Randomized phase III study of high-dose methotrexate and whole-brain radiotherapy with/without temozolomide for newly diagnosed primary CNS lymphoma: JCOG1114C.

BACKGROUND: The goal was to determine whether the addition of temozolomide (TMZ) to the standard treatment of high-dose methotrexate (HD-MTX) and whole-brain radiotherapy (WBRT) for primary central nervous system lymphoma (PCNSL) improves survival. METHODS: An open-label, randomized, phase III trial was conducted in Japan, enrolling immunocompetent patients aged 20-70 years with histologically confirmed, newly diagnosed PCNSL. After administration of HD-MTX, patients were randomly assigned to receive WBRT (30 Gy) ±â€…10 Gy boost (arm A) or WBRT ±â€…boost with concomitant and maintenance TMZ for 2 years (arm B). The primary endpoint was overall survival (OS). RESULTS: Between September 29, 2014 and October 15, 2018, 134 patients were enrolled, of whom 122 were randomly assigned and analyzed. At the planned interim analysis, 2-year OS was 86.8% (95% confidence interval [CI]: 72.5-94.0%) in arm A and 71.4% (56.0-82.2%) in arm B. The hazard ratio was 2.18 (95% CI: 0.95-4.98), with the predicted probability of showing the superiority of arm B at the final analysis estimated to be 1.3%. The study was terminated early due to futility. O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status was measured in 115 tumors, and it was neither prognostic nor predictive of TMZ response. CONCLUSIONS: This study failed to demonstrate the benefit of concomitant and maintenance TMZ in newly diagnosed PCNSL.

IgG4-related brain pseudotumor mimicking CNS lymphoma. A case report.

Here, we report a case of IgG4-related brain pseudotumor (IgG4-BP) in a 39-year-old woman, mimicking central nervous system (CNS) lymphoma. She presented with headache, fever, and fatigue. Her medical history was notable for appearance of a tumefactive brain lesion seven years before. Brain biopsy performed at the age of 32 revealed nonspecific inflammatory changes, and her condition improved with oral low-dose steroid therapy. Magnetic resonance imaging performed at the age of 39 identified a hyperintensity lesion with edema located at the medial temporal lobe region adjacent to the inferior horn of the left lateral ventricle on fluid-attenuated inversion recovery images, which showed gadolinium-contrast enhancement on T1-weighted images and a slightly hyperintensity signal on diffusion-weighted images. Methionine-positron emission tomography (PET) depicted a high methionine uptake in the lesion. Additionally, soluble levels of interleukin (IL)-2 receptor (sIL-2R) and IL-10 were increased in cerebrospinal fluid (CSF). Based on these findings, we suspected CNS lymphoma and performed partial resection of the brain lesion. Pathological examination revealed prominent lymphocytic infiltration associated with plasma cell infiltration. Most of the plasma cells were immunoreactive for IgG4. Storiform fibrosis and partially obliterative phlebitis were concomitantly observed. Thus, the patient was diagnosed as having IgG4-BP. To the best of our knowledge, this is the first case report of IgG4-BP with detailed findings obtained by CSF testing, methionine-PET, and pathological examination. Because IgG4-related diseases can present as a pseudotumor that mimics CNS lymphoma, it is essential to carefully differentiate IgG4-BP from CNS lymphoma.

Mucosal thickening of the maxillary sinus is frequently associated with diffuse glioma patients and correlates with poor survival prognosis of GBM patients: comparative analysis to meningioma patients.

Glioma patients were frequently associated with mucosal thickening of the maxillary sinus (MTMS), which reflects mucosal inflammation. We suspected that MTMS is associated with impaired mucosal immune response and correlated with dysfunction in the anti-tumor immune response in diffuse glioma patients. Therefore, the aim of this study was to determine whether the occurrence of diffuse glioma is correlated with MTMS compared to meningioma and control groups. Furthermore, we investigated whether MTMS is associated with overall survival (OS) in glioblastoma (GBM) patients. This study included 343 patients with newly diagnosed diffuse gliomas and 218 patients with meningioma treated at our institution between 2015 and 2018. As control, 201 patients with headache who did not have an intracranial organic lesion were included. Using three-axis MR images, we evaluated the incidence of MTMS in all patients. Additionally, we investigated the relationship between MTMS and OS. The incidence of MTMS in patients with diffuse glioma was significantly higher than that in the meningioma (p < .0001) and control groups (p < .0001). In 128 patients with GBM, MTMS status correlated significantly with OS (p = .0064). We revealed that the incidence of MTMS is significantly associated with patients with diffuse glioma. This suggests that MTMS is indirectly involved in the occurrence of diffuse gliomas. Furthermore, the presence of MTMS correlated significantly with shorter OS in GBM patients, indicating that MTMS is involved in suppression of anti-tumor immune response. Preoperative recognition of MTMS might be useful for improving the clinical management of GBM patients.

Pulvinar Locus is Highly Relevant to Patients' Outcomes in Surgically Resected Thalamic Gliomas in Children.

OBJECTIVE: Thalamic gliomas in children are less suitable for surgical resection because of their location. In cases of unavoidable resection, careful surgical planning in addition to histology and extent of resection affects prognosis. METHODS: A cohort of 10 pediatric patients with thalamic glioma underwent surgical resection at our department. The predominant location of tumor origins in the thalamus was defined in imaging studies. Histopathology was determined (retrospectively in a subset) according to the World Health Organization classification 2016, including the newly established type of "diffuse midline glioma, H3 K27M-mutant." RESULTS: Three low-grade gliomas (grade I/II) and 7 high-grade gliomas (grade III/IV) were identified. The mean follow-up period was 49.8 months. All 3 low-grade gliomas did not recur (progression-free survival, 58.3 months). Six of 7 high-grade gliomas recurred, and the patients died of the primary disease (overall survival, 28.1 months). Poor outcomes, especially when located at the pulvinar region, were noticeable, with strong predictive power for poor prognosis (P = 0.0018). The presence of H3 K27M mutation and pulvinar location were closely associated (P = 0.0036). Four of 5 patients with pulvinar region tumors developed dissemination and died of the primary disease. CONCLUSIONS: Pulvinar location is specifically associated with a high rate of malignancy in histology, the presence of H3 K27M mutation, and dissemination at an early disease stage. This association suggests that a distinct biological profile affects prognosis depending on location within the thalamus, especially the pulvinar. We report that tumor location is highly relevant to prognosis and should be taken into consideration when planning treatment.

Proton magnetic resonance spectroscopy differentiates tumefactive demyelinating lesions from gliomas.

BACKGROUND: It is often difficult to accurately differentiate tumefactive demyelinating lesions (TDLs) from gliomas using MRI. OBJECTIVE: To investigate the utility of proton magnetic resonance spectroscopy (MRS) in differentiating TDLs from gliomas. METHODS: Cohort 1 included 6 patients with TDLs and 5 with gliomas (3 high-grade), as assessed using a 1.5T MR unit. Cohort 2 included 6 patients with TDLs and 17 patients with gliomas (8 high-grade), as assessed using a 3.0T MR unit. Single-voxel proton MRS was performed to compare the following metabolite area ratios: choline (Cho)/creatine (Cr), N-acetylaspartate (NAA)/Cr, and Cho/NAA in both cohorts. Correlations between the target-to-normal-tissue ratio (TNR) obtained using methionine-positron emission tomography (MET-PET) and each MRS metabolite ratio were examined in a subset of cohort 2 (4 patients with TDLs and 11 with gliomas). RESULTS: Mean Cho/NAA ratio was significantly higher in gliomas than in TDLs or MS in cohort 1 (p < 0.05). Mean Cho/NAA ratio was significantly higher in high-grade gliomas than in TDLs in both cohorts (ps < 0.05). In the receiver operating characteristic analysis, high-grade glioma rather than TDL was indicated when the Cho/NAA ratio was >1.72 (the area under the curve was 0.958, and the maximum sensitivity and specificity were 100% and 87%, respectively). A significant positive correlation was observed between Cho/NAA ratio and the MET-PET TNR (r2 = 0.35, p < 0.05). CONCLUSION: MRS effectively differentiates TDLs from high-grade gliomas. Therefore, the clinical use of MRS is likely to enhance patient outcomes.

Imaging of Intracranial Gliomas.

Combined use of contemporary radiological modalities, particularly integration of structural, metabolic, and functional imaging, provides optimal multifaceted information for detailed characterization of intracranial gliomas. It allows differentiation of the tumor from non-neoplastic pathology, its non-invasive histopathological typing and grading, prediction of patient prognosis and clinical course of the disease, detailed planning of surgical resection or biopsy, critical postoperative assessment of the residual lesion, effective surveillance during follow-up with evaluation of effectiveness of the adjuvant therapy and timely identification of recurrence, and even insights into molecular signatures of the neoplasms. Therefore, advanced neuroimaging is one of the most important cornerstones of the modern neuro-oncology.

Carnosine activates the CREB pathway in Caco-2 cells.

Imidazole dipeptide, carnosine, is a versatile compound composed of ß-Ala and L-His. A recent study showed that carnosine might benefit the treatment of Alzheimer's disease and the maintenance of cognitive function. Based on the observation that carnosine is immediately degraded by serum carnosinase, we hypothesized that carnosine improves brain function by promoting brain-gut interaction. This study sought to present possible mechanisms regulating carnosine-induced activation of brain-gut interaction. We had previously found that carnosine augmented the expression of BDNF in human colorectal cancer cells, thus we became interested in cAMP-responsive element binding protein (CREB), which is a dominant regulator of BDNF transcription. We found that carnosine activates CREB and CREB-related pathways by activating Ca2+-related pathways. Our findings suggest that carnosine augments the expression of CREB-regulated genes in the intestine; this augmentation contributes to the carnosine-induced activation of brain-gut interaction.

Roles of the Wada Test and Functional Magnetic Resonance Imaging in Identifying the Language-dominant Hemisphere among Patients with Gliomas Located near Speech Areas.

This study examined the accuracy of functional magnetic resonance imaging (fMRI) in identifying the language-dominant hemisphere and the situations in which the Wada test can be skipped among patients with gliomas located near speech areas. We examined 74 patients [48 men (64.9%); mean ± standard deviation age of 42.7 ± 13.6 years (range: 13 to 70 years); 71 right-handed, 2 left-handed, and 1 ambidextrous] with gliomas located near speech areas. All patients underwent the Wada test and fMRI, and 34 patients underwent awake surgery. The "last-and-first" task was administered during fMRI. The Wada test was successful in determining the language-dominant hemisphere in 73 patients (98.6%): left hemisphere in 68 patients (91.9%), right hemisphere in 4 patients (5.4%), and bilateral in 1 patient (1.4%). The dominant hemisphere for right-handed patients (n = 71) was the left hemisphere in 67 patients (94.3%), right hemisphere in 3 patients (4.2%), and undetectable in 1 patient (1.4%). The fMRI was successful in determining the language-dominant hemisphere in 53 patients (71.6%). The results of the Wada test and fMRI were inconsistent in 5 patients (8.6%), of which 3 (5.2%) exhibited dominance in opposite hemispheres. Furthermore, 2 of these 3 cases (2.7%) were contralateral false positive cases, whereby fMRI identified the right-hemisphere as language dominant for right-handed individuals with tumors in the left hemisphere. Based on these findings, we concluded that the Wada test can be skipped if language dominancy can be detected by fMRI.

The role of 4D CT angiography for preoperative screening in patients with intracranial tumors.

INTRODUCTION: Four-dimensional computed tomography angiography (4D CTA) is now becoming an often used diagnostic imaging modality for the assessment of patients with intracranial tumors. The purpose of this study was to demonstrate the utility of 4D CTA for preoperative screening in patients with intracranial tumors as well as to examine the correlation between perfusion data and grading of gliomas. METHODS: We performed preoperative screening using 320-row detector CT scanner in 186 patients with intracranial tumors, and 115 patients were finally included in the study. Time-resolved subtracted maximum intensity projection images and volume-rendered images were reconstructed to evaluate vascular structures, tumor staining and incidental lesions. We also evaluated the perfusion functional map for gliomas to find correlations between their vascularity and tumor grading. RESULTS: We evaluated gliomas in 70 patients, meningiomas in 29, and other tumors in 16. Patients with gliomas of a pathologically higher grade showed high cerebral blood volume (p < 0.05). Tumor staining was observed on MIP images for 12 meningiomas, 4 gliomas, and 3 other tumors. Fifty patients showed a mass effect on vascular structures, seven had cerebral venous sinus obstruction, and two had aneurysms. No iatrogenic accidents with the CT procedure were reported. CONCLUSIONS: The 4D CTA technique is effective and safe for depicting vascular structures such as arteries, veins, tumor-related vessels, and direct and indirect anatomical complications such as vascular obstruction or vascular compression. This information is useful for preoperative screening. Although 4D CTA also provides perfusion data correlating with the tumor vascularity and grading of gliomas, its clinical value remains limited.

Comparison between Ki67 labeling index determined using image analysis software with virtual slide system and that determined visually in breast cancer.

BACKGROUND: In recent papers, Ki67 labeling index (LI) has been used to classify breast cancer patients into the low and high Ki67LI groups for comparison studies, which showed significant differences in many prognostic factors. It has not been clarified whether image analysis software can be used for calculating LI in breast cancer. In our study, we examined whether Ki67LI in breast cancer calculated using image analysis software correlates with that measured on the basis of visual. METHODS: Fifty patients were randomly selected among breast cancer patients who underwent surgical operation from March, 2010 to May, 2010 in our hospital without preoperative chemotherapy. In this study, for the virtual slide system (VSS: VS120-L100, Olympus, Tokyo, Japan), the high-resolution VSs of all the 50 patients were prepared as samples. The image analysis software use for calculating LI was Tissuemorph Digital Pathology (Tissuemorph DP: Visiopharm, Hoersholm, Denmark). The calculated LI was extracted from 3 to 5 views containing hot spots. The LI calculated using Tissuemorph DP was designed as LI/image/T. The digital image of 3 to 5 LI/image/T views was printed out, and on the digital photograph, we counted visually the number of Ki67-immunopositive cells in exactly the same area, and the percentage of Ki67-immunopositive cells was designed as LI/direct. Moreover, a pathologist's assistant (PA) determined the tumor area in the same specimen using VSS and calculated LI using Tissuemorph DP, which was designed as LI/image/PA. The chief pathologist (CP) similarly calculated LI which was designed as LI/image/CP. We evaluated the degree of agreement between different data sets "LI/image/T and LI/direct" and "LI/image/T, LI/image/CP, and LI/image/PA" by using interclass correlation coefficient (ICC). RESULTS: The average counts of cells were as follows: LI/direct, 3209.7 ± 1970.4 (SD); LI/image/T, 2601.6 ± 1697.1; LI/image/PA, 2886.5 ± 2027.5; LI/image/CP, 18805.5 ± 22293.4. The values of LI/direct and LI/image/T showed almost perfect agreement as showed by an ICC of 0.885 (95 % CI, 0.806-0.933; p < 0.001). The agreement among three investigators was almost perfect. The obtained ICC was 0.825 (95 % CI, 0.739-0.890; p < 0.001) among the data of LI/image/T, LI/image/CP and LI/image/PA. There were five cases that immunopositivity for Ki67 showed a more than 10 % disagreement between LI/direct and LI/image/T. CONCLUSION: The merits of calculating Ki67 LI using Tissuemorph DP are as follows. First, the staining intensity of the cells to be counted can be adjusted. Second, the portion of a tumor including "hot spots" for counting can be chosen. Third, many cancer cells can be counted more rapidly using Tissuemorph DP than by visual observation. However, it is important that pathologist should check and carry out the final decision of the data, when Ki67 LI using Tissuemorph DP is calculated.

Brain natriuretic peptide in acute ischemic stroke.

Elevated serum brain natriuretic peptide (BNP) levels are associated with cardioembolic stroke mainly because of atrial fibrillation (AF). However, the mechanisms of increased serum BNP levels are hitherto unclear. We aimed to identify the factors associated with increased BNP levels in patients with acute ischemic stroke. We measured serum BNP levels in consecutive patients aged 18 years or older. Stroke subtypes were classified using the Trial of ORG 10172 in Acute Stroke Treatment criteria. Categorical variables included age, sex, smoking status, alcohol consumption status, hypertension, diabetes mellitus, dyslipidemia, coronary artery disease (CAD), AF, antiplatelet therapy, and anticoagulant therapy. Continuous variables included hemoglobin, creatinine (Cr), ß-thromboglobulin, platelet factor 4, thrombin-antithrombin complex, and d-dimer levels. We further determined the relationship between serum BNP and intima-media thickness, left ventricular ejection fraction, size of infarction, National Institutes of Health Stroke Scale score on admission, and modified Rankin Scale (mRS) score at discharge. Of the 231 patients (mean age, 71 ± 12 years) with acute ischemic stroke (AIS), 36% were women. Serum BNP levels significantly correlated with CAD, AF, Cr, mRS, and cardioembolism (CE) (Dunnett method, P = .004). BNP levels were significantly higher in patients with larger infarcts, higher mRS scores, and higher CHADS2 scores. The levels were higher in patients with larger infarcts, higher mRS scores at discharge, and higher CHADS2 scores among AF patients.

Selection of the antifungal agent decides prognosis of invasive aspergillosis: case report of a successful outcome with voriconazole.

Invasive aspergillosis is a rare disease and is often misdiagnosed. The clinical course is quite aggressive and it is a potentially fatal disease. We report a case of invasive aspergillosis involving the dura mater and optic nerves which was successfully treated with voriconazole, even though the patient had residual monocular blindness. An 86-year-old Japanese man complained of developing loss of vision in his left eye while taking oral fluconazole prescribed by an otolaryngologist for mycosis of the left maxillary sinus. He was referred to our hospital. At the first visit, he already had no light perception in the left eye, with decreased ocular motility in all directions and orbital apex syndrome. His corrected distance visual acuity (CDVA) in the right eye was 20/25 with enlargement of Mariotte's blind spot. Magnetic resonance imaging revealed inflammation around both optic nerves that also involved the dura mater. His antifungal therapy was changed to intravenous voriconazole. Although his right CDVA temporarily declined to 20/50, it improved to 20/16 by 10 months after the initiation of treatment. Maxillary sinus biopsy detected Aspergillus. Invasive aspergillosis progresses rapidly and aggressively. The present case highlights the importance of early diagnosis and selection of an appropriate antifungal agent.

Optimal visualization of multiple brain metastases for gamma knife radiosurgery.

BACKGROUND: Optimal management of metastatic brain disease requires precise detection and detailed characterization of all intracranial lesions. METHODS: We analyzed an experience with 3200 brain MRI investigations performed at 1.5 T and 3.0 T for identification and/or evaluation of intracranial metastases. Usually axial T1- and T2-weighted images and contrast-enhanced T1-weighted images in axial and coronal and/or sagittal projections were obtained. Fluid-attenuated inversion recovery and diffusion-weighted imaging were sometimes used as well. Routinely, 0.2 mmol/kg of gadoteridol (ProHance®) was administered intravenously, but the dose was reduced to 0.1 mmol/kg in elderly patients or in patients with mild renal dysfunction. FINDINGS: Magnetic resonance imaging (MRI) provided excellent information on tumor location; interrelations with functionally important intracranial structures; type of growth; vascularity; recent, old or multiple hemorrhages within or in the vicinity of the mass; presence of peritumoral edema; necrotic changes; subarachnoid dissemination; meningeal carcinomatosis. However, without administration of gadoteridol or without contrast enhancement, small metastatic tumors could not be reliably distinguished from brain lacunes. Some metastases (malignant melanoma, thyroid cancer, endocrine carcinoma, small cell lung carcinoma) may demonstrate specific neuroimaging features. Non-metastatic -multiple brain lesions caused by vascular, inflammatory, demyelinative or lymphoproliferative diseases require a thorough differential diagnosis with metastatic brain tumors based not only on neuroimaging but on additional analysis of various clinical data. CONCLUSION: Contemporary MRI techniques provide excellent options for detection, detailed characterization, and differential diagnosis of metastatic brain tumors, which is extremely important when choosing the optimal treatment strategy, particularly with Gamma Knife radiosurgery.

Differentiation of tumor progression and radiation-induced effects after intracranial radiosurgery.

A number of intracranial tumors demonstrate some degree of enlargement after stereotactic radiosurgery (SRS). It necessitates differentiation of their regrowth and various treatment-induced effects. Introduction of low-dose standards for SRS of benign neoplasms significantly decreased the risk of the radiation-induced necrosis after -management of schwannomas and meningiomas. Although in such cases a transient increase of the mass volume within several months after irradiation is rather common, it usually followed by spontaneous shrinkage. Nevertheless, distinguishing tumor recurrence from radiation injury is often required in cases of malignant parenchymal brain neoplasms, such as metastases and gliomas. The diagnosis is frequently complicated by histopathological heterogeneity of the lesion with coexistent viable tumor and treatment-related changes. Several neuroimaging modalities, namely structural magnetic resonance imaging (MRI), diffusion-weighted imaging, diffusion tensor imaging, perfusion computed tomography (CT) and MRI, single-voxel and multivoxel proton magnetic resonance spectroscopy as well as single photon emission CT and positron emission tomography with various radioisotope tracers, may provide valuable diagnostic information. Each of these methods has advantages and limitations that may influence its usefulness and accuracy. Therefore, use of a multimodal radiological approach seems reasonable. Addition of functional and metabolic neuroimaging to regular structural MRI investigations during follow-up after SRS of parenchymal brain neoplasms may permit detailed evaluation of the treatment effects and early prediction of the response. If tissue sampling of irradiated intracranial lesions is required, it is preferably performed with the use of metabolic guidance. In conclusion, differentiation of tumor progression and radiation-induced effects after intracranial SRS is challenging. It should be based on a complex evaluation of the multiple clinical, radiosurgical, and radiological factors.

Gamma knife surgery for choroidal neovascularization in age-related macular degeneration. Technical note.

The authors conducted a study to determine a way of overcoming the poor-quality demonstration of choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD) on conventional magnetic resonance (MR) imaging studies. The poor MR imaging demonstration of CNV in patients with AMD makes the use of gamma knife surgery more difficult. This difficulty, however, can be overcome by use of a modified time-of-flight MR imaging,sequence with Gd enhancement and coronal reconstruction.

Pseudoaneurysm of the inferior epigastric artery successfully treated by ultrasound-guided compression.

An 82-year-old woman underwent right hemicolectomy by median laparotomy. Two weeks later, a pulsatile mass was found at the left side of the surgical wound, which was diagnosed as pseudoaneurysm of the inferior epigastric artery by color Doppler US and CT. The pseudoaneurysm was successfully treated by US-guided compression of the neck of the aneurysm for 30 minutes. US-guided compression should be considered the treatment of choice for postsurgical pseudoaneurysm of the inferior epigastric artery.

Early metabolic changes in metastatic brain tumors after Gamma Knife radiosurgery: 1H-MRS study.

Evaluation of early metabolic changes in metastatic brain tumors after Gamma Knife radiosurgery was performed by long-echo (TR, 2000ms; TE, 136ms; 128-236 acquisitions) volume-selected single-voxel proton magnetic resonance spectroscopy (MRS). Eighty-five brain metastases in 81 patients were investigated before treatment and 16-18h thereafter. Standard metabolic ratios, namely N-acetylaspartate (NAA)/creatine (Cr), phosphorylcholine/glycerophosphorylcholine (Cho)/Cr, NAA/Cho, lactate (Lac)/Cr, and mobile lipids (Lip)/Cr, were calculated, and comparison of their values before and after irradiation was done. No volumetric changes of any neoplasm were found in any case on the next day after treatment. At the same time, significant reduction of Cho/Cr (P < 0.001) and NAA/Cr (P < 0.01) ratios on the proton MRS of the tumor was disclosed. Reduction of Cho/Cr ratio was significantly more prominent in neoplasms with higher pretreatment Cho/Cr ratios (P < 0.001) and heterogeneous contrast enhancement (P < 0.01). Reduction of NAA/Cr ratio was predominantly determined by its pretreatment value (P < 0.001). The observed decrease of Cho/Cr ratio probably reflects inhibition of proliferative activity and early apoptotic cell loss, whereas reduction of NAA/Cr may result from radiation-induced modulation of neuronal activity in the peritumoral brain tissue. Serial proton MRS represents a valuable diagnostic tool for evaluation of metabolic changes in intracranial neoplasms after radiosurgical treatment.

Flare-up reaction on murine contact hypersensitivity. III. Effect of staphylococcal enterotoxin B.

Staphylococcal enterotoxin B (SEB), a bacterial superantigen, is known as an immunomodulator because it activates an extremely large number of T-cells, and induces the production of large amounts of cytokines. In this study, we examined the effects of SEB on the contact hypersensitivity reaction (CHR). BALB/c mice were first sensitized through haptens applied to the back, and CHR was then induced through challenge to the left ear using the same haptens. SEB was administered intravenously 4 weeks later, causing a flare-up, peaking at 24 h post-administration, in the left ear that had previously exhibited CHR. This flare-up reaction was hapten non-specific, and was inhibited by anti-mouse tumor necrosis factor (TNF)-alpha antibodies. The flare-up was also suppressed by the oral administration of cyclosporin A prior to the administration of SEB. These results suggest that SEB induces a flare-up of CHR via the production of TNF-alpha.