Inhibition of mouse mast cell proliferation and proinflammatory mediator release by benzodiazepines

Neuropsychiatric Manifestations of Mast Cell Activation Syndrome and Response to Mast-Cell-Directed Treatment: A Case Series

Mast cell activation syndrome (MCAS) is an immune disease with an estimated prevalence of 17%. Mast cell chemical mediators lead to heterogeneous multisystemic inflammatory and allergic manifestations. This syndrome is associated with various neurologic and psychiatric disorders, including headache, dysautonomia, depression, generalized anxiety disorder, and many others. Although MCAS is common, it is rarely recognized, and thus, patients can suffer for decades. The syndrome is caused by aberrant mast cell reactivity due to the mutation of the controller gene. A case series is presented herein including eight patients with significant neuropsychiatric disorders that were often refractory to standard medical therapeutics. Five patients had depression, five had generalized anxiety disorder, and four had panic disorder. Other psychiatric disorders included attention-deficit hyperactivity disorder, obsessive compulsive disorder, phobias, and bipolar disorder. All eight patients were subsequently diagnosed with mast cell activation syndrome; six had comorbid autonomic disorders, the most common being postural orthostatic tachycardia syndrome; and four had hypermobile Ehlers-Danlos syndrome. All patients experienced significant improvements regarding neuropsychiatric and multisystemic symptoms after mast-cell-directed therapy. In neuropsychiatric patients who have systemic symptoms and syndromes, it is important to consider the presence of an underlying or comorbid MCAS.

Sodium cromoglycate reduces short- and long-term consequences of status epilepticus in rats

Several studies indicate that sodium cromoglycate (CG) induces neuroprotective effects in acute neurological conditions. The present study focused on investigating if the use of CG in rats during the post-status epilepticus (post-SE) period reduces the acute and long-term consequences of seizure activity. Our results revealed that animals that received a single dose of CG (50 mg/kg s.c.: subcutaneously) during the post-SE period showed a lower number of neurons in the process of dying in the dentate gyrus, hilus, cornu ammonis 1 (CA1), and CA3 of the dorsal hippocampus than the rats that received the vehicle. However, this effect was not evident in layers V-VI of the sensorimotor cortex or the lateral-posterior thalamic nucleus. A second experiment showed that animals that received CG subchronically (50 mg/kg s.c. every 12 h for 5 days followed by 24 mg/kg/day s.c. for 14 days using osmotic minipumps) after SE presented fewer generalized convulsive seizures and less neuronal damage in the lateral-posterior thalamic nucleus but not in the hippocampus or cortex. Our data indicate that CG can be used as a therapeutic strategy to reduce short- and long-term neuronal damage in the hippocampus and thalamus, respectively. The data also indicate that CG can reduce the expression of generalized convulsive spontaneous seizures when it is given during the latent period of epileptogenesis.

The Relationship Between Sedatives, Sedative Strategy, and Healthcare-Associated Infection: A Systematic Review

BACKGROUND Healthcare-associated infections (HAIs) cause significant morbidity in critically ill patients. An underappreciated but potentially modifiable risk factor for infection is sedation strategy. Recent trials suggest that choice of sedative agent, depth of sedation, and sedative management can influence HAI risk in mechanically ventilated patients. OBJECTIVE To better characterize the relationships between sedation strategies and infection. METHODS Systematic literature review. RESULTS We found 500 articles and accepted 70 for review. The 3 most common sedatives for mechanically ventilated patients (benzodiazepines, propofol, and dexmedetomidine) have different pharmacologic and immunomodulatory effects that may impact infection risk. Clinical data are limited but retrospective observational series have found associations between sedative use and pneumonia whereas prospective studies of sedative interruptions have reported possible decreases in bloodstream infections, pneumonia, and ventilator-associated events. CONCLUSION Infection rates appear to be highest with benzodiazepines, intermediate with propofol, and lowest with dexmedetomidine. More data are needed but studies thus far suggest that a better understanding of sedation practices and infection risk may help hospital epidemiologists and critical care practitioners find new ways to mitigate infection risk in critically ill patients. Infect Control Hosp Epidemiol 2016;1-9.

Pharmacological treatment options for mast cell activation disease

Mast cell activation disease (MCAD) is a term referring to a heterogeneous group of disorders characterized by aberrant release of variable subsets of mast cell (MC) mediators together with accumulation of either morphologically altered and immunohistochemically identifiable mutated MCs due to MC proliferation (systemic mastocytosis [SM] and MC leukemia [MCL]) or morphologically ordinary MCs due to decreased apoptosis (MC activation syndrome [MCAS] and well-differentiated SM). Clinical signs and symptoms in MCAD vary depending on disease subtype and result from excessive mediator release by MCs and, in aggressive forms, from organ failure related to MC infiltration. In most cases, treatment of MCAD is directed primarily at controlling the symptoms associated with MC mediator release. In advanced forms, such as aggressive SM and MCL, agents targeting MC proliferation such as kinase inhibitors may be provided. Targeted therapies aimed at blocking mutant protein variants and/or downstream signaling pathways are currently being developed. Other targets, such as specific surface antigens expressed on neoplastic MCs, might be considered for the development of future therapies. Since clinicians are often underprepared to evaluate, diagnose, and effectively treat this clinically heterogeneous disease, we seek to familiarize clinicians with MCAD and review current and future treatment approaches.

Immunosuppressive aspects of analgesics and sedatives used in mechanically ventilated patients: an underappreciated risk factor for the development of ventilator-associated pneumonia in critically ill patients

OBJECTIVE

To evaluate the evidence describing the immunosuppressive and pharmacokinetic properties of commonly used analgesic and sedation agents in critically ill patients.

DATA SOURCES

MEDLINE (January 1980-September 2013) was searched.

STUDY SELECTION AND DATA EXTRACTION

All in vitro and in vivo studies that evaluated the immune-modulating properties of analgesic and sedation agents commonly used in the critically ill were included. Full-text and abstract-only articles (noted) were included in this review. Inclusion criteria were met by 46 studies and were evaluated.

DATA SYNTHESIS

Analgesic and sedation agents have been shown to be immunosuppressive in a variety of models. In vitro models use a variety of immune cells to demonstrate the immunosuppressive properties of opioids, benzodiazepines, and to a lesser extent, propofol. In each case, animal studies provide more robust data supporting the concept that opioids, benzodiazepines, and propofol exhibit immunosuppressive activities ranging from innate to adaptive immune alterations. Human studies, though more limited, provide further support that these agents inhibit the immune response. In contrast, data have shown that dexmedetomidine may attenuate the immune system. Clinical trial data evaluating the immunosuppressive properties of these agents is limited.

CONCLUSIONS

Analgesic and sedation agents have clearly been shown to alter cellular function and other mediators of the immune system; yet the clinical impact remains to be fully elucidated. The mechanism by which sedation interruption reduces ventilator-associated pneumonia may in fact be a reduction in immunosuppressive effects. Studies linking the immune-modulating effects of analgesic and sedation agents in critically ill patients are needed.

The 1,4-benzodiazepine Ro5-4864 (4-chlorodiazepam) suppresses multiple pro-inflammatory mast cell effector functions

Activation of mast cells (MCs) can be achieved by the high-affinity receptor for IgE (FcεRI) as well as by additional receptors such as the lipopolysaccharide (LPS) receptor and the receptor tyrosine kinase Kit (stem cell factor [SCF] receptor). Thus, pharmacological interventions which stabilize MCs in response to different receptors would be preferable in diseases with pathological systemic MC activation such as systemic mastocytosis. 1,4-Benzodiazepines (BDZs) have been reported to suppress MC effector functions. In the present study, our aim was to analyze molecularly the effects of BDZs on MC activation by comparison of the effects of the two BDZs Ro5-4864 and clonazepam, which markedly differ in their affinities for the archetypical BDZ recognition sites, i.e., the GABA_A receptor and TSPO (previously termed peripheral-type BDZ receptor). Ro5-4864 is a selective agonist at TSPO, whereas clonazepam is a selective agonist at the GABA_A receptor. Ro5-4864 suppressed pro-inflammatory MC effector functions in response to antigen (Ag) (degranulation/cytokine production) and LPS and SCF (cytokine production), whereas clonazepam was inactive. Signaling pathway analyses revealed inhibitory effects of Ro5-4864 on Ag-triggered production of reactive oxygen species, calcium mobilization and activation of different downstream kinases. The initial activation of Src family kinases was attenuated by Ro5-4864 offering a molecular explanation for the observed impacts on various downstream signaling elements. In conclusion, BDZs structurally related to Ro5-4864 might serve as multifunctional MC stabilizers without the sedative effect of GABA_A receptor-interacting BDZs.

Investigation into mechanisms mediating the inhibitory effect of 1,4-benzodiazepines on mast cells by gene expression profiling

AIMS

This study aims to identify by a molecular genetic approach potential targets in mast cells at which 1,4-benzodiazepines may cause their inhibitory effect on mast cell activity.

MAIN METHODS

Gene expression analyses with microarray gene chip and/or quantitative PCR were performed using 1,4-benzodiazepine-treated human mast cell leukemia HMC-1.2 cells, promyelocytic leukemia HL-60 cells and human mast cells from healthy volunteers and patients with mast cell activation disease (MCAD). Pathway analysis was applied to search for enriched biological functions and canonical pathways within differentially regulated genes.

KEY FINDINGS

Both neoplastic and normal human mast cells express several GABA(A) receptor subunits at the mRNA level. In mast cells from MCAD patients expression of some GABA(A) receptor subunits and expression of the translocator protein TSPO are increased compared with those from healthy controls. Expression of the protein tyrosine kinases Lyn, Fgr and Yes1 was increased in HMC-1.2 cells as compared with the ontogenetically related HL60 cells. Differences in gene regulation in HMC-1.2 cells after treatment with the 1,4-benzodiazepines clonazepam, flunitrazepam and 4-chlorodiazepam suggested that signaling and gene expression induced by clonazepam was similar to that of flunitrazepam but different from that of 4-chlorodiazepam. This conclusion is supported by the results of the pathway analysis.

SIGNIFICANCE

A novel type of GABA(A) receptors on mast cells appears to be involved in the inhibition of mast cell activity by 1,4-benzodiazepines. These receptors seem to be composed without γ subunits suggesting unique pharmacological properties. An action at Src-kinases, or at TSPO located in the plasma membrane may also be involved.

Inhibitory effects of benzodiazepines on the adenosine A(2B) receptor mediated secretion of interleukin-8 in human mast cells

The activation of adenosine A(2B) receptors in human mast cells causes pro-inflammatory responses such as the secretion of interleukin-8. There is evidence for an inhibitory effect of benzodiazepines on mast cell mediated symptoms in patients with systemic mast cell activation disease. Therefore, we investigated the effects of benzodiazepines on adenosine A(2B) receptor mediated interleukin-8 production in human mast cell leukaemia (HMC1) cells by an enzyme linked immunosorbent assay. The adenosine analogue N-ethylcarboxamidoadenosine (NECA, 0.3-3 μM) increased interleukin-8 production about 5-fold above baseline. This effect was attenuated by the adenosine A(2B) receptor antagonist MRS1754 (N-(4-cyanophenyl)-2-{4-(2,3,6,7-tetrahydro-2,6-dioxo-1,3-dipropyl-1H-purin-8-yl)phenoxy}-acetamide) 1 μM. In addition, diazepam, 4'-chlorodiazepam and flunitrazepam (1-30 μM) markedly reduced NECA-induced interleukin-8 production in that order of potency, whereas clonazepam showed only a modest inhibition. The inhibitory effect of diazepam was not altered by flumazenil 10 μM or PK11195 (1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxamide) 10 μM. Diazepam attenuated the NECA-induced expression of mRNA encoding for interleukin-8. Moreover, diazepam and flunitrazepam reduced the increasing effects of NECA on cAMP-response element- and nuclear factor of activated t-cells-driven luciferase reporter gene activities in HMC1 cells. Neither diazepam nor flunitrazepam affected NECA-induced increases in cellular cAMP levels in CHO Flp-In cells stably expressing recombinant human adenosine A(2B) receptors, excluding a direct action of benzodiazepines on human adenosine A(2B) receptors. In conclusion, this is the first study showing an inhibitory action of benzodiazepines on adenosine A(2B) receptor mediated interleukin-8 production in human mast (HMC1) cells. The rank order of potency indicates the involvement of an atypical benzodiazepine binding site.

Xenon anesthesia reduces TNFα and IL10 in bariatric patients

BACKGROUND

Anesthesia is able to modulate the balance between proinflammatory and anti-inflammatory cytokine production during surgery. The aim of this study is to assess the effect of three anesthesia approaches, total intravenous anesthesia (TIVA), inhalation anesthesia, and xenon anesthesia, on sieric levels of nitric oxide (NO), IL6, IL10, and TNFα in obese patients undergoing Roux-en-Y laparoscopic gastric bypass.

METHODS

Thirty adult morbidly obese patients (BMI > 35) scheduled for Roux-en-Y laparoscopic gastric bypass were randomly recruited and allocated to TIVA (N = 10), inhalation anesthesia (SEV, N = 10), and xenon anesthesia (XE, N = 10). Exclusion criteria were ASA IV, age <18 or >60 years, and Mallampati IV. Opioid dosage and ventilation parameters were standardized. Sieric levels of NO, IL6, IL10, and TNFα were assessed at T0 (before induction of anesthesia), T1 (end of surgery), and T2 (12 h after the end of surgery). We compared the relative cytokine level variations (delta) at T1 and T2 and the cytokine exposure levels calculated as the area under the curve (AUC) between T0 and T2 in the XE and non-XE (SEV + TIVA) groups.

RESULTS

At T1, we found a significant ΔIL10 (reduction) and ΔTNFα (reduction) between XE and SEV (p < 0.05) and XE and TIVA (p < 0.05) groups. At T2, ΔIL10 was still significant. Furthermore, we found a reduced AUC value for TNFα in the XE group.

CONCLUSIONS

Xenon anesthesia seems able to inhibit postoperative proinflammatory cytokine imbalance in morbidly obese patients undergoing Roux-en-Y laparoscopic gastric bypass; the reduced ΔTNFα at T1 and the reduced global exposition to TNFα in the XE group may explain the reduced ΔIL10 at T1 and T2.

A review of experimental evidence linking neurotoxic organophosphorus compounds and inflammation

Organophosphorus (OP) nerve agents and pesticides inhibit acetylcholinesterase (AChE), and this is thought to be a primary mechanism mediating the neurotoxicity of these compounds. However, a number of observations suggest that mechanisms other than or in addition to AChE inhibition contribute to OP neurotoxicity. There is significant experimental evidence that acute OP intoxication elicits a robust inflammatory response, and emerging evidence suggests that chronic repeated low-level OP exposure also upregulates inflammatory mediators. A critical question that is just beginning to be addressed experimentally is the pathophysiologic relevance of inflammation in either acute or chronic OP intoxication. The goal of this article is to provide a brief review of the current status of our knowledge linking inflammation to OP intoxication, and to discuss the implications of these findings in the context of therapeutic and diagnostic approaches to OP neurotoxicity.

Immunosedation: a consideration for sepsis

In a recent issue of Critical Care, Qiao and colleagues showed in a rat model of sepsis that dexmedetomidine and midazolam suppress the generation of pro-inflammatory mediators but the effects vary between agents. While dexmedetomidine limited apoptosis to a greater extent than midazolam, both agents significantly reduced short-term mortality compared with saline. This study, in addition to those by others, suggests there are disparate immunomodulating effects between sedatives. Clinical studies are warranted to investigate whether these effects impact outcomes of septic patients. Perhaps one day the choice of sedative in septic patients will not be based solely on sedative properties but rather immunosedative profiles.

Bifunctional compounds eliciting anti-inflammatory and anti-cholinesterase activity as potential treatment of nerve and blister chemical agents poisoning

Certain organophosphorus (OP) nerve agents (e.g. soman) induce neuroinflammatory processes during acute poisoning. An increased level of typical inflammation markers was also observed in poisoning by alkylating agents such as sulfur mustard (HD). The therapeutic potential of new bifunctional compounds was investigated, eliciting activity of non-steroidal anti-inflammatory drug (NSAID) and anti-cholinesterase (anti-ChE) activity, as an antidotal treatment for both soman and HD poisoning in mice. Three bifunctional compounds were used that include the ChE inhibitor pyridostigmine (PYR) coupled to either ibuprofen (IBU) or diclofenac (DICLO) through an eight (octyl) or ten (decyl) hydrocarbon chain spacer: IBU-PO, IBU-PD and DICLO-PD. These compounds are 15-25 fold less toxic than PYR in mice and exert peripheral and central anti-inflammatory and anti-ChE activity in vivo. IBU-PO (4 mg kg(-1), i.p.), IBU-PD (4 mg kg(-1), i.p.) and PYR (0.13 mg kg(-1), i.p.) reduced to control levels the brain edema in soman-poisoned mice (1.1 LD50, s.c.). Pre-treatment with IBU-PO, IBU-PD and DICLO-PD 4-5 h before soman challenge (2.2-2.3 LD50, s.c.) combined with antidotal treatment (atropine, 11 mg kg(-1), 2-PAM-Cl, 25 mg kg(-1), i.m.) afforded a longer 24 h survival rate (SR) than with PYR pre-treatment. DICLO-PD exhibited the largest protection efficacy (SR = 70% vs 17% with PYR). These results indicate a longer duration of action of bifunctional compounds compared with PYR. DICLO-PD (5% in propyleneglycol) reduced significantly the HD-induced edema in mouse ear-skin (51% increase in biopsy weight compared with 100% without treatment). Quantitative evaluation of ear-skin sections showed that only following DICLO-PD treatment was there a marked decrease in edema. DICLO-PD also elicited a significant decrease in HD-induced vesication as displayed by the reduced sub-epidermal blister level. The data indicate possible use of NSAID-ChEI bifunctional compounds for the medical treatment of both nerve and alkylating chemical agents.

Risk factors for diseases of ileal pouch-anal anastomosis after restorative proctocolectomy for ulcerative colitis

BACKGROUND & AIMS

Although pouchitis is considered the most common adverse sequela of ileal pouch-anal anastomosis (IPAA), inflammatory and noninflammatory conditions other than pouchitis are increasingly being recognized. The risk factors for these non-pouchitis conditions, including Crohn's disease (CD) of the pouch, cuffitis, and irritable pouch syndrome (IPS), have not been studied. The aim of this study was to assess risk factors for inflammatory and noninflammatory diseases of IPAA in a tertiary care setting.

METHODS

The study consisted of 240 consecutive patients who were classified as having healthy pouches (N = 49), pouchitis (N = 61), CD of the pouch (N = 39), cuffitis (N = 41), or IPS (N =50). Demographic and clinical features were assessed to determine risk factors for each of these conditions by using logistic regression analysis.

RESULTS

Risk factors remaining in the final logistic regression models were for pouchitis: IPAA indication for dysplasia (odds ratio [OR], 3.89; 95% confidence interval [CI], 1.69-8.98), never having smoked (OR, 5.09; 95% CI, 1.01-25.69), no use of anti-anxiety agents (OR, 5.19; 95% CI, 1.45-18.59), or use of NSAIDs (OR, 3.24; 95% CI, 1.71-6.13); for CD of the pouch: a long duration of IPAA (OR, 1.20; 95% CI, 1.12-1.30) and current smoking (OR, 4.77; 95% CI, 1.39-16.25); for cuffitis: arthralgias (OR, 4.13; 95% CI, 1.91-8.94) and younger age (OR, 1.16; 95% CI, 1.01-1.33); and for IPS: use of antidepressants (OR, 4.17, 95% CI, 1.95-8.92) or anti-anxiety agents (OR, 3.21; 95% CI, 1.34-7.47).

CONCLUSIONS

The majority of risk factors for the 4 inflammatory and noninflammatory conditions of IPAA are different, suggesting that each of these diseases has a different etiology and pathogenesis. The identification and modification of these risk factors might help patients and clinicians to make a preoperative decision for IPAA, reduce IPAA-related morbidity, and improve response to treatment.

Putative role of proteolysis and inflammatory response in the toxicity of nerve and blister chemical warfare agents: implications for multi-threat medical countermeasures

Despite the contrasts in chemistry and toxicity, for blister and nerve chemical warfare agents there may be some analogous proteolytic and inflammatory mediators and pathological pathways that can be pharmacological targets for a single-drug multi-threat medical countermeasure. The dermal-epidermal separation caused by proteases and bullous diseases compared with that observed following exposure to the blister agent sulfur mustard (2,2'-dichlorodiethyl sulfide) has fostered the hypothesis that sulfur mustard vesication involves proteolysis and inflammation. In conjunction with the paramount toxicological event of cholinergic crisis that causes acute toxicity and precipitates neuronal degeneration, both anaphylactoid reactions and pathological proteolytic activity have been reported in nerve-agent-intoxicated animals. Two classes of drugs already have demonstrated multi-threat activity for both nerve and blister agents. Serine protease inhibitors can prolong the survival of animals intoxicated with the nerve agent soman and can also protect against vesication caused by the blister agent sulfur mustard. Poly (ADP-ribose) polymerase (PARP) inhibitors can reduce both soman-induced neuronal degeneration and sulfur-mustard-induced epidermal necrosis. Protease and PARP inhibitors, like many of the other countermeasures for blister and nerve agents, have potent primary or secondary anti-inflammatory pharmacology. Accordingly, we hypothesize that drugs with anti-inflammatory actions against either nerve or blister agent might also display multi-threat efficacy for the inflammatory pathogenesis of both classes of chemical warfare agent.

Protective action of the serine protease inhibitor N-tosyl-L-lysine chloromethyl ketone (TLCK) against acute soman poisoning

Soman-poisoned rats display cholinergic crisis, a systemic mast cell degranulation characteristic of anaphylactic reactions and an excitotoxin-like sequential seizure and neuronal degeneration. The protection of guinea pigs from soman lethality by prophylactic administration of the serine protease inhibitor suramin suggests a possible proteolytic component in soman poisoning. The present study tested the effect of N-tosyl-L-lysine chloromethyl ketone (TLCK), an inhibitor of trypsin-like serine proteases, on soman-induced toxic signs (convulsions, righting reflex) and survival time. Nine control guinea pigs receiving 2 x LD(50) (56 microg kg(-1), s.c.) of soman immediately followed by a therapeutic dose of atropine sulfate (17.4 mg kg(-1) i.m.) experienced severe convulsions, and 8/9 lost the righting reflex. Six of these nine animals expired within 65 min; the three remaining animals survived 24 h to termination of the experiment. When a second group of animals were given TLCK (12 mg kg(-1), i.p.) 30 min prior to a 2 x LD(50) soman challenge and atropine-sulfate therapy, 5/9 experienced convulsions and only 3/9 lost the righting reflex. All nine animals survived beyond 4 h, with six surviving to 24 h. Compared with soman controls, prophylaxis with TLCK significantly prevented the loss of righting reflex (P = 0.05) and enhanced 4-h survival (P = 0.005). Although, convulsions were reduced and 24-h survival was improved in TLCK-treated animals, these results were not statistically significant. The protection from soman toxicity by chemically distinct protease inhibitors such as suramin and TLCK suggests a role for pathological proteolytic pathways in soman intoxication.

What are the most promising strategies for the therapeutic immunomodulation of allergic diseases?

Specific immunotherapy and other immunomodulatory strategies have long been a stronghold in the management of allergic diseases. In particular, "immunodeviation-therapy" or "vaccination for allergies", i.e. the redirection of Th2-type immune responses towards a Th1-response pattern, has become an ever more popular concept. The present feature of CONTROVERSIES complements our previous discussion of atopy (Röcken et al., Exp Dermatol 7: 97--104, 1998), and is dedicated to a critical analysis of the general problems and limitations one faces with the main immunomodulatory strategies traditionally considered in this context. We also explore alternative approaches that appear promising in order to achieve both a more effective and/or a more specific immunotherapy of allergic diseases. Given that the mast cell remains a key protagonist in the pathogenesis of allergic diseases finally, this feature examines how innovative, more selectively mast cell-targeted strategies may be developed for the management of allergic diseases.

The immunomodulatory effects of prolonged intravenous infusion of propofol versus midazolam in critically ill surgical patients

Both propofol and midazolam are known to inhibit immune function. The aim of this study was to investigate cytokine production in critically ill surgical patients as early markers of immune response to prolonged infusion of propofol and midazolam. The study enrolled 40 elective patients who were to receive long-term sedation for more than 2 days. Patients were randomly allocated to one of two equally sized groups. Central venous blood samples for measurement of interleukin-1beta (IL-1beta), interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were drawn prior to the start and after 48 h of infusion. After 48 h, propofol caused significant increases in IL-1beta (24%), IL-6 (23%) and TNF-alpha (4.8 times) levels, while midazolam caused significant decreases in IL-1beta (21%), IL-6 (21%) and TNF-alpha (19%). Both agents caused significant decreases in IL-8 levels (propofol: 30%, midazolam: 48%, p < 0.05). Propofol caused significant decreases in IL-2 levels (68%, p < 0.001) but increases in IFN-gamma (30%, p < 0.05), whereas there was no significant change with midazolam compared with the pre-infusion level. In conclusion, during 48 h of continuous infusion, propofol stimulated, while midazolam suppressed, the production of the pro-inflammatory cytokines IL-1beta, IL-6 and TNF-alpha, and both caused suppression of IL-8 production. Propofol inhibited IL-2 production and stimulated IFN-gamma production, whereas midazolam failed to do so. Therefore, sedative agents may have clinical implications in high-risk and immunocompromised patients.