Lymphocyte Subset Redistribution Research Articles

Effect of methylprednisolone shock therapy on immune function of electrical status epilepticus during sleep in children

Objective To study the effect of methylprednisolone shock therapy on electrical status epilepticus during sleep (ESES) in children and the changes of immune function before and after methylprednisolone shock therapy. Methods Thirty-five children hospitalized in pediatric neurology ward of Shengjing Hospital of China Medical University from October 2017 to October 2018 were selected, including 19 children with newly diagnosed temporal lobe epilepsy (TLE group) and 16 children with initial diagnosis of TLE with ESES (ESES group), and 21 healthy children in the same period were selected as normal control group.A total of 32 cases with ESES who were taken oral administration of more than 2 anti-epileptic drugs(AEDs)ineffective were given methylprednisolone shock treatment for 3 days.Changes of lymphocyte subsets and cytokines among groups were compared. Results The longer the course of disease, the worse the prognosis of children with ESES.Compared with normal control group, the NK cell activity were significantly lower in children of ESES group(P<0.05). The levels of IL-6 were higher in children of ESES group compared with that in children of TLE group, and there was significant difference between two groups(P<0.05). In children with ESES who had poor therapeutic effect of oral AEDs, the proportion of peripheral blood B lymphocytes increased after methylprednisolone shock treatment, and the proportion of T lymphocyte subsets and NK cells decreased, and the differences were statistically significant(P<0.05). The levels of IL-2, IL-4 and IL-10 were higher than those before treatment, the levels of IL-6, IL-17, INF-γ and TNF were lower than those before treatment, and the difference between the level of IL-6 before and after treatment was statistically significant(P<0.05). EEG spike waves index decreased significantly after treatment, some children′s growth and development and cognitive function improved, all children had no serious infection, high blood pressure, electrolyte imbalance and other adverse reactions.The correlation between therapeutic effect and changes of immune indexes was statistically significant in levels of NK cells(r=0.50, P<0.01), B lymphocytes (r=0.35, P=0.04) and IL-6(r=0.46, P=0.01), and all of them were positively correlated(P<0.05). Conclusion Children with ESES have immune dysfunction and may have excessive inactivation of NK cells and elevated levels of IL-6.Congenital immunity and adaptive immunity may play a role in the pathogenesis and pathophysiology of ESES syndrome.Methylprednisolone shock therapy could significantly reduce the non-rapid eye movement discharge index in children with ESES.The mechanism may be related to the significant decrease of IL-6 level.It may also be related to redistribution of lymphocyte subsets, affecting cell differentiation and balancing various cytokines. Key words: Electrical status epilepticus during sleep; Lymphocyte; Cytokines; Methylprednisolone

Oncolytic Adenovirus With Temozolomide Induces Autophagy and Antitumor Immune Responses in Cancer Patients

Oncolytic adenoviruses and certain chemotherapeutics can induce autophagy and immunogenic cancer cell death. We hypothesized that the combination of oncolytic adenovirus with low-dose temozolomide (TMZ) is safe, effective, and capable of inducing antitumor immune responses. Metronomic low-dose cyclophosphamide (CP) was added to selectively reduce regulatory T-cells. Preclinically, combination therapy inhibited tumor growth, increased autophagy, and triggered immunogenic cell death as indicated by elevated calreticulin, adenosine triphosphate (ATP) release, and nuclear protein high-mobility group box-1 (HMGB1) secretion. A total of 41 combination treatments given to 17 chemotherapy-refractory cancer patients were well tolerated. We observed anti- and proinflammatory cytokine release, evidence of virus replication, and induction of neutralizing antibodies. Tumor cells showed increased autophagy post-treatment. Release of HMGB1 into serum--a possible indicator of immune response--increased in 60% of treatments, and seemed to correlate with tumor-specific T-cell responses, observed in 10/15 cases overall (P = 0.0833). Evidence of antitumor efficacy was seen in 67% of evaluable treatments with a trend for increased survival over matched controls treated with virus only. In summary, the combination of oncolytic adenovirus with low-dose TMZ and metronomic CP increased tumor cell autophagy, elicited antitumor immune responses, and showed promising safety and efficacy.

Systemically Administered Hydrocortisone Exerts Differential Effects on B and T Lymphocytes and Natural Killer Cells in Healthy Donors

Abstract 2179Corticosteroids have been in widespread use as anti-inflammatory and immunomodulatory agents for decades, and there is a wealth of information on their immunosuppressive effects in animals and in human cells in vitro. However, there is a paucity of data on the effects of systemically administered corticosteroids on human immune cell subsets. We used modern multiplexed techniques to query the cellular and molecular immune response, or “immunome”, in 20 healthy volunteers at baseline and after systemic (IV) hydrocortisone (HC) administered at both moderate (250 mg) and low (50 mg) doses, to provide insight into how corticosteroids exert their immunomodulatory effects at doses that are commonly used therapeutically. We performed blood draws at baseline, and then 1, 4, 8, 12, and 24 hours, and 7 and 28 days after HC infusion. We assessed whole transcriptome gene expression using HumanGene 1.0 ST microarrays on both peripheral blood mononuclear cells and whole blood; plasma levels of 69 cytokines and chemokines by luminex assay; and high dimensional comprehensive lymphocyte phenotyping by flow cytometry. We observed a global decline in circulating numbers of B and T cells which nadired 4–8 hours after the administration of both 50mg and 250mg HC. Viability and Annexin V staining for apoptosis were consistent with peripheral lympho-depletion occurring as a consequence of redistribution of lymphocytes rather than direct HC-mediated cytotoxicity. Both B and T cell numbers rebounded significantly above baseline 24 hours after HC infusion, and the extent of this increase varied among specific lymphocyte subsets, with CD45+CD3-CD19+ B cell numbers exhibiting the highest rebound over baseline values after both the 50mg (P=0.0060) and 250mg (P=0.0036) HC doses, respectively (Figure 1). In contrast, CD3-CD56+CD16+ NK cell numbers remained stable at all time points after administration of 50mg or 250mg of HC. Microarray studies revealed a steroid-responsive gene expression signature that preceded redistribution of lymphocyte subsets, with 336 genes showing significant variation as early as 1 hour after HC administration (P value cutoff <0.001), and peak changes in gene expression (n=2135, P value cutoff <0.001) occurred 4 hours after HC administration. Further analysis is ongoing to assess for hidden variables. Protein profiling demonstrated significant decreases in circulating levels of immune-related cytokines within 24 hours of HC administration, including TNF-related apoptosis-inducing ligand (TRAIL, P=0.0164), IL-1b (P=0.009), IL-2 (P=0.034), IL-4 (P=0.0104), and IFN-g (P=0.0264). In contrast, circulating levels of IL-6, IL-10, IL-15, and IL-17 remained at baseline after HC infusion. Our study is the first to systematically characterize the effects of corticosteroid administration on the human immunome in vivo, and we demonstrate that corticosteroids exert differential effects on B and T lymphocytes and natural killer cells in humans. [Display omitted] Disclosures:No relevant conflicts of interest to declare.

Psychological stress during exercise: Lymphocyte subset redistribution in firefighters

The purpose of this study examined the changes in heart rate (HR), catecholamines (NE, EPI) and percentages of blood lymphocyte subsets (CD3+ T cells, CD3+ CD4+ helper T cells, CD3+ CD8+ cytotoxic T cells, CD3− CD56+ NK cells, CD4/CD8 ratio, CD19+ B cells, and total lymphocytes [NK cells+ T cells+ B cells]) in firefighters exposed to a computerized firefighting strategies and tactics decision-making challenge while participating in moderate intensity exercise. Furthermore, this study also examined the possible relationships between catecholamines (NE and EPI) and blood lymphocyte subsets following combined mental and physical challenge. Ten professional male firefighters participated in two counterbalanced exercise conditions on a cycle ergometer: (1) 37 min of cycle ergometry at 60% VO 2max (exercise alone condition; EAC) and (2) 37 min of cycle ergometry at 60% VO 2max along with 20 min of a computerized firefighting strategies and tactics decision-making challenge (firefighting strategies condition; FSC). FSC elicited significantly greater HR, NE, and EPI when compared to EAC. Both EAC and FSC elicited increases in CD3− CD56+ NK cells. The percentages of CD3+ T cells, CD3+ CD4+ helper T cells, CD4/CD8 ratio, CD19+ B cells, and total lymphocytes were lower immediately following both conditions. Following dual challenge NE AUC was negatively correlated with percentage of CD19+ B cells immediately post challenge, and HR was negatively associated with the percent change in the CD4/CD8 ratio from pre to post challenge. These elevations in NE and heart rate simultaneously in response to the dual challenge suggest greater sympathetic activation that in turn would possibly explain the alteration in the distribution of lymphocyte subsets.

Regulation of natural killer cell redistribution by prefrontal cortex during stochastic learning

Acute stress elicits redistribution of lymphocyte subsets, especially natural killer (NK) cells, probably for preparatory defense against potential invasion of antigens in fight–flight situations. We previously reported that regulation of lymphocyte redistribution is based on the evaluation of the controllability of a stressor (Kimura, K., Ohira, H., Isowa, T., Matsunaga, M., Murashima, S. 2007. Regulation of lymphocytes redistribution via autonomic nervous activity during stochastic learning. Brain Behav. Immun. 21, 921–934; Ohira, H., Isowa, T., Nomura, M., Ichikawa, N., Kimura, K., Miyakoshi, M., Iidaka, T., Fukuyama, S., Nakajima, T., Yamada, J. 2008. Imaging brain and immune association accompanying cognitive appraisal of an acute stressor. Neuroimage 39, 500–514). Specifially, lymphocyte redistribution is somewhat attenuated when a stressor is uncontrollable, probably to save biological energy in a situation where appropriate coping is unclear. We infer that this phenomenon might reflect top-down regulation over peripheral immune function by higher-ordered brain regions. To investigate the neural basis of such a phenomenon, we simultaneously recorded regional cerebral blood flow using 15O-water positron emission tomography and cardiovascular (blood pressure and heart rate), neuroendocrine (epinephrine, norepinephrine, and adrenocorticotropic hormone), and immune (proportions of NK cells and helper T cells in blood) indices in 16 male subjects who performed a stochastic learning task with manipulation of controllability (controllable vs. uncontrollable). Consistent with previous studies, the proportion of peripheral NK cells was attenuated in an uncontrollable stress condition. The dorsolateral prefrontal and orbitofrontal cortices were activated in the uncontrollable situation but not in the controllable condition, and additionally, these prefrontal brain regions significantly correlated with the degree of redistribution of NK cells in the uncontrollable condition. The results of the study suggest these brain regions are involved in both evaluation of the controllability of a stressor and regulation of immune function.

Regulation of lymphocytes redistribution via autonomic nervous activity during stochastic learning

Several studies reported that redistribution of lymphocyte subsets, especially CD3−CD16+CD56+ natural killer (NK) cells, was elicited by acute psychological stress tasks. It is known that lymphocyte redistribution was regulated based on active or passive emotional coping strategies, which can be elicited dependent on controllability of a stressor. Controllability can be evaluated gradually by learning of a contingency between actions and outcomes. Therefore, lymphocyte redistribution can be determined by learning of the contingency. To examine this issue, we used a stochastic learning task as an acute stress task and divided twenty healthy participants into reinforcement or yoked groups. Between the two groups, only whether they could learn the contingency was manipulated. As a result, patterns of changes in the NK cell numbers differed between the groups; NK cells remarkably increased at first and then gradually decreased to the baseline in the reinforcement group while the yoked group showed a moderate but sustained increase of NK cells. These patterns of changes in the NK cells were completely parallel with changes of the cardiovascular parameters but not with secretion of catecholamines. The present results suggest that cardiovascular and immune reactivity can be modulated along with progresses of adaptation for an acute stressor.

Early hyperbaric oxygen therapy attenuates disease severity in lupus-prone autoimmune (NZB × NZW) F1 mice

The effects of hyperbaric oxygen (HBO 2) therapy on the immune system are reported including potential changes to the CD4/CD8 ratio and a decreased proliferation of lymphocytes during exposure. The immunosuppressive effect of HBO 2 had been suggested to be applicable for the treatment of certain autoimmune diseases. (NZB × NZW) F1 hybrid mice, the unique lupus-prone mice, have been used for elucidating the pathogenesis of SLE. To investigate the effect of HBO 2 on NZB/W F1 lupus-prone mice, 32 female mice were divided into four groups. Three groups of mice were treated with HBO 2 (2.5 atm abs (ATA) for 90 min daily over 2 weeks) starting at (A) 3 months, (B) 6 months, or (C) 8 months of age, while the remaining group (D) served as control. Animals were followed until 11 months of age. Experimental parameters included life span, proteinuria, peripheral lymphocytes, anti-dsDNA antibody titers, and renal histopathology. HBO 2 treatment resulted in increased survival, decreased proteinuria, alterations in lymphocyte-subset redistribution, reduced anti-dsDNA antibody titers, and amelioration of immune-complex deposition in groups A and B. Our data demonstrated that HBO 2 therapy attenuated disease severity in NZB/W F1 mice. HBO 2 treatment may be of use in the clinical treatment of lupus patients and would benefit from further study.

The involvement of T lymphocytes in the pathogenesis of endometriotic tissues overgrowth in women with endometriosis.

BACKGROUND: Endometriosis, uncontrolled proliferation of ectopic and eutopic endometriotic tissues, is common in women at reproductive age, and may affect fertility. The role of macrophages in the pathogenesis is well proved, but engagement of T cells in the pathogenesis of endometriosis is a matter of controversy. AIMS: T-cell involvement in the pathogenesis of endometriosis was the objective of our study performed on women aged 24-46 years with diagnosed endometriosis. All the patients that were studied underwent diagnostic laparoscopy. METHODS: We evaluated the distribution of T-lymphocyte subpopulations in peripheral blood (PB), peritoneal fluid (PF) and in endometriotic tissues (ET), as well as cytokines [interleukin (IL)-2, IL-4, IL-10, IL-12, interferon (IFN)-gamma] production by peripheral blood lymphocytes. IFN-gamma, tumor necrosis factor (TNF)-alpha, IL-4 and IL-6 were investigated for their intracellular presence. The experiments were carried out before and after 6 months treatment with the GnRH-Analogous Goserelin (Zeneca Pharmaceuticals). The number of performed investigations is presented. Statistical analysis was performed using Statistica/Win 5.0 software and Student's t-test, the paired Student t-test and Fisher's exact test when appropriate. RESULTS: We have compared the lymphocyte subset re-distribution with regard to the American Fertility Society (AFS) stages and scores, but no differences were observed. The significant increase in CD4:CD8 ratio, the decrease in the number of natural killer (NK) cells in PB and the decrease in CD4:CD8 ratio in PF and ET of women with endometriosis was noted. The diminished IFN-gamma secretion by phytohemagglutinim (PHA)-stimulated lymphocytes in vitro derived from women with endometriosis and increased IL-4 production may be responsible for defective immunosurveillance against overgrowth of endometriotic tissues. The diminished NK cells number in PB of women with endometriosis argues for such a hypothesis. The increased deposits of proinflammatory IL-6 and TNF-alpha in the T lymphocytes of women with endometriosis may be related to T-regulatory lymphocyte function and their inability to suppress cell proliferation in endometriosis. GnRH-Analogous Goserelin treatment normalises cytokine production and induces patient recovery. CONCLUSIONS: The significant functional and phenotypic differences between the lymphocytes from healthy women and women with endometriosis were noted. The diminished IFN-gamma production in relation to decreased NK cells number and the increased IL-4 production before the treatment and normalisation after the treatment suggest the involvement of the deregulated T-cell system in the growth stimulation and recruitment of endometriotic cells. The increased CD4:CD8 ratio, IL-6, TNF-alpha deposits and diminished anti-inflammatory IL-10 production by lymphocytes may participate in the pathogenesis of endometriosis, and may secondarily affect the monocyte/macrophage function.

Short-term hyperglycemia induces lymphopenia and lymphocyte subset redistribution

Alterations in lymphocytes are a common finding in both type I and type II diabetes. Autoimmune phenomena in type I diabetes, the stage of the diabetic disorder and metabolic effects of therapeutic interventions may also affect actual distribution of lymphocyte phenotypes. This study investigated immunological effects specific to standardized hyperglycemia in non-diabetic individuals to exclude immunological changes potentially related to diabetes stage and treatment. 37 subjects (mean age ± SD 39 ± 5 years) underwent a sequence-controlled crossover with oral administration of a solution containing either 75 g glucose or artificial sweetener (i.e. placebo). At rest and at two hours, counts of white blood cells (WBC), mixed lymphocytes, mature T-cells (CD3), T-helper cells (CD4), T-suppressor/cytotoxic cells (CD8), B-cells (CD19), natural killer cells (CD16/CD56), and interleukin-2 receptor bearing peripheral blood mononuclear cells (CD25) were measured by flow cytometry. Subjects showed a significant decrease in WBC, lymphocytes, and all lymphocyte subsets with the OGTT compared with the placebo solution (p< .05 to p< .001). In non-diabetic individuals, short-term hyperglycemia induces immunological changes that may be relevant to explain similar findings in patients with diabetes mellitus. Future studies need to validate these findings and their potential clinical implications in a diabetic population.

Lymphocyte subset redistribution during acute laboratory stress in young adults: Mediating effects of hemoconcentration.

Lymphocyte subset redistribution during acute laboratory stress in young adults: Mediating effects of hemoconcentration.

Catecholamines, Catecholamine Receptors, Cell Adhesion Molecules, and Acute Stressor-Related Changes in Cellular Immunity

Publisher Summary Typical changes in the immune system because of acute stress include a lymphocytosis, with marked changes in natural killer and T-suppressor cells and more modest effects on T-helper cells. This chapter presents data from two separate studies that were designed to determine β 2 -adrenergic receptor and catecholamine involvement in lymphocyte subset redistribution following acute sympathetic activation and whether cellular adhesion molecules (CAMs) expression on lymphocytes might influence this phenomenon. Subjects were studied following both a psychologic and an exercise stressor. These studies sought to identify adrenergic and CAMs involvement in lymphocytosis following acute immune activation. The studies found that an individual's initial sympathetic state (baseline catecholamines and β 2 -adrenergic receptors) and the magnitude of sympathetic (catecholamine) activation are important factors underlying lymphocyte subset redistribution. The findings also suggest that experimental stress results in differential expression of CAMs on lymphocytes and that CAM expression may influence β -adrenergic effects. For example, the presence or absence of L-selectin on T-suppressor cells determined their post exercise distribution in circulation, with those expressing L-selectin remaining unchanged and those not expressing L-selectin showing a marked redistribution. In addition, only those T-suppressor cells not expressing L-selectin showed a significant attenuating effect of propranolol. These results suggest that L-selectin expression on T-suppressor cells inhibits the effects of sympathetic activation and β blockade.

Changes in Lymphocyte β2-Adrenoceptors after Hepatic Resection

Hepatic resection promotes such a high degree of surgical stress that it induces deterioration of various vital functions, which may involve the breakdown of signal transduction systems. To investigate the influence of surgical stress on signal transduction, we studied ligand-receptor specific binding activity after hepatic resection, focusing on lymphocyte β2-adrenoceptors. The maximum binding capacity ( B max) and the dissociation constant (KD) were determined by radioligand binding assay using (-) 3H-CGP12177 as a ligand. In the hepatectomy group, B max significantly decreased from 1380 ± 109 to 799 ± 49 receptors/cell on postoperative day (POD) 3 and to 802 ± 93 receptors/cell on POD 7 ( P < 0.05). In the control group, however, it did not significantly change after the operation. No significant changes in K dcl025; were found in either of these groups. The B max alteration was not due to the redistribution of lymphocyte subsets or receptor down regulation, but to the decrease in the B max of the individual subset. The hepatectomy group was divided into two groups according to the postoperative arterial ketone body ratio (AKBR): Group A, AKBR maintained at 0.7 or more; and Group B, AKBR decreased to below 0.7. The B max decrease, a percentage of the preoperative value, of Group B was significantly smaller than that of Group A (48.4 ± 3.9 and 72.3 ± 7.3%, respectively, P < 0.05). These results suggest that intense surgical stress, produced by hepatic resection, may influence even ligand-receptor binding parameters, and the decrease in AKBR can indicate the magnitude of surgical stress.

Lymphocyte Subset Redistribution in Response to Acute Experimental Stress: Effects of Gender, Ethnicity, Hypertension, and the Sympathetic Nervous System

This study examined demographic and adrenergic characteristics associated with enumerative immune responses to acute laboratory stress. Lymphocyte subsets and plasma catecholamines were measured in 110 subjects at rest and following a naturalistic speaking stressor. Lymphocyte β2-adrenergic receptor sensitivity and density were measured at rest. The speaking task caused marked increase in natural killer cells, T-suppressor/cytotoxic cells, total WBC, norepinephrine, and epinephrine and decreases in T-helper cells, B cells, and the T-helper/suppressor ratio. Multiple regression analyses demonstrated that, in general, cellular immune responses were best predicted by a combination of lower basal norepinephrine, higher β2-adrenergic receptor sensitivity, and a greater stress-induced increase in norepinephrine. The findings suggest that traditional epidemiologic characteristics such as gender, ethnicity, and mild hypertension have limited influence on lymphocytosis. Rather, interindividual differences in sympathetic nervous system characteristics play a more prominent underlying role in acute cellular immune system activation.

Cell-type specific response of peripheral blood lymphocytes to methotrexate in the treatment of rheumatoid arthritis

The mode of action of methotrexate in the treatment of rheumatoid arthritis is still questionable. Although in vitro results suggest an immunosuppressive effect of methotrexate, several clinical studies have failed to confirm these effects in patients treated with oral low-dose methotrexate. With respect to the highly variable bioavailability of methotrexate, we investigated the effects of an intravenous administration of 15 mg methotrexate per week on peripheral blood lymphocyte subsets in eight patients with rheumatoid arthritis. Methotrexate after 12 weeks significantly (P < 0.01) reduced total peripheral blood lymphocytes and led to a pronounced redistribution of lymphocyte subsets with a preferred reductive effect on B-lymphocytes (P < 0.005) and T-lymphocytes (P < 0.05). Natural killer cells and killer cell-like T cells, on the other hand, were unaffected by the treatment. Our results suggest a cell-type specific effect of intravenously administered low-dose methotrexate on peripheral blood lymphocytes. This effect, in our opinion, may contribute to the mode of action of methotrexate as an immunosuppressive drug in the treatment of rheumatoid arthritis.

Cellular Immune Response Analysis of Patients with Leptospirosis

Peripheral blood mononuclear cells (PBMC) from acute leptospirosis patients with and without acute renal failure were studied in order to investigate the status of cellular immunity in this disease. We analyzed the lymphocyte subsets of leptospirosis patients by immunofluorescence and their responsiveness to the mitogens phytohemagglutinin (PHA) and pokeweed mitogen (PWM). Additionally, we investigated the effect of the patients' sera on normal PBMC proliferative response. We observed a decrease in the CD3+ and CD4+ cell subsets in patients with and without acute renal failure, or in percentage values alone in those who had recovered from renal failure. An increase in the number of B lymphocytes was observed in all patients, compared with controls. This increase in B lymphocytes was seen even in patients who had recovered from renal failure, when the number of CD3+ and CD4+ lymphocytes had already returned to normal levels. The low PHA response observed only with lymphocytes from patients with acute renal failure suggests a suppressive effect. The proliferative response to PWM was comparable to controls, even in the patients with acute renal failure. This latter result and the expansion of the B cell number could be related to leptospiral-derived factor(s). We also showed that sera from patients with and without acute renal failure exerted some inhibitory activity on normal PBMC responses to PHA and PWM. Although the redistribution of lymphocyte subsets and the serum suppressor activity were related to acute renal failure and leptospiral factor(s), we suggest that the cellular immune system was not irreversibly affected, which is compatible with the good prognosis seen in the patients studied.

FK506 suppression of heart and liver allograft rejection. II: The induction of graft acceptance in rats.

Lewis recipients of orthotopic ACI livers had permanent graft acceptance induced with 3 doses of i.m. FK506 in the early postoperative period. They were studied 100 and 300 days posttransplantation. The recipients rejected ACI as well as Brown Norway (BN) (third-party) skin grafts, and had lymphocytes with substantial reactivity by mixed lymphocyte culture testing against ACI and third-party (BN) alloantigens. Lymphocyte subset redistribution had not occurred in the peripheral blood or spleens of these animals, and there was no evidence of suppressor cell activation by in vitro and in vivo tests. Graft-versus-host reactivity in splenic lymphoid tissues of these recipients was demonstrated with the popliteal lymph node assay. Attempts at adaptive transfer with recipient lymphocytes were unsuccessful. Heart graft acceptance was far more difficult to accomplish than liver graft acceptance, and probably was never permanent. ACI heart graft prolongation in LEW recipients after a brief induction with FK506 lasted for no more than 3 months in most animals. The temporary heart graft acceptance was specific for hearts of the original ACI donor strain but not for ACI skin. Results of studies of lymphocyte subsets and suppressor cell activity were similar to those in the liver recipients. These studies illustrate how poorly graft acceptance is understood and how badly further work is needed to clarify its mechanism.

Effects of Insulin-Induced Hypoglycemia onβ2-Adrenoceptor Density and Proliferative Responses of Human Lymphocytes*

We studied the effects of insulin (0.1 IU/kg BW, iv)-induced hypoglycemia on lymphocyte beta 2-adrenoceptor function, lymphocyte subset distribution, and proliferative response to mitogen stimulation in 10 healthy volunteers. Thirty minutes after insulin injection plasma glucose levels were markedly decreased; concomitantly, plasma epinephrine levels had increased about 10-fold; plasma norepinephrine levels, however, increased only moderately. Lymphocyte beta 2-adrenoceptor density and the cAMP response to 10 mumol/L isoproterenol stimulation were elevated; lymphocyte Ts/c-cells had increased, whereas Th-cells had decreased, resulting in a decrease in the Th-/Ts/c-cell ratio from 1.7 to 1.0. These changes were accompanied by a significantly reduced lymphocyte proliferative response (measured as [3H]thymidine uptake) to mitogen stimulation. Two hours after insulin injection plasma catecholamines, lymphocyte beta 2-adrenoceptor function, lymphocyte subset distribution, and proliferative responses had returned to nearly preinsulin levels. We conclude that acute vigorous increases in endogenous epinephrine evoked by insulin-induced hypoglycemia are associated with increases in lymphocyte beta 2-adrenoceptor function, redistribution of lymphocyte subsets, and an (at least transiently) attenuated in vitro immune responsiveness.