in the therapy of pancreatic cancer for inducing tumor antigen-specific CTLs.

Systemic Interleukin-2 and Adoptive Transfer of Lymphokine-Activated Killer Cells Improves Antibody-Dependent Cellular Cytotoxicity in Patients with Relapsed B-Cell Lymphoma Treated with Rituximab

Murine models have shown that antibody-dependent cellular cytotoxicity (ADCC) can be improved with addition of lymphokine-activated killer (LAK) cells to monoclonal antibodies. A pilot trial of rituximab and LAK cells in patients with rituximab-refractory CD20+ lymphoma was conducted to evaluate this approach. Ten patients received 3 million units/m2 of interleukin-2 (IL-2) i.v. qd on days 1 to 5 and leukapheresed on days 8, 9, and 10. The leukapheresis product was cultured with IL-2 for 48 h to produce LAK cells. Patients then received 375 mg/m2 i.v. rituximab and LAK cells on days 10, 11, and 12. The patients also received 3 million units/m2 of IL-2 i.v. for 5 days starting day 10. For safety purposes, the first three patients did not receive any LAK cell infusions. The LAK cell infusions improved the ADCC activity of peripheral blood lymphocytes compared with pretreatment activity and prevented the decline in ADCC seen after infusion of rituximab alone. Therapy was well tolerated and the most clinically significant toxicities were fever and fatigue. Two patients achieved a partial remission and five had stable disease. The results from these studies suggest that the addition of LAK cells to rituximab augments ADCC in patients with rituximab-refractory lymphoma.

Effect of intraportal adoptive immunotherapy on liver metastases after resection of pancreatic cancer

The prognosis of patients with resected pancreatic cancer remains poor. This study evaluated the effect of adoptive immunotherapy (AIT) using intraportal infusion of lymphokine-activated killer (LAK) cells after curative resection and intraoperative radiation therapy (IORT) on advanced pancreatic cancer. Twenty-nine consecutive patients with advanced pancreatic cancer (Japan Pancreas Society stage III or IV) were divided into two groups. The control group (n = 17) underwent tumour resection and IORT. The treatment group (n = 12) underwent resection, IORT and intraportal infusion of LAK cells combined with recombinant interleukin 2 (rIL-2). The incidence of liver metastasis and the survival rate of these two groups were compared. Although the overall survival between groups was not statistically different (P = 0.082), there were more patients (four) alive 3 years after operation in the test group (36 per cent versus zero), and the incidence of liver metastases in the treatment group was significantly lower (three of 12 versus ten of 15; P < 0.05). LAK therapy influenced survival positively in multivariate analysis. These preliminary observations suggest that AIT warrants further study as a possible adjuvant for patients undergoing curative resection and IORT for pancreatic cancer.

The immunostimulating activities of anti-tumor polysaccharide from K1 capsular (polysaccharide) antigen isolated from Klebsiella pneumoniae

We have previously shown that K1 capsular polysaccharide antigen (K1CPS) of Klebsiella exhibits anti-tumor activities. In the present study, we examined the effect of K1CPS on cytotoxic effector cells. We found that K1CPS could activate many cytotoxic effector cells including alloreactive cytotoxic T cells and tumor-infiltrating lymphocytes (TILs). Moreover, K1CPS could increase the anti-tumor activity of lymphokine-activated killer (LAK) cells, both in vitro and in vivo. The i.p. injection of K1CPS in low dose could enhance the LAK cytotoxicity and the effect was further potentiated by coculture of LAK cells with K1CPS and low concentration of murine rIL-2 in vitro. The phenotypic characterization revealed that K1CPS might contribute to the increase in CD3+ LAK cell subpopulation by its in vivo priming effect. In addition, the K1CPS-treated LAK cells were able to inhibit the growth of WEHI-164 tumor cells in vivo in Winn-type inhibition assay. Subcutaneous (s.c.) and intraperitoneal (i.p.) adoptive infusion of LAK cells (splenocytes from K1CPS-treated WEHI-164-bearing mice cultured with K1CPS-plus-rIL-2) into WEHI-164 sarcoma-bearing mice could slightly cause regression in terms of tumor diameter, and more significantly in sarcoma weight.

A Phase II Clinical Trial of Interleukin-2 and Lymphokine-Activated Killer Cells in Advanced Colorectal Carcinoma

Patients (n = 22) with metastatic or unresectable colorectal carcinoma were treated with interleukin (IL)-2 and lymphokine-activated killer (LAK) cells in a phase II study conducted by the IL-2/LAK Working Group (ILWG). Eligibility criteria for the study included bi-dimensionally measurable disease, performance status 0 or 1, and normal function of all vital organs. The median age of patients was 49 (range, 28-61) years. Eight (36%) patients had never received prior treatment other than their initial surgery; eight (36%) had received prior radiotherapy, and 12 (55%) chemotherapy. No patients had received prior immunotherapy. Treatment consisted of IL-2, 600,000 IU/kg administered by 15-min intravenous infusion every 8 h on days 1-5 and 12-16. Patients underwent 4-h leukapheresis on days 8-12, and cells were placed in in vitro culture with IL-2 for 3-4 days and the activated LAK cells were infused over 1 h on days 12, 13, and 15. All doses of IL-2 and LAK cells were administered to patients in intensive care unit (ICU) settings. The mean +/- SD number of IL-2 doses administered during days 1-5 was 13.4 +/- 1.2, the mean number of LAK cells reinfused was 6.8 +/- 2.2 x 10(10), and the mean number of IL-2 doses administered during the last phase was 9.8 +/- 2.5. Nineteen patients completed the IL-2 priming phase and received at least one LAK cell infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic effect of neuraminidase-treated LAK cells on liver metastasis of Colon 26.

To improve the lymphokine-activated killer (LAK) cell therapy for liver metastasis, two methods which enhance accumulation of LAK cells in the liver were examined for their effects on the liver metastasis of Colon 26 cancer cells in BALB/c mice. Distribution of LAK cells in the mice was examined by the 51Cr labeling method. Portal vein infusion of LAK cells or tail vein infusion of neuraminidase treated-LAK (N-LAK) cells showed an augmented accumulation of infused cells in the liver. In the first experiment, LAK cells (5 x 10(7) cells) were infused in the portal vein or tail vein at days 3 and 7 after the inoculation of 5 x 10(4) tumor cells and 1 x 10(4) units of IL-2 were given three times a day from day 3 to day 7. The portal infusion of LAK cells produced a greater reduction of liver metastases compared with the peripheral infusion. In the second experiment, 5 x 10(7) LAK cells or N-LAK cells were infused via the tail vein on days 1 and 3, and 1 x 10(4) units of IL-2 were given once a day from day 1 to day 5 after the inoculation of 1 x 10(4) tumor cells. The therapeutic effect of N-LAK cells was greater than non-treated LAK cells on the number of metastatic lesions and the survival time of mice. Since access to the human portal vein is difficult and risky in clinical situation, peripheral infusion of N-LAK cells is preferable.

Pilot study of interleukin-2 and lymphokine-activated killer cells combined with immunomodulatory doses of chemotherapy and sequenced with interferon alfa-2a in patients with metastatic melanoma and renal cell carcinoma.

Experiments in animal tumor models suggest that the antitumor effects of interleukin-2 (IL-2) or IL-2 in combination with lymphokine-activated killer (LAK) cells can be enhanced by chemotherapy agents such as cyclophosphamide or doxorubicin or by the biologic agent interferon alpha. We determined the toxicity and clinical response rate of an IL-2-LAK cell regimen modified by the addition of moderate, immunomodulatory doses of chemotherapy and sequenced with interferon alfa-2a (IFN alpha-2a) in patients with metastatic melanoma and renal cell carcinoma. IL-2 (3-6 million units/m2 per day) was administered by continuous infusion on days 0-5 and days 11-16. LAK cells were infused on days 11 and 12 or on days 11, 12, and 14. Low doses of cyclophosphamide (300 mg/m2) and doxorubicin (25 mg/m2) were given on day 9 before the LAK cell infusions. Following the IL-2-LAK cell infusion, IFN alpha-2a (12 million units/m2) was administered for a total of nine doses to complete a cycle of treatment. A total of 89 patients were enrolled in the study. For each histology, there were eight partial responses in 40 assessable patients, for an overall response rate of 20% (90% confidence interval = 10%-33%). The median response duration was 5 months, although two patients with renal cell carcinoma and one patient with metastatic melanoma had almost complete disappearance of tumor and are still responding after 26+, 22+, and 26+ months, respectively. Toxic effects were severe in patients receiving the highest dose of IL-2 administered in this study and similar to those reported with other high-dose IL-2-LAK cell regimens. Although toxic effects were completely reversible in most patients, there were four treatment-related deaths. This regimen is active in patients with metastatic melanoma and renal cell carcinoma and produces meaningful responses in a small percentage of these patients; however, it is not clear whether cyclophosphamide, doxorubicin, and IFN alpha-2a as used in this protocol appreciably augmented the antitumor activity of the IL-2-LAK cell regimen.

Colonic ischemia complicating immunotherapy with interleukin-2 and interferon-alpha

Colonic ischemia (CI) is a rare complication of high-dose interleukin-2 (IL-2) immunotherapy. This complication occurred in three of 141 patients (2.1%) with metastatic cancer treated with high-dose IL-2 therapy; CI only developed in patients receiving interferon-alpha (IFN) with IL-2 (three of 21, 14%) compared with none of 120 in those patients receiving IL-2 alone (P equals 0.0009). Severe diarrhea (greater than or equal to 7 bowel movements/day) also was significantly more common in patients receiving IFN with IL-2 (six of 21, 29%) than in those receiving IL-2 alone (three of 120, 2.5%, P equals 0.001) and preceded the clinical diagnosis of CI in all three patients. Three of nine patients with severe diarrhea had CI. Hematochezia occurred in four patients, all of whom received IFN with IL-2; three had CI, and the other patient had nonspecific colitis. Differences in vasopressor use did not explain the increased risk of CI in patients receiving IFN; those receiving IFN with IL-2 required phenylephrine less often than patients receiving IL-2 alone (P equals 0.01). The administration of lymphokine-activated killer (LAK) cells had no significant effect on the incidence of CI, severe diarrhea, peritonitis, or vasopressor use; two of three patients with CI, however, had their ischemic episode within 24 hours after the last of three LAK cell infusions. In conclusion, CI is an unusual complication of high-dose IL-2 and IFN immunotherapy. In patients receiving such combination therapy, severe diarrhea is a risk factor for the subsequent occurrence of CI.

進行腎癌に対する lymphokine-activated killer cell および interleukin-2 による併用療法の有用性ならびにその限界

Fourteen patients with metastatic renal cell carcinoma (RCC) were treated by systemic administration of autologous lymphokine-activated killer (LAK) cells and interleukin-2 (IL-2). Pulmonary metastases alone were found in 9 cases, pulmonary and mediastinal nodal metastases in 3, and pulmonary and bone metastases in 2. LAK cells, generated by incubation in 2 units/ml of IL 2 for 3-4 days, were intravenously administered once or twice a week. In addition, beginning on the day of the first LAK cell infusion, 1000 units of IL 2 diluted in normal saline were intravenously infused once or twice a day with occasional supplementation of 1000 units of IL-2 on each day of LAK cell infusion. The total number of LAK cells and total amount of IL-2 administered per patient in this study ranged from 0.8 x 10(10) to 6.9 x 10(10) cells and from 3.3 x 10(4) to 21.4 x 10(4) units, respectively. As toxic effects caused by the infusion of LAK cells, headache, shaking chills, fever and leukocytosis were found in all 14 cases. Side effects possibly induced by IL-2 infusion were tolerable fever, fluid retention (body weight gain of 2-3 kg) and eosinophilia. No objective regression of mediastinal nodal or bone metastases was observed. In regard to lung metastases, however, partial and minor responses were observed in 3 and 2 cases, respectively. One of the 3 patients with a partial response was clinically free of disease after undergoing a thoracotomy for resection of residual lesions, but a brain metastasis was detected 10 months after the thoracotomy. The remaining 2 patients are being closely followed up at present. In 3 of 11 patients who showed a minor response, no change or progressive disease, brain metastases were observed during or after the immunotherapy. Furthermore, we examined the possibility of selection of suitable candidates for this therapy on the basis of the degree of in vitro LAK activity against autologous cultured tumor cells in 6 patients, but there was no significant correlation between in vitro autologous tumor cell lysis by LAK cells and the clinical response to immunotherapy. In conclusion, although a complete response could not be obtained, it can be said that this immunotherapy may be effective against RCC, in particular lung metastases, since a partial response was achieved in 3 of 14 patients. However, it should be taken into consideration that this immunotherapeutic approach may have a risk of increasing the frequency of brain metastases.

Lymphokine-Activated Killer Traffic Assay and Our Preliminary Clinical Results of Regional Arterial Infusion of Lymphokine-Activated Killer Cells for Renal Cell Carcinoma

In vivo distribution of radiolabeled lymphokine-activated killer (LAK) cells that were administered either through the caudal vein or the abdominal aorta of Lewis rats was studied. The LAK traffic study showed remarkable increase in radioactivity in several organs peripheral to the arterial injection site. We began treating the patients with metastatic renal cancer by means of regional arterial administration of LAK cells. This treatment was supported by the results of the traffic assay. Our regional LAK therapy, which involves a weekly leukapheresis in combination with daily systemic low dose interleukin-2 administration, has been in practice for over 2.5 years. Seven out of 12 metastatic lesions in the 7 patients treated showed regression. Two responding cases have been alive for over 2 years. Responding lesions were bone, muscle, para-aortic lymph node, and/or retroperitoneum. The regional arterial administration of LAK cells is local therapy. However, this mode of therapy could be useful for those patients with extrapulmonary nonresectable metastasis and at least one injectable feeding artery. This study shows our laboratory data concerning the localization of LAK cells transferred via arterial route and our clinical cases treated with regional arterial administration of LAK cells.

Interstitial Nephritis in a Patient Receiving Adoptive Immunotherapy with Recombinant Interleukin-2 and Lymphokine-Activated Killer Cells

A patient receiving adoptive immunotherapy with recombinant interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells for metastatic melanoma developed acute renal insufficiency out of proportion to the decrease in her renal perfusion after 4 days of receiving IL-2. On the 8th day of IL-2 and the 3rd day of LAK cell infusion she expired suddenly from an acute intra-abdominal hemorrhage due to rupture of a metastasis. Postmortem examination of the kidneys showed an interstitial infiltrate consisting largely of lymphocytes and concomitant tubulitis. Immunoperoxidase staining of the infiltrating cells with a panel of lymphocyte-specific monoclonal antibodies showed the majority of cells to be T lymphocytes (70-75%), with a more focal infiltrate of B lymphocytes (25-30%) and rare monocytes, granulocytes and natural killer cells. This patient represents the first reported case of acute interstitial nephritis associated with IL-2 immunotherapy. Our finding is consistent with the hypothesis that the acute renal failure that accompanies this therapy may sometimes be due to intrinsic renal disease as well as the usual pre-renal failure. Nephritis may be caused by IL-2-mediated effects on lymphocytes, resulting in renal parenchymal infiltration.

The influence of autologous lymphokine-activated killer cell infusions on the toxicity and antitumor effect of repetitive cycles of interleukin-2

Twenty patients with refractory malignancies were treated with a protocol evaluating the addition of ex vivo-activated autologous lymphokine-activated killer (LAK) cells to a clinically tolerable interleukin-2 (IL-2) regimen (four weekly cycles of human recombinant IL-2 at 3 x 10(6) U/m2/day by continuous infusion for 4 days/week). Sixteen patients completed their induction month of therapy, two had a partial response, six had stable disease, and eight had progressive disease. Four patients had clinical toxicity preventing completion of the induction month of therapy, and one of these patients died during therapy. Significant clinical toxicities included decreased performance status, weight gain, catheter-related thromboses, infectious complications, fever, hypotension, and dyspnea or hypoxemia requiring oxygen. Thus, the addition of LAK cell infusions to this IL-2 regimen did not cause a noticeable change in antitumor response rate but did not cause more severe toxicity.

Pathologic findings associated with interleukin-2—Based immunotherapy for cancer: A postmortem study of 19 patients

The use of interleukin-2 (IL-2), either alone or in combination with lymphokine-activated killer cells, tumor infiltrating lymphocytes, or other immunotherapeutic agents has added a new list of alternatives to conventional antineoplastic regimens. Little information is available about the pathologic changes occurring in patients treated with these agents. In this study, we reviewed the necropsy materials from 19 patients, 12 men and 7 women, with a variety of malignancies including melanoma, renal cell carcinoma, gastrointestinal and pulmonary adenocarcinoma, and metastatic gastrinoma, who died after receiving IL-2—based immunotherapy. Death occurred at intervals ranging from less than 1 hour to 143 days following the last dose of therapy. All patients dying at or less than 43 days following cessation of therapy had lymphoid infiltrates of varying intensity in residual tumor. At necropsy, the major cause of death unrelated to the presence of metastatic tumor was bacterial sepsis. In addition, we found evidence of significant cardiac and pulmonary toxicity: two patients with acute myocardial infarction, one with and one without significant coronary artery disease, two cases of unexplained lymphocytic myocarditis, and one case of fatal pulmonary capillary plugging following an infusion of lymphokine-activated killer cells. Thus, not unlike other forms of therapy for cancer, IL-2—based immunotherapy does not appear to be without significant toxicity.

Combined therapy for unresectable hepatocellular carcinoma with hepatic arterial infusion of lymphokine-activated killer cells from autologous splenocytes and of lipiodolized antitumor agent

Combined therapy for unresectable hepatocellular carcinoma with hepatic arterial infusion of lymphokine-activated killer cells from autologous splenocytes and of lipiodolized antitumor agent

頭頚部癌に対する局所養子免疫療法と放射線治療との併用療法

Adoptive immunotherapy is a treatment approach in which lymphokine-activated killer (LAK) cells with antitumor reactivity and interleukin-2 (IL-2) are administrated to a tumor-bearing host. It has been shown that the incubation of human peripheral blood lymphocytes with IL-2 generates LAK cells that can lyse natural killer (NK) cell resistant, or fresh, autologous tumor cells but not normal cells. Adoptive immunotherapy has therapeutic benefit for advanced or metastatic cancer patients whose treatments are difficult. Two patients with adenoid cystic carcinomas of maxillary sinus and another two with squamous cell carcinomas of upper alveolus and gingiva were treated by local adoptive immunotherapy using intra-arterial infusion in combination with radiotherapy. In this study, the therapeutic effect of this combined therapy and changes of patient's immunoparameters are reported.Patients were treated by radiotherapy (60Co: 2 Gy per day) for five days. Thereafter, each patient received recombinant IL-2 (rIL-2; 5×105 units per day) as constant infusion and intermittent administration of LAK cells (5×106 to 107 cells: 1 to 2 times per week) using intra-arterial infusion into superficial temporal artery. LAK cells were generated by in vitro incubation of patient's peripheral blood mononuculear cells in presence of 1, 000 units per ml of IL-2 for 3 to 4 days. The total amounts of IL-2 and LAK cells were 2.1 to 2.7×107 units and 1.8 to 4.5×106 cells, respectively. The total doses of irradiation ranged from 40 to 80 Gy.As a result of this treatment, complete responses were observed in all treated patients. There was no side effect due to this treatment.In the study of the surface markers of the peripheral blood lymphocytes, it was found that the percentage of Leull positive cells markedly incresed during and after the treatment as compared with that determined before the therapy. A significant increase of the percentage of OKM1 or Leu 7 positive cells after the treatment was also observed, sugesting that NK cells containing OKM1, Leu 7 or Leull may be induced by this therapy, whereas NK or LAK activity of peripheral blood lymphocytes did not show a significant increase.In conclusion, the treatment with local adoptive immunotherapy in combination with radiotherapy was effective therapy for head and neck cancer patients.

A phase II study of the administration of recombinant interleukin 2 (rIL-2) plus lymphokine activated killer (LAK) cells in stage IV melanoma patients.

From January 1987 to February 1988, 15 stage IV melanoma patients were treated with two courses of bolus injection of rIL-2 plus LAK cell infusions at the National Cancer Institute of Milan. The original treatment regimen included a first course of rIL-2 administration (400 micrograms/m2 bolus injection 3 times a day [TID] for 4 days) and a second course of rIL-2 administration (800 micrograms/m2 bolus injection TID for 7 days) separated by 4 consecutive daily leukaphereses. Autologous lymphokine activated killer (LAK) cells were reinfused into each patient on three occasions during the second period of rIL-2 administration. Due to the appearance of grade III-IV neurological, hepatic and cardiopulmonary toxicity, 7 patients discontinued dosing before the end of treatment, one patient desired to be withdrawn and one patient died from rapidly progressive disease, although complications of rIL-2 administration may have contributed to her death. Only 6 patients completed the schedule without evidence of major intolerance, even though the planned dose during the second course of rIL-2 was reduced to 400 micrograms/m2. The complete duration of treatment ranged from 11 to 19 days. The total dose of rIL-2 injected ranged from 12.6 to 30.4 mg. The number of infused LAK cells ranged from 15.5 x 10(9) to 60 x 10(9)/patient. Two of the 14 evaluable patients showed a minor anti-tumor response. In 5 patients new metastases in other sites were documented from 2 to 5 months after completion of dosing. No apparent association was found between progression of the disease (or the appearance of new metastases) and the total dose of rIL-2 injected, the number of LAK cells administered or the number of days of treatment. By December 1988, all patients had died of their disease in a period ranging from 3 to 14 months from the last injection of rIL-2. The lack of significant clinical responses in this study and the high toxicity of this treatment lead us to conclude that at least as far as melanoma patients are concerned, adoptive immunotherapy with rIL-2 plus LAK cells (as described here) is not a justifiable treatment option unless new evidence presents itself.

Therapeutic uses of interleukin-2 and lymphokine-activated killer (LAK) cells

Interleukin-2 (IL-2) is the first of a growing list of lymphokines to be cloned and available for preclinical and clinical evaluation. A product of T-helper lymphocytes, IL-2 augments the cytolytic activity of T-lymphocytes and natural killer (NK) cells, stimulates the proliferation of these cells, and induces the formation of lymphokine-activated killer (LAK) cells. LAK cells exhibit cytolytic activity against a broad range of both freshly isolated and cultured tumor cells, while exhibiting limited cytolytic activity against normal cells. The apparently large therapeutic index suggested by in vitro studies is strongly supported by the antitumor responses seen in preclinical studies. Initial clinical studies reported encouraging response rates, but the actual role of IL-2 and/or LAK cell infusion in cancer therapy has yet to be determined, and may only represent the first step in managing the tumoricidal potential of the immune system.

Immunomodulatory effects of systemic low-dose recombinant interleukin-2 and lymphokine-activated killer cells in humans.

The adoptive immunotherapy of human cancer using lymphokine-activated killer (LAK) cells in combination with high-dose systemic recombinant interleukin-2 (rIL-2) has been associated with global changes in several hematological and immunological parameters while imposing profound toxicity on patients. We have evaluated an alternative LAK cell therapy utilizing low-dose systemic rIL-2 is also characterized by significant changes in immunological and hematological parameters, which are qualitatively similar to those induced by high-dose rIL-2. Low-dose systemic rIL-2, given by i.v. bolus, is cleared to baseline levels within 240 min of administration. The induction of lymphocytosis and eosinophilia, which has characterized other protocols, is also a feature of this protocol. In addition, low-dose systemic rIL-2/LAK cell immunotherapy results in increased peripheral blood mononuclear cell (PBMC) expression of T-cell activation markers such as OKIa, OKT10 and IL-2 receptor. PBMC sampled approximately 100 h after the final infusion of LAK cells demonstrated a statistically significant increase in their ability to kill natural killer (NK)-sensitive and NK-resistant cell lines such as K562 and Daudi compared to baseline values (P less than .05). These data suggest that rIL-2-based immunotherapy using low-dose rIL-2 is capable of inducing quantitative hematological and immunological changes while (in combination with LAK cells) retaining the ability to mediate tumor regression in vivo.

Continuous infusion of recombinant interleukin‐2 and lymphokine‐activated killer cells in refractory malignancies

Adoptive immunotherapy with recombinant interleukin-2 (rIL-2) and lymphokine-activated killer (LAK) cells has been reported to effect the regression of tumor in patients with a variety of malignancies. Responses have occurred in patients treated with high-dose bolus rIL2 as well as lower-dose continuous intravenous infusion. Ten patients who had been extensively pretreated with systemic chemotherapy with or without additional radiation therapy were treated with continuous infusion rIL2 and LAK cells. Five patients received rIL2 alone for 96-120 hours prior to leukapheresis in addition to rIL2 at the time of LAK cell infusion. Three patients received LAK cells that had been cultured for 14 days in an automated tissue culture system. No responses were seen in this ten-patient cohort. While the lack of response in these patients may be related to any one or more of several variables, patients who have been heavily pretreated may not respond as well as patients who have received little to no systemic chemotherapy.

A New Regimen of Interleukin 2 and Lymphokine-Activated Killer Cells

Adoptive immunotherapy with high-dose interleukin 2 and lymphokine-activated killer (LAK) cells has proved to be successful in the treatment of some patients with metastatic cancer, but not without a significant degree of associated toxic effects. The primary goal of this study was to substantially reduce the toxicity of this complex and expensive treatment, while maintaining or improving efficacy. To this end, 29 patients were treated with LAK cells in conjunction with a low-dose regimen of interleukin 2 and a prolonged period of administration following LAK cell infusion. This protocol resulted in a considerable reduction in toxicity, as compared with that described in previous studies, without compromising the efficacy. This study offers further confirmation that adoptive immunotherapy of metastatic cancer can be clinically beneficial to patients for whom no other effective therapy is presently available.