Structural changes in the sacroiliac joint on MRI and relationship to ASDAS inactive disease in axial spondyloarthritis: a 2-year study comparing treatment with etanercept in EMBARK to a contemporary control cohort in DESIR.

BACKGROUND: Limited information is available on the impact of treatment with a tumor necrosis factor inhibitor (TNFi) on structural lesions in patients with recent-onset axial spondyloarthritis (axSpA). We compared 2-year structural lesion changes on magnetic resonance imaging (MRI) in the sacroiliac joints (SIJ) of patients with recent-onset axSpA receiving etanercept in a clinical trial (EMBARK) to similar patients not receiving biologics in a cohort study (DESIR). We also evaluated the relationship between the Ankylosing Spondylitis Disease Activity Score (ASDAS) and change in MRI structural parameters. METHODS: The difference between etanercept (EMBARK) and control (DESIR) in the net percentage of patients with structural lesion change was determined using the SpondyloArthritis Research Consortium of Canada SIJ Structural Score, with and without adjustment for baseline covariates. The relationship between sustained ASDAS inactive disease, defined as the presence of ASDAS < 1.3 for at least 2 consecutive time points 6 months apart, and structural lesion change was evaluated. RESULTS: This study included 163 patients from the EMBARK trial and 76 from DESIR. The net percentage of patients with erosion decrease was significantly greater for etanercept vs control: unadjusted: 23.9% vs 5.3%; P = 0.01, adjusted: 23.1% vs 2.9%; P = 0.01. For the patients attaining sustained ASDAS inactive disease on etanercept, erosion decrease was evident in significantly more than erosion increase: 34/104 (32.7%) vs 5/104 (4.8%); P < 0.001. A higher proportion had erosion decrease and backfill increase than patients in other ASDAS status categories. However, the trend across ASDAS categories was not significant and decrease in erosion was observed even in patients without a sustained ASDAS response. CONCLUSIONS: These data show that a greater proportion of patients achieved regression of erosion with versus without etanercept. However, the link between achieving sustained ASDAS inactive disease and structural lesion change on MRI could not be clearly established. TRIAL REGISTRATION: EMBARK: ClinicalTrials.gov identifier: NCT01258738 , Registered 13 December 2010; DESIR: ClinicalTrials.gov identifier: NCT01648907 , Registered 24 July 2012.

An Analysis of Real-World Data on the Safety of Etanercept in Older Patients with Rheumatoid Arthritis.

OBJECTIVE: The aim of this study was to use real-world data to evaluate potential interactions between age, treatment, and the risk of developing four adverse events (AEs) common in the elderly: congestive heart failure, serious infections, non-melanoma skin cancer, and interstitial lung disease. These AEs were identified as important in a prior age-based analysis (≤ 65 vs > 65 years) of etanercept- or placebo-treated patients with rheumatoid arthritis (RA) in controlled clinical trials. METHODS: Real-world data (1 January 2013 to 31 January 2018) were obtained from the IBM Watson Health MarketScan® Database. Patients were included if aged ≥ 18 years, enrolled for ≥ 1 year prior to RA diagnosis, and without any of the four AEs of interest prior to RA diagnosis or between RA diagnosis and first etanercept exposure. Logistic regression analysis was applied following propensity matching of patients receiving or not receiving etanercept based on age at diagnosis, age status at the beginning of observation (> 65 years or not), sex, geographic region, and follow-up duration. RESULTS: The overall cohort comprised 403,689 patients. The absolute risk of each of the four AEs increased with age. In propensity-matched cohorts, etanercept was associated with significantly higher odds of developing each of the four AEs (p < 0.001 for all). However, the relative risk of experiencing the four AEs in patients who received etanercept versus those who did not was similar between patients ≤ 65 years of age and those > 65 years of age. CONCLUSIONS: In patients with RA, the relative increase in etanercept-associated risk of experiencing congestive heart failure, serious infection, non-melanoma skin cancer, or interstitial lung disease was similar between elderly and non-elderly.

Efficacy and Safety of Etanercept in Elderly Patients with Rheumatoid Arthritis: A Post-Hoc Analysis of Randomized Controlled Trials.

BACKGROUND: Elderly individuals are disproportionately affected by rheumatoid arthritis (RA), but few studies have addressed the efficacy and safety of treatments in this population. OBJECTIVE: Our objective was to assess the efficacy and safety of etanercept in elderly patients (aged ≥ 65 years) with RA. METHODS: The efficacy analysis was a post hoc analysis of data from the open-label period of three phase IV clinical trials of etanercept for RA. Least squares (LS) change from baseline (cfb) in 28-joint Disease Activity Score (DAS28), Health Assessment Questionnaire Disability Index (HAQ-DI), and modified Total Sharp Scores (mTSS) were analyzed by age (< 65 vs. ≥ 65 years) for each study. The safety analyses were of data pooled from the double-blind, placebo-controlled periods of 19 phase I-IV randomized studies of etanercept in patients with RA. The percentage occurrence of adverse events (AEs) in placebo- and etanercept-treated patients was analyzed by age (< 65 vs. ≥ 65 years). RESULTS: There were no significant differences in LS mean cfb in DAS28 or mTSS between the two age groups. LS mean cfb in HAQ-DI scores was consistently lower in elderly than in non-elderly patients, although significant differences were not observed in all trials. Overall, AE occurrence was higher in elderly than non-elderly patients, regardless of treatment. In etanercept-treated patients, there were small yet statistically significant increases in the occurrence of congestive heart failure, serious infections, and non-melanoma skin cancers in elderly versus non-elderly patients. For most AEs, occurrence did not significantly differ between elderly and non-elderly patients. CONCLUSION: Overall, there were no substantial differences in the efficacy or safety of etanercept between elderly and non-elderly patients with RA.

Etanercept treatment for extended oligoarticular juvenile idiopathic arthritis, enthesitis-related arthritis, or psoriatic arthritis: 6-year efficacy and safety data from an open-label trial.

BACKGROUND: To describe the 6-year safety and efficacy of etanercept (ETN) in children with extended oligoarticular juvenile idiopathic arthritis (eoJIA), enthesitis-related arthritis (ERA), and psoriatic arthritis (PsA) METHODS: Patients who completed the 2-year, open-label, phase III CLinical Study In Pediatric Patients of Etanercept for Treatment of ERA, PsA, and Extended Oligoarthritis (CLIPPER) were allowed to enroll in its 8-year long-term extension (CLIPPER2). Children received ETN at a once-weekly dose of 0.8 mg/kg, up to a maximum dose of 50 mg/week. Efficacy assessments included the JIA core set of outcomes, the JIA American College of Rheumatology response criteria (JIA-ACR), and the Juvenile Arthritis Disease Activity Score (JADAS). Efficacy data are reported as responder analyses using a hybrid method for missing data imputation and as observed cases. Safety assessments included treatment-emergent adverse events (TEAEs). RESULTS: Out of 127 patients originally enrolled in CLIPPER, 109 (86%) entered CLIPPER2. After 6 years of trial participation (2 years in CLIPPER and 4 years in CLIPPER2), 41 (32%) patients were still taking ETN, 13 (11%) entered the treatment withdrawal phase after achieving low/inactive disease (of whom 7 had to restart ETN), 36 (28%) discontinued treatment for other reasons but are still being observed, and 37 (29%) discontinued treatment permanently. According to the hybrid imputation analysis, proportions of patients achieving JIA ACR90, JIA ACR100, and JADAS inactive disease after the initial 2 years of treatment were 58%, 48%, and 32%, respectively. After the additional 4 years, those proportions in patients who remained in the trial were 46%, 35%, and 24%. Most frequently reported TEAEs [n (%), events per 100 patient-years] were headache [28 (22%), 5.3], arthralgia [24 (19%), 4.6], and pyrexia [20 (16%), 3.8]. Number and frequency of TEAEs, excluding infections and injection site reactions, decreased over the 6-year period from 193 and 173.8, respectively, during year 1 to 37 and 61.3 during year 6. A single case of malignancy (Hodgkin's lymphoma) and no cases of active tuberculosis, demyelinating disorders, or deaths were reported. CONCLUSIONS: Open-label etanercept treatment for up to 6 years was safe, well tolerated, and effective in patients with eoJIA, ERA, and PsA. TRIAL REGISTRATION: ClinicalTrials.gov: CLIPPER, NCT00962741 , registered 20 August, 2009, CLIPPER2, NCT01421069 , registered 22 August, 2011.

Modification of structural lesions on MRI of the sacroiliac joints by etanercept in the EMBARK trial: a 12-week randomised placebo-controlled trial in patients with non-radiographic axial spondyloarthritis.

OBJECTIVE: To evaluate the impact on structural lesions observed on MRI in the sacroiliac joints (SIJ) at 12 weeks in patients with non-radiographic axial spondyloarthritis (nr-axSpA) receiving etanercept or placebo in EMBARK (Effect of Etanercept on Symptoms and Objective Inflammation in nr-axSpA, a 104 week study). METHODS: Patients were randomised to double-blind etanercept 50 mg/week or placebo for 12 weeks. Structural lesions at baseline and 12 weeks were scored by two independent readers using the Spondyloarthritis Research Consortium of Canada (SPARCC) SIJ structural score (SSS) on T1-weighted MRI. Change in SPARCC SSS and correlation with improvement in clinical outcomes was evaluated. RESULTS: MRI scans from 185 patients (etanercept, n=88; placebo, n=97) were reviewed. At baseline, there were no significant differences in mean SPARCC SSS between etanercept and placebo. From baseline to 12 weeks, change in mean SPARCC SSS was significantly greater for etanercept than placebo for erosion (-0.57 vs -0.08, respectively, adjusted p value=0.017) and backfill (0.36 vs 0.06, adjusted p value=0.022). A treatment difference was also present for the subgroup of patients with SIJ inflammation on MRI (SPARCC bone marrow oedema ≥2): erosion: -0.81 versus -0.13 for etanercept versus placebo, respectively, p=0.007; backfill: 0.48 versus 0.08, respectively, p=0.032. Decrease in erosion and increase in backfill correlated with improvement in more clinical outcomes for etanercept than placebo. CONCLUSION: Treatment with etanercept was associated with significantly greater reduction in erosions and increase in backfill at 12 weeks compared with placebo, consistent with a very early reparative response to antitumour necrosis factor therapy. The impact on disease progression in spondyloarthritis should be studied further. TRIAL REGISTRATION NUMBER: NCT01258738; Post-results.

Evaluation of the change in structural radiographic sacroiliac joint damage after 2 years of etanercept therapy (EMBARK trial) in comparison to a contemporary control cohort (DESIR cohort) in recent onset axial spondyloarthritis.

OBJECTIVE: To compare 2 years of radiographic sacroiliac joint (SIJ) changes in patients with recent onset axial spondyloarthritis (axSpA) receiving etanercept in a clinical trial (EMBARK) to similar patients not receiving biologics in a cohort study (DESIR). METHODS: Endpoints were changes at week 104 per the modified New York (mNY) grading system in total SIJ score (primary endpoint) and net percentage of patients with progression defined three ways. Treatment effect was analysed with and without adjustment for baseline covariates. RESULTS: At 104 weeks, total SIJ score improved in the etanercept group (n=154, adjusted least-squares mean change: -0.14) and worsened in the control group (n=182, change: 0.08). The adjusted difference between groups (etanercept minus control) was -0.22 (95% CI -0.38 to -0.06), p=0.008. The net percentage of patients with progression was significantly lower in the etanercept versus the control group for two of three binary endpoints: -1.9% versus 1.6% (adjusted difference for etanercept minus control: -4.7%,95% CI -9.9 to 0.5, p=0.07) for change in mNY criteria; -1.9% versus 7.8% (adjusted difference: -18.2%,95% CI -30.9 to -5.6, p=0.005) for change ≥1 grade in ≥1 SIJ; and -0.6% versus 6.7% (adjusted difference: -16.4%,95% CI -27.9 to -5.0, p=0.005) for change ≥1 grade in ≥1 SIJ, with shift from 0 to 1 or 1 to 0 considered no change. CONCLUSION: Despite the slow radiographic SIJ progression rate over 2 years in axSpA, this study suggests a lower rate of progression in the SIJ with etanercept than without anti-tumour necrosis factor therapy. TRIAL REGISTRATION NUMBERS: NCT01258738, NCT01648907; Post-results.

MRI evidence of structural changes in the sacroiliac joints of patients with non-radiographic axial spondyloarthritis even in the absence of MRI inflammation.

BACKGROUND: Studies have shown that structural lesions may be present in patients with non-radiographic axial spondyloarthritis (nr-axSpA). However, the relevance of structural lesions in these patients is unclear, particularly without signs of inflammation on magnetic resonance imaging (MRI). We assessed the presence of structural lesions at baseline on MRI in the sacroiliac joints (SIJ) of patients with nr-axSpA with and without SIJ inflammation on MRI. METHODS: Bone marrow edema (BME) was assessed on short tau inversion recovery (STIR) scans from 185 patients with nr-axSpA, by two independent readers at baseline using the Spondyloarthritis Research Consortium of Canada (SPARCC) score. Structural lesions were evaluated on T1 weighted spin echo scans, with readers blinded to STIR scans, using the SPARCC MRI SIJ structural score. Disease characteristics and structural lesions were compared in patients with SIJ BME (score ≥2) and without SIJ BME (score <2). RESULTS: Both SIJ BME and structural lesions scores were available for 183 patients; 128/183 (69.9%) patients had SIJ BME scores ≥2 and 55/183 (30.1%) had scores <2. Frequencies of MRI structural lesions in patients with vs without SIJ BME were: erosions (45.3% vs 10.9%, P < 0.001), backfill (20.3% vs 0%, P < 0.001), fat metaplasia (10.9% vs 1.8%, P = 0.04), and ankylosis (2.3% vs 1.8%, P = ns). Significantly more patients with both SIJ BME and structural lesions were male and/or HLA-B27 positive than patients with only SIJ BME. Mean (SD) spinal scores (23 discovertebral units) were significantly higher in patients with SIJ structural lesions than without: 6.5 (11.5) vs 3.3 (5.1), respectively, P = 0.01. CONCLUSIONS: In patients with nr-axSpA, SIJ structural lesions, particularly erosions, may be present on MRI when radiographs are normal or inconclusive, even in patients negative for MRI SIJ inflammation. They may reflect more severe disease with greater spinal inflammation. TRIAL REGISTRATION: ClinicalTrials.gov, NCT01258738 . Registered on 9 December 2010.

Effects of Long-Term Etanercept Treatment on Clinical Outcomes and Objective Signs of Inflammation in Early Nonradiographic Axial Spondyloarthritis: 104-Week Results From a Randomized, Placebo-Controlled Study.

OBJECTIVE: To evaluate the long-term clinical and imaging efficacy of etanercept in patients with early, active nonradiographic axial spondyloarthritis (SpA). METHODS: Adult patients who satisfied the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial SpA (but not the modified New York radiographic criteria), with symptom duration >3 months to <5 years, and who were unresponsive to ≥2 nonsteroidal antirheumatic drugs (NSAIDs) received double-blind etanercept 50 mg/week or placebo for 12 weeks, followed by open-label etanercept 50 mg/week to week 104. Clinical, magnetic resonance imaging (MRI; Spondyloarthritis Research Consortium of Canada [SPARCC] scores), and safety outcomes at 104 weeks were analyzed. RESULTS: Of 215 randomized patients (etanercept: n = 106; placebo: n = 109), 205 entered the study (etanercept/etanercept: n = 100; placebo/etanercept: n = 105) and 169 completed the open-label period (etanercept/etanercept: n = 83; placebo/etanercept: n = 86). At week 104, 61 of 81 (75%), 49 of 81 (61%), 48 of 80 (60%), and 57 of 81 (70%) patients who received etanercept throughout the trial achieved ASAS20, ASAS40, Ankylosing Spondylitis Disease Activity Score (ASDAS) inactive disease, and Bath Ankylosing Spondylitis Disease Activity Index criteria for 50% improvement (BASDAI 50) scores, respectively (observed). From baseline to week 104, continued improvements in clinical outcomes (ASDAS-C-reactive protein: -1.5 and -1.7; BASDAI: -3.3 and -3.8 [last observation carried forward]), and SPARCC MRI scores (sacroiliac joint: -6.0 and -3.4; spinal: -2.1 and -0.8 [observed]) were seen in patients receiving etanercept/etanercept and placebo/etanercept. During the study, 8% in the etanercept/etanercept group and 7% in the placebo/etanercept group had serious adverse events; no new safety signals were seen. CONCLUSION: Patients with early, active nonradiographic axial SpA and an inadequate response to at least 2 NSAIDs demonstrated improvement in clinical and imaging outcomes that were sustained through 104 weeks of etanercept treatment.

Symptomatic efficacy of etanercept and its effects on objective signs of inflammation in early nonradiographic axial spondyloarthritis: a multicenter, randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To assess the efficacy of etanercept in the treatment of early active nonsteroidal antiinflammatory drug (NSAID)-refractory nonradiographic axial spondyloarthritis (SpA). METHODS: The study population consisted of patients who met the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axial SpA but not the modified New York radiographic criteria for ankylosing spondylitis (as assessed by a radiologist at the central trial site), had a symptom duration of >3 months but <5 years, had a score of ≥4 on the Bath Ankylosing Spondylitis Disease Activity Index, and had been treated unsuccessfully with ≥2 NSAIDs. Patients were randomized to receive etanercept 50 mg/week or placebo and continued background NSAID treatment for 12 weeks (double-blind study); during the subsequent open-label period, all patients received etanercept 50 mg/week. The primary study end point was meeting the ASAS criteria for 40% improvement (ASAS40) at week 12. Magnetic resonance imaging (MRI) of the sacroiliac joints and spine was performed at baseline and week 12. RESULTS: One hundred six patients were randomized to the etanercept group and 109 to the placebo group. Of the 215 patients, the mean ± SD age at baseline was 32.0 ± 7.8 years, 154 (72%) were HLA-B27 positive, and 174 (81%) had MRI-confirmed sacroiliitis. At 12 weeks, the proportion of patients with improvement according to the ASAS40 was significantly higher in the etanercept group than in the placebo group (34 of 105 [32%] versus 17 of 108 [16%]; P = 0.006). Patients who received etanercept exhibited a greater reduction in MRI-based scores for sacroiliac joint inflammation (-46.9% versus -10.9%; P < 0.001) and spinal inflammation (-45.4% versus -33.4%; P = 0.04) compared with placebo-treated patients at week 12. Post hoc analyses suggested a possible association between higher baseline C-reactive protein levels or MRI sacroiliac joint inflammation scores and higher rates of ASAS40 response to etanercept. At week 24, patients in the placebo group who had switched to etanercept at 12 weeks exhibited improvement similar to that observed in patients who had received etanercept for 24 weeks. CONCLUSION: In patients with nonradiographic axial SpA, etanercept treatment was associated with rapid, significant improvement in symptomatic disease activity, function, and systemic and skeletal inflammation over 12 weeks; clinical/functional improvement was sustained over 24 weeks.

L-theanine intervention enhances human gammadeltaT lymphocyte function.

Human gammadeltaT lymphocytes are a subset of T cells and are a first line of defense against microbes and tumors. These gammadeltaT cells can be primed by nitrogen-containing bisphosphonates, and certain short-chain alkylamines. These primed gammadeltaT cells have an enhanced capacity to proliferate and to secrete cytokines upon ex vivo exposure to a wide variety of microbes and tumor cells. The largest dietary source of alkylamines is L-theanine, an amino acid unique to tea beverages that is catabolized to ethylamine. Supplementation of subjects with capsules containing L-theanine and catechins has recently been shown to decrease the incidence of cold and flu symptoms, while enhancing gammadeltaT cell function.

Bioactive food components that enhance gammadelta T cell function may play a role in cancer prevention.

Gammadelta T cells are found largely within the epithelium and recognize antigens differently than their alphabeta T cell counterparts. TCR delta-/- knock out mice exhibit a rapid tumor onset, along with increased tumor incidence. Although limited, research demonstrates that nutrients and bioactive food components can influence gammadelta T cell cytotoxicity, cytokine secretion, and proliferative capacity, and the results are nonetheless intriguing. Among other functions, gammadelta T cells play a role in immunosurveillance against malignant cells, as shown by the T cell receptor (TCR)delta-/- knock out mice that exhibit a rapid tumor onset and increased tumor incidence. Some common dietary modifiers of gammadelta T cell numbers or activity are apple condensed tannins, dietary nucleotides, fatty acids, and dietary alkylamines. A recent clinical study demonstrated that ingesting a fruit and vegetable juice concentrate increased the number of circulating gammadelta T cells. Clinical studies also document that the oral consumption of a tea component, L-theanine, enhances gammadelta T cell proliferation and interferon-gamma secretion. The significance of these studies awaits additional examination of the influence of exposures and duration on these and other food components. Adoptive transfer and TCRdelta-/- knock out mice models should be used more extensively to determine the physiological impact of the number and activity of these cells as a function of dietary component exposures. While clarifying the diet and gammadelta T interrelationship may not be simple, the societal implications are enormous.

Alternative bisphosphonate targets and mechanisms of action.

As the number of bisphosphonates continues to increase, they have found widespread use in an increasing number of clinical conditions. Ongoing examination of their targets and mechanisms of action has revealed that this surprisingly diverse class of drugs has effects beyond those first described for osteoclasts. These additional targets include osteoblasts, osteocytes, angiogenesis, and gammadelta T lymphocytes of the human immune system. The immune system effects are specifically targeted to gammadelta T cells and are reminiscent of the effects seen after ingestion of tea beverage. BP effects on such alternate targets may explain not only their antiresorptive effect, but also their effect on bone quality, tumors, and microbes.

Antigens in tea-beverage prime human Vgamma 2Vdelta 2 T cells in vitro and in vivo for memory and nonmemory antibacterial cytokine responses.

Human gammadelta T cells mediate innate immunity to microbes via T cell receptor-dependent recognition of unprocessed antigens with conserved molecular patterns. These nonpeptide alkylamine antigens are shared by tumor cells, bacteria, parasites, and fungi but also by edible plant products such as tea, apples, mushrooms, and wine. Here we show that priming of gammadelta T cells with alkylamine antigens in vitro results in a memory response to these antigens. Such priming results also in a nonmemory response to whole bacteria and to lipopolysaccharide, characterized by IL-12-dependent secretion of IFN-gamma by gammadelta T cells and by gammadelta T cell proliferation. Drinking tea, which contains l-theanine, a precursor of the nonpeptide antigen ethylamine, primed peripheral blood gammadelta T cells to mediate a memory response on reexposure to ethylamine and to secrete IFN-gamma in response to bacteria. This unique combination of innate immune response and immunologic memory shows that gammadelta T cells can function as a bridge between innate and acquired immunity. In addition, these data provide an explanation for the health benefits of tea.

Conservation of nonpeptide antigen recognition by rhesus monkey V gamma 2V delta 2 T cells.

We have previously found that monkey Vgamma2Vdelta2(+) T cells mount adaptive immune responses in response to Mycobacterium bovis bacillus Calmette-Guérin infections. We have now analyzed rhesus monkey gammadelta T cell responses to nonpeptide Ags and superantigens. Like human Vgamma2Vdelta2(+) T cells, rhesus monkey gammadelta T cells are stimulated when exposed to prenyl pyrophosphate, bisphosphonate, and alkylamine Ags. Responsiveness was limited to gammadelta T cells expressing Vgamma2Vdelta2 TCRs. Rhesus monkey Vgamma2Vdelta2(+) T cells also responded to the superantigen, staphyloccocal enterotoxin A. Sequencing of the rhesus monkey Vgamma2Vdelta2 TCR revealed a strong sequence homology to human Vgamma2Vdelta2 TCR that preserves important sequence motifs. Moreover, chimeric TCRs that pair human Vgamma2 with monkey Vdelta2 and monkey Vgamma2 with human Vdelta2 retain reactivity to nonpeptide Ags and B cell lymphomas. A molecular model of the rhesus monkey Vgamma2Vdelta2 TCR has a basic region in the complementarity-determining region 3 binding groove that is similar to that seen in the human Vgamma2Vdelta2 TCR and preserves the topology of the complementarity-determining region loops. Thus, recognition of nonpeptide prenyl pyrophosphate, bisphosphonate, and alkylamine Ags is conserved in primates suggesting that primates can provide an animal model for human gammadelta T cell Ag responses.

Human V gamma 2V delta 2 T cells augment migration-inhibitory factor secretion and counteract the inhibitory effect of glucocorticoids on IL-1 beta and TNF-alpha production.

In immune cells, proinflammatory cytokine gene expression is regulated by glucocorticoids, whereas migration-inhibitory factor (MIF), a pleiotropic cytokine, has the unique property of counteracting the inhibitory effect of glucocorticoids on TNF-alpha and IL-1beta secretion. A few lines of evidence suggest that gammadelta T cells play an important role in immunoregulation. However, it is unknown whether human gammadelta T cells participate in regulating MIF secretion, and how gammadelta T cells, glucocorticoids, and cytokines converge to give a unified physiological response. In this study, we demonstrate that human Vgamma2Vdelta2 T cells augment MIF secretion. Remarkably, these Vgamma2Vdelta2 T cells, functioning similarly to MIF in part, counteracted inhibition of dexamethasone on production of IL-1beta and TNF-alpha. SCID mice reconstituted with human PBMC that were mock depleted of Vdelta2 T cells and repeatedly infected with lethal dose of Escherichia coli had shorter survival time than those reconstituted with PBMC that were depleted of Vdelta2 T cells. Thus, human Vgamma2Vdelta2 T cells are likely to play broad-spectrum roles in immunoregulation and immunopathology by influencing MIF secretion and the immunomodulatory function of glucocorticoids.