Induction of circulating tumor necrosis factor (TNF alpha) as the mechanism for the febrile response to interleukin-2 (IL-2) in cancer patients

Suppression and transient induction of lymphokines in cancer patients after administration of polyethylene glycolated interleukin-2

Polyethylene glycolated (pegylated) interleukin-2 (PEG IL-2) was administered as a weekly i.v. bolus to patients with metastatic cancer in a phase-I trial. Efficacy, toxicity and pharmacokinetics have been described previously. To explore mechanism of IL-2 action and discover predictors of efficacy, the levels of several lymphokines were measured in pharmacokinetic serum samples. IL-1 beta and IL-6 were elevated in many patients before PEG IL-2 administration, forming a continuous, log-normal distribution among patients. The levels of the two lymphokines were strongly correlated. However, no significant correlation could be found between these levels, clinical chemistry, or tumor regression seen after PEG IL-2 administration. Three hours after PEG IL-2 administration, IL-1 beta and IL-6 levels, if elevated, fell to normal. In all patients, independent of initial levels, IL-6 and IFN-gamma, but not IL-1 beta, increased 4 to 6 h after the injection and then fell rapidly, even though PEG IL-2 levels were high and often changed only slightly during this period. This suggests an active shut down of lymphokine synthesis, or an increase in elimination rate. After the fourth administration of PEG IL-2, the peak level of IFN-gamma was 2 to 20 times higher than after the first, while the peak level of IL-6 did not change in a consistent direction. Responding patients had typical peak levels of IL-6 and IFN-gamma. Low levels of TNF and IL-4 were occasionally seen before and after PEG IL-2 administration, but no consistent pattern was evident.

Evidence for cytokine-inducible nitric oxide synthesis from L-arginine in patients receiving interleukin-2 therapy

An interferon-gamma, tumor necrosis factor, and interleukin-1-inducible, high-output pathway synthesizing nitric oxide (NO) from L-arginine was recently identified in rodents. High-dose interleukin-2 (IL-2) therapy is known to induce the same cytokines in patients with advanced cancer. Therefore, we examined renal cell carcinoma (RCC; n = 5) and malignant melanoma (MM; n = 7) patients for evidence of cytokine-inducible NO synthesis. Activity of this pathway was evaluated by measuring serum and urine nitrate (the stable degradation product of NO) during IL-2 therapy. IL-2 administration caused a striking increase in NO generation as reflected by serum nitrate levels (10- and 8-fold increase [P less than 0.001, P less than 0.003] for RCC and MM patients, respectively) and 24-h urinary nitrate excretion (6.5- and 9-fold increase [both P less than 0.001] for RCC and MM patients, respectively). IL-2-induced renal dysfunction made only a minor contribution to increased serum nitrate levels. Metabolic tracer studies using L-[guanidino-15N2]arginine demonstrated that the increased nitrate production was derived from a terminal guanidino nitrogen atom of L-arginine. Our results showing increased endogenous nitrate synthesis in patients receiving IL-2 demonstrate for the first time that a cytokine-inducible, high-output L-arginine/NO pathway exists in humans.

Chest roentgenographic abnormalities in IL-2 recipients. Incidence and correlation with clinical parameters

The chest roentgenograms of 54 patients receiving high dose interleukin-2 with or without lymphokine-activated killer cell therapy for advanced cancer were retrospectively reviewed. Thirty-nine patients (72 percent) developed chest roentgenographic abnormalities consisting of pleural effusions, 28 (52 percent); diffuse infiltrates (pulmonary edema), 22 (41 percent); and focal infiltrates, 12 (22 percent). These abnormalities resolved in 30 of 39 (77 percent) patients by four weeks after therapy. Simple pleural effusions were the only residual roentgenographic abnormalities seen and were present primarily in patients receiving IL-2 by bolus intravenous injection (8 of 28) (29 percent) as compared to continuous intravenous infusion (1 of 24) (4 percent) (p = 0.03). Only roentgenographic evidence of pulmonary edema appeared to correlate with the degree of clinical pulmonary toxicity (p = 0.001). The development of chest roentgenographic abnormalities correlated with the administration of IL-2 solely by bolus intravenous injection (p = 0.04), a pretreatment FEV1 of less than 3 L (p = 0.04), and treatment associated bacteremia (p = 0.09), but not with prior therapy, the presence of pulmonary metastases or the degree of systemic capillary leak as measured by percentage of weight gain during therapy. Although the roentgenographic abnormalities did not relate to the number of LAK cells received, two patients developed sudden onset of dyspnea and chest roentgenographic evidence of pulmonary edema shortly after the first LAK cell administration, implying that a direct cause-and-effect relationship exists in some patients. Possible mechanisms for these IL-2 related chest roentgenographic abnormalities and pulmonary toxicity in general are discussed.

Tumour necrosis factor mediates the survival benefit of interleukin 2 in a murine pulmonary metastases model

Antibody to tumour necrosis factor (TNF Ab) markedly decreases the toxicity of systemic interleukin-2 (IL-2) in mice but does not completely abrogate the anti-tumour response in terms of number of pulmonary metastases. Experiments were performed with a murine model of pulmonary metastases treated with high-dose IL-2 and concomitant TNF Ab or control antibody (CON Ab) to determine the effects of TNF Ab on survival. Mice were given either equal doses of IL-2 and TNF Ab or CON Ab or equitoxic doses of IL-2. In four consecutive experiments mice given TNF Ab tolerated 5 to 6 additional IL-2 doses (a 40-60% increase in total doses) in the equitoxic IL-2 dose group compared to the maximally tolerated dose with CON Ab. In all four experiments TNF Ab-treated mice had decreased survival compared to the CON Ab group given equal doses of IL-2 and in two of four experiments this difference was statistically significant (P2 < 0.01). Mice given 40-60% additional doses of IL-2 with TNF Ab had no improvement in survival compared with equitoxic doses of IL-2 with CON Ab in three of four experiments (P2 = 0.32, P2 = 0.67, P2 = 0.69). The TNF Ab preparation had no direct inhibition of IL-2 activity in an in vitro IL-2 proliferation bioassay. TNF Ab consistently blocks IL-2 toxicity and it also abrogates IL-2 therapeutic efficacy such that survival parallels treatment toxicity in this experimental model.

The activation of polymorphonuclear neutrophils and the complement system during immunotherapy with recombinant interleukin-2

The toxicity due to interleukin-2 (IL-2) strongly resembles the clinical picture seen during septic shock. In septic shock activation of polymorphonuclear neutrophils (PMN) and the complement system contribute significantly to the pathophysiology of the condition. We therefore investigated whether similar events contributed to the toxicity observed with IL-2. Four patients received seven cycles of escalating dose IL-2 (18.0 to 72.0 X 10(6) IU m-2 day-1) and 16 were treated with 20 cycles of fixed dose IL-2 (12.0 or 18.0 X 10(6) IU m-2 day-1). Toxicity, as judged by hypotension (P = less than 0.005) and capillary leakage (fall in serum albumin 18.2 vs 4.0 gm l-1; P = less than 0.0005 and weight gain 4.0 vs 1.2 kg; P = less than 0.025) were worse with the esc. dose protocol. PMN became activated following IL-2 with mean peak elastase/alpha 1-antitrypsin (E alpha 1 A) and lactoferrin values of 212 (SEM = 37) and 534 (SEM = 92) ng ml-1 respectively occurring 6 h after the IL-2. Peak values for the esc. dose IL-2 group being generally higher than 500 ng ml-1. Activation of the complement cascade was evidenced by a dose dependent elevation of peak C3a values (fixed dose 9.1 (SEM = 0.6); esc. dose 25.7 (SEM = 6.33); P = less than 0.005) on day 5 of IL-2. There was a significant correlation between C3a levels and the degree of hypotention during the first 24 h after IL-2 (r = 0.91) and parameters of capillary leakage such as weight gain and fall in serum albumin (r = 0.71). These data suggest that activation of PMN initiates endothelial cell damage which subsequently leads to activation of the complement cascade. This latter system then contributes to the haemodynamic changes and capillary leakage seen in IL-2 treated patients.

Correlation of eosinophilia with clinical response in patients with advanced carcinoma treated with low-dose recombinant interleukin-2 and mitomycin C

On the basis of our clinical findings that the ability of cancer patients to generate lymphokine-activated killer cells became markedly augmented after mitomycin C administration, we designed a treatment regimen comprising mitomycin C 12 mg/m2, i.v. on day 1 and recombinant interleukin-2 700 U/m2 (8000 IU/kg), i.v. every 12 h from day 4 through day 8. The treatment course was repeated at almost 7-day intervals. Altogether 33 patients with advanced carcinoma, including mainly gastrointestinal carcinoma, were treated with this regimen. Of these, 10 had a partial response (PR) and 4 had a minor response (MR). Since eosinophil counts peaked 1 day after either the first or second course of the therapy, the posttreatment values were compared to each pretreatment level, with regard to the clinical antitumor response to this treatment. When patients who showed PR were defined as responders, absolute eosinophil counts and the percentage of eosinophils in responders after both the first and second courses of the therapy were significantly greater than each pretreatment value or the posttreatment level in nonresponders. Further, these findings were almost identical, when both PR and MR were considered to be a true remission and therefore patients who exhibited PR or MR were defined as responders, although the difference between posttreatment levels of eosinophils in responders and nonresponders was not significant at the second course. These results indicate that eosinophilia induced by this treatment correlates with the clinical response to this therapy.

Clinical trial of natural human lymphocyte-derived interleukin 2 in cancer patients: effects on cytokine production and suppressor cell status

Lymphocyte-derived, natural, glycosylated interleukin 2 (IL 2) may have different effects in vivo than the non-glycosylated recombinant IL 2 hitherto employed in clinical trials. To test this, 9 tumor patients were given 3-6 x 10(6) U/day natural IL 2 by continuous infusion for 5 days. Compared with previously published results obtained using recombinant IL 2, as far as similar tests were performed, no unexpected results were obtained with natural IL 2 in the present study. Plasma TNF-alpha levels increased considerably during therapy, IFN-gamma very slightly, whereas IL 2-stimulated secretion of either cytokine in vitro fluctuated greatly. CD16+ and CD25+ cells increased and CD45R+ cells decreased after treatment, consistent with significant lymphocyte activation in vivo. MHC-unrestricted cytotoxicity increased after treatment. The level of CD8+ cells was and remained within the normal range, although suppressive activity generated in mixed lymphocyte culture was deficient prior to therapy. Interestingly, this normalised after therapy. These results extend studies of immunological monitoring of patients receiving IL 2, based on the first trial using natural rather than recombinant IL 2.

Appearance of cytokine-associated central nervous system myelin damage coincides temporally with serum tumor necrosis factor induction after recombinant interleukin-2 infusion in rats

Endogenous tumor necrosis factor (TNF) activity, assessed by L-929 fibroblast bioassay, was determined in serum samples from rats infused intravenously with recombinant interleukin-2 (rIL-2) or rIL-2 vehicle. Parallel studies of cerebral ultrastructure were conducted in additional rats, comparably infused. Rats received rIL-2 or vehicle either one time only or 3 times daily for 3 days. TNF activity was assessed at 2, 4, and 8 h after the single or final infusion. Rats employed for ultrastructural studies were sacrificed at 4 h after the single or final infusion. Every rIL-2-infused rat exhibited unusual abnormalities of axonal ultrastructure, identical to those previously described after in vitro TNF application to living spinal cord slices. Serum samples drawn during and after the development of axonal changes revealed significantly elevated circulating TNF activity. Controls exhibited neither TNF activity nor altered axons. These studies demonstrate that, following rIL-2 infusion in rats, endogenous TNF circulates at elevated levels during the development of rIL-2-related central nervous system abnormalities similar to those produced in vitro by recombinant TNF. Whether rIL-2-induced circulating TNF is causally-related to the observed myelin damage remains to be determined but merits further investigation, particularly since blood-brain barrier function has been shown to be compromised following rIL-2 infusion.

Interleukin-2 induces early multisystem organ edema mediated by neutrophils

Interleukin-2 (IL-2), an agent known to activate neutrophils (PMN) with thromboxane (Tx)B2 release, produces pulmonary edema within 6 hours of intravenous infusion. This study tests the role of PMN in mediating the edema. Anesthetized rats received 10(6)U recombinant human IL-2 (n = 15) or vehicle (n = 14) as a constant intravenous infusion during a period of 1 hour. At this time there was leukopenia 3.63 +/- 0.43 (x10(3)/mm3) relative to vehicle-infused control rats 6.12 +/- 0.86 and a decline in PMN, 2.19 +/- 0.14 relative to control value of 3.33 +/- 0.05 (both p less than 0.05). After 6 hours edema, as measured by increase in the wet to dry weight (W/d) ratio, was present in the lungs (4.93 +/- 0.20 relative to control 4.06 +/- 0.10), heart (4.09 +/- 0.11 versus 3.76 +/- 0.08), liver (3.50 +/- 0.10 versus 3.18 +/- 0.10), and kidney (4.25 +/- 0.07 versus 4.00 +/- 0.07) (all p less than 0.05). There was increased lung permeability demonstrated by bronchoalveolar lavage fluid protein concentration of 1970 +/- 210 micrograms/mL relative to control 460 +/- 90 micrograms/mL (p less than 0.05). Interleukin-2 resulted in lung PMN sequestration of 53 +/- 7 PMN/10 high-power fields (HPF) relative to 23 +/- 2 PMN/10 HPF in controls (p less than 0.05) and increased plasma TxB2 levels to 1290 +/- 245 pg/mL relative to control 481 +/- 93 pg/mL (p less than 0.05). Pretreatment of other rats (n = 8) with selective anti-rat neutrophil antiserum 18 hours before the experiment led to a peripheral PMN count 10% of baseline and prevented edema in the lungs (W/d ratio 4.20 +/- 0.16) and heart (3.67 +/- 0.07) (both p less than 0.05) but not liver or kidney. Protein in lung lavage was reduced to 760 +/- 220 micrograms/mL (p less than 0.05). The protection afforded by leukopenia was associated with lack of PMN sequestration and prevention of the increase in plasma Tx levels (484 +/- 120 pg/mL, p less than 0.05). These data indicate that the rapid induction of lung and heart edema with a 1-hour infusion of IL-2 in the rat is mediated, in large part, by activated PMNs.

Acute renal failure with preserved renal plasma flow induced by cancer immunotherapy

Adoptive immunotherapy in patients with advanced cancer produces significant regression of metastatic disease in selected patients, but it is complicated by severe side effects. Prevention of these complications is still limited because their precise mechanisms remain unknown. For this reason we have investigated renal function and hemodynamic parameters in 16 patients with renal cell carcinoma before and during treatment with a combination of high doses of both recombinant interleukin-2 (rIL2) and recombinant alpha-interferon. After patients had received three injections of combined immunotherapy, there was a decrease in mean blood pressure (-20%), glomerular filtration rate (-25%), urine output (-50%), and fractional sodium excretion (-0.8%). This was associated with an increase in heart rate (+30%), plasma creatinine level (+30%), fractional potassium excretion (+14%) and microalbuminuria (+130%). However, renal plasma flow remained constant. The increment in microalbuminuria may reflect an alteration of glomerular capillary permeability. The reduction in GFR may be accounted either for a decrease in efferent to afferent arteriolar resistance ratio, leading to a decrease in glomerular capillary pressure, or for a decrease in ultrafiltration coefficient, or both. Nonsteroidal antiinflammatory drugs, such as ketoprofen, used to minimize side effects, could considerably worsen renal function and should be avoided in patients treated by rIL2. Our results bring new insights into the pathogenesis of functional acute renal failure and provide a rational basis for the use of vasopressors in the treatment of cytokine-induced acute renal failure.

Interleukin 2 induces tumor necrosis factor gene expression in vivo

Interleukin 2 (IL-2) treatment of malignancies is often associated with severe toxicity, and the alterations observed after high dose administration of IL-2 are similar to those induced by recombinant tumor necrosis factor (TNF). We therefore examined the hypothesis that IL-2 induces TNF gene expression in vivo. Purified, recombinant human IL-2 was injected intraperitoneally into mice which had been previously primed with complete Freund's adjuvant (CFA). Biologically-active TNF was detected in the ascites fluid of CD-1 mice; it was detectable 30 minutes after IL-2 and peaked at 1 hour (500 +/- 158 units/ml). Plasma levels of TNF also peaked at 1 hour at 32 +/- 4 units/ml. Similar kinetics were observed in CBA/J mice. TNF specific mRNA was also present in the ascites cells, and peaked 30 minutes after IL-2 injection into CBA/J mice. Injection of vehicle containing 10 times the maximum contaminating dose of endotoxin did not induce TNF above background levels. As a further control for potential endotoxin contamination, IL-2 was injected into endotoxin hyporesponsive C3H/HeJ mice. These mice also demonstrated the rapid upregulation of biologically-active TNF in the ascites, with peak production occurring at 1 hour (125 +/- 47 units/ml). The induction of biologically-active TNF in the C3H/HeJ mice was associated with a peripheral blood neutrophilia and lymphopenia, pathophysiologic alterations that have been attributed to TNF. These data show that a single injection of purified, recombinant IL-2 induces TNF gene expression in vivo.

The role of cytokines in oncology

The availability of sufficient quantities of recombinant human cytokines and promising preclinical data have led to their introduction into clinical trials. Cytokines have potential as new therapeutic agents in a variety of hematological disorders as well as in solid tumors. Only a few of the still increasing number of these glycoprotein hormones have been studied in humans so far, either as single agents or in combination with chemotherapy and other cytokines. Their clinical effects, beneficial role in supportive care, and use in the treatment of certain cancer patients are reviewed.

OKT3 first-dose reaction: association with T cell subsets and cytokine release

Use of the monoclonal antibody OKT3 to prevent or treat allograft rejection has become commonplace. Its administration is often complicated by serious side effects, usually occurring within one to two hours after OKT3 is given, and is termed first-dose reaction. The mechanism underlying these signs and symptoms is poorly defined, but may be related to cytokine release. Twenty-three kidney or kidney/pancreas transplant recipients received OKT3 as treatment of acute rejection. Signs and symptoms occurring after the first dose were observed and quantitated prospectively, and a reaction score was calculated. Blood was drawn immediately before, and at 2 and 24 hours after the first dose of OKT3 for determination of interleukin-2 (IL2), interferon-gamma (IFN gamma), and tumor necrosis factor-alpha (TNF alpha) levels, and flow cytometric analysis of T cell subsets. Two groups were defined based on severity of first-dose reaction. Group 1 patients (N = 11) had very mild reactions (reaction score less than or equal to 3); Group 2 patients (N = 12) had more severe reactions (score greater than or equal to 5). All patients demonstrated a significant rise in serum TNF alpha from baseline to two hours after OKT3 (9 +/- 3 pg/ml to 378 +/- 54 pg/ml, P less than 0.0001), and there was significant correlation between reaction scores and two-hour TNF alpha levels (P = 0.005). Group 2 patients had higher TNF alpha levels at two hours than did Group 1 patients (484 +/- 75 pg/ml vs. 263 +/- 62 pg/ml, P = 0.04). Levels of IL2 and IFN gamma were not elevated at any sampling time.(ABSTRACT TRUNCATED AT 250 WORDS)

Prolonged interleukin-2 (IL-2) treatment can augment immune activation without enhancing antitumor activity in renal cell carcinoma

Preliminary studies involving small numbers of patients have suggested that interleukin-2 (IL-2) administered by continuous infusion in repetitive weekly cycles using doses of 3 x 10(6) U/M2/day is immunologically active and can induce tumor responses in patients with renal cell carcinoma. This study was designed to examine both the immunological and clinical effects of prolonged infusion IL-2 given by repetitive weekly cycles; first at moderate doses for 4 weeks as an impatient followed by lower doses of IL-2 for up to 5 months. Prolonged IL-2 treatment was investigated because previous studies revealed that patients had a return to their baseline immune status within 4 weeks after completing IL-2 treatment. Twenty-five patients (including 18 with renal cell carcinoma) were treated with one of two regimens utilizing IL-2 as sole therapy. These regimens were designed to induce augmented and prolonged immune activation based upon in vitro and in vivo data. Though patients on both arms of the study demonstrated sustained lymphocytosis, increase in numbers of natural killer cells, and induction of lymphokine-activated killer activity with prolonged IL-2 administration, only 1 out of the 18 patients with renal cell carcinoma demonstrated a sustained partial antitumor response to therapy. Furthermore, several patients demonstrated profound immune activation, without any evidence of tumor regression. The lack of clinical responses in these patients showing marked activation of LAK cytotoxicity suggests that other variables must also influence the likelihood of antitumor effects for patients receiving IL-2 therapy.

Proposed link between cytokines, nitric oxide and human cerebral malaria

Nitric oxide (NO), also known as endothelial-derived relaxing factor (EDRF), is generated by a range of cell types including endothelial cells, smooth muscle cells and neurons, and mediates a range of different physiological functions, such as maintenance of vascular tone and neuro-transmission. In this article, Ian Clark, Kirk Rockett and Bill Cowden propose that when vascular generation of NO is particularly high (for example, if local intravascular levels of tumour necrosis factor (TNF) are markedly increased) this mediator could diffuse to nearby neurons, be misinterpreted as being of synaptic origin and thus interfere with orderly neuro-transmission. NO of vascular origin could also, through vasodilation of cerebral vessels, contribute to increased intracranial pressure and thus to certain of the clinical signs seen in cerebral malaria. As well as contributing to cerebral malaria, these phenomena could also lead to the neurological changes observed in certain other systemic diseases.

IL-2 dose regulates TNF-alpha mRNA transcription and protein secretion in human peripheral blood lymphocytes

TNF-alpha is an inducible cytokine with widely divergent effects on numerous target tissues. Secretion and response to TNF-alpha appear to be required in cellular immune function including that of classical cytotoxic T cell development, non-MHC restricted cytotoxicity, and the mixed lymphocyte reaction. In addition, production of TNF-alpha has been implicated in a number of pathophysiologic processes involving lymphocytes. In this report, we have investigated the regulation of TNF-alpha in normal lymphocytes stimulated with IL-2. Our results demonstrate that the level of TNF-alpha gene expression can be determined by the quantity of IL-2 present during lymphocyte activation. The increased steady-state levels of TNF-alpha mRNA were attributable to an enhanced rate of nuclear transcription. TNF-alpha secretion increased with escalating IL-2 dose in parallel to that of mRNA production. The modulation of TNF-alpha gene expression by IL-2 concentration has been previously unrecognized and may be an important mechanism in normal immunohomeostasis, cellular dysregulations involving TNF production, and the dose-dependent toxicities observed with high-dose IL-2 immunotherapy.

Involvement of thromboxane and neutrophils in multiple-system organ edema with interleukin-2

Interleukin-2 (IL-2) produces toxicity characterized by generalized edema within 24 hours. This study tests whether the rate of IL-2 administration modulates the onset of edema and examines thromboxane (Tx) and neutrophils as possible mediators of this event. Recombinant human IL-2, 10(5) U (n = 7), 10(6) U (n = 9), or vehicle (n = 8) were given to anesthetized rats intravenously during a period of 1 hour. At 6 hours edema, as measured by increase in wet to dry weight (w/d) ratio, was present in the heart, liver, and kidney, with 10(5) U IL-2 and in the lung, heart, liver and kidney, with 10(6) U IL-2, relative to values with vehicle-infused controls (all p less than 0.05). With a 1-hour infusion of 10(6) U IL-2, there was an increase in plasma thromboxane (Tx)B2 level to 1290 +/- 245 pg/mL, higher than 481 +/- 93 pg/mL in control rats (p less than 0.05); lung polymorphonuclear leukocyte (PMN) sequestration of 53 +/- 7 PMN/10 higher-power fields (HPF) relative to 23 +/- 2 PMN/10 HPF in controls (p less than 0.05); and increased bronchoalveolar lavage (BAL) fluid protein concentration of 1970 +/- 210 micrograms/mL relative to 460 micrograms/mL in controls (p less than 0.05). When 10(6) U IL-2 was given as a 1-minute intravenous bolus (n = 9), edema was not demonstrated, plasma TxB2 levels were similar to controls, there was no leukosequestration, and BAL protein levels were normal. These data indicate that a constant infusion but not the rapid bolus administration of IL-2 produces in rats multiple-system organ edema, increased plasma TxB2, sequestration of PMNs, and microvascular permeability. These findings may explain the early toxicity seen in patients given high-dose IL-2 in cancer treatment.

Cutaneous response to recombinant interleukin 2 in human immunodeficiency virus 1-seropositive individuals

We report that 11 human immunodeficiency virus 1 (HIV-1)-seropositive patients, including three AIDS patients, were able to generate a cellular immune response to the intradermal injection of low doses (2-10 micrograms) of recombinant interleukin 2 (rIL-2). A dose-dependent zone of induration appeared at the site of injection, peaked at 24 hr, and was accompanied by the local accumulation of T cells, monocytes, and Langerhans cells. Despite the reductions in the CD4+ T-cell counts in the peripheral blood of most patients, CD4+ T-cells could still be mobilized with rIL-2 injections into the skin. The total number of immigrant cells was equivalent to those in HIV-1-seronegative patients, although the CD4+/CD8+ ratio of the dermal population was reduced. In response to rIL-2, major histocompatibility complex (MHC) class II antigen was expressed on the surface of keratinocytes, Langerhans cells, lymphocytes, and macrophages. In addition, the gamma interferon (IFN-gamma)-induced protein IP-10 rapidly appeared in dermal inflammatory cells and keratinocytes. A majority of HIV-1-seropositive patients demonstrated low or absent responses to common skin-test antigens. Those with positive zones of induration were often defective in the cellular expression of the IFN-gamma-induced MHC class II antigen. The simultaneous administration of rIL-2 and soluble antigen at widely separated cutaneous sites led to an enhancement of skin-test antigen reactivity in seropositive patients. The results suggest that local administration of rIL-2 to seropositive patients may act systemically, stimulating cellular immunity to recall antigens, and thus may be of potential benefit in the defense against opportunistic pathogens encountered in HIV-1 infection.

Differential central nervous system responses following single and multiple recombinant interleukin-2 infusions

The effects of systemic recombinant human interleukin-2 (rIL-2) infusion on cerebrovascular permeability to an endogenous circulating macromolecule, immunoglobulin G (IgG), were assessed in rats after single and multiple rIL-2 infusions. Ultrastructural detail of the cerebral vasculature and the related brain parenchyma was also examined for rIL-2-related changes following single and multiple infusions. Animals examined 6 and 24 h after a single rIL-2 infusion exhibited moderately increased permeability to IgG that was not observed in those animals examined 6 h after 5 days of rIL-2 infusion. Alterations of cerebrovascular morphology were evident as early as 6 h after a single infusion and were accompanied by occasional axonal degeneration and demyelination. Such structural changes persisted, becoming more widespread after 5 days of rIL-2 infusion, at which time they were associated with other neuronal as well as glial alterations.

An acquired chemotactic defect in neutrophils from patients receiving interleukin-2 immunotherapy

Bacterial sepsis is a frequent complication in patients with cancer who are receiving high doses of interleukin-2. We evaluated the function of neutrophils from such patients to determine whether there was any abnormality in this form of host defense. Before interleukin-2 therapy, neutrophils from 31 patients with metastatic cancer were normal in assays of random migration and chemotaxis. Superoxide production, phagocytosis, secretion of granule proteins, and bactericidal activity were also normal. Neutrophils from the patients near the end of the first course of interleukin-2 had severely impaired chemotaxis in response to a formylated peptide stimulus (mean [+/- SEM], 49.6 +/- 7.4 percent of base line; P less than 0.001). The detect in chemotaxis improved 5 to 10 days after patients completed the first course of interleukin-2 therapy but recurred toward the end of the second course of such therapy (35.3 +/- 6.9 percent of base line; P less than 0.001). The chemotactic response to a second stimulus (zymosan-activated serum) was also abnormal, but random migration, superoxide production, bactericidal activity, and the secretion of neutrophil granule constituents remained normal or increased throughout treatment with interleukin-2. We conclude that patients who receive interleukin-2 immunotherapy acquire an acute, profound, and reversible defect in neutrophil chemotaxis that may contribute to the high morbidity resulting from bacterial infections in these patients.

Haemodynamic effects induced by intravenous administration of high doses of r-Met Hu IL-2 [ala-125] in patients with advanced cancer

We analyzed the haemodynamic effects of high doses of r-Met Hu IL-2 [ala-125] in four patients with advanced cancer. Haemodynamic parameters were measured daily from days 1 to 6 of treatment. Mean arterial pressure decreased significantly (98 +/- 11 mmHg on day 1 versus 84 +/- 7 mmHg on day 5; p = 0.0435) as did systemic vascular resistance (2042 +/- 296 dynes s cm-5 m-2 on day 1 versus 1166 +/- 87 dynes s cm-5 m-2 on day 5; p = 0.003). There was a significant increase in mean pulmonary artery pressure (13.25 +/- 3.30 mmHg on day 1 versus 20.75 +/- 7.41 mmHg on day 5; p = 0.03), systemic oxygen consumption (173.5 +/- 37.8 ml min-1 m-2 on day 1 versus 257.8 +/- 20.5 ml min-1 m-2 on day 5; p = 0.02) and cardiac index (3.86 +/- 0.58 l min-1 m-2 on day 1 versus 5.77 +/- 0.21 l min-1 m-2 on day 5; p = 0.008). There was no significant decrease in the arteriovenous oxygen content difference (4.5 +/- 0.8 ml dl-1 on day 1 versus 4.46 +/- 0.22 ml dl-1 on day 5). Increases in oxygen delivery (570 +/- 163 ml min-1 m-2 on day 1 versus 750 +/- 109 ml min-1 m-2 on day 5 and oxygen extraction ratio (29.95% +/- 6.37% on day 1 versus 34.60% +/- 4.35% on day 5) were not statistically significant. We concluded that the haemodynamic effect induced by high doses of r Hu-IL-2 is similar to that seen in septic shock.

Primary hypothyroidism associated with interleukin-2 and interferon alpha-2 therapy of melanoma and renal carcinoma

Four patients out of twenty with renal cancer and melanoma undergoing cancer immunotherapy with interleukin 2 (IL-2) and interferon alpha-2 (IFN-alpha 2) had laboratory evidence of hypothyroidism starting at cycle three to six, with a decline in serum thyroxine below normal and, in three cases, a rise in serum thyrotropin and thyroglobulin. One hypothyroid patient had elevated serum antimicrosomal antibody titres before the start of treatment and two others responded similarly during therapy. Three of the sixteen euthyroid patients also developed elevated titres of this antibody. Partial or complete remission was observed in seven of the patients--three of the four with hypothyroidism showed tumour regression. Thus IL-2 and IFN-alpha 2 can cause hypothyroidism, presumably via induction or exacerbation of autoimmune thyroid reactions. The occurrence of hypothyroidism may be mediated by high-dose IL-2 (rather than by LAK cell therapy as previously suggested) and potentiated by IFN-alpha 2.

Cytokines in cancer therapy

Cytokines, small biological response modifying proteins produced by hematopoietic and other cells, may one day play a significant role in the treatment of human cancer. This article presents an overview of the cytokines, including descriptions of their origins, mechanisms of action, and antitumor activities. Several classes of cytokines are discussed, including the interferons, the interleukins, and tumor necrosis factor. Several of these agents, either alone or in combination, are currently involved in clinical trials for the treatment of specific cancers. Th interaction of cytokines and monoclonal antibodies is also discussed.

Passive immunization against tumor necrosis factor partially abrogates interleukin 2 toxicity

Passive immunization against TNF allowed non-tumor-bearing C3H/HEN mice and tumor-bearing C57BL/6 mice to tolerate significantly more doses of IL-2 before death (p less than 0.005 and p less than 0.001, respectively). The antitumor effect of IL-2 against both 3-d and 10-d pulmonary metastases was maintained in mice treated concurrently with neutralizing antibodies to TNF. In one experiment with 10-d pulmonary metastases, increased administration of IL-2 made possible by passive immunization against TNF significantly improved the antitumor response compared to equitoxic doses of IL-2 and control antibody. The results indicate that TNF is a mediator of IL-2 toxicity but contributes minimally to the antitumor effects of IL-2. Strategies to inhibit TNF may improve the therapeutic index of IL-2 as a neoplastic agent.