Whole-blood lymphocyte cultures

An updated view into the cell cycle kinetics of human T lymphocytes and the impact of irradiation

Even though a detailed understanding of the proliferative characteristics of T lymphocytes is imperative in many research fields, prior studies have never reached a consensus on these characteristics, and on the corresponding cell cycle kinetics specifically. In this study, the general proliferative response of human T lymphocytes to phytohaemagglutinin (PHA) stimulation was characterized using a carboxyfluorescein succinimidyl ester-based flow cytometric assay. We were able to determine when PHA-stimulated T lymphocytes complete their first division, the proportion of cells that initiate proliferation, the subsequent division rate of the cells, and the impact of irradiation on these proliferative properties. Next, we accurately visualized the cell cycle progression of dividing T lymphocytes cultured in whole blood using an adapted 5-ethynyl-2'-deoxyuridine pulse-chase method. Furthermore, through multiple downstream analysis methods, we were able to make an estimation of the corresponding cell cycle kinetics. We also visualized the impact of X-rays on the progression of the cells through the cell cycle. Our results showed dose-dependent G2 arrest after exposure to irradiation, and a corresponding delay in G1 phase-entry of the cells. In conclusion, utilizing various flow cytometric assays, we provided valuable information on T lymphocyte proliferation characteristics starting from first division to fully dividing cells.

Assessment of cellular response to mitogens in long-term allogeneic hematopoietic stem cell transplantation survivors

Infection is one of the major causes of death in hematopoietic stem cell transplantation (HSCT) survivors. Precise assessments of immune function after HSCT will be critical in establishing appropriate treatment and prophylaxis, such as re-vaccination. Although several surrogate markers for prediction of clinical outcomes after HSCT have been proposed, definitive markers of immune reconstitution and data on those markers in long-term survivors are lacking. In this study, cellular response to mitogens was assessed and clinical features associated with a poor response to mitogens were investigated in long-term allogeneic HSCT survivors. Age at transplantation and age at the time of mitogen stimulation test were each identified as significant risk factors for poor response to phytohemagglutinin and concanavalin A, respectively (P < 0.001 each). However, time elapsed since transplantation was not found to be correlated with responsiveness to mitogens in this study. Prospective, in-depth studies on immune reconstitution are needed to establish appropriate prophylaxis against infections after HSCT and a schedule for re-vaccination.

Substituting whole grains for refined grains in a 6-wk randomized trial has a modest effect on gut microbiota and immune and inflammatory markers of healthy adults

Background: Observational studies suggest an inverse association between whole-grain (WG) consumption and inflammation. However, evidence from interventional studies is limited, and few studies have included measurements of cell-mediated immunity.Objective: We assessed the effects of diets rich in WGs compared with refined grains (RGs) on immune and inflammatory responses, gut microbiota, and microbial products in healthy adults while maintaining subject body weights.Design: After a 2-wk provided-food run-in period of consuming a Western-style diet, 49 men and 32 postmenopausal women [age range: 40-65 y, body mass index (in kg/m2) <35] were assigned to consume 1 of 2 provided-food weight-maintenance diets for 6 wk.Results: Compared with the RG group, the WG group had increased plasma total alkyresorcinols (a measure of WG intake) (P < 0.0001), stool weight (P < 0.0001), stool frequency (P = 0.02), and short-chain fatty acid (SCFA) producer Lachnospira [false-discovery rate (FDR)-corrected P = 0.25] but decreased pro-inflammatory Enterobacteriaceae (FDR-corrected P = 0.25). Changes in stool acetate (P = 0.02) and total SCFAs (P = 0.05) were higher in the WG group than in the RG group. A positive association was shown between Lachnospira and acetate (FDR-corrected P = 0.002) or butyrate (FDR-corrected P = 0.005). We also showed that there was a higher percentage of terminal effector memory T cells (P = 0.03) and LPS-stimulated ex vivo production of tumor necrosis factor-α (P = 0.04) in the WG group than in the RG group, which were positively associated with plasma alkylresorcinol concentrations.Conclusion: The short-term consumption of WGs in a weight-maintenance diet increases stool weight and frequency and has modest positive effects on gut microbiota, SCFAs, effector memory T cells, and the acute innate immune response and no effect on other markers of cell-mediated immunity or systemic and gut inflammation. This trial was registered at clinicaltrials.gov as NCT01902394.

Modest weight loss through a 12-week weight management program with behavioral modification seems to attenuate inflammatory responses in young obese Koreans

Obesity has been reported to impair immune functions and lead to low-grade long-term inflammation; however, studies that have investigated the impact of weight loss on these among the young and slightly obese are limited. Thus, we investigated the effect of a 12-week weight management program with behavioral modifications on cell-mediated immune functions and inflammatory responses in young obese participants. Our hypothesis was that weight loss would result in improved immune functions and decreased inflammatory responses. Sixty-four participants (45 obese and 19 normal weight) finished the program. Obese (body mass index ≥25) participants took part in 5 group education and 6 individual counseling sessions. Normal-weight (body mass index 18.5-23) participants only attended 6 individual sessions. The goal for the obese was to lose 0.5 kg/wk by reducing their intake by 300 to 500 kcal/d and increasing their physical activity. Program participation resulted in a modest but significant decrease in weight (2.7 ± 0.4 kg, P < .001) and lipopolysaccharide-stimulated interleukin-1β production (from 0.85 ± 0.07 to 0.67 ± 0.07 ng/mL, P < .05) in the obese. In the obese group, increase in phytohemagglutinin-stimulated interleukin-10 production, a TH2 and anti-inflammatory cytokine, approached significance after program participation (from 6181 ± 475 to 6970 ± 632 pg/mL, P = .06). No significant changes in proliferative responses to the optimal concentration of concanavalin A or phytohemagglutinin were observed in the obese after program participation. Collectively, modest weight loss did not change the cell-mediated immune functions significantly but did attenuate the inflammatory response in young and otherwise healthy obese adults.

Toxic potencies of metabolite(s) of non-cylindrospermopsin producing Cylindrospermopsis raciborskii isolated from temperate zone in human white cells

Cylindrospermopsis raciborskii (Nostocales, Cyanobacteria) has worldwide distribution and is well known for producing the toxic alkaloid, cylindrospermopsin (CYN). Strains unable to synthesize this compound but potentially toxic were recently identified in Europe. Here, for the first time the effect of cell-free extracts of a non-CYN-producing strain of C. raciborskii was studied in human cells (neutrophils and lymphocytes) isolated from healthy donors. The observed effects were compared to those induced by CYN (1.0-0.01 μg mL(-1)). Short-term (1h) extract treatments resulted in altered viability of cells demonstrated by increased necrosis and apoptosis in neutrophils and elevated apoptosis in lymphocytes. CYN did not induce similar effects, regardless of the toxin concentration. Exposure of T-lymphocytes to 100% C. raciborskii extract in isolated and whole-blood 72 h cultures resulted in decrease of proliferation by 20.6% and 32.5%, respectively. In comparison, exposure to 1.0 μg mL(-1) of CYN caused lymphocytes proliferation to be inhibited by 91.0% in isolated cultures and 56.5% in whole-blood assay. Significant antiproliferative properties were also found for 0.1 μg mL(-1) of CYN in whole-blood culture. From the results we conclude that strains occurring in temperate zones may pose a threat to human health through the production of hitherto unknown metabolites that reveal a toxic pattern different to that of CYN. At the same time our study demonstrates that CYN is a powerful but slowly-acting toxin in human immune cells.

Increased maternal cytokine production and congenital heart defects

Congenital heart defects (CHDs) are a major cause of infant mortality. Most CHDs are thought to result from genetic, lifestyle, and environmental factors that include maternal obesity, diabetes, toxicant exposure, and alterations in anti-oxidant capacity. Since these well-documented risk factors are also associated with immune dysregulation, we sought to compare the maternal immune response in mothers carrying a fetus with a CHD with those mothers whose pregnancies were not affected by any birth defect. We conducted a case-control study to examine the maternal cytokine profile using multiplex technology in pregnant mothers (subject mean=26 weeks' gestation). This investigation revealed that whole blood cultures derived from case mothers produced higher levels of certain cytokines and chemokines compared with cultures from control subjects when activated with mitogen. Cultures from case subjects produced higher levels of IL-10, IL-13, IL-4, IL-5, IL-17, and IL-6, when stimulated with mitogen compared with control subjects. Plasma levels of chemokine MIP-1α were higher in cases compared with controls. In contrast, C-reactive protein levels were not statistically different. These results demonstrate the need to further examine the maternal cytokine signature in CHD-affected pregnancies. This information could pave the way toward maternal immunotherapeutic intervention to prevent CHDs, and novel biomarker discovery to improve pre-natal diagnosis.

Novel soybean oils differing in fatty acid composition alter immune functions of moderately hypercholesterolemic older adults

Linoleic acid (LA) and α-linolenic acid (ALA) are essential fatty acids that play an important role in modulation of T cell proliferation. The effects of consuming novel soybean oils varying in LA:ALA ratios on T cell proliferation and inflammatory responses were assessed in older adults. Eighteen participants (>50 y old) with elevated cholesterol concentrations (3.37-4.14 mmol/L LDL cholesterol) consumed 5 experimental diets in random order for periods of 35 d. Each diet contained 30% of energy as fat, two-thirds of which was high-oleic acid soybean oil (HiOleic-SO), soybean oil (SO), low-SFA soybean oil (LoSFA-SO), hydrogenated soybean oil (Hydrog-SO), or low-ALA soybean oil (LoALA-SO), resulting in LA:ALA ratios of 2.98, 8.70, 9.69, 15.2, and 18.3, respectively. Participants had higher proliferative responses to phytohemagglutinin (PHA) compared with baseline following consumption of SO (26%; P < 0.05), LoSFA-SO (22%; P < 0.05), or HiOleic-SO (24%; P < 0.05) diets. Proliferative response was similar to the baseline after participants consumed diets with an LA:ALA ratio >10 (Hydrog-SO and LoALA-SO). Post-diet intervention, LA:ALA ratios correlated with proliferative responses to PHA (r = -0.87; P = 0.05). An optimal proliferative response was observed at an LA:ALA ratio of 8.70, with an inverse correlation between proliferative response and LA:ALA ratios >8.70. These effects were independent of changes in the production of PGE(2), inflammatory cytokines, or cytokines involved in growth of lymphocytes. These data suggest that the LA:ALA ratio modulates the proliferative ability of T lymphocytes, which may be due to subtle changes in fatty acid composition of the phospholipids in immune cells.

A gender-related action of IFNbeta-therapy was found in multiple sclerosis

Background

Understanding how sexual dimorphism affects the physiological and pathological responses of the immune system is of considerable clinical importance and could lead to new approaches in therapy. Sexual dimorphism has already been noted as an important factor in autoimmune diseases: the aim of this study was to establish whether sexual dimorphism in autoimmune diseases is the result of differing pathways being involved in the regulation of T-helper (Th) cell network homeostasis.

Methods

We focused on sexually dimorphic changes in the immune response in multiple sclerosis (MS) patients in order to ascertain how these alterations relate to the pathway regulation of the cytokine homeostasis and the Th cell networks. We studied antigen presenting cell (APC)-dependent T cell activation in groups of healthy subjects, in patients under interferon (IFN) β-therapy and untreated. Cytokines, soluble (s) CD30 and the expanded disability status scale (EDSS) were used as biomarkers for T cell differentiation and neurological deficit.

Results

The data confirm our belief that sexual dimorphism in autoimmune diseases is the result of differing pathways that regulate Th cell network homeostasis: interleukin (IL) 6 pathways in women and IFNγ pathways in men. Given the increased susceptibility of women to MS and the significance of IL6 in the autoimmune process compared to IFNγ, it is logical to assume that IL6 pathways are in some way implicated in the prevalence of autoimmune diseases in women. Indeed, our data indicate that IL6 pathways are also involved in T regulatory (Treg) cell imbalance and an increase in neurological deficit in both men and women groups of MS patients, underlining the autoimmune etiology of multiple sclerosis. In further support of differing cytokine pathways in men and women, we noted that the efficacy of IFNβ-treatment in the re-establishment of Th-network balance and in the delaying of the neurological disability progression is linked to the IL6 pathway in women, but to the IFNγ pathway in men. Lastly, we also identified specific gender biomarkers for the use in therapy.

Conclusions

The identification of gender-specific drugs is of considerable importance in translational medicine and will undoubtedly lead to more appropriate therapeutic strategies and more successful treatment.

Gender-specific cytokine pathways, targets, and biomarkers for the switch from health to adenoma and colorectal cancer

Studies focusing on gender have shown that differences exist in how the immune system responds to disease and therapy. Understanding how gender influences immunological mechanisms in health and disease and identifying gender-specific biomarkers could lead to specifically tailored treatment and ultimately improve therapeutic success rates. T helper1 (Th1) and Th2 cytokines (Th1/Th2) have pivotal roles in the homeostasis of Th1 and Th2 cell network functions in the immune response but sex steroids affect Th1/Th2 production in different ways and a natural sexual dimorphism in the immune response has been shown. In order to investigate these differences further, we developed Th-cytokine data-driven models of the immune response and evaluated healthy subject peripheral blood samples. Independent cohorts of colorectal cancer and adenoma patients were also studied for comparison purposes. Our results show that the interferon (IFN)γ production pathway for immune response homeostasis is specific to men whilst the interleukin- (IL-) 6 production pathway for immune response homeostasis is specific to women. The IL-10 pathway for restoring immune system resting homeostasis was common to both but was controlled by the respective gender-specific pathways. These gender pathways could well be used as targets and biomarkers in translational research into developing new clinical strategies.

Obesity with a body mass index under 30 does not significantly impair the immune response in young adults

Obesity accompanies various metabolic and immunologic changes. Evidence from epidemiological, animal, and human studies has linked obesity to impaired immunity. However, human studies that have investigated the immunocompetence of the obese are still limited. We studied the immune and inflammatory responses of obese (body mass index [BMI], 28.3 ± 0.5 kg/m²; n = 30) and normal-weight (BMI, 21.2 ± 0.3 kg/m²; n = 15) young adults to test the hypothesis that obesity is associated with an impaired immune function and dysregulated inflammatory response. Serum levels of adipokines and subpopulations of immune cells were examined. In vitro proliferative response of whole blood lymphocytes, the production of inflammatory cytokines (interleukin [IL] 1β, IL-6, and tumor necrosis factor α) and T helper 1/T helper 2 cytokines (IL-2, interferon γ, IL-4, and IL-10) were determined. Serum leptin levels were significantly higher (P < .001) and CD8+ T-cell subpopulation was significantly lower (P = .044) in the obese than normal-weight subjects. There was no difference in the proliferative response of whole-blood lymphocytes to T-cell mitogens between 2 groups. Phytohemagglutinin-stimulated peripheral blood mononuclear cells from the obese group produced significantly higher levels of IL-2 (P = .002) and tended to produce higher levels of IL-4 (P = .053) than those from the normal-weight group. No significant differences in the production of inflammatory cytokines by either whole-blood lymphocytes or peripheral blood mononuclear cells stimulated with lipopolysaccharide were observed between the obese and normal-weight subjects. These results suggest that obesity with a BMI less than 30 does not significantly impair immune function in young adults. However, further research is needed to investigate the clinical significance of a lower CD8+ T-cell population associated with obesity.

Soluble CD30: a biomarker for evaluating the clinical risk versus benefit of IFNbeta1A treatment in multiple sclerosis patients

Aberrant redox regulation occurs in immune and neurological pathologies, hence targeting the pathways involved in the regulation of the redox system could provide further insights into these diseases and open up new avenues for therapy. Soluble (s) CD30 is of key clinical importance in this respect, as its levels reflect the functionality of the CD30 receptor (CD30R), the specific lymphocyte receptor for thiol disulfide/oxidoreductase thioredoxin 1 (Trx1) which is known to regulate important immune and neurological processes. Increased levels of sCD30 appear to be a common element of oxidative stress, immunological alterations and neurological deficit, therefore these increases could be used as a clinical biomarker and target for therapy. We targeted sCD30 in our study of dendritic cell (DC) regulation of the T helper (Th) cell network in multiple sclerosis (MS) patients, as abnormalities in T regulatory (Treg)/Th1/Th17 pathways contribute to the pathogenesis of this immunological/neurological disease. DC profiles in Treg/Th1/Th2/Th17-types of cytokine production in culture supernatants were used as they determine the type of Th differentiation. Our results show that sCD30 levels increase significantly in MS patients, reflecting the disruption in the regulation of the Treg/Th1/Th17 cell network. A fall in the level of soluble CD30, induced by IFNbeta1a therapy, opposed the increase of neurological deficit through increasing IL10 and TGFbeta levels, thus re-establishing network homeostasis but only when this was accompanied by an increase in IL12p70 levels. Since IL12p70 cytokine production is regulated by Trx1, our results indicate that redox system alterations may be the cause of IFNbeta1a therapeutic inefficacy. We conclude that an increase in the level of IL10, TGFbeta and IL12p70 and a fall in the level of sCD30 represent a means of evaluating the clinical risk/benefit of IFNbeta1a treatment.

Social-evaluative threat and proinflammatory cytokine regulation: an experimental laboratory investigation

This study experimentally tested whether a stressor characterized by social-evaluative threat (SET), a context in which the self can be judged negatively by others, would elicit increases in proinflammatory cytokine activity and alter the regulation of this response. This hypothesis was derived in part from research on immunological responses to social threat in nonhuman animals. Healthy female participants were assigned to perform a speech and a math task in the presence or absence of an evaluative audience (SET or non-SET, respectively). As hypothesized, stimulated production of the proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) increased from baseline to poststressor in the SET condition, but was unchanged in the non-SET condition. Further, the increases in TNF-alpha production correlated with participants' cognitive appraisals of being evaluated. Additionally, the ability of glucocorticoids to shut down the inflammatory response was decreased in the SET condition. These findings underscore the importance of social evaluation as a threat capable of eliciting proinflammatory cytokine activity and altering its regulation.

Micronutrient deficiencies are associated with impaired immune response and higher burden of respiratory infections in elderly Ecuadorians

The proportion of the Latin American population above age 65 y is expected to rise substantially. To better define the prevalence of infectious diseases and micronutrient deficiencies, assess immunological status, and evaluate associations between nutritional status and infection, we performed a cross-sectional study of elderly Ecuadorians in a low-income peri-urban community in Quito, Ecuador. Culturally adapted questionnaires, delayed type hypersensitivity (DTH) skin response, micronutrient, and immunological assays were performed in randomly selected Ecuadorians aged > or = 65 y. Multiple linear and logistic regression models were developed to assess relationships between micronutrient concentrations and history of infection, DTH, and immune function. Participants (n = 352; mean age +/- SD, 74.4 +/- 6.4 y) recalled recent episodes of colds/influenza-like syndromes (62.8%), cough (61.0%), urinary tract infection (37.9%), diarrhea (32.2%), fever (24.1%), and pneumonia (3.5%). A prospective substudy of respiratory infections (RI) in 203 elderly revealed similar findings. Colds and pneumonia occurred in 42.8 and 7.9% of participants, respectively, during 737 person-weeks of observation (3.6 +/- 1.1 wk per person). Anemia and micronutrient deficiencies, especially for vitamins C, D, B-6, and B-12 and folic acid and zinc, were common. Plasma vitamin C was associated with interferon-gamma (IFNgamma) (P < 0.01) and zinc with IFNgamma and interleukin-2 (each P < 0.0001). RI history was associated with any micronutrient deficiency (P < 0.001). The burden of infectious diseases, micronutrient deficiencies, and anemia was substantial in this elderly Ecuadorian population. Deficiencies of essential vitamins and minerals place these elderly adults at risk for infections through their negative impact on immune function.

Life history theory and the immune system: steps toward a human ecological immunology

Within anthropology and human biology, there is growing interest in immune function and its importance to the ecology of human health and development. Biomedical research currently dominates our understanding of immunology, and this paper seeks to highlight the potential contribution of a population-based, ecological approach to the study of human immune function. Concepts from life-history theory are applied to highlight the major challenges and demands that are likely to shape immune function in a range of ecological contexts. Immune function is a major component of maintenance effort, and since resources are limited, trade-offs are expected between investment in maintenance and other critical life-history functions involving growth and reproduction. An adaptationist, life-history perspective helps make sense of the unusual developmental trajectory of immune tissues, and emphasizes that this complex system is designed to incorporate information from the surrounding ecology to guide its development. As a result, there is substantial population variation in immune development and function that is not considered by current biomedical approaches. In an attempt to construct a framework for understanding this variation, immune development is considered in relation to the competing life-history demands that define gestation, infancy, childhood, adolescence, and adulthood. Each life stage poses a unique set of adaptive challenges, and a series of hypotheses is proposed regarding their implications for immune development and function. Research in human ecological immunology is in its earliest stages, but this is a promising area of exploration, and one in which anthropology is well-positioned to make important contributions.

Markers to measure immunomodulation in human nutrition intervention studies

Normal functioning of the immune system is crucial to the health of man, and diet is one of the major exogenous factors modulating individual immunocompetence. Recently, nutrition research has focused on the role of foods or specific food components in enhancing immune system responsiveness to challenges and thereby improving health and reducing disease risks. Assessing diet-induced changes of immune function, however, requires a thorough methodological approach targeting a large spectrum of immune system parameters. Currently, no single marker is available to predict the outcome of a dietary intervention on the resistance to infection or to other immune system-related diseases. The present review summarises the immune function assays commonly used as markers in human intervention studies and evaluates their biological relevance (e.g. known correlation with clinically relevant endpoints), sensitivity (e.g. within- and between-subject variation), and practical feasibility. Based on these criteria markers were classified into three categories with high, medium or low suitability. Vaccine-specific serum antibody production, delayed-type hypersensitivity response, vaccine-specific or total secretory IgA in saliva and the response to attenuated pathogens, were classified as markers with high suitability. Markers with medium suitability include natural killer cell cytotoxicity, oxidative burst of phagocytes, lymphocyte proliferation and the cytokine pattern produced by activated immune cells. Since no single marker allows conclusions to be drawn about the modulation of the whole immune system, except for the clinical outcome of infection itself, combining markers with high and medium suitability is currently the best approach to measure immunomodulation in human nutrition intervention studies. It would be valuable to include several immune markers in addition to clinical outcome in future clinical trials in this area, as there is too little evidence that correlates markers with global health improvement.

Relations of plasma ACTH and cortisol levels with the distribution and function of peripheral blood cells in response to a behavioral challenge in breast cancer: an empirical exploration by means of statistical modeling

This study explores by means of statistical modeling the relations between adrenocorticotrophin hormone (ACTH) and cortisol levels and distribution and function of peripheral blood cells in response to an acute stressor consisting of a standardized speech task in breast cancer patients with axillary lymph node metastases and distant metastases. As a control group age-matched women participated in this study. The preliminary findings show that the effect of ACTH on immunoreactivity is related to the health of the doctor. In node-positive breast cancer patients and healthy women, ACTH has a modest positive effect on T lymphocyte percentages and on pokeweed-induced proliferation at baseline and in response to the speech task. In contrast, in breast cancer patients with distant metastases, ACTH has a negative effect on T lymphocyte and function at baseline and in response to the stressor. Interestingly, neither ACTH nor cortisol levels were related to natural killer (NK) cell percentages and natural killer cell activity (NKCA). In addition, it appeared that cortisol had a positive effect on CD3 cell percentages when the health of the donor was taken into account. This effect was most distinct on CD3 cells measured at baseline. If replicated on a larger scale, these findings may indicate that the hypothalamic pituitary adrenal axis plays a role in the adaptation of the host defenses in reaction to acute stress, particularly those involving T lymphocytes. Moreover, these findings may suggest that the health of the donor may be an important effect modification factor in the relations between neuroendocrines and immunoreactivity.

Nutritional status predicts primary subclasses of T cells and the lymphocyte proliferation response in healthy older women

Aging is often associated with a dysregulation in immune function, particularly in T-cell responses, even in the healthy elderly. Adequate nutrition is important for optimal immune function. The literature on the relation of nutritional status with immune function in the elderly offers mixed findings. Because several nutrients can influence immune response, and there are interactions among nutrients, examining the association of various nutrients measured simultaneously with tests of immune function is important. We examined the association of protein, iron, zinc, vitamin B-12, and folic acid with tests of acquired immunity in healthy older women (76.7 +/- 7.0 y; n = 130). Discriminant analysis was used to identify the predictive subset of nutrients that could correctly classify subjects into the lowest or highest quartiles (< or =25th or >75th percentile) on various immune function tests (T cells and subsets and lymphocyte proliferation in response to culture with mitogens). Protein and iron status variables were identified in the predictive subset for all immune tests; in addition, zinc emerged in the predictive model for T cells and their subsets as well as for the proliferation response to concanavalin A. The probability of correctly classifying women into the lowest or highest quartiles of immune tests by the predictive subset of nutrition variables was high, i.e., 62.8-83.5% for T cells and their subsets, and 79.3-89.7% for the proliferation response to mitogens. In conclusion, protein, iron, and zinc were significant predictors of immune function in older women. Adequate status of these nutrients may help maintain immunity in older adults.

IFNbeta-1a treatment and reestablishment of Th1 regulation in MS patients: dose effects

The authors evaluated the relationships between clinical and pharmacologic parameters and the Th1/Th2/Th3 cytokine network in patients with relapsing-remitting multiple sclerosis treated with differing doses of interferon-beta1a (IFN-beta1a). Their results show that low doses are ineffective but that high doses restore Th1 regulation of the maturation and activation of monocytes, T cells, immature dendritic cells, dendritic cells, and T regulatory cells for central and peripheral self-tolerance. Interaction between interleukin (IL)-10, IL-12 p70, and IL-6 production appears to play an important role in the control of the maturation and activation states of dendritic cells and T regulatory cells, and is at the basis of the benefit of high doses. The results also indicate that the physiologic mechanisms involved in aging help immunologic reestablishment in IFNbeta-1a-treated patients. Finally, it would appear that the failure of IFNbeta-1a therapy to resolve multiple sclerosis completely is due to the suppression of IL-12 p70 mechanisms (responsible for the physiologic deletion of self-reactive cells) in activation conditions, probably by IFNbeta-1a itself.

Pharmacodynamics in the development of new immunosuppressive drugs

Over the past 10-20 years a number of immunosuppressive drugs, such as cyclosporine A, tacrolimus, sirolimus, or mycophenolate mofetil have been approved for clinical use and have been highly successful in preventing or delaying graft rejection. Nevertheless, there is an incessant need for better and safer drugs to improve short-term and long-term outcomes following transplantation. A number of low-molecular-weight molecules that interfere with immune cell functions are in development. These include molecules that inhibit the janus protein tyrosine kinase JAK3, compounds that alter lymphocyte trafficking (the sphingosine-1-phosphate receptor antagonist FTY720), and new malononitrilamides (FK778). All seem to show promising therapeutic potential. Among the biologic agents, there are high expectations for antibodies or recombinant chimeric molecules targeting costimulatory surface molecules or pathways involved in the migration of immune cells. The list of such targets includes the ligand pairs CD28:B7, CD154:CD40, LFA-1:ICAM-1, ICOS:B7RP-1, and VLA-4:VCAM-1. However, the clinical development of drugs for transplantation has proved to be difficult, complex, and time consuming. Therefore, newly emerging drug candidates will also demand better methods for monitoring their efficacy as well as their side effects in vivo. Pharmacokinetics (PK) and pharmacodynamics (PD) are complementary approaches used to select drugs on the basis of their in vivo efficacy as well as safety. Whereas PK monitors the handling of the drug by the body, PD focuses on the biologic effect of the drug on its target. Therefore, PD studies of in vivo efficacy are useful for clinical decisions to determine the optimal dose and type of immunosuppressant. At the preclinical stage, PD is aimed at accelerating the selection of lead compounds via PD-controlled trials in animals. Moreover, PD can help to discover new mechanisms of action for a drug or a drug candidate. However, its full potential has not been used, mainly because of laborious and time-consuming methodology. This review focuses on established and novel PD/PK approaches to assess immunosuppressive compounds in the context of new evolving drugs or drug combinations.

Immunological study of IFNbeta-1a-treated and untreated multiple sclerosis patients: clarifying IFNbeta mechanisms and establishing specific dendritic cell immunotherapy

OBJECTIVES

A comparative immunological evaluation of multiple sclerosis (MS) patients receiving IFNbeta treatment and patients who are not receiving treatment may help clarify IFNbeta neurological mechanisms and lead the way to an effective dendritic cell (DC) immunotherapy. This type of study helps clarify the pathological function of T cells and DCs within the TH1/TH2/TH3 network as well as the specific interactions between TH1/TH2/TH3 cytokines implicated in MS pathological mechanisms and determine the best way of reestablishing the TH1/TH2/TH3 network equilibrium.

METHODS

We studied network interactions between TH1/TH2/TH3 cytokine levels in serum and supernatants of whole blood and CD14+ monocyte-derived DCs in the remission phase of the disease and in correlation to the Expanded Disability Status Scale (EDSS).

RESULTS

We found that TH1 dysregulation results in a disruption of the maturation and activation of dendritic and T cells, and a lack of T-regulating cells for the induction of self-tolerance; IFNbeta mechanisms restore regulation by reestablishing the network balance but fail to resolve the disease completely due to in vivo IL12p70 network interactions leading to the deletion of self-aggressive cells.

CONCLUSIONS

Our results indicate that a specific DC immunotherapy could cure rather than treat MS. The best point to reestablish the normal physiological cycle is at the immature DC stage which can be done in vitro with treated peripheral blood CD14+ cells and used in vivo to stimulate the expansion of specific regulatory T cells.

Selected hormonal and immunological responses to strenuous live-fire firefighting drills

This study investigated the effects of strenuous live-fire firefighting drills and a 90 min recovery period on selected hormonal, immunological and psychological variables. Apparently healthy, male, professional firefighters (n = 11) performed three trials of standardized firefighting tasks in a live-fire training structure. There was significant leukocytosis immediately post firefighting activity that persisted following recovery, although there was a variable response among the leukocyte subsets. Most notable was the decrease in number and percentage of lymphocytes following 90 min of recovery. Plasma levels of ACTH and cortisol were significantly elevated post firefighting activity and cortisol remained elevated following 90 min of recovery. Elevated cortisol immediately following activity was related to reduced feelings of energy. These data demonstrate the magnitude of the physiological and psychological disruption following strenuous firefighting activity and suggest that immune function may be altered following such activity. This is a finding that may have practical consequences for this group of first responders.

Optimum culture conditions for specific and nonspecific activation of whole blood and PBMC for intracellular cytokine assessment by flow cytometry

The assessment of cytokine production is an important component of studies of cell-mediated immune responses (CMI) to immunological challenges. In this study, we present a method to enhance the detection of cytokine-producing cells by allowing antigen-specific cells to expand in long-term culture. We investigated the influence of the degree of dilution of whole blood and the duration of the incubation period on whole blood as well as peripheral blood mononuclear cells (PBMCs), cultured in the absence or presence of mitogens, superantigens or specific antigens, for intracellular cytokine production (IFNgamma, TNFalpha, IL-2, IL-4, IL-10 and IL-13) by CD4+ and CD8+ T lymphocytes using four-colour flow cytometry. Whole blood was diluted 1/1, 1/2, 1/5 and 1/10, and cultured for 6, 24, 48, 72 and 120 h in the presence of antibodies against the co-stimulatory molecules CD28 and CD49d, and, during the last 4 h of culture, in the presence of brefeldin A. Optimum conditions for detection of a high number of IFNgamma-positive cells were observed after 72 h of culture in blood diluted 1/10. Median frequencies of IFNgamma+ cells obtained after activation by PMA-ionomycin, PHA or SEA-B were 29.3%, 20.0% and 6.8% for CD4+ cells, and 67.8%, 20.6% and 6.8% for CD8+ cells. In blood samples diluted 1/5 or 1/10, and cultured in the presence of cytomegalovirus (CMV) or varicella-zoster virus (VZV), mean peak levels of 2.8% and 1.4% IFNgamma+CD4+ cells were recorded at 120 h. The levels of cells producing cytokines other than IFNgamma were generally much lower and, in the case of IL-4 and IL-13, difficult to distinguish from background levels recorded in cultures with medium only. Kinetic studies of cytokine production by PBMCs showed a pattern similar to that of whole blood with peak levels of IFNgamma-producing cells recorded at 72 h. The increased levels of IFNgamma production after culture for 72 h were due to an expansion of the numbers of cytokine-producing cells responsive to a specific stimulus. Antigen-specific cells are usually present only at low levels in peripheral blood and may not be detected following simple activation for a few hours. To reach a level of detection in such cases, culture of diluted blood for several days is recommended.

CD30 antigen: not a physiological marker for TH2 cells but an important costimulator molecule in the regulation of the balance between TH1/TH2 response

Understanding the physiological role of CD30 would be an important step forward in transplants because CD30+ T cells can be induced by alloantigens even in the presence of immunosuppressives such as cyclosporine (Csa) and hence can act as regulatory cells in allograft. The results of functional studies on purified T CD30+ cell populations led us to hypothesize that the CD30 costimulator molecule is not a specific marker for TH2 cells in normal conditions, as has been suggested, but rather a marker for an important immunoregulatory subpopulation that regulates the balance between TH1 and TH2 (TH1/TH2) type response. To substantiate this hypothesis we studied the TH1/TH2 cytokine network in peripheral whole blood cultures stimulate with M44 CD30 ligand (CD30L), an agonistic monoclonal antibody (mAb). Four types of whole blood culture were used: the first had been stimulated with anti-CD3 mAb which generates a CD30 cytokine profile similar to alloreactive stimulation; the second with anti-CD3 mAb+M81 (an anti-CD30L mAb) to inhibit CD30/CD30L interaction; the third with anti-CD3+anti-interleukin (IL)4 mAbs to counteract IL4 activity and the fourth with anti-CD3+anti-interferon (IFN)gamma mAbs to counteract IFNgamma activity. Network interactions between soluble CD30 (sCD30, a maker of CD30 expression), sBcl2 (a marker of cell survival) and TH1/TH2 cytokines (IFNgamma, IL2, IL12p70, IL12p40, IL4, IL5 and IL10) were then studied in the supernatants obtained. Our results confirm the hypothesis above by showing that CD30 signals trigger functional mechanisms responsible for changes in levels of production of several important TH1 and TH2 cytokines involved in the regulation of the physiological balance between TH1/TH2 functions. The CD30-stimulated network, in fact, induces IFNgamma production linked to TH1 activity (-->TH1) which is subsequently integrated by IL4 production linked to TH2 activity (-->TH2). This production appears to be regulated, respectively, by IL12p40 (-->TH2) and IL12p70 (-->TH1) production which could maintain the balance between TH1/TH2 type response (TH1<-->TH2). Further CD30 mechanisms are the regulation of the interactions between: IL5-IFNgamma, IL5-IL4, IL2-IL10, IL2-IL12p40 and IL10-IL12p70 production. The immunoregulatory activity of CD30 was confirmed by the lack of production balance between the above-mentioned cytokines observed in cultures in which the interaction between CD30 and its natural ligand (CD30/CD30L) and IL4 or IFNgamma activity had been blocked. We therefore conclude that CD30 may be an important costimulatory molecule and marker for the physiological balance between TH1/TH2 immune response. Consequently, further study of CD30 immunoregulatory mechanisms may allow for the identification of methods for re-establishing equilibrium and hence more effective strategies for the prevention and treatment of immunopathological conditions such as transplant rejection.

Cellular immune responses in multiple myeloma patients with treatment-induced cytopenia early after high-dose chemotherapy and autologous peripheral blood stem cell transplantation

Proliferative T cell responses were compared for two patient groups with severe treatment-induced leukopenia (white blood cell counts < 0.5 x 10(9)/l): (i). multiple myeloma patients receiving high-dose melphalan and autologous peripheral blood stem cell transplantation; (ii). patients receiving conventional intensive chemotherapy for acute leukemia or myelodysplasia. Although the majority of circulating leukocytes were CD2(+)TCRalphabeta(+) in both groups, the myeloma patients showed significantly lower T cell proliferation in responses to several activation signals (anti-CD3, anti-CD3 + IL2, anti-CD3 + anti-CD28, anti-CD3 + anti-CD28+IL2. Our results suggest that myeloma patients with post-transplant cytopenia have a more severe cellular immune defect than patients with other hematological malignancies and severe cytopenia due to conventional intensive chemotherapy.

Passage from normal mucosa to adenoma and colon cancer: alteration of normal sCD30 mechanisms regulating TH1/TH2 cell functions

The pathogenesis of cancer is currently under intensive investigation to identify reliable prognostic indices for the early detection of disease. Adenomas have been identified as precursors of colorectal cancer and tumor establishment, and disease progression has been found to reflect a malfunction of the immune system. On the basis of the role of the CD30 molecule in the regulation of TH1/TH2 functions and our previous results, strongly suggesting the validity of serum TH1/TH2 cytokines in the study of tumor progression, we studied network interaction between the production of soluble (s) CD30/sBCl2 in whole blood culture [in basic conditions and after PHA, LPS, and anti-CD3 monoclonal antibody (mAb) stimulation] and levels of TH1/TH2 cytokines (IL2, IFN gamma, IL12, IL4, IL5, IL10). Peripheral blood from a group of healthy subjects, as well as from patients with adenoma and colorectal cancer was used. Our objective was to gain a better insight into the role of the CD30 molecule in the passage from normal mucosa to adenoma and tumor and identify specific disease markers. Our results suggest that the decrease in CD30 expression and the abnormal increase in Bcl2 expression, observed in the peripheral cells of both adenoma and tumor groups determine an imbalance between TH1/TH2 functions. Consequently, changes in sCD30/sBcl2 culture production and TH1/TH2 cytokine serum levels may be reliable markers for tumor progression. In fact, our overall data show that a decrease of sCD30 levels in basic and PHA conditions and an increase of IFN gamma, IL4, IL5, and IL12 serum levels and sBcl2 in all activation condition are indicative of the passage from normal mucosa to adenoma; whilst a decrease of sBcl2 level in basic, LPS and anti-CD3 conditions and of IL2, IFN gamma serum levels, together with an increase of IL5 are indicative of the passage from adenoma to tumor.

Promoter haplotypes of the interleukin-10 gene influence proliferation of peripheral blood cells in response to helminth antigen

Since interleukin (IL)-10 is a key mediator of immunosuppression, and immunosuppression is considered an important element of helminth infection, we studied variants of the putative IL-10 gene promoter in 337 individuals from 130 families heavily exposed to infection by the tissue nematode Onchocerca volvulus. As shown by transmission disequilibrium tests, variants of the IL-10 promoter at positions -1082(G/A), -819(C/T), and -592(C/A) in the haplotype of ATA were significantly associated with high peripheral blood cell (PBC) proliferative responses to O. volvulus antigen (OvAg). No associations were observed using phytohemagglutinin-induced PBC proliferation or with qualitative or quantitative phenotypes of onchocerciasis or onchocerciasis-related skin disease. The findings are compatible with the hypothesis that the ATA haplotype causes a decrease in IL-10 production by OvAg-reactive type-1 regulatory T-lymphocytes, thereby alleviating the suppression of other T cells. To our knowledge, this is the first time that an influence of IL-10 promoter variants is shown on the adaptive immune response.

FTY720 MEDIATES APOPTOSIS-INDEPENDENT LYMPHOPENIA IN HUMAN RENAL ALLOGRAFT RECIPIENTS: DIFFERENT EFFECTS ON CD62L+ AND CCR5+ T LYMPHOCYTES

BACKGROUND

The sphingolipid FTY720 (FTY), a novel immune modulator, induces lymphopenia and prevents allograft rejection. This study was designed to study the effect of FTY on lymphocyte subpopulations and apoptosis in stable renal allograft recipients.

METHODS

Stable renal allograft recipients received a single oral dose of 0.25 to 3.5 mg of FTY (n= 13) or placebo (n= 3). Whole blood was drawn immediately before and at 4, 8, 12, 24, 72, and 96 hr after administration. The number of lymphocyte subpopulations, with an emphasis on surface markers involved in lymphocyte migration, was analyzed by flow cytometry. Apoptotic lymphocytes were detected following Annexin V-FITC/PI staining. Lymphocyte mobility was investigated in a modified Boyden chamber.

RESULTS

FTY induced a transient lymphopenia by an apoptosis-independent mechanism. In vitro experiments with peripheral blood mononuclear cells (PBMC) confirmed that clinically relevant concentrations of FTY (0.1 microM) increased lymphocyte mobility, whereas only suprapharmacologic concentrations of FTY (10 microM) could induce apoptosis. FTY-treated patients had reversible changes in the composition of peripheral lymphocyte subpopulations. CD62L+ T cells decreased to the greatest extent (-57%). In contrast, CCR5+ T-cell counts declined only marginally (-10%). In vitro, treatment of PBMC with FTY (1 mM-10 microM) did not induce changes in the expression of these surface markers.

CONCLUSIONS

The data indicate that FTY mediates apoptosis-independent lymphopenia in human renal allograft recipients. FTY-induced lymphopenia preferentially affects CD62L+ and CCR5- T-lymphocyte subpopulations.

Lymphocyte Numbers and Function in Relation to Periodontitis and Smoking

BACKGROUND

T and B lymphocytes play important roles in periodontitis. Smoking is considered a risk factor for periodontitis and may exert its negative effects through leukocytes. Taking smoking into consideration, the aim of this study was to analyze numbers of circulating T (CD3+) cells and their CD4+ and CD8+ subpopulations, B (CD19+) cells, and T-cell proliferative capacity in periodontitis.

METHODS

Lymphocyte immunophenotyping for T cells, their CD4+ and CD8+ subsets, and B cells was performed on peripheral blood from 76 periodontitis patients and 36 controls. Proliferative capacity of T cells was determined in whole-blood lymphocyte culture assays after mitogenic stimulation.

RESULTS

Total T cells, CD4+ and CD8+ subpopulations, and responsiveness to specific T-cell stimuli did not differ between patients and controls; in addition, B cells were not significantly elevated in periodontitis patients. However, more periodontal breakdown in smoking patients was associated with higher numbers of CD3+ T cells, as well as with CD4+ and CD8+ T-cell subsets, and increased T-cell proliferation. Numbers of B cells were not affected by smoking.

CONCLUSIONS

The increased numbers of T-cells and elevated T-cell responsiveness in patients who smoke may be one of several explanations why smoking is a risk factor for periodontitis. The mechanism of how T-cell function contributes to increase the severity of periodontal breakdown in smoking periodontitis patients needs to be investigated further.

Immunosuppressive Interactions among Calcium Channel Antagonists and Selected Corticosteroids and Macrolides Using Human whole Blood Lymphocytes

The immunosuppressive interactions of calcium channel antagonists [diltiazem (Dil), verapamil (Ver) and nifedipine (Nif)], with corticosteroids [methylprednisolone (Mpl), prednisolone (Prd)], and macrolides [tacrolimus (Tac) and sirolimus (Sir)] were examined in human whole blood lymphocyte cultures. Gender-related differences in responses in the interactions between these drug classes were studied using blood from 6 males and 6 females. The nature and intensity of interactions were determined using an extended Loewe additivity model. All immunosuppressants exhibited higher potency than the calcium channel antagonists with mean IC50 values of: Dil Ver Nif Mpl Prd Tac Sir (mM) (mM) (mM) (nM) (nM) (nM) (nM) Male 135 41.9 213 12.1 18.6 150 327 Female 114 31.8 47.4 4.6 8.8 111 106 Gender-related differences in responses to Mpl and Prd were observed while the others were not significant. Additive interactions were found among calcium channel antagonists and corticosteroids. Significant synergistic interactions were observed between calcium channel antagonists and tacrolimus and sirolimus, although these are unlikely to be of clinical importance. These studies demonstrate diverse drug interactions in the examination of an important array of immunosuppressant drug combinations.

Functional Evaluation of Proliferative T Cell Responses in Patients with Severe T Lymphopenia: Characterization of Optimal Culture Conditions and Standardized Activation Signals for a Simple Whole Blood Assay

In this methodological study, we describe an assay for analysis of proliferative T cell responses in patients with severe leukopenia. Severe treatment-induced cytopenia is observed in patients with malignant disorders who receive conventional intensive chemotherapy or autologous stem cell transplantation. The quantitative T cell defect can then be characterized by flow cytometric analysis of membrane molecule expression, whereas the functional status of the remaining T cell population is more difficult to evaluate. In the present study, we describe a standardized whole blood assay that requires small sample volumes and can be used for repeated analysis even in severely ill patients. The assay is based on the following strategy: (i) blood samples are diluted with the serum-free medium X-vivo 10, (ii) T cells are activated either with monoclonal immunoglobulin E (IgE) anti-CD3 or anti-CD3 plus anti-CD28; (iii) T cell proliferation is assayed by [(3)H]thymidine incorporation after 4 days of in vitro culture. These proliferative responses are not affected by the plasma levels of interleukin-2 (IL-2), sIL-2-R alpha, IL-7 and IL-15, and the kinetics of the response are not altered by the presence of exogenous cytokines. Detectable proliferation is observed for most patients with treatment-induced cytopenia. We conclude that the assay can be used for functional characterization of remaining T lymphocytes in patients with severe T lymphopenia.

Relative immunosuppressive potency of therapeutic corticosteroids measured by whole blood lymphocyte proliferation

The in vitro immunosuppressive potency of several therapeutic corticosteroids was investigated using a whole-blood lymphocyte proliferation assay. The selected steroids included beclomethasone dipropionate (BDP), betamethasone (BET), budesonide (BUD), dexamethasone (DEX), flunisolide (FLU), fluticasone propionate (FTP), hydrocortisone (HC), methylprednisolone (MPL), prednisolone (PNL), and triamcinolone acetonide (TAA). The ability of phytohemagglutinin to stimulate lymphocytes in whole blood samples obtained from six drug-free male volunteers was tested against drug concentrations ranging from approximately 0.2 to 2000 nM. Data analysis was conducted employing an inhibitory Hill function and nonlinear regression analysis in ADAPT II. The order of drug concentrations producing 50% inhibition (IC(50)) from highest to lowest was HC > PNL > MPL > BDP > BET > DEX > TAA > FLU > BUD > FTP. These IC(50) values are an inverse measure of drug potency, with FTP representing the most potent corticosteroid examined. A linear correlation was found between the log-transformed 1/IC(50) values and the log of the relative receptor affinity (RRA) values obtained from the literature (r(2) = 0.95). These results extend previous studies to include relatively new corticosteroids and further support the use of RRA values as an indirect measure of relative in vitro immunosuppressive potency.

Development and evaluation of a flow-cytometric assay of specific cell-mediated immune response in activated whole blood for the detection of cell-mediated immunity against varicella-zoster virus

A new assay for the detection of specific cell-mediated immune (CMI) responses is described. Whole blood, diluted 1/10 in medium, was cultured in the presence or the absence of specific antigens. Results were assessed by flow cytometric analysis with or without immunophenotyping to detect proliferating lymphoblasts among cultured cells. Interferon-gamma, IL-10, and IL-5 in culture supernatants are measured by ELISAs. The assay was evaluated using samples from 37 VZV-antibody-positive children with a history of chickenpox and samples from 15 seronegative children without a history of chickenpox; it displayed a sensitivity of 95% and a specificity of 100% for the detection of varicella-zoster virus (VZV)-specific CMI. The intraassay and interassay variations of the new test were lower than with the conventional assay for CMI, detecting thymidine incorporation in peripheral blood mononuclear cells (PBMCs). Cytokines were detected in only 70% of cultures from VZV-antibody-positive subjects. The cytokine response was restricted to IFN-gamma in most cases. The Flow-cytometric Assay of Specific Cell-mediated Immune response in Activated whole blood (FASCIA) is a precise and accurate yet simple and convenient test that can be readily employed for the examination of single samples as well as for large-scale studies.

Laboratory assessment of immune function in renal transplant patients

BACKGROUND

Advances in immunosuppression have made renal transplantation an effective therapy for end stage renal failure; with low rejection rates and long graft survival times. However, the major adverse consequences, infection and malignancy have not diminished. To predict this risk a score of immune competence has been developed from the simultaneous laboratory assessment of multiple parameters of immune function.

METHODS

The immune status of 152 transplant recipients (138 renal and 14 pancreas/renal) was assessed by measurement of lymphocyte subsets, mitogen-induced T-cell proliferative responses, neutrophil phagocytic capacity and reactive oxygen species (ROS) generation. A scoring system was devised based on the average number of these parameters below 10th percentile of normal.

RESULTS

The most common abnormality was B-cell lymphopenia (85%) followed by reduced neutrophil ROS production (63% of patients), NK cell lymphopenia (50%), lymphocyte mitogen response (49%) and CD4 number (23%). The abnormalities were unrelated to the duration of immunosuppression (up to 15 years), and variable combinations of cyclosporine A, azathioprine, prednisolone and mycophenolate mofetil (MMF) (except for a consistent reduction in lymphocyte mitogen response in MMF treated patients). Retrospective comparison of infective episodes showed a significantly greater index of infections in patients with the worst score compared with a normal score.

CONCLUSIONS

The data suggests that this quantification of immune function may allow assessment of the level of host immune defence reflecting the level of drug-induced immunosuppression and thus risks of immunosuppressive complications.

Early activation of peripheral lymphocytes in human acute pancreatitis

BACKGROUND

The CD69 antigen is an indicator of early lymphocyte activation.

GOALS

To evaluate the early activation of peripheral lymphocytes T, B, and NK in patients with acute pancreatitis in comparison with patients with acute abdomen of nonpancreatic origin.

STUDY

Thirty patients with acute pancreatitis were studied; 20 of them had the mild form of the disease and 10 had the severe form. Thirty patients with nonpancreatic acute abdomen were used as controls. All patients were enrolled within 48 hours of the onset of pain. In all patients, leukocytes and total lymphocyte and lymphocyte subset counts (CD4+, CD8+, CD56+, CD19+, CD4+CD69+, CD8+CD69+, CD56+CD69+, CD19+CD69+) were determined upon hospital admission.

RESULTS

The percentage of total lymphocytes was significantly lower in acute pancreatitis patients than in those with nonpancreatic acute abdomen (P = 0.014); patients with severe pancreatitis had a percentage of total lymphocytes significantly lower when compared with patients with mild pancreatitis (P < 0.001). The CD19+CD69+ count was significantly lower in patients with severe pancreatitis (24.6 +/- 14.6%) than in patients with mild pancreatitis (46.7 +/- 16.5%; = 0.006). The counts of the other lymphocyte subsets were not statistically different between patients with acute pancreatitis and those with nonpancreatic acute abdomen, as well as between patients with mild and severe acute pancreatitis.

CONCLUSIONS

Patients with severe pancreatitis show impaired early activation of peripheral CD19+ cells.

Baseline T cell reactivity in multiple sclerosis is correlated to efficacy of interferon-beta

BACKGROUND

Measuring proliferative responses of T lymphocytes is a simple, reproducible and widely used assay of immune competence. Evidence suggests a role of T cell reactivity in autoimmune diseases. Interferon (IFN)-beta blocks in vitro proliferation of human T cells.

OBJECTIVES

To assess (i) the relation between T cell proliferation and disease characteristics of MS patients, (ii) differences in T cell proliferation between subgroups and HC, and (iii) the predictive value of T cell proliferation for efficacy of IFN-beta.

METHODS

Proliferative responses were measured in phytohaemagglutinin (PHA), anti-CD2/CD28 and anti-CD3 stimulated whole blood of 189 MS patients and 249 healthy controls (HC). Forty-eight patients started treatment with IFN-beta. Based on EDSS progression, number of relapses and steroid interventions, patients were classified as either clinical responder or nonresponder to IFN-beta.

RESULTS

Significant differences between MS subgroups and HC were found in T cell responses upon both PHA stimulation (RR>HC: p=0.001 and SP>HC: p=0.001) and CD2/CD28 stimulation (RR>HC, SP>HC and PP>HC: all p values <0.001). No significant differences were found between the MS subgroups. A probability of 88% (95% CI, 71-95%) for a favorable response to IFN-beta was found with increased baseline proliferative T cell responses to PHA; a probability of only 16% (95% CI, 7-33%) with decreased values.

CONCLUSION

Our results suggest that the level of T cell proliferation in whole blood predicts efficacy of IFN-beta in MS.

The effects of chromium and copper supplementation on mitogen-stimulated T cell proliferation in hypercholesterolaemic postmenopausal women

The purpose of this study was to analyse effects of chromium and/or copper supplementation on immune function in hypercholesterolaemic postmenopausal women. A 2 x 2 factorial research design was used and 40 subjects were supplemented with 0.394 g lactose, 200 microg Cr, 3.0 mg Cu, or 200 microg Cr and 3.0 mg Cu/d for 12 weeks. A significant interactive effect of Cr and Cu supplementation on lymphocyte proliferation was observed with ConA 50 microg/ml stimulation. After 12 weeks of supplementation, ConA-stimulated (50 microg/ml) lymphocyte proliferation was significantly lower when Cu was added to the Cr supplementation group. Moreover, ConA-stimulated (100 microg/ml) lymphocyte proliferation was significantly lower in the Cu supplementation group compared to the Cr supplementation group after 12 weeks of supplementation. These results suggest that Cu blocks enhancement of lymphocyte proliferation by Cr supplementation and that Cu supplementation has potential suppressive effects on the immune function in these subjects.

Therapeutic immune reconstitution in HIV-1-infected children is independent of their age and pretreatment immune status

OBJECTIVE

To evaluate long-term immune reconstitution of children treated with highly active antiretroviral therapy (HAART).

METHODS

The long-term immunological response to HAART was studied in 71 HIV-1-infected children (aged 1 month to 18 years) in two prospective, open, uncontrolled national multicentre studies. Blood samples were taken before and after HAART was initiated, with a follow-up of 96 weeks, and peripheral CD4 and CD8 T cells plus naive and memory subsets were identified in whole blood samples. Relative cell counts were calculated in relation to the median of the age-specific reference.

RESULTS

The absolute CD4 cell count and percentage and the CD4 cell count as a percentage of normal increased significantly (P < 0.001) to medians of 939 x 106 cells/l (range, 10-3520), 32% (range, 1-50) and 84% (range, 1-161), respectively, after 48 weeks. This increase was predominantly owing to naive CD4 T cells. There was a correlation between the increase of absolute naive CD4 T cell counts and age. However, when CD4 T cell restoration was studied as percentage of normal values, the inverse correlation between the increase of naive CD4 T cell count and age was not observed. In addition, no difference in immunological reconstitution was observed at any time point between virological responders and non-responders.

CONCLUSIONS

Normalization of the CD4 cell counts in children treated with HAART is independent of age, indicating that children of all age groups can meet their CD4 T cell production demands. In general, it appears that children restore their CD4 T cell counts better and more rapidly than adults, even in a late stage of HIV-1 infection.

Interactions of aspirin and salicylic acid with prednisolone for inhibition of lymphocyte proliferation

The anti-inflammatory properties of salicylates and prednisolone were investigated using inhibition of in vitro phytohemagglutinin-stimulated lymphocyte proliferation in human whole blood from healthy male and female subjects. Steroids and salicylates are used in conjunction for the treatment of inflammatory disorders such as rheumatoid arthritis and inhibit the proinflammatory transcription factor, NFKB, by different mechanisms. Data generated using various combinations of these drugs were analyzed using isobolograms and the universal surface response approach based on the Loewe additivity principle. The interaction between aspirin and prednisolone was mildly antagonistic while that between salicylic acid and prednisolone was modestly synergistic at therapeutic concentrations. Further, aspirin was slightly more potent in males, but the nature of the steroid-salicylate interaction was similar across genders. This study helps rationalize part of the beneficial effects of steroids and salicylates in treatment of inflammatory disorders.

Flow cytometric quantitation of calcium-dependent and -independent mitogen-stimulation of T cell functions in whole blood: inhibition by immunosuppressive drugs in vitro

We have optimized assays to measure mitogen-stimulated rat lymphocyte activation in whole blood and have used these assays to quantitate the potencies of immunosuppressive drugs with different mechanisms of action. To define the optimal conditions for measuring T cell functions in whole blood, the effects of different concentrations of mitogens that activate T cells through calcium-dependent and -independent pathways were measured over time. Proliferation was measured by tritium-labeled thymidine ([3H]-TdR) incorporation and by flow cytometric analysis of proliferating cell nuclear antigen (PCNA)/DNA content. Furthermore, we detected the increases in percent expression of cell-surface activation antigens (CD25, CD134, CD71, CD11a and CD54). Concanavalin A (Con A) stimulated maximum lymphocyte proliferation and expression of T cell surface activations by 72-96 h, which was 48 h later than stimulation by phorbol 12-myristate 13-acetate (PMA) plus anti-CD28 monoclonal antibody (mAb) or PMA plus ionomycin (IONO). Addition of sirolimus, tacrolimus, cyclosporine or the active metabolite of leflunomide, A77 1726, to mitogen-stimulated whole blood produced drug concentration-dependent inhibitions of lymphocyte proliferation and expression of cell surface activation antigen expression. From these data, we determined drug potencies (inhibitory concentration of 50%, IC(50)) and drug concentrations causing maximum inhibition of T cell functions (I(max)). We developed simple and reproducible assays to measure different lymphocyte functions in whole blood cultures. These assays were used to investigate the mechanisms of different immunosuppressive drugs. These methods can be exploited to measure T cell functions in blood collected from subjects treated with immunosuppressants in vivo.

The cellular immune system of patients with acute leukemia and severe chemotherapy-induced leukopenia: characterization of T lymphocyte subsets responsive to IL-16 and IL-17

The aim of the present study was to characterize the effects of IL-16 and IL-17 on CD4+ and CD8+ T cell responses in patients with acute leukemia and severe chemotherapy-induced leukopenia. We investigated (1) the function of cytokines as growth factors for preactivated monoclonal T cell populations which had been prepared by long-term in vitro culture, and (2) the ability of cytokines to modulate anti-CD3-stimulated proliferation of polyclonal, nonexpanded T cells. A subset of CD4+ and CD8+ clones could utilize IL-16 and IL-17 as growth factors after previous mitogenic activation, but for the CD4+ subset IL-16 responses were significantly higher than IL-17 responses. Cytokine-dependent proliferation was higher for the CD4+ than for the CD8+ clones in the presence of both IL-16 and IL-17. The effects of IL-16/IL-17 were modulated by the presence of exogenous IL-2 and IL-4. The IL-16-responsive CD8+ clones seemed to represent a minor subset expressing the phenotype CD4lowCD8high. The anti-CD3-stimulated polyclonal responses were generally lower for the cytopenic patients than for healthy individuals, and this decreased responsiveness was probably caused by a combination of quantitative T cell defects and suboptimal accessory cell costimulation. Although IL-16 and IL-17 could function as growth factors for a large subset of our T cell clones, both cytokines had either no or only minor effects on the polyclonal T cell responses for cytopenic patients (e.g. only weak enhancement of anti-CD3 and anti-CD3+anti-CD28 responses, no alteration of the cytokine responsiveness profile after anti-CD3 stimulation). We conclude that both IL-16 and IL-17 are potentially immunostimulatory cytokines in patients with acute leukemia and chemotherapy-induced leukopenia, but the final effects of IL-16/IL-17 on proliferative T cell responses are modulated by local immunoregulatory networks.

Ex vivo induction of cytokine mRNA expression in human blood samples

The interest in the quantitative analysis of cytokine mRNA profiles has increased substantially in recent years. This is based on the potential use of basal cytokine mRNA expression as sensitive markers for in vivo lymphocyte activation in a variety of clinical settings. However, it is less well known to what extent differences in blood collection and preparation techniques may cause ex vivo alteration of quantitative cytokine mRNA levels. We therefore evaluated the effect of blood sampling and the impact of cell separation on interleukin (IL)-2, IL-4, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha mRNA expression in an intraindividual study design (n=8). Two different blood sampling procedures were applied. A whole blood sample 1 was collected by constant moderate blood flow into a blood collection tube containing lithium-heparin. Moreover, a second sample from the same donor was collected by a 5-fold acceleration of blood flow. Furthermore, peripheral blood mononuclear cell (PBMC) were isolated from the first whole blood sample by density separation over Ficoll-Hypaque. The quantification of cytokine mRNA expression was performed by real-time PCR in native whole blood/PBMC samples or unstimulated cultures. We found a significant increase of IL-2, IL-4 and TNF-alpha mRNA expression (P=0.018, P=0.028, P=0.018) in whole blood samples collected by rapid sampling. The isolation of PBMC by density gradient separation prompted on upregulation of the mRNA levels of IL-2, IL-4 and TNF-alpha 5-9-fold (P=0.018, P=0.018, P=0.018). In contrast, IFN-gamma mRNA expression was not significantly influenced by differences in blood sample preparation. Our data clearly demonstrate that differences in the blood sampling technique or cell separation should be considered as important factors for non-physiological ex vivo induction of cytokine mRNA expression. The current data emphasize the need for data on the impact of ex vivo variation in order to extract reliable and consistent information, particularly when cytokine mRNA expression data from healthy blood donors are included in clinical studies.

Whole blood assay for assessment of the mixed lymphocyte reaction

When lymphocytes from genetically different individuals are mixed together in tissue culture blast transformation occurs, a reaction known as the mixed lymphocyte reaction (MLR). The MLR is a clinically relevant in vitro assay where lymphocytes from one individual (effector, E) are incubated with the lymphocytes of another individual (stimulator, S) which have been previously rendered incapable of blast transformation by gamma-irradiation. We have standardised a whole blood (WB) MLR assay where the E lymphocytes were provided by 20 microl of WB and the S lymphocytes were provided by irradiated peripheral blood mononuclear cells (PBMCs) either as a mixed pool of 20 donor PBMCs or as single donor PBMC. The optimum number of S lymphocytes needed was comparatively higher than in the standard PBMC MLR: the optimum calculated E:S ratio was 1:20 compared to a E:S ratio of 1:1 or 3:2 in the standard PBMC MLR. In ten normal individuals the WB/PBMC MLR was similar to the standard PBMC/PBMC MLR. As a clinical example, the WB/PBMC MLR proliferative capacity of 13 patients with malignant mesothelioma was no different from the proliferative capacity of their age-sex matched controls. This standardised WB/PBMC MLR assay is a simple and more practical assay than the standard MLR assay and can be incorporated easily in clinical studies with biological end-points.

Pharmacodynamics of mycophenolic acid in heart allograft recipients: correlation of lymphocyte proliferation and activation with pharmacokinetics and graft histology

BACKGROUND

Assays of drug blood levels are used for therapeutic immunosuppressive drug monitoring (pharmacokinetics, PK). We monitored lymphocyte functions (pharmacodynamics, PD) in allograft recipients treated with mycophenolic acid (MPA) to determine its mechanisms and the relationships among dose levels, PK, PD, and histological severity of graft rejection.

METHODS

Lewis rats transplanted with Brown Norway (BN) rat hearts were treated with different dose levels of MPA for 8, 15, or 29 days at which times grafts were removed and scored for rejection grade. Blood was analyzed (high-performance liquid chromatography) for MPA plasma concentrations (area under the concentration-time curve0-24 hr, C6 hr, trough) and for lymphocyte functions using concanavalin A-stimulated whole blood assays to measure lymphocyte proliferation (tritium labeled thymidine incorporation and flow cytometric bivariate proliferating nuclear cell antigen/DNA analysis) and activation (percent lymphocytes expressing CD25 or CD134). PD values were AUE0-24 hr (area under the PD effect-time curve), maximum inhibition and trough.

RESULTS

MPA equipotently suppressed (by flow cytometry) both proliferation and activation and these effects correlated with MPA plasma levels (r2=0.80-0.91). Relationships among MPA dose levels, PK and PD were clear, direct, and reproducible. Correlation coefficients after 8 days of MPA treatment were: 0.90, 0.87, and 0.49 for MPA PK (AUC0-24 hr, C6 hr and trough) versus rejection scores; 0.80-0.89, 0.86-0.92, and 0.25-0.52 for PD flow cytometric assays (AUE0-24 hr, maximum inhibition, and trough) versus rejection scores.

CONCLUSIONS

MPA inhibits both lymphocyte proliferation and activation. PD by flow cytometry (FCM) correlates highly with severity of graft rejection, showing that PD of MPA measured in peripheral blood predicts immune cell activity in graft tissue.

Pharmacodynamics of immunosuppressive drugs

The inability to measure the effects of immunosuppressive drugs on immune cells in vivo has always severely limited preclinical drug development, the design and interpretation of clinical trials and the optimal clinical use of this drug class in transplantation. Now, new technologies using microliter samples of whole blood and exploiting the specificity, sensitivity and versatility of flow cytometry have been developed. These novel techniques not only are illuminating the 'black box' that has obscured the pharmacodynamic effects of immunosuppressants but also are uncovering new mechanisms of action of these drugs. Pharmacodynamic assays measure biologically relevant events in vivo, since changes in lymphocyte functions in blood collected from immunosuppressed graft recipients faithfully reflect histopathologic events within allograft tissue.

Lymphocyte response to mitogens: influence of life events and personality

The aim of the present study was to examine the possibility that the accumulation of life events is associated with low lymphoproliferative response to mitogens in undergraduate students. We also analyzed the possible interaction between life events and personality traits. Lymphocyte response to phytohemagglutinin (PHA) was lower in subjects with high life events compared to those with low levels. Introverted subjects were found to exhibit lower lymphocyte responses to PHA than those who were extraverted, and there was no interaction between the effect of introversion and life events on the proliferative capacity. Lymphocyte proliferation was low in subjects with high anxiety scores, whether they had high or low levels of life events. In the group with high scores on independence a high accumulation of life events was not associated with lower lymphoproliferation; while in the group with low scores it was, suggesting that independence buffers the association between life stress and lower cellular immunity.

Comparison of the in vitro antiproliferative effects of five immunosuppressive drugs on lymphocytes in whole blood from cats

OBJECTIVE

To compare the in vitro immunosuppressive effects of cyclosporine and 4 novel immunosuppressive drugs on lymphocytes in whole blood collected from healthy cats.

SAMPLE POPULATION

Whole blood samples collected from 10 healthy adult domestic shorthair cats.

PROCEDURE

Mitogen-stimulated lymphocyte proliferation in whole blood incubated with and without various concentrations of cyclosporine, tacrolimus, sirolimus, mycophenolic acid (MPA), or A771726 was measured by use of [3H]thymidine incorporation. Drug concentrations that resulted in a 50% inhibition of mitogen-induced proliferation (IC50) were calculated. Lymphocyte viability was determined by use of the trypan blue dye exclusion method.

RESULTS

An obvious dose-response relationship for the antiproliferative effects of each drug was detected. Mean IC50 determined with concanavalin A was 46 nM for cyclosporine, 9 nM for tacrolimus, 12 nM for sirolimus, 16 nM for MPA, and 30 mM for A771726, whereas with pokeweed mitogen, mean IC50 was 33 nM for cyclosporine, 5 nM for tacrolimus, 15 nM for sirolimus, 14 nM for mycophenolic acid, and 25 mM for A771726. Mitogen-stimulated and nonstimulated lymphocytes remained viable, regardless of drug evaluated.

CONCLUSIONS AND CLINICAL RELEVANCE

Tacrolimus, sirolimus, MPA, and A771726 inhibited in vitro mitogen-stimulated proliferation of feline lymphocytes in a dose-dependent manner. These novel immunosuppressive drugs may be useful for management of immune-mediated inflammatory diseases and prevention and treatment of rejection in cats that undergo organ transplantation.

Antibody response after influenza vaccination in HIV-infected individuals: a consecutive 3-year study

In a consecutive 3-year study the antibody response after immunization with influenza vaccine of a cohort of HIV-infected adults was studied. The haemagglutination-inhibiting (HAI) antibody titres after vaccination correlated with the number of CD4(+) T lymphocytes (p<0.001), the prevaccination antibody titres (p<0.001), and the proliferative response to anti-CD3 (p<0.001). Severely impaired antibody responses were observed in HIV-infected individuals with CD4(+) T-lymphocyte counts < or =100x10(6)/l. Significantly higher prevaccination antibody titres were observed in healthy controls in the 2nd or 3rd year of vaccination, but not in HIV-infected individuals. Annually repeated vaccination of HIV-infected individuals did not lead to higher postvaccination antibody titres. Annual vaccination of HIV-infected individuals with CD4(+) T-lymphocyte counts exceeding 100x10(6)/l seems to be worthwhile, although it may not be expected to render the same level of protection against influenza as in non-infected individuals.