Dietary soy protein is associated with reduced intestinal mucosal polyamine concentration in male Wistar rats.

Quantitation of polyamine levels has been correlated with biomarkers of proliferation in the colon mucosa where dysregulated epithelial hyperproliferation is associated with colorectal cancer risk. This study was performed to assess the response of polyamine measurements to dietary factors in an animal model. Male Wistar rats were fed purified diet or diets substituted by 20% lard fat, 20% beet fiber and 20% soy protein. After 2 wk, mucosal polyamines were measured along intestinal tracts by HPLC. In rats fed the control diet (n = 10), mucosal polyamines were found at high levels in the duodenum, jejunum and ileum but at low levels in the cecum, colon and rectum. Compared with rats fed the control diet, those fed the 20% lard diet showed greater polyamine levels in the large intestine (P < 0.05, n = 10), but those fed the 20% fiber diet exhibited lower polyamine levels in the small intestine (P < 0.05, n = 9). However, rats fed the 20% soy protein diet had lower polyamine levels in both small and large intestines (P < 0.05, n = 15). Significant linear correlations were observed between rectal polyamine levels and the dietary energy intakes in these four diet groups (r = 0.972-0.991, P < 0.001). Supplementation of 0.1% soy isoflavones to the basal diet or 0.3% DL-methionine to the 20% soy protein diet for 4 wk did not affect polyamine levels. The results indicate that soy protein reduced mucosal polyamine levels, at least in part, through reduction of energy intakes. Further studies are warranted to verify that polyamine levels in intestinal mucosa are useful as an intermediate endpoint of the dietary risk factors.

Induction of NADPH:quinone reductase by dietary phytoestrogens in colonic Colo205 cells.

Phytoestrogens are a group of naturally occurring diphenolic compounds present in legumes, whole grains, fruits, and vegetables. High consumption of phytoestrogen-rich foods has been linked to a reduced incidence of cancers at many sites. A potential mechanism of dietary anticarcinogenesis involves the induction of detoxifying phase II enzymes such as NADPH:quinone reductase (QR). This study, therefore, examined the ability of six prominent phytoestrogens to affect cellular expression of QR in colonic cells. Colo205 cells were cocultured with various concentrations (0.001 to 10.0 microM) of each phytoestrogen, and then were assessed for cytosolic QR activity, cell growth, and QR mRNA expression. A maximum of 6- to 8-fold induction of QR activity was observed for both enterolactone and genistein, although at high concentrations they showed an adverse effect upon cell growth. The concentrations required to double the specific activity of QR for enterolactone and genistein were about 0.04 and 0.14 microM, respectively. A 2- to 3-fold increase of QR specific activity was found with either biochanin A (1.1 microM) or coumestrol (12.0 microM) treatments. No significant effects were found for daidzein or formononetin treatments. QR induction was further confirmed by using reverse transcription-polymerase chain reaction (RT-PCR) techniques to measure mRNA expression. A significant correlation between the expression of QR mRNA and the corresponding QR activity was observed (r = 0.76, P < 0.001). The results demonstrated that certain dietary phytoestrogens are capable of QR induction in Colo205 cells by promoting QR mRNA expression, and suggest a novel mechanism by which dietary phytoestrogens may be implicated in colorectal cancer chemoprevention.

Individual and combinatory effects of soy isoflavones on the in vitro potentiation of lymphocyte activation.

Daidzein and genistein are two prominent soy isoflavones that have been reported as promising protectors against cancers at many sites. In a study focusing on the chemopreventive mechanisms, we previously demonstrated that daidzein was an effective immune stimulator in an in vivo murine system. In this study we further evaluated the effects of daidzein and genistein, individually and in combination, on in vitro mitogen-stimulated activation of murine lymphocytes. At physiologically relevant concentrations (0.01-10.0 microM), daidzein significantly potentiated proliferation of mixed splenocyte cultures activated with concanavalin A or lipopolysaccharide in a dose-dependent manner in comparison with vehicle control, whereas genistein had no influence on the response. Although a significant cooperativity with genistein (1 microM) was observed at low concentrations of daidzein (0.01 microM) in comparison with daidzein alone, genistein failed to augment or counteract the effects of high concentrations of daidzein on lymphocyte proliferation. The secretion of cytokine interleukins-2 and -3 from concanavalin A-activated lymphocytes was significantly increased again by daidzein and was unaffected or mildly decreased by genistein. Taken together, these results demonstrate that daidzein, rather than genistein, is able to enhance in vitro activation of murine lymphocytes and suggest that more studies focusing on the immunoregulatory mechanism of soy daidzein and the potential clinical relevance are warranted.

Mucosal polyamine measurements and colorectal cancer risk.

Polyamines are short-chain aliphatic amines required for normal cellular growth that are ubiquitously found in all living tissues. Polyamine content has been shown to correlate with cellular proliferation. Quantitation of polyamines may thus provide a biochemical measure of proliferation in the colorectal mucosa where dysregulated epithelial proliferation is associated with colorectal cancer risk. A case-control study was conducted to validate the hypothesized association between mucosal polyamine measurements and colorectal cancer risk. Polyamines were measured in 4-6 multiple rectal mucosal biopsies from 11 normal control subjects and seven case patients with colon cancer. Compared with the controls, mean polyamine measurements, after adjustment for age and sex, were significantly increased for spermidine (P < 0.003) and spermine (P < 0.017). Subsequent analysis indicated that in controls 1-4 biopsies appeared adequate to characterize an individual. However, mucosal polyamines in the cases exhibited more sampling variability, requiring 4-8 biopsies to achieve an acceptable level of reliability. After adjustment for age and sex, the odds ratios for spermidine and spermine levels, compared to the controls, were 4.8 (95% confidence interval: 1.6-33.7) and 2.3 (1.2-6.3), respectively. The results of this study indicate that increases of mucosal polyamine measurements, after taking the sampling and methodological variability into account, are significantly associated with colorectal cancer risk, and suggest that polyamine measurements in rectal mucosa may play an important role as biomarkers for identifying high-risk individuals and/or for using as intermediate endpoints in prevention trials.

Reproducibility of erythrocyte polyamine measurements and correlation with plasma micronutrients in an antioxidant vitamin intervention study.

Erythrocyte polyamine measurements have been previously investigated as candidate biomarkers for hyperproliferation and recently as a potential intermediate endpoint in clinical chemoprevention trials with difluoromethylornithine, an inhibitor of polyamine biosynthesis. This study was performed to determine the reproducibility of erythrocyte polyamine measurements and their possible correlation with plasma micronutrients in seven healthy adults in an antioxidant vitamin intervention study. As part of this cross-over intervention study, three subjects took beta-carotene (31.4 mg/day) plus D-alpha-tocopherol acetate (720 IU/day) supplements during the first 3 months and four subjects took the supplements during the second 3 months. Heparinized blood samples were collected at baseline and every month over total 6 months for simultaneous determination of erythrocyte polyamines and plasma micronutrients by the high-performance liquid chromatographic method. For all the measures of erythrocyte polyamines the intraindividual variation was smaller than that between subjects, and three or four measurements required to accurately characterize long-term erythrocyte polyamines for an individual. The intra-class correlations were moderately high for all erythrocyte polyamine measurements, indicating a good reproducibility for intra-individual erythrocyte polyamine measurements. Based on monthly values, significant inverse correlations were found between erythrocyte spermidine and the plasma levels of retinol (r = -0.50) and lutein (r = -0.52). There were also significant inverse associations between erythrocyte spermine and plasma levels of alpha-tocopherol (r = -0.29), lutein (r = -0.44), lycopene (r = -0.29), beta-cryptoxanthin (r = -0.30), and total carotenoids (r = -0.29). The effects of supplementation upon the associations between erythrocyte polyamines and plasma nutrient levels were additionally addressed. The results indicate an acceptable longitudinal reproducibility of erythrocyte polyamine measurements, support the hypothesis that erythrocyte polyamine measurements may be correlated with plasma levels of certain nutrients, and suggest a further biomarker application in cancer prevention trials involving dietary modifications or specific relevant micronutrients.

Induction of NAD(P)H:quinone reductase by vitamins A, E and C in Colo205 colon cancer cells.

High consumption of fruits and vegetables which are abundant in dietary antioxidants has been linked to a reduced incidence of colorectal cancer. A potential mechanism of dietary anticarcinogenesis involves the induction of detoxifying phase II enzymes, including NAD(P)H:quinone reductase (QR) and glutathione-S-transferase (GST). This study therefore examined the ability of the dietary antioxidant vitamins beta-carotene, alpha-tocopherol and ascorbic acid to induce cellular expression of QR and GST activities in human colon cancer cells. Colo205 cells were cultured in the presence or absence of various concentrations (10(-10) to 10(-5) M) of each antioxidative micronutrient, then assessed for cytosolic QR and GST activities and cell growth. beta-Carotene, alpha-tocopherol and ascorbic acid each resulted in dose-dependent increases in QR activity, without adverse effects upon cell proliferation. To investigate whether the ability of beta-carotene to induce QR may be attributable to its conversion to vitamin A and/or to its antioxidant capacity as a carotenoid, retinol, retinoic acid, and lycopene were similarly tested for their capacity for enzyme induction. Although retinol and retinoic acid were both noted to be antiproliferative at higher concentrations (10(-6) to 10(-5) M), both retinoids stimulated QR at physiological concentrations. Lycopene, a carotenoid which is not converted to vitamin A, was devoid of biologic activity. By contrast with the effects upon QR, GST activity was unaffected by treatment with any of the micronutrients tested in this in vitro model. The results support a hypothesis that a high dietary consumption of vitamins A, E and C may confer partial protection against colorectal cancer by the induction of specific detoxifying enzymes. The antioxidant capacity of beta-carotene appears to have less biologic impact vis-a-vis QR induction than its function as a non-toxic reservoir of vitamin A. Measurements of QR activity within the colorectal mucosa may provide an index of cancer susceptibility, and may be an appropriate surrogate endpoint biomarker for colorectal cancer prevention studies involving diet modification or specific relevant micronutrients.

Correlations between mutagen sensitivity and plasma nutrient levels of healthy individuals.

Increased mutagen sensitivity and decreased intake of antioxidant-rich fruits and vegetables have been associated with an increased risk of upper aerodigestive tract cancers. The objective of this study was to investigate the intraindividual variation in mutagen sensitivity and its possible correlation with plasma nutrient levels in a group of 25 healthy individuals in Hawaii. Mutagen sensitivity, as assessed by bleomycin-induced chromosomal breaks in cultured peripheral blood lymphocytes and plasma nutrient levels were measured monthly for 11 months. The monthly numbers of chromosomal breaks/cell ranged from 0.04 to 0.80 and showed considerable intraindividual variation. Based on individual means, significant inverse correlations were found between mutagen sensitivity scores and the plasma levels of alpha-carotene (r = -0.64), total carotenoids (r = -0.41), and ascorbic acid (r = -0.40). There were also significant inverse associations between monthly mean plasma levels of alpha-carotene (r = -0.58), beta-carotene (r = -0.76) and total carotenoids (r = -0.72) and monthly mean chromosomal breaks. In contrast, there was a significant positive correlation between monthly mean plasma triglyceride level (r = 0.60) and monthly mean mutagen sensitivity. These results suggest that mutagen sensitivity as assessed by the bleomycin assay may be influenced by plasma levels of certain nutrients and could potentially be modified by dietary interventions or micronutrient supplementation.

Comodulation of cellular polyamines and proliferation: biomarker application to colorectal mucosa.

Polyamines are low molecular weight aliphatic amines required for normal cellular growth which are ubiquitously found in all living tissues. Polyamine biosynthesis is known to increase with mitogenesis, and elevated polyamine concentrations are found in hyperproliferative tissues. Quantitation of tissue polyamine content may thus provide a biochemical measure of proliferation, with potential biomarker application to the colonic mucosa where dysregulated epithelial proliferation is associated with cancer risk. This study was performed to validate polyamine analyses as a measure of cellular proliferation, and to preliminarily assess polyamine characteristics when applied to clinical samples. Using FHC, a human colonic epithelial cell line, for in vitro experimentation, deoxycholic acid or retinol was added to freshly passaged cultures to either stimulate or inhibit proliferation, respectively. Parallel cultures were then assayed for (1) proliferation by sulforhodamine B staining; and (2) polyamine content by a high-performance liquid chromatographic method. Deoxycholic acid stimulated, and retinol inhibited proliferation in dose-dependent fashion. Polyamine content, specifically the spermidine content and the spermidine/spermine ratio, also increased or decreased in response to culture with deoxycholic acid or retinol, respectively. Significant linear correlations between proliferation and spermidine (r = 0.858, P < 0.001), and with the spermidine/spermine ratio (r = 0.574, P < 0.05) were observed. When quantitative polyamine analyses were applied to human colonic specimens, replicate mucosal sampling revealed a high degree of intra-individual variability, indicating a heterogeneous distribution of polyamines within anatomically confined colonic segments. The results support a role for quantitative polyamine analyses as a correlative measure of colonic epithelial proliferation; however, intraindividual variability may limit the utility of colorectal biomarker measurements.

Proliferative response of mammary glandular tissue to formononetin.

Dietary phytoestrogens have been implicated in infertility among ruminants and may relate to human breast cancer risk. Formononetin is an isoflavonoid phytoestrogen found in animal fodder and in certain human foodstuffs. To investigate a possible mechanism by which phytoestrogens might influence mammary carcinogenesis, this study examined the capacity of formononetin to stimulate mammary gland proliferation. Formononetin was administered to castrated female BALB/c mice by daily subcutaneous injection; then mammary gland proliferation and estrogen receptor expression were quantified, and plasma prolactin levels were measured. A preliminary dose-finding study demonstrated an estrogenic effect on vaginal cytology when formononetin was injected at 40 mg/kg sc. Peak plasma concentrations of 2.5 +/- 0.8 (SD) micrograms/ml at two hours and peak mammary tissue concentrations of 2.0 +/- 0.2 ng/mg tissue at four hours were noted after a single injection at this minimally bioactive dose. Among animals treated with formononetin at 40 mg/kg/day for five days, mammary gland proliferation was enhanced 3.3-fold over saline-treated controls and was comparable to that of animals treated with estradiol-17 beta at 1 microgram/kg/day for five days. Mammary tissue estrogen receptor expression was 2-fold higher among the formononetin-treated animals (P < 0.01 vs. saline-treated controls), and plasma prolactin concentrations were increased 1.7-fold (P < 0.001 vs. saline-treated controls). In subsequent in vitro binding studies, formononetin competitively bound murine mammary estrogen receptors, but with a relative binding affinity 15,000 times less potent than that of estradiol-17 beta. The results demonstrate an ability of formononetin to support mammary gland proliferation. However, the estrogenic potency of formononetin appears extremely weak compared with that of estradiol-17 beta and is roughly proportional to estrogen receptor-binding capacity.

Growth and autologous tumor lysis by tumor-infiltrating lymphocytes from metastatic melanoma expanded in interleukin-2 or interleukin-2 plus interleukin-4.

Optimal conditions for expanding tumor-infiltrating lymphocytes (TILs) specifically cytotoxic for autologous melanoma for clinical use have not yet been identified. In several small studies, interleukin (IL)-4 was reported to promote the growth of such TILs in IL-2. Given the potential implications for TIL therapy, we attempted to confirm these findings in a larger study. Baseline data were first obtained on the proliferation, immunophenotype, and cytotoxic reactivity to autologous melanoma of TILs cultured in IL-2 alone. Similar studies were performed with TIL cultured concurrently in either IL-2 alone or in a combination of IL-2 and IL-4. TILs were obtained by excisional biopsy of tumors from 52 patients with metastatic malignant melanoma; TILs from 38 patients were expanded in IL-2 (1,000 U/ml). TILs from 19 biopsies were maximally expanded 6- to 24,000-fold (median, 300-fold) over 4-10 weeks. Expansion did not correlate with the weight of, or number of lymphocytes in, the biopsy specimen, or the site of the biopsy (lymph node vs. subcutaneous metastases). During weeks 5-8, TILs from 19 of 25 biopsy specimens lysed autologous melanoma with little or no lysis of allogeneic melanoma. Lysis of autologous tumor was blocked by antibody to class I antigens. Twenty-four TIL specimens were cultured concurrently in IL-2 alone and in IL-2 plus IL-4 and tested for growth and for lysis of autologous and allogeneic melanomas.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-2 with or without lymphokine-activated killer cells as consolidative immunotherapy after autologous bone marrow transplantation for acute myelogenous leukemia.

IL-2 with or without autologous lymphokine-activated killer (LAK) cells, administered early after ABMT for AML may eradicate residual disease and reduce relapses. This paper reports 14 patients who received IL-2 or IL-2 plus LAK cells after ABMT for AML in first relapse or at a later stage, in two separate trials. Patients with AML in first relapse (n = 9), second CR (n = 3) or second relapse (n = 2) underwent ABMT after busulfan (BU), CY and total body irradiation (n = 11) or BU/CY alone (n = 3), with marrow that was (n = 6) or was not (n = 8) purged with 4-HC. In a previously-reported Phase I trial, eight patients received IL-2 (Roche) by continuous infusion at 0.3-3.0 x 10(6) U/m2/day x 5 days and, after 6 days of rest, 0.3 x 10(6) U/m2/day x 10 days. In a subsequent trial, five patients received IL-2 at 3.0 x 10(6) U/m2/day x 5 days, underwent leukapheresis for 3 days and received their LAK cells plus IL-2 (0.3 x 10(6) U/m2/day x 10 days). A sixth patient received only 2 days of IL-2, developed sepsis and died of multiorgan failure. All other patients had mild to moderate toxicity which was reversible. All patients developed neutrophilia, lymphocytosis and thrombocytopenia. IL-2 with or without LAK therapy was initiated 21-91 days (median 51 days) after ABMT. Severe thrombocytopenia (< 10 x 10(9)/l) occurred during the apheresis days.(ABSTRACT TRUNCATED AT 250 WORDS)

Histopathological predictors of breast cancer death among Caucasians and Japanese in Hawaii.

In the United States, Caucasian women are at higher risk of death from breast cancer than age-matched Japanese-Americans. The tumors of Japanese-Americans exhibit a greater uniformity of nuclear grade (NG), greater degrees of intratumoral lymphocytic infiltration (LI), and more conspicuous sinus histiocytosis (SH) in the regional lymph nodes. To assess the impact of histopathology upon the ethnic disparity in breast cancer mortality, we compared the survival experience of Japanese and Caucasian women with breast cancer in Hawaii. The study group consisted of 443 women, aged 45-74, whose cancers were diagnosed between 1975 and 1980. Survival status at 9 or more years after diagnosis, known for 416 of these women, was used in the analyses. Age and tumor stage at diagnosis were significant predictors of breast cancer death in the logistic regression analysis. When histopathological predictor variables (NG, LI, and SH) were included in the model, age, stage, NG, and LI were independently predictive. Although NG predicted stage among all patients, and SH predicted stage among the women with invasive disease, race was an independent predictor breast cancer stage in multivariate analyses. Finally, analysis within stage subgroups revealed that race was independently predictive of cancer death among women with localized disease (confined to the breast) but not among women with regional spread (local extension or axillary nodes involves). These results indicate that histopathological differences contribute to, but only partially explain, the disparity in breast cancer mortality between Caucasians and Japanese in Hawaii.

Toxicity and immunomodulatory effects of interleukin-2 after autologous bone marrow transplantation for hematologic malignancies.

Autologous bone marrow transplantation (ABMT) for advanced hematologic malignancies is associated with high relapse rates. Interleukin-2 (IL-2) and lymphokine-activated killer (LAK) cells represent a potentially non-cross-resistant therapeutic modality that might prevent or delay relapses if used early after ABMT at a time when the tumor burden is minimal. However, high-dose chemoradiotherapy and ABMT might increase patients' susceptibility to IL-2 toxicity, and might interfere with immunologic responses to IL-2 in vivo. Therefore, to determine safety, tolerance, and immunomodulatory effects of IL-2 therapy early after ABMT, IL-2 was administered by continuous intravenous infusion to 16 patients 14 to 91 days (median, 33) after ABMT for acute leukemia, lymphoma, or multiple myeloma. Patients were sequentially assigned to escalating IL-2 "induction" doses (0.3 to 4.5 x 10(6) U/m2/d, days 1 to 5), and all patients received a nonescalating IL-2 "maintenance" dose (0.3 x 10(6) U/m2/d, days 12 to 21). Most patients exhibited mild to moderate fever, nausea, diarrhea, and/or skin rash with IL-2 infusions. The maximum tolerated "induction" dose was 3.0 x 10(6) U/m2/d; dose-limiting toxicities were hypotension and thrombocytopenia. All toxicities reversed on stopping the IL-2 infusions, and all patients completed "maintenance." Postinfusion lymphocytosis was exhibited by patients at all IL-2 dose levels. With the higher IL-2 doses, increased percentages of patients' PBMC expressed CD16 and CD56, with augmented lysis of K562 and Daudi, reflecting the induction of natural killer and circulating LAK effector activities. Increased LAK precursor activity was exhibited by patients at all IL-2 dose levels. Thus, the IL-2 therapy regimen was safely tolerated after ABMT, and pronounced immunomodulatory effects were observed with the higher IL-2 doses. These studies support the planned use of IL-2 and LAK cells after ABMT in an attempt to reduce relapses of advanced hematologic malignancies.

Enhancement by interleukin 4 of interleukin 2- or antibody-induced proliferation of lymphocytes from interleukin 2-treated cancer patients.

Systemic interleukin 2 (IL-2) and IL-2-activated lymphocytes have induced tumor regression in some cancer patients. The IL-2-activated cells have usually been generated by obtaining peripheral blood mononuclear cells (PBMC) from cancer patients shortly after systemic IL-2 therapy and culturing them with IL-2 in vitro. In an effort to augment the ex vivo generation of such cells preactivated in vivo, we examined the proliferative responses of PBMC from IL-2-treated cancer patients to several proliferative signals including IL-2, interleukin 4 (IL-4), and mitogenic antibodies to CD3 and CD28. Although much is known about the response of normal PBMC to these signals, the possibility was considered that the response of lymphocytes preactivated by IL-2 in vivo might differ from that of normal PBMC. Accordingly, PBMC obtained from ten normal, healthy controls and from 17 patients with advanced cancer 1 to 3 days after systemic IL-2 therapy were cultured for 4 days with IL-4 (1000 units/ml) and/or IL-2 (10 units/ml or 1000 units/ml) or with combinations of IL-4 and anti-CD3 +/- anti-CD28, and they were then tested for proliferation by [3H]thymidine incorporation. IL-4 failed to induce proliferation of normal PBMC and inhibited IL-2-induced proliferation, whereas IL-4 alone induced proliferation in PBMC from five of 11 IL-2-treated patients and did not inhibit but augmented the proliferation induced by IL-2 (10 units/ml and 1000 units/ml) in PBMC from six of nine patients and five of 11 patients, respectively. Anti-CD3 induced proliferation in PBMC from eight of nine patients, and the proliferation was consistently augmented by coculture with anti-CD28. Finally, IL-4 significantly augmented the proliferative responses of PBMC from IL-2-treated patients to anti-CD3, as well as to the combination of anti-CD3 and anti-CD28. Thus, in PBMC from IL-2-treated cancer patients, IL-4 enhanced the in vitro proliferation induced by IL-2 or by anti-CD3 +/- anti-CD28. The results suggest that IL-4 and/or mitogenic antibodies may be useful in augmenting the ex vivo generation of lymphocytes for clinical adoptive immunotherapy.

Induction of lymphokine-activated killer activity by interleukin 4 in human lymphocytes preactivated by interleukin 2 in vivo or in vitro.

In an attempt to augment the generation of human cytotoxic effector cells for potential cancer therapy with interleukin 2 (IL2) and lymphokine-activated killer (LAK) cells, the effect of interleukin 4 (IL4) on LAK cell induction was studied. In normal human peripheral blood lymphocytes (PBL), IL4 does not induce LAK activity and inhibits LAK induction by IL2. However, since lymphocyte activation, such as with antigen or mitogen, can render them responsive to IL4, the ability of IL4 to induce LAK activity in lymphocytes preactivated in vivo or in vitro with IL2 was investigated. PBL obtained from 12 patients with advanced cancer 1 to 3 days after IL2 therapy and from eight healthy control subjects were cultured 4 to 5 days with or without IL4 and/or IL2 and then tested for LAK activity as assessed by lysis of Daudi in a 4-h 51Cr release assay. In normal PBL, IL4 failed to induce LAK activity and consistently inhibited LAK induction by a suboptimal concentration of IL2 (10 units/ml). By contrast, IL4 induced LAK activity in PBL from seven of twelve IL2-treated patients and augmented LAK induction by the suboptimal IL2 in PBL from five of twelve IL2-treated patients. With an optimal LAK-inducing concentration of IL2 (1000 units/ml), IL4 less consistently inhibited LAK induction in normal PBL and had a variable effect upon LAK induction in PBL from IL2-treated patients. IL4 induced LAK activity in PBL obtained from a cancer patient after, but not before, systemic IL2 therapy. Similarly, IL4 induced LAK activity in normal PBL only after they had been preincubated with IL2. Thus, IL4 induces LAK activity in lymphocytes preactivated by IL2 in vivo or in vitro. Fluorescence-activated cell sorting revealed that the LAK activity, whether induced by IL4 or by IL2, was mediated largely by non-T (CD5-) natural killer-like (CD56+) cells. The results suggest a regulatory relationship between IL2 and IL4 in the induction and/or maintenance of LAK activity, which might be exploited to augment the generation of cytotoxic cells for lymphokine-mediated immunotherapy of human cancer.

Lymphokine-activated killer function following autologous bone marrow transplantation for refractory hematological malignancies.

Disease recurrence remains the major factor which limits the success of autologous bone marrow transplantation (ABMT) for refractory hematological malignancies. The administration of interleukin 2 (IL2) with or without ex vivo generated lymphokine-activated killer (LAK) cells represents a potential approach to eradicating residual disease after ABMT. However, since LAK precursor activity is radiosensitive, high dose chemoradiotherapy may abrogate LAK function and preclude clinical responsiveness to IL2 after ABMT. Furthermore, since lymphocyte subsets which mediate LAK activity may recover at different rates after ABMT, LAK cells may be phenotypically and/or functionally altered after ABMT. To determine whether IL2 responsive LAK precursor cells are present in the circulation after ABMT, peripheral blood mononuclear cells (PBMC) from 21 patients with acute leukemia or lymphoma were tested for IL2-inducible LAK activity 17-83 days after ABMT. Cells were cultured with IL2 (1000-2000 units/ml) for 4 or 5 days and then tested for cytolytic activity and/or cell phenotype. LAK activity against the Daudi cell line was detected in every PBMC sample from every patient at every time point tested. The Raji cell line and a fresh allogeneic ovarian carcinoma were also lysed by LAK cells generated after ABMT. In the subgroup of patients transplanted for non-Hodgkin's lymphoma, LAK precursor activity appeared comparable to that of healthy controls. Culture with IL2 resulted in increased mean IL2 receptor expression in lymphocytes from patients after ABMT (3.1-9.9%) and from healthy controls (3.1-12.0%). After culture with IL2, the percentage of cells bearing the natural killer cell-associated Leu-19 determinant was significantly higher in patient PBMC than in normal control PBMC (28.3 versus 8.7%). Positive and negative cell selection by fluorescence sorting after culture with IL2 revealed that most of the LAK activity after ABMT was mediated by the Leu-19+ cells. Although CD5+ T-cells were devoid of LAK activity, a subset LAK effectors was CD8+. Thus, LAK activity is rapidly reconstituted after ABMT and is mediated by cells phenotypically similar to those in normal controls. These results support the feasibility of IL2 +/- LAK as consolidative immunotherapy after ABMT.