Direct stimulation of cytokines (IL-1 beta, TNF-alpha, IL-6, IL-2, IFN-gamma and GM-CSF) in whole blood. I. Comparison with isolated PBMC stimulation

In vivo modulation of cytokine synthesis by intravenous immunoglobulin

We examined the effects of intravenous immunoglobulin (IVIG) on cytokine regulation in vivo using samples taken before and after replacement-dose (200-400 mg/kg) IVIG in a group of patients with common variable immunodeficiency (CVID) and X-linked agammaglobulinaemia (XLA). The intracellular cytokine content of CD4+ and CD8+ lymphocytes, and their CD28+/- subsets, were measured following in vitro activation with phorbol myristate acetate (PMA) and ionomycin. The cytokines IL-2, interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha), and the early activation marker CD69, were assessed by four-colour flow cytometry of whole blood cultures taken before and after IVIG infusion. There was a significant increase in IL-2 expression in CD4+ (and CD4+28-) cells and an increase in TNF-alpha expression in CD8+28- cells following IVIG in CVID, but not in XLA patients. IFN-gamma and CD69 expression were not affected by IVIG infusion. This increase in TNF-alpha and IL-2, combined with unchanged IFN-gamma expression, is evidence against the putative 'anti-inflammatory' role of IVIG, and may explain the failure of resolution of granulomata in CVID patients treated with IVIG alone.

A human whole-blood assay for analysis of T-cell function by quantification of cytokine mRNA

A whole blood assay was developed for T-lymphocyte analysis which allows the quantification of induced cytokine mRNA expression. We applied a novel kinetic reverse transcription polymerase chain reaction method which directly measures product accumulation using Taqman technology. Quantitative results were obtained by using beta-actin and cytokine standard curves generated from synthetic external standards. Since quantification relies on threshold cycles for fluorescence detection (Ct), this technique proved to be accurate over a dynamic range of at least five orders of magnitude. To evaluate the method a study was undertaken to find optimal conditions for whole-blood stimulation with soluble anti-CD3 monoclonal antibodies in the presence of a costimulatory signal mediated by anti-CD28 monoclonal antibody. Therefore, whole blood was taken from healthy individuals (n = 10) and aliquots for mRNA measurement were withdrawn after 0, 4, 8 and 24 h of stimulation. Optimal assay conditions were reached with 1 : 10 diluted heparinized whole blood and after stimulation with equimolar amounts of anti-CD3 and anti-CD28 monoclonal antibodies (1 microgram/ml). Interferon-gamma and tumour necrosis factor-alpha proved to be early response cytokines with peak expression at 4 h. In contrast, interleukin (IL)-2, IL-4 and IL-10 required 8 h of stimulation. This novel whole-blood assay is potentially useful for monitoring T-cell-specific immune functions in a variety of clinical settings. Using whole blood obviates the need for T-cell purification and may therefore closely approximate the state of responsiveness of circulating T cells in vivo.

Polymorphic haplotypes of the interleukin-10 5' flanking region determine variable interleukin-10 transcription and are associated with particular phenotypes of juvenile rheumatoid arthritis

OBJECTIVE

To determine the distribution of the interleukin-10 (IL-10) 5' flanking region haplotypes in children with arthritis and in controls, and to investigate the functional significance of each haplotype.

METHODS

Sequence-specific oligonucleotide probing was used to determine haplotype frequency. Transient transfection studies were used to investigate the transcription of reporter genes driven by each haplotype. Whole blood cultures were performed to assess IL-10 production by each genotype.

RESULTS

Patients with arthritis involving >4 joints were more likely to have a genotype with an ATA haplotype than those whose arthritis remained restricted to <4 joints. This ATA haplotype was associated with lower transcriptional activity than the GCC haplotype (P = 0.02), and the ATA/ATA genotype was associated with lower IL-10 production under lipopolysaccharide stimulation than other genotypes (P < 0.02).

CONCLUSION

The results of this study demonstrate the functional significance of the ATA haplotype and reveal a significant association of genotypes containing this haplotype with extended oligoarthritis.

Cytokines in detoxified patients with chronic alcoholism without liver disease: increased monocytic cytokine production

BACKGROUND

The aim of the present study was to examine the production of interferon-gamma, tumor necrosis factor-alpha (TNF-alpha), granulocyte-macrophage colony stimulating factor (GM-CSF), interleukin-6 (IL-6), IL-10, IL-4, IL-5, IL-1 receptor antagonist (IL-1RA), and prostaglandin E2 in relation to the number of leukocytes in the blood of detoxified, chronic alcoholic patients without apparent liver disease (AWLD).

METHODS

Phytohemagglutinin + lipopolysaccharide-induced production of the above variables as well as the number of white blood cells and differentials were determined in detoxified AWLD patients and normal volunteers.

RESULTS

Detoxified AWLD patients have a significantly higher production of IL-6, IL-10, TNF-alpha, GM-CSF, and IL-1RA and significantly increased numbers of leukocytes and neutrophils compared to normal volunteers.

CONCLUSIONS

Detoxified AWLD patients show an increased production of proinflammatory cytokines, i.e., IL-6, TNF-alpha, and GM-CSF, as well as negative immunoregulatory proteins, such as IL-10 and IL-1RA.

Capacity to produce cytokines during weight restoration in patients with anorexia nervosa

OBJECTIVE

Anorexic patients are surprisingly free of infectious complications despite their seriously undernourished state. To study this phenomenon, we longitudinally measured the capacity to produce cytokines in restricting-type anorexic patients.

METHODS

Lymphoproliferative responses with phytohemagglutinin (PHA) and the capacity of whole blood to produce cytokines, such as interleukin-1 (IL-1), IL-6, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and granulocyte-colony stimulating factor (G-CSF), were longitudinally measured before and after weight gain, that is, at admission and at less than 60, 65, and 75% of standard body weight (SBW), in 17 patients with restricting-type anorexia nervosa and in 17 control subjects.

RESULTS

Cytokine production of IL-1, IL-6, and TNF-alpha per monocyte in the anorexic patients recovered only with the start of refeeding, whereas IFN-gamma production per lymphocyte was similar to that in control subjects and did not change during weight restoration. Only G-CSF production, even at 75% SBW, did not improve during weight restoration. Between the weight at admission and 65% SBW, the increase in the percentage of SBW and improvement of the total protein level were significantly correlated with improvement of the lymphocyte proliferative response with PHA.

CONCLUSIONS

The capacity to produce most cytokines recovered with the start of weight gain; however, recovery was not correlated with weight gain. The results suggest that the capacity to produce cytokines in these anorexic patients was dependent on something other than the absolute value of body weight, such as the start of refeeding, the neuroendocrine system, or the autonomic nervous system.

Peroxisome proliferator activated receptor-gamma, leptin and tumor necrosis factor-alpha mRNA expression during very low calorie diet in subcutaneous adipose tissue in obese women

BACKGROUND

PPAR gamma, leptin and TNF alpha are three major factors that play a key role in influencing adipocyte differentiation and both adipose tissue function and metabolism. However, the regulation of these three genes during a dynamic period of weight loss is unknown. We therefore investigated the concomitant regulation of the mRNA expression of PPAR gamma, leptin and TNF alpha in adipose tissue during a 21-day very low calorie diet (VLCD) in 12 non-diabetic obese women.

METHODS

The mRNA levels of PPAR gamma, leptin and TNF alpha were quantified by quantitative RT-competitive PCR in abdominal subcutaneous adipose tissue before and during VLCD (940 kcal/day).

RESULTS

VLCD induced weight loss (approximately 6 kg) and improved insulin sensitivity. Simultaneously, VLCD induced the reduction in the adipose tissue mRNA abundances of PPAR gamma (-13%, p < 0.05) and of leptin (-58%, p < 0.005), whereas TNF alpha mRNA levels increased (+78%, p < 0.005). PPAR gamma and leptin mRNA levels were correlated before (r = 0.778, p < 0.01) and after VLCD (r = 0.797, p < 0.01). Serum HDL-cholesterol concentrations were positively associated with PPAR gamma (r = 0.696, p < 0.03) and leptin (r = 0.806, p < 0.01) mRNA levels.

CONCLUSIONS

The increase in TNF alpha mRNA levels suggested that a local increased expression of this cytokine in adipose tissue might play a role in the control of the fat mass during weight loss. PPAR gamma and leptin mRNA levels were positively associated both before and after VLCD, suggesting that common regulatory mechanism(s) might control their expression. More strikingly, we found strong positive correlations between circulating HDL-cholesterol and both PPAR gamma and leptin mRNA levels, suggesting the existence of physiological links between circulating lipoprotein metabolism and adipose tissue function.

In vitro measurement of lymphocyte steroid sensitivity: lack of agreement between whole blood culture and separated lymphocyte culture

The use of a whole blood culture to measure steroid sensitivity has previously been compared to the use of a separated lymphocyte assay. Good correlation between the two methods was reported. However the number of subjects studied appears to have been small and no patients with steroid resistance were studied. We have studied a large number of subjects and compared steroid sensitivity measured by a whole blood culture with an established separated lymphocyte assay. Proliferation was stimulated with phytohaemagglutinin and inhibited by dexamethasone. A wide range of steroid sensitivity was found between individuals. In steroid sensitive subjects, good agreement was seen between the two assays. However in individuals identified as steroid resistant by the separated lymphocyte assay, steroid resistance was not seen using the whole blood assay. This is important because in vitro lymphocyte steroid resistance, as measured by the separated lymphocyte assay has been shown to predict a poor in vivo response to steroid therapy. Using the whole blood culture this steroid resistance would not be demonstrated. Hence the use of a whole blood assay can not be recommended.

Alterations in immune functions during normal aging and Alzheimer's disease

It is thought that aging induces immune changes, which are related to the pathophysiology of Alzheimer's disease (DAT). In this study, the total number of leukocytes, white blood cell differentiation, mitogen-induced lymphocytic proliferation, neutrophil phagocytosis and superoxide release, and prostaglandin E2 (PGE2) production by mitogen-stimulated whole blood cultures were comparatively investigated between healthy adults (range 22-45 years) and healthy elderly volunteers (range 70-91 years), and between DAT patients (range 56-94 years) and age-matched control subjects. Healthy elderly volunteers showed significantly lower phytohemagglutinin (PHA)-induced lymphocyte proliferation and percentage and absolute number of basophils than young volunteers. In normal volunteers, there were significant and negative correlations between age and the number of basophils. Patients with DAT showed a trend toward significantly higher PHA-induced lymphocyte proliferation and significantly decreased percentage and absolute number of large unstained cells than healthy volunteers. In DAT patients, the total number of leukocytes and the percentage and number of neutrophils were positively correlated with age. All other immune-inflammatory variables were not significantly altered either by the aging process or DAT. The present study suggests that aging and DAT may differently affect some immune variables.

Th1 (IL-2, interferon-gamma (IFN-gamma)) and Th2 (IL-10, IL-4) cytokine production by peripheral blood mononuclear cells (PBMC) from patients with systemic lupus erythematosus (SLE)

We investigated the production of IL-2, IFN-gamma, IL-10 and IL-4 by PBMC from 24 patients with SLE and 10 healthy individuals. Basal and mitogen-stimulated (lipopolysaccharide and phytohaemagglutinin (LPS + PHA)) cytokine production was determined in a whole blood assay (WBA). Supernatants were collected and assayed with specific ELISAs. Although the IL-2 and IFN-gamma contents did not differ significantly between patients and controls under both conditions, statistically significant correlations were found between each cytokine and disease activity (SLAM index) after stimulation (respectively, r = 0.501, P = 0.01 and r = 0.631, P = 0.001). PBMC IL-10 production was significantly higher for patients than controls (P = 0.05), but no correlation between IL-10 levels and the SLAM index was obtained. IL-4 production was not statistically different between SLE patients and controls. For stimulated WBAs, the IL-10/IL-2 and IL-10/IFN-gamma ratios were significantly correlated with disease severity (P = 0.02; P = 0.001, respectively). Overall, our data suggest that SLE is characterized by an elevated production of IL-10, reflecting the basal state of activation of the immune system. During exacerbation of SLE, IL-2 and IFN-gamma are synthesized in larger amounts and may cause the tissue damage observed.

Lower activity of serum peptidases in abstinent alcohol-dependent patients

This study examines i) the activity of serum prolyl endopeptidase (PEP) and dipeptidlyl peptidase IV (DPP IV) in detoxified alcohol-dependent patients without liver disease versus normal controls, and ii) the relationships between serum DPP IV and PEP activity and the production of cytokines or cytokine receptors, such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), interferon-y (IFN-y), IL-1 receptor antagonist (IL-1RA), and IL-10, and granulocyte-macrophage colony stimulatory factor (GM-CSF). Alcohol-dependent patients had significantly lower serum PEP and DPP IV activity than normal controls. We found that 58.3% and 50.0% of the alcohol-dependent patients, respectively, had PEP and DPP IV activities, which were lower than the mean control values minus 2 SD. There were significant inverse correlations between lowered serum DPP IV and PEP activity and the increased production of IL-6, INF-gamma, IL-IRA, IL-10, and GM-CSF. These results show that lower serum DPP IV and PEP activity may be related to the pathophysiology of alcohol dependence.

Plasmodium coatneyi: differential clinical and immune responses of two populations of Macaca fascicularis from different origins

Two species of macaques, including two Macaca fascicularis from the Philippines, two M. fascicularis from Mauritius, and one Macaca mulatta, were experimentally infected with blood stages of Plasmodium coatneyi and followed during their clinical, parasitological, biological, and immunological evolution. Plasma cytokine (TNF-alpha, IL-1beta, IL-6, IFN-gamma) production peaked for all monkeys 11 days after inoculation, concomitantly with peaks of parasitemia. Only the M. fascicularis from the Philippines survived the infection. The main features, which discriminated nonfatal from fatal cases, were the observation in M. fascicularis from the Philippines of a mean CD4+/CD8+ ratio below I and of their ability, as revealed by mitogenic stimulation of whole blood, to produce increasing amounts of IFN-gamma as infection evolved. The contribution of environmental and genetic factors, which may differentiate the three groups of monkeys and therefore explain fatal or nonfatal evolution of the infection among them, is discussed.

Procalcitonin is not produced by circulating blood cells

A large number of clinical studies has described procalcitonin (ProCT) as a marker of bacterial infection and a good predictor of disease severity and antibiotherapy efficacy. Nevertheless, the mechanism of ProCT synthesis remains unclear. The aim of this study was to demonstrate potential ProCT production by peripheral blood mononuclear cells as is the case for cytokines involved in sepsis. In a whole blood model, LPS (10 micrograms/ml) stimulation on blood samples from healthy volunteers (n = 14) was tested. Early (TNF-alpha and IL1-beta) and late (IL-6 and IL-8) cytokines were produced in large amounts in contrast to the absence of ProCT. Additional experiments with nitric oxide or detection of intra-cellular ProCT (cell lysis, flow cytometry) had negative results. It was concluded that ProCT is not produced in this model. Data are still needed to investigate the cellular origin of ProCT in order to better define its clinical usefulness.

Disease-specific ex vivo stimulation of whole blood for cytokine production: applications in the study of tuberculosis

As a simple method for field studies to assess the cytokine-status of patients with tuberculosis (TB), the use of whole blood instead of isolated cells has advantages, especially since the risk of contamination is minimal. Therefore, cytokine production in whole blood cultures was determined using non-specific and disease-specific stimuli. Heparinized blood from healthy volunteers was either incubated in closed vacutainer tubes or in tissue culture wells after dilution in culture medium. Dose-response and kinetics were investigated for the production of TNFalpha, IL-1beta, IL-1ra, IL-10 and IFNgamma. Patients with TB and healthy individuals were examined for IFN-gamma production in whole blood. In the absence of a stimulus, the production of cytokines is negligible in whole blood cultures. LPS induces the production of TNFalpha, IL-1beta, IL-1ra and IL-10; PHA induces the production of IFNgamma and IL-10. Live BCG induces the production of proinflammatory cytokines, irrespective of tuberculin skin status. In contrast, PPD and MTB-culture filtrate induce production of IFNgamma in skin-test positive and not in skin-test negative healthy subjects. Five out of 13 patients with TB had a low antigen-specific IFNgamma production, suggestive of a minimal or absent specific T-cell response. For most purposes, cultures in closed vacutainer tubes are optimal. If one wishes to focus on T-cell cytokines or if only small volumes of blood are available, dilution of whole blood in culture medium before incubation in tissue culture wells may be preferable.

Tumor necrosis factor-alpha production by human hepatoma cell lines is resistant to drugs that are inhibitory to macrophages

Little is known about the potential of immunomodulatory agents to lower tumor necrosis factor-alpha (TNF-alpha) synthesis in tissues of nonmonocytic origin. We studied effects of diverse drugs on the formation of immunoreactive TNF-alpha in the human hepatoma cell lines HepG2 and Hep3B, in which TNF-alpha production was induced by treatment (3 h incubation periods) with interleukin-1beta (IL-1beta, 300 pg/ml) or phorbol myristate acetate (PMA, 100 nmol/l). TNF-alpha production in IL-1beta-stimulated or PMA-stimulated hepatocyte cultures was not altered following the addition of dihydrocortisone (< or = 1 microg/ml), dibutyryl-cAMP (db-cAMP, < or = 100 micromol/l), adenosine (< or = 1 mmol/l), thalidomide (< or = 25 microg/ml), or cyclosporine (< or = 300 ng/ml). TNF-alpha production was inhibited by taurolidine (> or = 300 microg/ml), but this inhibition was associated with reduced cell viability. Pentoxifylline (1 mg/ml) did not influence PMA-induced TNF-alpha production, but it augmented IL-1beta-induced TNF-alpha production. Measurements of TNF-alpha mRNA by RT-PCR indicated that pentoxifylline exerted its effect posttranscriptionally. Additional studies with PMA-treated human whole blood cultures confirmed that pentoxifylline, db-cAMP, and adenosine reduced TNF-alpha production by leukocytes. These results provide first evidence to assume cell type-specific effects of immunomodulatory drugs on TFN-alpha synthesis, which may be relevant with respect to their clinical application.

Increased production of a Th2 cytokine profile by activated whole blood cells from rheumatoid arthritis patients

T cells produce regulatory cytokines which control inflammation. In rheumatoid arthritis (RA), a Th1 cytokine profile has been described in the synovium. In order to assess the Th1/Th2 cytokine balance in blood, a one step culture-immunoassay procedure was used to measure the ex vivo production of IFN gamma and IL-4 by whole blood cells from 26 RA patients and 25 controls. For comparison, the same cytokines were measured by ELISA in supernatants of activated whole blood cells. The direct whole blood assay was 10-fold more sensitive than standard ELISA to measure IL-4 levels. IL-4 production was higher in RA patients than in controls, whereas that of IFN gamma was lower. Accordingly, the IL-4/IFN gamma ratio, which reflects the Th2/Th1 cytokine balance in blood, was higher in RA patients (P < 0.0001). The present findings indicate a Th2-over-Th1 cytokine balance profile in RA blood. These results are in contrast with the Th1-over-Th2 pattern previously found in the joint, indicating that the two compartments appear to be differently regulated.

Antibody and cytokine responses in kittens during the development of feline infectious peritonitis (FIP)

Two recombinant FIPV spike proteins were assessed for their immunogenic properties in 8-week-old kittens, which were then challenged intranasally with FIPV 79-1146. Humoral responses were assessed by ELISA and serum neutralisation test. Changes in PBMC cytokine mRNA levels were detected by a reverse transcription, semiquantitative polymerase chain reaction assay (RT-sqPCR), assessing IL-2, IL-4, IL-6, IL-10, IL-12 and IFNgamma. All of the kittens developed clinical signs typical of FIP, which were confirmed on gross post mortem examination. The recombinant proteins induced little or no specific antibody response prior to challenge, and failed to alter the course of disease compared to controls. One week after virus challenge, the stimulated PBMCs showed small increases in the expression of IL-6 and IFNgamma mRNA, which correlated with a transient pyrexia. After this time expression of IL-6 mRNA remained unaltered but, as FIP developed, mRNA levels of IL-2, IL-4, IL-10, IL-12 and IFNgamma became markedly depressed.

Effects of estrogen therapy of postmenopausal women on cytokines measured in peripheral blood

Estrogen replacement therapy (ERT) is known to prevent bone loss following the menopause, but the mechanism for this is unclear. Estrogen may suppress the secretion of certain bone-resorbing cytokines. The aim of this study was to assess the effect of ERT on the levels of cytokines measured in peripheral blood. We measured cytokines in 10 postmenopausal women (ages 56-59, 3-9 years since menopause) treated with ERT and 10 age-matched (54-59 years, 4-10 years since menopause) untreated women as controls. Samples of blood were taken and used for mononuclear cell cultures, whole blood (WB) cultures, and the separation of serum. The cultures were treated with lipopolysaccharide (LPS; 500 ng/ml) and hydrocortisone (10(-6) M). The conditioned medium from cultures and the serum were then assayed for interleukin-6 (IL-6), IL-1alpha IL-1beta, IL-1 IL-1ra, tumor necrosis factor alpha (TNF-alpha), and granulocyte macrophage colony stimulating factor (GM-CSF) by enzyme-linked immunosorbent assay. M-CSF and the soluble cytokine receptors soluble IL-6 receptor (sIL-6r) and soluble TNF receptor type 1 (sTNFr1) were also measured in serum and M-CSF in stimulated WB cultures. Measurements were corrected for mononuclear cell count. We also measured serum bone-specific alkaline phosphatase (ibAP) in all subjects. We found that LPS stimulated secretion of all cytokines both in WB and isolated cell cultures, and that this was attenuated by hydrocortisone. A significantly higher ratio of IL-1beta/IL-1ra (p = 0.02) in LPS stimulated WB cultures was seen in the untreated women. Levels of IL-1beta and IL-1alpha measured in WB cultures were lower and IL-1ra was higher in the ERT-treated group but these results were not significant. BAP was higher in the untreated group (p = 0.005) and correlated with IL-alpha/IL-1ra in the whole group (r = 0.49, p = 0.03). Results of other measurements showed no significant differences between groups. We conclude that estrogen may prevent bone loss following the menopause by altering the balance between IL-1beta and IL-1ra.

Production of interleukin-4, interferon (IFN)-gamma and IFN-alpha in human immunodeficiency virus-1 infection: an imbalance of type 1 and type 2 cytokines may reduce the synthesis of IFN-alpha

Interferon-alpha (IFN-alpha) is an important molecule in the antiviral response, but cells from HIV-1-infected individuals show a reduced ability to secrete IFN-alpha. We investigated an association between an imbalance of type 1/type2 cytokines and the production of IFN-alpha in HIV-1 infection. We used whole blood culture to study the cytokine production profile, interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), in response to HIV-1 antigens and to study the Sendai Virus and HSV-1-induced-production of IFN-alpha in seven HIV-1-infected patients. An impaired synthesis of IFN-alpha was obtained in patients with a predominant IL-4 production (IL-4 > IFN-gamma), and we found a positive correlation between the ex vivo production of IFN-alpha and the IFN-gamma/IL-4 ratio but not with the HIV RNA copy number in plasma. We investigated the role of T-cell-derived cytokines in the in vitro production of IFN-alpha by PBMC from eight healthy donors, activated with Sendai Virus or HSV-1. Whereas type 2 cytokines (IL-4, IL-13) inhibited virus-induced IFN-alpha synthesis, on the contrary, type 1 cytokines (IL-2, IFN-gamma) enhanced it. A disarray in the T-cell-derived cytokine response may play a role in the defect of IFN-alpha production in HIV-1-infected individuals. Further investigations are needed to explore this hypothesis.

Tumour necrosis factor (TNF) gene polymorphism influences TNF-alpha production in lipopolysaccharide (LPS)-stimulated whole blood cell culture in healthy humans

TNF-alpha is involved in infectious and immuno-inflammatory diseases. Different individuals may have different capacities for TNF-alpha production. This might determine a predisposition to develop some complications or phenotypes of these diseases. The aims of our study were to assess the inter-individual variability of TNF-alpha production and to correlate this variability to a single base pair polymorphism located at position -308 in TNF gene. We studied 62 healthy individuals. TNF-alpha production after LPS stimulation was evaluated using a whole blood cell culture model. The TNF gene polymorphism was studied by an allele-specific polymerase chain reaction. Other cytokines produced in the culture, soluble CD14 concentrations and expression of CD14 on blood cells were also measured. Among the 62 individuals, 57 were successfully genotyped. There were 41 TNF1 homozygotes and 16 TNF1/TNF2 heterozygotes. TNF-alpha production after LPS stimulation of whole blood cell culture was higher among TNF2 carriers than among TNFI homozygotes (929pg/ml (480-1473pg/ml) versus 521 pg/ ml (178-1307 pg/ml); P<0.05). This difference was even more significant after correction of TNF-alpha production for CD14 expression on blood cells. In conclusion, the single base pair polymorphism at position -308 in the TNF gene may influence TNF-alpha production in healthy individuals.

Determination of tumour necrosis factor-alpha and interleukin-10 production in a whole blood stimulation system: assessment of laboratory error and individual variation

Ex vivo production of cytokines as determined by whole blood stimulation and supernatant ELISA is partly determined by heritability. To assess the ability of this system to distinguish between high and low producers the laboratory error and individual variation were investigated. Whole blood samples from healthy volunteers were collected using endotoxin-free tubes and were incubated with 0 to 1000 ng/ml lipopolysaccharide concentrations for 4 and 24 h, and subsequently centrifuged. In the supernatants, TNF-alpha and IL10 were measured by ELISA. Coefficients of variation for the day-to-day variation in the blood sampling, transport and stimulation as well as in the whole blood stimulation per se ranged from 7.5% to 12.3%. The intra-individual variation was 15% (TNF-alpha) and 19% (IL10) in contrast to the inter-individual variation of, on average, 35%. No interchanging of ranks between high and low producers was observed after repeating the whole blood stimulation on distinct days. The whole blood stimulation system is able to distinguish high and low producers of TNF-alpha and IL10.

Cytokine assays in human sera and tissues

The use of accurate and sensitive methods for the measurement of cytokines in body fluids is an absolute prerequisite for the proper use of these mediators in clinical practice. Many factors contribute to the complexity of cytokines quantitation: these molecules circulate at very low levels (e.g. pg/ml) under various molecular forms, the existence of circadian rhythms has been described, and the presence of inhibitors (binding proteins, soluble receptors, autoantibodies) can potentially interfere in the assays. Blood collection for cytokines needs particular attention to prevent possible contamination by endotoxins, which can trigger cytokines cellular production after sampling. Bioassays historically preceded immunoassays; the latter techniques are now very popular, but there is an urgent need for standardisation between the different kits commercially available. Nevertheless, due to the essentially local effects of cytokines, the study of their circulating levels only represents the 'tip of the iceberg' and is of limited value for a global understanding of the pathophysiology of these mediators. This explains the development of other approaches to assess the ability of cells to produce cytokines. These include the ELISPOT assay, the measurement of cell-associated cytokines by flow cytometry, and the study of cytokine secretion by isolated peripheral blood mononuclear cells or by whole blood test. All these techniques, associated with a local detection of cytokines by immunohistochemistry or in situ hybridization and reverse transcriptase polymerase chain reaction (RT-PCR), appear to be complementary tools for a better understanding of the multiple aspects of the biology of cytokines.

Interleukin 10 secretion in relation to human IL-10 locus haplotypes

Stimulation of human blood cultures with bacterial lipopolysaccharide (LPS) shows large inter-individual variation in interleukin 10 (IL-10) secretion, which has been shown to have a genetic component of over 70%. Alleles at two microsatellite loci in the 4 kb immediately upstream of the human IL-10 transcription initiation site in 132 individuals from 56 Dutch families were defined and assigned as haplotypes. LPS-induced IL-10 secretion was measured by ELISA and related to the IL-10 promoter haplotypes present in 78 unrelated individuals obtained from these families. Analysis showed that LPS-induced IL-10 secretion from unrelated individuals varied with IL-10 promoter haplotypes (P = 0.024; Kruskal-Wallis test). Two observations were made in relation to secreted IL-10 levels and promoter haplotypes; first, those haplotypes containing the allele IL10.R3 were associated with lower IL-10 secretion than haplotypes containing any other IL10.R allele. Second, the haplotype IL10.R2/IL10.G14 was associated with highest IL-10 secretion overall, whereas the haplotype IL10.R3/IL10.G7 was associated with lowest IL-10 secretion. These data demonstrate that the ability to secrete IL-10 can vary in man according to the genetic composition of the IL-10 locus.

Differences in the anti-inflammatory effects of theophylline and pentoxifylline: important for the development of asthma therapy?

Antiasthma drugs are now being re-evaluated for their anti-inflammatory effects. Theophylline is an immunomodulator; however, weak effects and the narrow therapeutic window make it a controversial drug. We compared the immunomodulatory potencies of theophylline with those of the xanthines pentoxifylline (POF) and A802715. Using a whole-blood, cell-culture system, we studied the effects on the release of tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and interleukin-6 (IL-6) in six healthy subjects, and, in granulocyte suspensions, the effects on the release of reactive oxygen species (ROS). We also studied the influence of a 14-day treatment with theophylline or POF on the release of the cytokines named above in 14 asthmatics. We found that equimolar concentrations of A802715 most effectively inhibit ROS generation, followed by POF; the effects of theophylline were weakest. A802715-inhibited release of TNF-alpha was four times as potent as that of theophylline, and POF two times as potent. Inhibition of IFN-gamma by A802715 was three times as potent, and by POF two times. Neither drug influenced IL-6 release. After a 14-day treatment of asthmatics, POF proved to inhibit TNF-alpha release more effectively (by 44.3%) than theophylline (7.5%). It is concluded that study of xanthine derivatives in asthmatics might help the development of asthma therapy. POF seems to be an especially promising candidate.

RANTES production in HIV-1 antigen-stimulated whole blood culture: relationship with type 1 immune response and plasma viral load in individuals infected with HIV-1

Host factors which control replication and clearance of human immunodeficiency virus (HIV) are poorly understood. RANTES (regulated on activation, normal T cell expressed and secreted) and other beta-chemokines may be HIV-1-suppressive factors but their role in the progression of HIV-1 infection is a subject of controversy. We investigated the relationship between production of RANTES and correlates of disease progression in 15 patients infected with HIV-1. We used whole blood culture to study the production of RANTES, interferon (IFN)-gamma, interleukin (IL)-4 and IL-13 in response to supernatant of T cells infected with HIV-1. A defect of RANTES production was associated with a predominant type 2 and decreased type 1 cytokine profile (IL-4 and/or IL- 13 > IFN-gamma). We obtained a positive correlation between RANTES and IFN-gamma (P = 0.004) and the ratio of type 1 and type 2 cytokines IFN-gamma/IL-4 (P = 0.04) and IFN-gamma/IL-13 (P = 0.003), and a negative correlation between RANTES production and HIV-1 RNA copy number in plasma (P = 0.01). The same pattern of correlation was observed between HIV-1 p24-stimulated production of RANTES and the plasma viral load (P = 0.02, n = 15). The measurement of RANTES produced by heparinized whole blood in response to HIV-1 antigens appears as a potentially valuable tool to assess the defect of type 1 immune response in individuals infected with HIV-1 and to define whether the absence of a RANTES response may play a role in the increased rate of HIV-1 replication.

A decreased production of IL12 in vitro is associated with isolation of cytopathic HIV-1 strains in HIV-1-infected patients

The changes in type 1 (IL12, IFN gamma, IL2) and type 2(IL4, IL10) cytokine profiles may be associated with virological parameters of progression of the disease in HIV-1-infected patients. The production of cytokines was studied in LPS + PHA-activated whole-blood culture in HIV-1-infected individuals at different stages of the disease. The association was investigated between IL12p40 and IL12p70 profiles and other cytokines (IFN gamma, IL4, IL10), as well as the isolation of cytopathogenic HIV-1 strains. The phenotype of HIV strains was studied by a micromethod based on P4 cell line, allowing detection of cytopathic effects of HIV-1 isolates (syncytium-induction and cell-killing without syncytium induction). The individual variations in IL12p40 and IL12p70 production were limited in the healthy controls. Low values were observed in HIV-1-infected patients. The production of IL12 (p40 and p70) and the IL12p70/IL4 ratio and the IFN gamma/IL4 ratio were significantly lower in patients with cytopathic isolates compared with patients with noncytopathic isolates, and a correlation was obtained between the values of IL12 (IL12p40 and IL12p70) and those of IFN gamma/IL4 ratio. There was no increase in the secretion of IL4 and IL10 in patients with cytopathic strains compared with other patients. The results indicate a decreased production of type 1 cytokines (IL12, IFN gamma) in the presence of a relatively preserved production of type 2 cytokines (IL4, IL10) in HIV-1-infected patients. In conclusion, the defect of production of IL12 by whole blood is associated with virological correlates of progression of HIV-1 disease.

Gender-related assessment of cyclosporine/prednisolone/sirolimus interactions in three human lymphocyte proliferation assays

BACKGROUND

Cyclosporine (CsA), prednisolone (Pred), and sirolimus (Sir) are immunosuppressive compounds inhibiting lymphocyte proliferation at the cytokine gene transcription (CsA and Pred) or signal transduction (Sir) levels.

METHODS

Double- and triple-drug interactions were simultaneously studied using lectin-induced proliferation of isolated cell lymphocytes (ICLP) and whole blood lymphocytes from men and women as well as two-way mixed lymphocyte reaction assays. Drug interactions were described with isobolograms and quantitated with the universal response surface approach by estimating the interaction parameter alpha.

RESULTS

All compounds inhibited more than 89% of control proliferative responses. In each assay, CsA was less potent than Pred (3- to 14-fold) and Sir (5- to 11-fold). Sir was of similar or higher potency than Pred and 1.5-fold more potent in men than women. Pred was 1.4 times more potent in women but this was found only in the ICLP assay. All combinations were synergistic (alpha>0), with greater synergism found for combinations involving Sir, especially in the ICLP (alpha>13) and two-way mixed lymphocyte reaction (alpha>40) assays. Moreover, the Sir/Pred interaction in the ICLP assay was two to five times more synergistic in women, because their mean alpha was 56 compared with 13 in men. Double-combination alpha values were able to reasonably describe CsA/Pred/Sir triple-interaction effects.

CONCLUSIONS

These studies indicate that CsA, Pred, and Sir act and synergistically interact in vitro, with gender and assay as additional factors, and that whole blood lymphocyte proliferation cultures are useful in assessing the nature and intensity of drug interactions.

Rapid assessment of antigen induced cytokine expression in memory T cells by flow cytometry

Methods for analysis of T cell responses to specific antigen have traditionally relied on measurements of proliferation or cytokine expression in bulk cultures of PBMC in long term incubations with putative antigen. These techniques suffer from the drawback that they do not enable analysis of single cell responses in the context of unselected cellular backgrounds. It is increasingly important to not only identify cells on the basis of expression of unique surface antigens but also to determine functional and molecular parameters of individual cells in response to a variety of stimuli. We have recently developed methodologies to rapidly assess T-cell subset responses to polyclonal activators and specific antigen in whole blood. These procedures determine the percentages of activated cells and the identification of leucocyte subsets capable of expressing various cytokines and cell surface antigens. Multiparameter analysis of CD69+ /cytokine + expression in T cells in response to specific antigen (e.g. CMV, mumps) demonstrated a range of frequencies from 0.05% to 5.0% within 6 h. Frequencies of responding T cells were consistent but varied depending upon the antigen. Antigen specific T cell responses were host specific and both positively and negatively regulated by antibodies to co-receptors involved in APC-T cell interactions. These technologies will be discussed in terms of application to problems of measuring immune function parameters in disease. The modified technique described in this report is compatible with simple and rapid analysis of clinical samples and provides a means to directly examine the effects of in vivo drug concentrations on T cell immunity. Studies are in progress to examine the sensitivity of this cellular assay to drugs and other therapeutic modalities in clinical samples.

Serotonin-immune interactions in detoxified chronic alcoholic patients without apparent liver disease: activation of the inflammatory response system and lower plasma total tryptophan

The aims of the present study were to examine (1) the inflammatory response system (IRS), through measurements of serum interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), sgp130 (the soluble form of the IL-6 transducer signal protein), CC16 (Clara Cell protein; an endogenous anti-cytokine), IL-1R antagonist (IL-1RA), IL-8 and sCD14; and (2) the availability of plasma total tryptophan to the brain in chronic alcoholic patients without apparent liver disease (AWLD). Detoxified AWLD patients had significantly lower plasma tryptophan and serum CC16 and significantly higher serum IL-1RA and IL-8 concentrations than normal volunteers. There were significant correlations between the availability of tryptophan to the brain and serum IL-6, IL-8 and IL-1RA (all negative) and CC16 (positive). The results suggest that (1) there is, in detoxified AWLD patients, an activation of the monocytic arm of cell-mediated immunity and a lowered anti-inflammatory capacity of the serum; and that (2) lower availability of plasma tryptophan to the brain in detoxified AWLD patients is related to activation of the IRS. Lower CC16 may be one factor predisposing chronic alcoholic patients toward infectious disorders.

Production of TNFalpha and IL-6 by activated whole blood from HIV-1 infected patients detected by a one-stage procedure: relationship with the phenotype of HIV-1 isolates

Diluted whole blood (WB) culturing may be the most appropriate milieu in which to study cytokine production in vitro. We tested TNFalpha and IL-6 production using small volumes of WB (25 microl) from HIV-1 positive patients with a one-step procedure that combines WB stimulation with LPS, PHA and cytokine measurement. We studied 49 patients without secondary infection or at distance of secondary infection staged according to the 1993 classification of the CDC and 12 healthy seronegative subjects. Heparinized blood from 5 control subjects had been collected sequentially during a period of 5 months. The individual variations of TNFalpha and IL-6 production were limited for all these individuals. In 1 out of 20 CDC group A patients, 6 out of 17 CDC group B patients and 3 out of 12 CDC group C patients, we obtained higher values of TNFalpha than the mean + 2 S.D. of the control group. In 3 out of 20 CDC group A patients, 1 out of 17 CDC group B patients without AIDS and 5 out of 12 CDC group C patients, the TNFalpha values were lower than the mean - 2 S.D. of the control group. Low IL-6 values were obtained in 1 out of 20 CDC group A patients and 1 out of 17 CDC group B patients and 3 out of 12 CDC group C patients. There was no correlation between TNFalpha production in vitro and plasma level of TNFalpha. We found no correlation between the levels of cytokines and monocyte count or between the levels of cytokines and CD4 T-cell count in peripheral blood. Our data point out a disarray in TNFalpha and IL-6 production by WB from HIV-1 infected patients. The relationship between the disarray of cytokine production and cytopathogenicity of HIV-1 isolates in the P4 cell line was investigated in this study. We found a correlation between the high level of TNFalpha produced by WB and the phenotype of HIV-1 isolates isolated from patients. The one-stage procedure used in this work is of potential value to investigate the activation status of cells for monitoring HIV-1 positive individuals and predicting HIV-1 phenotype.

Detection of human TNF-alpha mRNA by NASBA

A method to amplify and detect TNF-alpha mRNA from primed Mono Mac 6 cells is described. A silica-based extraction system was utilised for preparation of cell extracts and specific oligonucleotide primers were designed for amplification of TNF-alpha mRNA by the NASBA process. Amplification products were detected using either a liquid hybridisation assay, with analysis by polyacrylamide gel electrophoresis, or a plate hybridisation system. The method has many potential applications for the study of inflammatory cytokines and cellular mRNAs in cell culture and clinical samples.

Tumor necrosis factor-alpha hyporesponsiveness of rat intestinal mononuclear cells and whole portal venous blood after hemorrhagic shock

OBJECTIVE

To determine the effect of hemorrhagic shock on spontaneous and endotoxin-induced cytokine release from intestinal mononuclear cells compared with whole portal venous blood and splenic macrophages.

DESIGN

Random assignment to either unmanipulated control group, sham operation group, or hemorrhagic shock group.

SETTING

University animal laboratory.

SUBJECTS

Male Wistar rats, weighing between 300 and 350 g.

INTERVENTIONS

Rats were bled to 30 mm Hg for 30 mins by withdrawal/reinfusion of shed blood and Ringer's lactate equivalent to the shed blood volume.

MEASUREMENTS

Rats were killed immediately, 4 hrs, or 24 hrs after reperfusion. Portal venous blood, splenic macrophages, and small bowel mononuclear cells were obtained and spontaneous (unstimulated) and endotoxin-induced supernatant tumor necrosis factor (TNF)-alpha (WEHI 164 subclone 13) and interleukin (IL)-6 (B 13-29 clone 9) release was measured by bioassay.

MAIN RESULTS

Increased endotoxin-induced TNF release from gut mononuclear cells and portal venous blood was suppressed 4 and 24 hrs after reperfusion compared with sham operated animals (p < .05). TNF release from splenic macrophages could be significantly increased (p < .05) by addition of endotoxin in all groups with no difference between control, sham, and shock animals. In shock animals, endotoxin-stimulated IL-6 release was significantly greater (p < .05) than control and sham operated rats 4 hrs after reperfusion in portal blood and from splenic macrophages. In contrast to splenic macrophages, gut mononuclear cells and portal venous blood demonstrated high spontaneous IL-6 concentrations without further stimulation by endotoxin.

CONCLUSIONS

Hemorrhagic shock induced a hyporesponsiveness from gut mononuclear cells and whole portal venous blood 4 and 24 hrs after reperfusion. Spontaneous and endotoxin-induced stimulation of IL-6 indicates a different modulation of cytokines in gut, portal vein and spleen. The differences of gut mononuclear cells and portal blood compared with the splenic macrophages indicate a compartmentalized cytokine response.

Tumor necrosis factor alpha levels in plasma and whole-blood culture in dengue-infected patients: relationship between virus detection and pre-existing specific antibodies

The pathogenesis of dengue hemorrhagic fever (DHF) is not well known, but the role of host factors has been suggested. The level of immunoreactive circulating and cell-generated tumor necrosis factor alpha (TNF alpha) was studied in 35 patients with DHF; its relationship with virus isolation and/or genome detection by reverse transcription polymerase chain reaction (RT-PCR) and specific antibodies were detected by hemagglutination inhibition (HI). Large variation of TNF alpha plasma levels was obtained in dengue-infected patients at the same stage of the disease and at the same day after infection. Most of the patients (14 out of 17 patients) who displayed augmented spontaneous in vitro production of TNF alpha by heparinized whole-blood culture compared with controls also had elevated levels of TNF alpha in the plasma. The TNF alpha values in lipopolysaccharide and phytohemagglutinin heparinized whole-blood cultures were not higher in patients than in controls, but low TNF alpha levels were obtained in three out of 30 patients. An inverse correlation was observed between spontaneous in vitro TNF alpha production and viral replication, which raises the issue of the antiviral effect of TNF alpha in dengue infection. The results do not support the hypothesis of the role of antibody-dependent enhancement giving rise to increased viremic titers and production of TNF alpha in patients. The present study demonstrates the activation of the TNF alpha-producing cells in dengue-infected patients and suggests further investigation to define the mechanism and the role of TNF alpha in the pathogenesis of dengue virus infection.

Increased IL-10 production by stimulated whole blood cultures in primary IgA nephropathy

Most patients with primary IgA nephropathy (IgAN) have a significantly higher memory repertoire of IgA1-producing B lymphocytes in their bone marrow together with high plasma levels of IgA1. The connection between the mucosal immune system and the bone marrow compartment is probably based on traffic of either antigen-presenting cells (APC) or antigen-specific lymphocytes. Cytokines play an important role in the proliferation and differentiation of lymphoid cells. In order to mimic the in vivo situation as much as possible, we assessed cytokine production profiles ex vivo in 23 IgAN patients and matched controls, using lipopolysaccharide (LPS)- or phytohaemagglutinin (PHA)-stimulated whole blood (WB) cultures. Interferon-gamma (IFN-gamma), IL-2, IL-6, IL-10 and tumour necrosis factor-alpha (TNF-alpha) production in culture supernatants were determined by cytokine-specific ELISAs. Compared with controls, PHA-stimulated cultures resulted in significantly higher IL-10 (P<0.001), IL-2 (P<0.005) and IFN-gamma (P<0.001) levels in IgAN patients, but no significant differences in TNF-alpha or IL-6 levels were found. In LPS-stimulated cultures, the only significant difference (P<0.001) between the two groups was the increased IL-10 production in IgAN patients. The enhanced cytokine production in stimulated WB cultures suggests altered monocyte-related T cell responses in patients with IgAN. Increased IL-10 production may eventually result in an increased number of IgA-producing B lymphocytes in the bone marrow. In addition, high levels of endogenous IL-10 may down-regulate the effector functions of monocytes, or possibly APC in general, and consequently the IgA response at the mucosal level.

Effects of dexamethasone on the profile of cytokine secretion in human whole blood cell cultures

EXPERIMENTAL OBJECTIVES

The interaction between the endocrine and immune systems is a very intriguing area. Endogenous glucocorticoids, as end-effectors of the hypothalamo-pituitary-adrenal axis, inhibit the immune and inflammatory responses and are used as immunosuppressive drugs in many inflammatory, autoimmune and allergic diseases. The aims of this study were to investigate the effects of dexamethasone on the profile of cytokine secretion in whole blood cell cultures from healthy subjects and to analyse the gender-related sensitivity to dexamethasone on each cytokine secretion.

RESULTS

There was a significant inhibition by dexamethasone (from 1 to 100 nM) on the secretion of monokines (IL-1beta, IL-6, IL-8 and TNF alpha) and lymphokines (IL-2, IL-4, IL-10 and IFN gamma), either after LPS or PHA stimulation (P < 0.01). Interleukin 4 and IL-10 were less inhibited than IFN gamma (P < 0.05 at 1 nM, P < 0.01 at 10 nM and P < 0.001 from 100 nM to 10 microM). No gender difference was observed in the rate of inhibition of the secretion of each cytokine.

CONCLUSION

This study shows that the inhibition of cytokine secretion by dexamethasone is more marked on Th1-type cytokines than on Th2-type cytokines. These data support the idea that glucocorticoids may induce a shift from the Th1 to Th2 profile of cytokine secretion.

Effects of three avocado/soybean unsaponifiable mixtures on metalloproteinases, cytokines and prostaglandin E2 production by human articular chondrocytes

The in-vitro effects of avocado and soybean unsaponifiable residues on neutral metalloproteinase activity, cytokines and prostaglandin E2 (PGE2) production by human articular chondrocytes were investigated. Avocado and soybean unsaponifiable residues were mixed in three ratios: 1:2 (A1S2), 2:1 (A2S1) or 1:1 (A2S2). Freshly isolated human chondrocytes were cultured for 72 h in the absence or presence of interleukin-1beta, (IL-1beta) (17 ng/ml), with or without unsaponifiable residue mixtures at a concentration of 10 microg/ml. A/S unsaponifiable residues were also tested separately at concentrations of 3.3, 6.6 and 10 microg/ml. All A/S unsaponifiable mixtures reduced the spontaneous production of stromelysin, interleukin-6 (IL-6), interleukin-8 (IL-8) and prostaglandin E2 (PGE2) by chrondrocytes. At concentrations of 3.3 and 6.6 microg/ml, A/S residues, tested separately, were potent inhibitors of the production of IL-8 and PGE2. Nevertheless, only avocado residue inhibited IL-6 production at these concentrations. A/S unsaponifiable mixtures had a more pronounced inhibitory effect on cytokine production than avocado or soybean residues added alone. As anticipated, IL-1beta induced a marked release of collagenase, stromelysin, IL-6, IL-8 and PGE2. A/S unsaponifiable mixtures partially reversed the IL-1 effects on chrondrocytes. These findings suggest a potential role for A/S unsaponifiable extracts in mitigating the deleterious effects of IL-1beta: on cartilage.

Studies on the biological effects of ozone: 8. Effects on the total antioxidant status and on interleukin-8 production

Ozone (O3) is a controversial gas because, owing to its potent oxidant properties, it exerts damaging effects on the respiratory tract and yet it has been used for four decades as a therapy. While the disinfectant activity of O3 is understandable, it is less clear how other biological effects can be elicited in human blood with practically no toxicity. On the other hand plasma and cells are endowed with a powerful antioxidant system so that a fairly wide range of O3 concentrations between 40 and 80 microg/ml per gram of blood (approximately 0.83-1.66 mM) are effective but not deleterious. After blood ozonation total antioxidant status (TAS) and plasma protein thiol groups (PTG) decrease by 20% and 25%, respectively, while thiobarbituric acid reactive substances (TBARS) increases up to five-fold. The increase of haemolysis is negligible suggesting that the erythrocyte membrane is spared at the expense of other sacrificial substrates. While there is a clear relationship between the ozone dose and IL-8 levels, we have noticed that high TAS and PTG values inhibit the cytokine production. This is in line with the current idea that hydrogen peroxide, as a byproduct of O3 decomposition, acts as a messenger for the cytokine induction.

Inverse modulation of IL-10 and IL-12 in the blood of women with preneoplastic lesions of the uterine cervix

It has been postulated that an impaired immune response may contribute to the progression of human papillomavirus (HPV)-associated preneoplastic lesions. Based on this hypothesis, we evaluated the cytokine production in the blood of patients with squamous intraepithelial lesions (SIL) of the uterine cervix. The levels of type-1 (interferon-gamma (IFN-gamma) and IL-12) and type-2(IL-4 and IL-10) cytokines were measured in whole blood culture supernatants of patients with low- and high-grade SIL and control women. There was no difference in IL-4 and IFN-gamma levels between patients with SIL and the control group. In contrast, the ratio of IL-12/IL-10 levels was significantly lower in patients with SIL compared with the control group. A lower IL-12/IL-10 ratio in women with SIL was also observed when peripheral blood mononuclear cell (PBMC) culture supernatants and plasma samples were analysed. In patients, neither the lower expression of the CD3epsilon chain nor the higher frequency of HLA-DRB1*1501 expression could be correlated with abnormal cytokine production. These results suggest that a part of the cytokine network, namely IL-10 and IL-12, is perturbed in patients with SIL. A better knowledge of the role of these cytokines in regulating the growth of HPV-associated SIL might have practical implications for the development of vaccines or immunomodulatory strategies in the treatment of cervical cancers.

Epinephrine inhibits endotoxin-induced IL-1 beta production: roles of tumor necrosis factor-alpha and IL-10

Epinephrine has been found to inhibit the production of the proinflammatory cytokine tumor necrosis factor (TNF)-alpha and to enhance the production of anti-inflammatory cytokine interleukin (IL)-10. To determine the effect of epinephrine on IL-1 beta production, the following experiments were performed: 1) blood obtained from subjects at 4-21 h after the start of a continuous infusion of epinephrine (30 ng.kg-1.min-1) produced less IL-1 beta after ex vivo stimulation with lipopolysaccharide (LPS), compared with blood drawn from subjects infused with saline; 2) in whole blood in vitro, epinephrine caused a dose-dependent decrease in LPS-induced IL-1 beta production, which was likely mediated via adrenergic receptors; and 3) inhibition of TNF and enhancement of IL-10 both contributed to epinephrine-induced inhibition of IL-1 beta production. Epinephrine, either endogenously produced or administered as a component of sepsis treatment, may attenuate excessive activity of proinflammatory cytokines early in the course of systemic infection.

Catecholamines increase monocyte TNF receptors and inhibit TNF through beta 2-adrenoreceptor activation

Postinjury deficits in monocyte tumor necrosis factor receptors (moTNFR) activity may alter beneficial functions during an inflammatory response. Several counter-regulatory hormones elicited during inflammation may modulate tumor necrosis factor (TNF) activity, but little is known about their influence on moTNFR. Also, catecholamines inhibit TNF production, but the adrenoreceptor mechanism of this effect has not been fully clarified. To determine the effect of catecholamines and corticosteroids on moTNFR, whole blood was coincubated for up to 8 (moTNFR) or 24 h (cytokines) in the presence of lipopolysaccharide (100 ng/ml) and 1) epinephrine (Epi, 10(-6) M), dexamethasone (Dex, 10(-6) M) or both (EpiDex, 10(-6) M) to assess the expression of total moTNFR, moTNFR-I, and moTNFR-II. 2) Epi and norepinephrine (EpiNE, 10(-6) M) and the alpha 1 + 2-, beta 1 + 2-, beta 1-, or beta 2-adrenergic antagonists were used to assess the role of such adrenoreceptors on total moTNFR and TNF production, and N6,2'-O-dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP) alone or in combination with the phosphodiesterase inhibitor Ro-20-1724/000, to study the cAMP-dependent pathway on total moTNFR. We found that Epi upregulated total moTNFR and moTNFR-II. Dex did not significantly influence total moTNFR or moTNFR-II. Also, EpiNE increased total moTNFR and inhibited TNF by a beta 2-dependent mechanism. DBcAMP (10(-5) M) modestly enhanced total moTNFR. This suggests a common mechanism for acutely enhancing moTNFR and attenuation of soluble TNF appearance during conditions of severe stress.

Determination of intracellular cytokines by flow-cytometry following whole-blood culture

Various methods have been reported for measuring intracellular cytokines in peripheral blood mononuclear cells isolated by density-gradient centrifugation. In this report, we describe a whole-blood method for the determination of intracellular cytokines (IFN-gamma, TNF-alpha and IL-2) that uses small-volume (500 microl) blood samples. Directly conjugated anti-cytokine antibodies and commercial cell membrane fixation and permeabilisation reagents were used. Blood was cultured in a 1:3 dilution with a combination of PMA and ionomycin to reveal the cytokine synthetic potential of each cell, together with monensin to increase the sensitivity by retaining cytokines within the cell to detectable levels. The optimum concentrations of PMA (10 ng/ml (16.2 nmol/l)), ionomycin (2 micromol/l) and monensin (3 micromol/l) were determined. Kinetic studies showed maximal cytokine expression after 2 h of culture for TNF-alpha and IFN-gamma and 4 h for IL-2. Assessment of TNF-alpha and IFN-gamma production within the CD4 and CD8 lymphocytes from 10 normal volunteers showed that considerably more CD8 + than CD4 + cells produced IFN-gamma. This technique could be used by routine immunology laboratories and will be of use in studies to determine whether cytokine assays are of value in the investigation of immune disorders.

Human monocytoid cell lines as indicators of endotoxin: comparison with rabbit pyrogen and Limulus amoebocyte lysate assay

The aim of this study was to develop an in vitro test system for pyrogenic substances. Three clones derived from human monocytoid cell lines, which were selected by their high sensitivity to lipopolysaccharide (LPS), were assessed for tumor necrosis factor (TNF) production. Their response to pyrogen-containing samples was compared with that in a Limulus amoebocyte lysate assay and the rabbit pyrogen test. We show here that the induction of TNF in these clones is a valid in vitro alternative to determine endotoxin in commercial preparations requiring pyrogenicity testing. Cell clones derived from Mono Mac 6 (MM6 2H8 and MM6 4B5) responded to sub-ng/ml concentrations of complete rough-strain and smooth-strain LPS, to ng/ml concentrations of diphosphoryl-lipid A, and to microgram/ml concentrations of monophosphoryl-lipid A and to detoxified LPS. Cells reacted to > or = 1 microgram/ml lipoteichoic acid by TNF production, and were relatively insensitive to toxic shock syndrome toxin-1 (TSST-1) and to muramyl dipeptide adjuvant peptide. The reaction pattern of a clone derived from THP-1 (THP-1 1G3) was in general, similar to that of the MM6 clones, except that THP-1 1G3 failed to react to diphosphoryl-lipid A. When tested on commercial samples destined for parenteral use, there was a close correlation between a sensitive Limulus amoebocyte lysate (LAL) test and the cell culture test on the one hand, and between the pyrogen test and the cell culture test on the other hand. The data suggest that this cell-based test is able to recognize pyrogens derived from gram-negative organisms in test samples with appropriate sensitivity and specificity. This test appears to be able to eliminate some of the false-positive data obtained in the LAL test.

Zinc supplementation reconstitutes the production of interferon-alpha by leukocytes from elderly persons

The elderly are more prone to virus infections and neoplasias than are young adults. During a virus infection, interferon-alpha (IFN-alpha), proteins with antiviral, antiproliferative, and immunomodulatory properties, are transiently expressed. We here report that peripheral white blood cells from 16 subjects with a mean age of 72 years yielded less IFN when stimulated with a virus in vitro than those from 16 young adults with a mean age of 28 years. Monocytes are the main source of this IFN. However, yields of another monocyte product, interleukin-6 (IL-6), were greater in cells from the older subjects than from the young adults, so there is no general defect in monocytes from the former. Immunodeficiency in the elderly has been reported to be associated with a deficiency of zinc. When cultures of white blood cells from the elderly were supplemented with 15 microM zinc (the physiologic concentration), they produced IFN in amounts comparable to those from the younger subjects.

Correlation between interferon production and clinical disease activity in patients with multiple sclerosis

We determined the interferon (IFN) serum levels and in vitro activated IFN production in eight patients with relapsing/ remitting multiple sclerosis (MS), using a whole-blood test system and the mitogen concanavalin A and the viral antigen Newcastle disease virus for induction of the IFN production. During the overall study period of 12 months we observed, in relation to clinical disease progression, a biphasic increase in the individual IFN alpha and IFN gamma production. While mitogen-induced IFN gamma synthesis showed a significant augmentation prior to the onset of a new relapse (P < 0.05), virus-induced IFN alpha production showed a temporal delayed increase which was related to clinical remission (P < 0.01). The observed fluctuations in the individual production of both IFN subtypes were not reflected in the sera of the patients. Although the reason for the temporal different imbalance in the production of both IFN subtypes remains unknown, the observed association between increased IFN alpha production and clinical remission emphasizes a possible role for type 1 IFNs in the resolution of the MS relapse.

Genetic influence on cytokine production and fatal meningococcal disease

BACKGROUND

To assess the genetic influence on cytokine production and its contribution to fatal outcome, we determined the capacity to produce tumour necrosis factor-alpha (TNF alpha) and interleukin-10 (IL-10) in families of patients who had had meningococcal disease.

METHODS

We studied 190 first-degree relatives of 61 patients with meningococcal disease; we also studied 26 monozygotic twins. Production of cytokines was determined during endotoxin stimulation of whole-blood samples ex-vivo. Heritability was estimated in a pedigree-based maximum-likelihood model. DNA was typed for the G to A transition polymorphisms at position -308 and -238 in the TNF gene promoter.

FINDINGS

Heritability in monozygotic twins was 0.60 for the production of TNF and 0.75 for the production of IL-10. Families with low TNF production had a tenfold increased risk for fatal outcome (OR 8.9, 95% CI 1.8-45), whereas high IL-10 production increased the risk 20-fold (19.5, 2.3-165). Families with both characteristics had the greatest risk. The transition polymorphisms in the TNF gene promoter were not associated with outcome.

INTERPRETATION

Genetic factors substantially influence production of cytokines. An innate anti-inflammatory cytokine profile may contribute to fatal meningococcal disease.