Is PTSD-Phenotype Associated with HPA-Axis Sensitivity? Feedback Inhibition and Other Modulating Factors of Glucocorticoid Signaling Dynamics.

Previously, we found that basal corticosterone pulsatility significantly impacts the vulnerability for developing post-traumatic stress disorder (PTSD). Rats that exhibited PTSD-phenotype were characterized by blunted basal corticosterone pulsatility amplitude and a blunted corticosterone response to a stressor. This study sought to identify the mechanisms underlining both the loss of pulsatility and differences in downstream responses. Serial blood samples were collected manually via jugular vein cannula at 10-min intervals to evaluate suppression of corticosterone following methylprednisolone administration. The rats were exposed to predator scent stress (PSS) after 24 h, and behavioral responses were assessed 7 days post-exposure for retrospective classification into behavioral response groups. Brains were harvested for measurements of the glucocorticoid receptor, mineralocorticoid receptor, FK506-binding protein-51 and arginine vasopressin in specific brain regions to assess changes in hypothalamus-pituitary-adrenal axis (HPA) regulating factors. Methylprednisolone produced greater suppression of corticosterone in the PTSD-phenotype group. During the suppression, the PTSD-phenotype rats showed a significantly more pronounced pulsatile activity. In addition, the PTSD-phenotype group showed distinct changes in the ventral and dorsal CA1, dentate gyrus as well as in the paraventricular nucleus and supra-optic nucleus. These results demonstrate a pre-trauma vulnerability state that is characterized by an over-reactivity of the HPA and changes in its regulating factors.

Combining Magnetic Resonance Imaging with Systemic Monocyte Evaluation for the Implementation of GBM Management.

Magnetic resonance imaging (MRI) is the gold standard for glioblastoma (GBM) patient evaluation. Additional non-invasive diagnostic modalities are needed. GBM is heavily infiltrated with tumor-associated macrophages (TAMs) that can be found in peripheral blood. FKBP51s supports alternative-macrophage polarization. Herein, we assessed FKBP51s expression in circulating monocytes from 14 GBM patients. The M2 monocyte phenotype was investigated by qPCR and flow cytometry using antibodies against PD-L1, CD163, FKBP51s, and CD14. MRI assessed morphologic features of the tumors that were aligned to flow cytometry data. PD-L1 expression on circulating monocytes correlated with MRI tumor necrosis score. A wider expansion in circulating CD163/monocytes was measured. These monocytes resulted in a dramatic decrease in patients with an MRI diagnosis of complete but not partial surgical removal of the tumor. Importantly, in patients with residual tumor, most of the peripheral monocytes that in the preoperative stage were CD163/FKBP51s- had turned into CD163/FKBP51s+. After Stupp therapy, CD163/FKBP51s+ monocytes were almost absent in a case of pseudoprogression, while two patients with stable or true disease progression showed sustained levels in such circulating monocytes. Our work provides preliminary but meaningful and novel results that deserve to be confirmed in a larger patient cohort, in support of potential usefulness in GBM monitoring of CD163/FKBP51s/CD14 immunophenotype in adjunct to MRI.

Role of FK506 Binding Protein on Tacrolimus Distribution in Red Blood Cells.

PURPOSE: Tacrolimus is distributed mainly in red blood cells (RBCs) after transfer into blood. This study aimed to evaluate the effect of FK506-binding proteins (FKBPs) on RBC distribution of tacrolimus in a physiological environment. METHODS: Human RBCs were isolated from fresh blood samples from healthy volunteers. The effect of FKBPs on each process of the RBC distribution of tacrolimus was evaluated in vitro. Effect of intracellular FKBPs was assessed by inhibition experiment with rapamycin, which competitively inhibits the binding of tacrolimus to FKBPs. Effect of extracellular FKBPs was examined by pre-exposure of RBCs to FKBP and preincubation of tacrolimus with FKBP. RESULTS: Pretreatment with rapamycin significantly reduced the rate of tacrolimus distribution in RBCs in a concentration-dependent manner. Pre-exposure of RBCs to FKBP12 followed by exposure to tacrolimus significantly decreased tacrolimus distribution in RBCs in a concentration-dependent manner. In addition, preincubation of tacrolimus with FKBP12 significantly reduced the rate of tacrolimus distribution in RBCs. CONCLUSIONS: FKBP played an important role in the distribution of tacrolimus in RBCs. The effect of intracellular and extracellular FKBPs on RBC distribution of tacrolimus in circulating blood was substantial. FKBP was shown as a potential biomarker for predicting the pharmacokinetics and pharmacodynamics of tacrolimus.

Proteomic analysis of infected primary human leucocytes revealed PSTK as potential treatment-monitoring marker for active and latent tuberculosis.

Markers for monitoring clearance of Mycobacterium tuberculosis (Mtb) infection during anti-TB drug treatment could facilitate management of tuberculosis (TB) treatment, but are lacking. We aimed to screen for Mtb clearance markers from in-vitro-infected leucocytes and to evaluate these markers in followed-up active TB (ATB) patients and latent TB (LTBI) cases after anti-TB drug treatment. Extracellular proteins from primary leucocytes infected with each of the Mtb lineages (East-Asian, Indo-Oceanic, Euro-American and the laboratory strain H37Rv) were screened as possible clearance markers. Leucocytes infected with Staphylococcus aureus acted as controls. The proteomic analysis was performed using GeLC-MS/MS. Several quantitative and qualitative candidate clearance markers were found. These proteins were suppressed during the infection stage of all Mtb lineages and re-expressed after bacillary clearance. PSTK, FKBP8 and MGMT were common clearance markers among the four Mtb lineages in our model. Only PSTK was a potential clearance marker based on western blot validation analysis from culture supernatants. The PSTK marker was further validated with western blot analysis using serum samples (n = 6) from ATB patients and LTBI cases during anti-TB drug treatment, and from healthy controls (n = 3). Time-dependent increase of PSTK was found both in ATB and LTBI patients during the course of anti-TB drug treatment, but not in healthy controls. We have demonstrated that PSTK is a potential treatment-monitoring marker for active and latent TB.

Towards precision medicine for stress disorders: diagnostic biomarkers and targeted drugs.

The biological fingerprint of environmental adversity may be key to understanding health and disease, as it encompasses the damage induced as well as the compensatory reactions of the organism. Metabolic and hormonal changes may be an informative but incomplete window into the underlying biology. We endeavored to identify objective blood gene expression biomarkers for psychological stress, a subjective sensation with biological roots. To quantify the stress perception at a particular moment in time, we used a simple visual analog scale for life stress in psychiatric patients, a high-risk group. Then, using a stepwise discovery, prioritization, validation, and testing in independent cohort design, we were successful in identifying gene expression biomarkers that were predictive of high-stress states and of future psychiatric hospitalizations related to stress, more so when personalized by gender and diagnosis. One of the top biomarkers that survived discovery, prioritization, validation, and testing was FKBP5, a well-known gene involved in stress response, which serves as a de facto reassuring positive control. We also compared our biomarker findings with telomere length (TL), another well-established biological marker of psychological stress and show that newly identified predictive biomarkers such as NUB1, APOL3, MAD1L1, or NKTR are comparable or better state or trait predictors of stress than TL or FKBP5. Over half of the top predictive biomarkers for stress also had prior evidence of involvement in suicide, and the majority of them had evidence in other psychiatric disorders, providing a molecular underpinning for the effects of stress in those disorders. Some of the biomarkers are targets of existing drugs, of potential utility in patient stratification, and pharmacogenomics approaches. Based on our studies and analyses, the biomarkers with the best overall convergent functional evidence (CFE) for involvement in stress were FKBP5, DDX6, B2M, LAIR1, RTN4, and NUB1. Moreover, the biomarker gene expression signatures yielded leads for possible new drug candidates and natural compounds upon bioinformatics drug repurposing analyses, such as calcium folinate and betulin. Our work may lead to improved diagnosis and treatment for stress disorders such as PTSD, that result in decreased quality of life and adverse outcomes, including addictions, violence, and suicide.

Low Circulating Levels of GR, FKBP5, and SGK1 in Medicated Patients With Depression Are Not Altered by Electroconvulsive Therapy.

OBJECTIVES: Hypothalamic-pituitary-adrenal axis dysregulation is frequently observed in patients with depression, with increased levels of the glucocorticoid (GC) cortisol commonly reported. Hypothalamic-pituitary-adrenal axis dysregulation may be a consequence of impaired feedback inhibition due to GC receptor (GR) impairments or dysfunction, termed "glucocorticoid resistance." Here, our objective was to assess mRNA levels of GC-related markers (GR, FKBP5, serum glucocorticoid kinase 1 [SGK1]) in patients with depression versus controls and in patient samples after electroconvulsive therapy (ECT). We also examined the relationship between these GC-related markers and 24-item Hamilton Depression Rating Scale (HAM-D24) scores to assess the utility of using them as biological markers for depression or the therapeutic response to ECT. METHODS: GR, FKBP5, and SGK1 mRNA levels were examined in whole blood samples from 88 medicated patients with depression pre-/post-ECT and 63 controls using quantitative real-time polymerase chain reaction. Exploratory subgroup correlational analyses were performed to determine the relationship between GR, FKBP5, and SGK1 and 24-item Hamilton Depression Rating Scale scores. RESULTS: GR, FKBP5, and SGK1 mRNA levels were significantly lower in medicated patients with depression compared with controls (P < 0.001, P = 0.03, P < 0.001, respectively), but ECT did not alter their levels (all P > 0.05). There was no relationship between GR, FKBP5, or SGK1 and 24-item Hamilton Depression Rating Scale scores. CONCLUSIONS: GR, FKBP5, and SGK1 do not seem to be involved in the peripheral molecular response to ECT and do not represent useful biomarkers for predicting the therapeutic response to ECT in a real-world clinical setting.

Identification and characterization of a pig FKBP5 gene with a novel expression pattern in lymphocytes and granulocytes.

The immunophilins are an important group of regulatory molecules in the immune system. FKBP5, expressed throughout mammals and in fish and birds, functions in both physiological and pathogenic pathways, including innate immunity and steroid-based diseases. In this study, we cloned the first porcine FKBP5 from Rongchang pig by the rapid amplification of cDNA ends technique. The full-length cDNA is 4097 bp, with an open reading frame of 1371 bp that codes for a 457-aa protein. Western blotting detected the porcine FKBP5 protein at highest levels in thymus, followed by spleen and lung. Immunohistochemistry detected the porcine FKBP5 protein in lymphocytes and granulocytes of the blood, and flow cytometry identified greater expression in unactivated (vs. activated) T lymphocytes. Finally, the expression level of porcine FKBP5 in the granulocytes was found to decline significantly from the time of birth to one-year-old. These collective data suggest that the newly identified porcine FKBP5 may function in activation of T cells in pig and in innate immunity in the newborn pig in particular.

The effects of early trauma and the FKBP5 gene on PTSD and the HPA axis in a clinical sample of Gulf War veterans.

Previous research indicates that interactions between FKBP5 single nucleotide polymorphisms (SNPs) and child abuse are associated with posttraumatic stress disorder (PTSD) in adulthood. We examined the relationship between the T-allele of the rs1360780 FKBP5 SNP and child abuse on PTSD and the HPA axis in a clinical sample of Gulf War veterans. Genotyping was completed on 266 veterans and 174 veterans additionally participated in a low dose dexamethasone suppression test (DST). The CAPS was used to determine PTSD status and the THQ was used to determine child abuse operationalized as either childhood physical or sexual abuse. Hierarchical regression models were used to assess FKBP5 × child abuse interactions on PTSD, basal cortisol levels, and post DST cortisol levels. The FKBP5 risk allele and child abuse were separately associated with PTSD diagnosis. The risk allele was also associated with significantly lower cortisol levels at baseline. However, no significant FKBP5 × child abuse interaction on PTSD diagnosis, basal cortisol levels, or greater cortisol suppression was observed. Our results suggest that FKBP5 may be a viable biomarker for PTSD. Nonetheless, further work will be required to reconcile our findings with previous reports of an FKBP5 × child abuse interaction on posttraumatic stress response.

Epigenetic Changes of FKBP5 as a Link Connecting Genetic and Environmental Risk Factors with Structural and Functional Brain Changes in Major Depression.

The gene for the glucocorticoid receptor regulator FK506 binding protein 5 (FKBP5) plays a role for risk, response to treatment, and changes in brain areas in major depressive disorder (MDD). Chronic stress is associated with lower methylation of FKBP5. Our aim was to investigate whether methylation of FKBP5 reflected exposure to childhood adversity in MDD and controls and whether it was associated with structure and function of emotional processing regions. FKBP5 intron 7 GR response element region methylation and rs1360780 allelic status were assessed from whole blood in 56 MDD adults and 50 controls. Using magnetic resonance imaging, we assessed gray matter concentration of selected areas and their function during valence recognition of emotional images. Childhood adversity was investigated using the Childhood Trauma Questionnaire. In MDD patients carrying the high-risk T allele of rs1360780, lower methylation of FKBP5 was predicted by childhood adversity (F=4.95, p=0.04). In all participants, lower FKBP5 intron methylation levels were associated with reduced gray matter concentration in the inferior frontal orbital gyrus bilaterally (Wald chi-square=11.93, pFDR<0.01) and, in MDD, with its bilaterally higher activation during valence recognition (Wald chi-square=5.58, p=0.02). Activation of this region, regardless of side, was found to be lower in MDD compared to controls (Wald chi-square=3.88, p=0.049) and to be inversely correlated with depression severity (Wald chi-square=4.65, p=0.03). Our findings support the hypothesis that, in genetically predisposed individuals carrying a high-risk variant of the gene, childhood maltreatment might induce demethylation of FKBP5. This is in turn associated with structural and functional changes in the inferior frontal orbital gyrus, a relevant area for the clinical symptoms of MDD.

FKBP5 mRNA Expression Is a Biomarker for GR Antagonism.

CONTEXT: Endogenous Cushing's syndrome is caused by chronically elevated levels of cortisol. Mifepristone, a glucocorticoid receptor (GR) antagonist, is approved for the treatment of Cushing's syndrome. Currently there is an unmet clinical need for a direct biochemical method for monitoring the immediate effectiveness of mifepristone in patients with Cushing's syndrome. The glucocorticoid induction of FK506-binding protein 5 (FKBP5) expression is rapid and has been shown to be attenuated by GR antagonists in a range of in vitro and in vivo models. OBJECTIVE: The objective of the study was to develop a quantitative PCR assay for FKBP5 mRNA expression in blood and apply it to measure the inhibition of glucocorticoid-induced FKBP5 expression by GR antagonists in healthy human subjects. METHODS: Briefly, blood samples were acquired from a phase I study in which healthy human subjects were administered either a single dose of the GR agonist prednisone with and without coadministration of a single oral dose of mifepristone or glucocorticoid receptor antagonist (CORT125134) or multiple daily doses of CORT125134 over 14 days with coadministration of prednisone with the final dose. FKBP5 mRNA levels were analyzed by quantitative PCR in blood samples collected at selected time points. SETTING: The study was conducted at Quotient Clinical (Nottingham, United Kingdom). RESULTS: Oral administration of the glucocorticoid prednisone to healthy human subjects resulted in a time-dependent increase of FKBP5 mRNA to peak levels of approximately 12-fold compared with unstimulated levels within 4 hours of steroid administration, followed by a reduction to baseline levels within 24 hours. Furthermore, oral administration of mifepristone or the selective GR antagonist CORT125134 had the desired effect of inhibiting prednisone-mediated activation of GR as seen by a reduction of FKBP5 mRNA levels. CONCLUSIONS: The inhibition of FKBP5 mRNA expression by a selective GR antagonist is a potential clinical biomarker of GR antagonism.

Determinants of altered intracellular endocrine-immune interplay in Bosnian war refugees suffering from PTSD.

Posttraumatic Stress Disorder (PTSD) has been repeatedly linked to changes in glucocorticoid (GC) sensitivity. To increase our understanding of this phenomenon and its potential relevance for PTSD development and treatment, the current study investigates the interplay between two key moderators, glucocorticoid receptor (GRα) and GR co-chaperone FKBP5, and their relation to GC sensitivity. A GC sensitivity assay was performed in 52 Bosnian war refugees (19m; 40.8±8.7 years) clinically diagnosed with PTSD to divide the patient group into a high (HS) and a low (LS) GC sensitivity group. Expression of GRα and FKBP5 mRNA was quantified by real-time RT-PCR. Links between gene expression and GC sensitivity were driven by the HS group of PTSD patients, which also showed increased expression of GRα but not FKBP5 compared to the LS group. Further, expressions of FKBP5 and GRα were strongly correlated in the HS patient group, while this association was missing in the LS PTSD group. Our findings suggest that PTSD phenotypes may be characterized by differences in intracellular signaling transduction processes. The associations of expression of GRα and FKBP5 in the high-sensitive PTSD subgroup may thereby reflect physiological adaptation to preserve immune-relevant GC signaling. Further research is needed to understand the role and consequences of GRα-FKBP5 dissociation in low GC sensitivity PTSD patients.

Association of Epidemiologic Factors and Genetic Variants Influencing Hypothalamic-Pituitary-Adrenocortical Axis Function With Postconcussive Symptoms After Minor Motor Vehicle Collision.

OBJECTIVES: To determine the influence of epidemiologic factors and the influence of genetic variants affecting FKBP5, a protein known to modulate hypothalamic-pituitary-adrenocortical axis function, on the severity of somatic symptoms commonly termed "postconcussive" 6 and 12 months after motor vehicle collision (MVC). METHODS: European Americans 18 to 65 years of age who presented to one of eight emergency departments (EDs) after MVC were enrolled. Exclusion criteria included hospital admission. Blood samples were collected in the ED for genotyping. Participants completed evaluations including an adapted Rivermead Post-Concussive Symptoms Questionnaire in the ED and at 6 weeks, 6 months, and 1 year. Repeated-measures analysis of covariance was used to evaluate the association between epidemiologic factors (sociodemographic, pre-MVC health, collision characteristics, head injury, peritraumatic pain, and stress), FKBP5 genetic variants, and postconcussive symptom severity. RESULTS: Among 943 patients recruited in the ED, follow-up was completed on 835 (88%) at 6 months and 857 (90%) at 1 year. Self-reported head impact during collision was not associated with chronic postconcussive symptom severity. After correction for multiple testing, three FKBP5 single-nucleotide polymorphisms (rs3800373, rs7753746, and rs9380526) predicted chronic postconcussive symptom severity, with an average symptom severity of 1.10 (95% confidence interval = 0.96-1.24), 1.36 (1.21-1.51), and 1.55 (1.23-1.88) for one, two, or three copies of minor allele at rs3800373 (p = .001). Similar effect sizes were observed for the minor alleles of rs7753746 and rs9380526. CONCLUSIONS: Postconcussive symptoms after minor MVC are not generally related to the severity of mild brain injury. This study shows that neurobiologic stress systems may play a role in the pathogenesis of postconcussive symptoms.

FKBP5 genotype-dependent DNA methylation and mRNA regulation after psychosocial stress in remitted depression and healthy controls.

BACKGROUND: Polymorphisms in the FK506 binding protein 5 (FKBP5) gene have been shown to influence glucocorticoid receptor sensitivity, stress response regulation, and depression risk in traumatized subjects, with most consistent findings reported for the functional variant rs1360780. In the present study, we investigated whether the FKBP5 polymorphism rs1360780 and lifetime history of major depression are associated with DNA methylation and FKBP5 gene expression after psychosocial stress. METHODS: A total of 116 individuals with a positive (n = 61) and negative (n = 55) lifetime history of major depression participated in the Trier Social Stress Test. We assessed plasma cortisol concentrations, FKBP5 mRNA expression, and CpG methylation of FKBP5 intron 7 in peripheral blood cells. RESULTS: Genotype-dependent plasma cortisol response to psychosocial stress exposure was observed in healthy controls, with the highest and longest-lasting cortisol increase in subjects with the TT genotype of the FKBP5 polymorphism rs1360780, and healthy controls carrying the T risk allele responded with a blunted FKBP5 mRNA expression after psychosocial stress. No genotype effects could be found in remitted depression. CONCLUSIONS: The FKBP5 rs1360780 polymorphism is associated with plasma cortisol and FKBP5 mRNA expression after psychosocial stress in healthy controls but not in remitted depression. Preliminary results of the DNA methylation analysis suggest that epigenetic modifications could be involved.

Changes in FKBP5 expression and memory functions during cognitive-behavioral therapy in posttraumatic stress disorder: a preliminary study.

Posttraumatic stress disorder (PTSD) is characterized by hyperarousal, flashbacks, avoidance, and memory dysfunctions. Although psychotherapy improves the clinical symptoms, its effect on memory has not been explored. In addition, there is no information about gene expression changes related to hippocampal functions. We assessed PTSD patients (n=20) using the Wechsler Memory Scale-Revised (WAIS-R) and a paired associates learning (PAL) test, as well as changes in blood FK506 binding protein (FKBP5) mRNA expression before and after cognitive behavioral therapy (CBT). Results revealed that before CBT PTSD patients were impaired on WAIS-R delayed recall, attention/concentration, and PAL compared with trauma-exposed control subjects (n=20). These memory dysfunctions showed a significant improvement after CBT. Better performance on the PAL test correlated with enhanced blood FKBP5 mRNA expression. These results suggest that elevated FKBP5 expression during CBT is related to improved associative memory linked to the hippocampal formation.

Pre-existing high glucocorticoid receptor number predicting development of posttraumatic stress symptoms after military deployment.

OBJECTIVE: The development of posttraumatic stress disorder (PTSD) is influenced by preexisting vulnerability factors. The authors aimed at identifying a preexisting biomarker representing a vulnerability factor for the development of PTSD. To that end, they determined whether the dexamethasone binding capacity of leukocytes, as a measure of glucocorticoid receptor (GR) number, before exposure to trauma was a predictor of development of PTSD symptoms. In addition, the authors analyzed mRNA expression for GR subtypes and GR target genes. METHOD: Participants were selected from a large prospective study on deployment-related disorders, in which peripheral blood mononuclear cells (PBMCs) were obtained prior to and 1 and 6 months after military deployment. Participants included armed forces personnel with high levels of PTSD symptoms 6 months after deployment (N=34) and comparison subjects without high levels of PTSD or depressive symptoms (N=34) matched for age, rank, previous deployments, educational level, and function during deployment. RESULTS: Before military deployment, the GR number in PBMCs was significantly higher in participants who developed high levels of PTSD symptoms after deployment relative to matched comparison subjects. Logistic regression analysis showed that the risk for inclusion in the PTSD group after deployment increased 7.5-fold with each GR increase of 1,000. No group differences were observed in mRNA expression of GR-α, GR-P, GR-ß, glucocorticoid-induced leucine zipper (GILZ), serum and glucocorticoid-inducible kinase-1 (SGK-1), and FKBP5. The higher GR number in the PTSD group was maintained at 1 and 6 months after deployment. CONCLUSIONS: These results demonstrate that a preexisting high GR number in PBMCs is a vulnerability factor for subsequent development of PTSD symptoms.

Doping control analysis of emerging drugs in human plasma - identification of GW501516, S-107, JTV-519, and S-40503.

An important aspect of preventive doping research is the rapid implementation of tests for emerging drugs with potential for misuse into routine doping control assays. New therapeutics of different classes such as PPARdelta-agonists (e.g. GW501516), ryanodine-calstabin-complex stabilizers (e.g. S-107 and JTV-519), and selective androgen receptor modulators (SARMs, e.g. S-40503) are currently used for the treatment of particular medical conditions such as metabolic syndrome, cardiac arrhythmia, debilitating diseases and osteoporosis, respectively. Due to their being at an early stage of clinical trials and the limited availability of data on the metabolism and possible renal elimination of the active drugs, the development of protocols for doping control analyses of plasma specimens could be an option for the detection of the circulating agents. The mass spectrometric fragmentation of four emerging drug candidates (GW501516, S-107, JTV-519, and S-40503) was elucidated by positive electrospray ionization and collision-induced dissociation using a high resolution/high accuracy mass spectrometer. A screening and confirmation procedure was established based on liquid chromatography/tandem mass spectrometry requiring a volume of 100 microL of plasma. Proteins were precipitated using acetonitrile, the specimens were centrifuged and the supernatant analyzed using a triple-quadrupole mass spectrometer employing multiple reaction monitoring of diagnostic ion transitions. The method was validated with regard to specificity, limits of detection (0.4-8.3 ng/mL), recoveries (72-98%), intraday and interday precisions (12-21%), and ion suppression/enhancement effects.

Monitoring protein expression by proteomics: human plasma exposed to benzene.

Low levels and long term exposure to benzene is associated with hematotoxicity including aplastic anemia, acute myelogenous leukemia, and lymphoma. Current biomonitoring methods such as urinary phenol, S-phenylmercapturic acid, and trans-trans muconic acid were found to be unreliable as analytical methods to detect benzene exposure. Therefore, to search for a specific protein for biomonitoring benzene exposure, we investigated plasma proteins from workers (n = 50) at a printing company who were exposed to benzene, by two-dimensional gel electrophoresis. The protein profiles are significantly different (p < 0.05) between benzene exposed and unexposed groups, as identified by matrix-assisted laser desorption ionization/time of flight mass spectrometry and confirmed by Western blot analyses. T cell receptor beta chain (TCR beta), FK506-binding protein, and matrix metalloproteinase-13 were expressed only in benzene exposed workers. In addition, interleukin-4 receptor alpha chain and T cell surface glycoprotein CD1b precursor were found to be up-regulated in the plasma of benzene exposed workers. When we treated Jurkat cells with benzene (10 microM-10 mM), TCR beta expression was increased in the membrane more than 6-9-fold compared to untreated cells. In addition, the amount of TCR beta released into the culture media, at benzene concentrations greater than 50 microM, increased up to 10 mM. Therefore, TCR beta levels in plasma could be used as a biomarker and a possible therapeutic target for benzene exposure.