Perioperative Mortality in Nonelderly Adult Patients With Cancer: A Population-based Study Evaluating Health Care Disparities in the United States According to Insurance Status.

OBJECTIVES: The purpose of this study was to evaluate whether insurance status predicts for perioperative mortality (death within 30 d of cancer-directed surgery) for the 20 most common surgically treated cancers. METHODS: The SEER database was examined for the 20 most common surgically resected cancers and included nonelderly adults, aged 18 to 64 years. The database was queried from 2007 to 2011, with a total of 506,722 patients included in the analysis. RESULTS: Insurance status for all patients were the following: non-Medicaid insurance (83%), any Medicaid (10%), uninsured (4%), and unknown (3%). In univariate analyses, predictors for perioperative mortality included insurance status (P<0.001), age (P=0.015), race (P<0.001), marital status (P<0.001), residence (P=0.002), percent of county below the federal poverty level (P<0.001), and median county-level income (P<0.001). Perioperative mortality was also associated with advanced disease (P<0.001). Under multivariate analysis, patients with either Medicaid (Cochran-Mantel-Haenszel odds ratio [CMH OR], 1.21; 95% confidence interval [CI], 1.14-1.29; P<0.001) or uninsured status (CMH OR, 1.56; 95% CI, 1.44-1.70; P<0.001) were more likely to die within 30 days of surgery compared with patients with non-Medicaid insurance. When comparing Medicaid with the uninsured, Medicaid patients had significantly lower rates of perioperative mortality when compared with the uninsured (CMH OR, 0.80; 95% CI, 0.73-0.89, P<0.001). CONCLUSIONS AND RELEVANCE: In the largest reported analysis of perioperative mortality evaluating the 20 most common surgically treated malignancies, patients with Medicaid coverage or without health insurance were more likely to die within 30 days of surgery, with the uninsured having the worst outcomes.

Estimating Survival in Melanoma Patients With Brain Metastases: An Update of the Graded Prognostic Assessment for Melanoma Using Molecular Markers (Melanoma-molGPA).

PURPOSE: To update the Diagnosis-Specific Graded Prognostic Assessment (DS-GPA) for a markedly heterogeneous patient population, patients with melanoma and brain metastases, using a larger, more current cohort, including molecular markers. METHODS: The original Melanoma-GPA is based on data from 483 patients whose conditions were diagnosed between 1985 and 2005. This is a multi-institutional retrospective database analysis of 823 melanoma patients with newly diagnosed brain metastases from January 1, 2006, to December 31, 2015. Multivariable analyses identified significant prognostic factors, which were weighted and included in the updated index (Melanoma-molGPA). Multiple Cox regression was used to select and weight prognostic factors in proportion to their hazard ratios to design the updated Melanoma-molGPA in which scores of 4.0 and 0.0 are associated with the best and worst prognoses, as with all of the diagnosis-specific GPA indices. Log-rank tests were used to compare adjacent classes. RESULTS: There were 5 significant prognostic factors for survival (age, Karnofsky performance status [KPS], extracranial metastases [ECM], number of brain metastases, and BRAF status), whereas only KPS and the number of brain metastases were significant in the original Melanoma-GPA. Median survival improved from 6.7 to 9.8 months between the 2 treatment eras, and the median survival times for patients with Melanoma-molGPA of 0 to 1.0, 1.5 to 2.0, 2.5 to 3.0, and 3.5 to 4.0 were 4.9, 8.3, 15.8, and 34.1 months (P<.0001 between each adjacent group). CONCLUSIONS: Survival and our ability to estimate survival in melanoma patients with brain metastases has improved significantly. The updated Melanoma-molGPA, a user-friendly tool to estimate survival, will facilitate clinical decision making regarding whether and which treatment is appropriate and will also be useful for stratification of future clinical trials. To further simplify use, a free online/smart phone app is available at brainmetgpa.com.

The Prognostic Value of BRAF, C-KIT, and NRAS Mutations in Melanoma Patients With Brain Metastases.

PURPOSE: Brain metastases are a common problem in patients with melanoma, but little is known about the effect of gene mutations on survival in these patients. METHODS AND MATERIALS: We created a retrospective multi-institutional database of 823 patients with melanoma and brain metastases diagnosed between 2006 and 2015. Clinical parameters, gene mutation status (BRAF, C-KIT, NRAS), and treatment were correlated with survival. Treatment patterns and outcomes were compared with a prior era (1985-2005). RESULTS: BRAF status was known in 584 of 823 patients (71%). BRAF, NRAS, and C-KIT mutations were present in 51%, 22%, and 11% of tested patients, respectively. The median time from primary diagnosis to brain metastasis was 32 months, and overall median survival (MS) from the time of initial treatment of brain metastases was 10 months. MS for BRAF-positive and BRAF-negative patients was 13 months and 9 months, respectively (P=.02). There was no significant difference in MS in patients with or without NRAS or C-KIT mutations. The time from primary diagnosis to brain metastasis did not vary by mutation and was not associated with survival after the diagnosis of brain metastases. MS for the 1985 to 2005 and 2006 to 2015 cohorts was 6.7 months and 10.0 months, respectively (P<.01). Reflecting treatment-trend changes, use of whole-brain radiation therapy decreased from 48% to 26% during this period. Among BRAF-positive patients, 71% received targeted BRAF and/or MEK inhibitors and 57% received some combination of targeted therapy, chemotherapy, and/or immunotherapy. CONCLUSIONS: For melanoma patients with brain metastases, BRAF-positive patients survive longer than BRAF-negative patients and overall survival has improved from 1985-2005 to 2006-2015.

Hypofractionated re-irradiation to the brainstem in children with recurrent brain tumors.

To characterize radiation necrosis following hypofractionated brainstem re-irradiation in pediatric patients, we reviewed 23 cases with 28 tumors invading or abutting brainstem and treated with hypofractionated re-irradiation from 2004 to 2014. Re-irradiation delivered total doses of 16-30 Gy in two to five fractions. The most commons regimens used were 24 Gy in three fractions and 25 Gy in five fractions. At median follow-up of 12.8 months, median overall survival was 14.7 months and eight in-field recurrences were detected (median time 10.5 months). Five patients experienced symptomatic brainstem necrosis, and all having received 24 Gy in three fractions. Hypofractionated brainstem re-irradiation may be safer in five fractions.

Estimating Survival in Patients With Lung Cancer and Brain Metastases: An Update of the Graded Prognostic Assessment for Lung Cancer Using Molecular Markers (Lung-molGPA).

IMPORTANCE: Lung cancer is the leading cause of cancer-related mortality in the United States and worldwide. As systemic therapies improve, patients with lung cancer live longer and thus are at increased risk for brain metastases. Understanding how prognosis varies across this heterogeneous patient population is essential to individualize care and design future clinical trials. OBJECTIVE: To update the current Diagnosis-Specific Graded Prognostic Assessment (DS-GPA) for patients with non-small-cell lung cancer (NSCLC) and brain metastases. The DS-GPA is based on data from patients diagnosed between 1985 and 2005, and we set out to update it by incorporating more recently reported gene and molecular alteration data for patients with NSCLC and brain metastases. This new index is called the Lung-molGPA. DESIGN, SETTING, AND PARTICIPANTS: This is a multi-institutional retrospective database analysis of 2186 patients diagnosed between 2006 and 2014 with NSCLC and newly diagnosed brain metastases. The multivariable analyses took place between December 2015 and May 2016, and all prognostic factors were weighted for significance by hazard ratios. Significant factors were included in the updated Lung-molGPA prognostic index. MAIN OUTCOMES AND MEASURES: The main outcome was survival. Multiple Cox regression was used to select and weight prognostic factors in proportion to their hazard ratios. Log rank tests were used to compare adjacent classes and to compare overall survival for adenocarcinoma vs nonadenocarcinoma groups. RESULTS: The original DS-GPA was based on 4 factors found in 1833 patients with NSCLC and brain metastases diagnosed between 1985 and 2005: patient age, Karnofsky Performance Status, extracranial metastases, and number of brain metastases. The patients studied for the creation of the DS-GPA had a median survival of 7 months from the time of initial treatment of brain metastases. To design the updated Lung-molGPA, we analyzed data from 2186 patients from 2006 through 2014 with NSCLC and newly diagnosed brain metastases (1521 adenocarcinoma and 665 nonadenocarcinoma). Significant prognostic factors included the original 4 factors used in the DS-GPA index plus 2 new factors: EGFR and ALK alterations in patients with adenocarcinoma (mutation status was not routinely tested for nonadenocarcinoma). The overall median survival for the cohort in the present study was 12 months, and those with NSCLC-adenocarcinoma and Lung-molGPA scores of 3.5 to 4.0 had a median survival of nearly 4 years. CONCLUSIONS AND RELEVANCE: In recent years, patient survival and physicians' ability to predict survival in NSCLC with brain metastases has improved significantly. The updated Lung-molGPA incorporating gene alteration data into the DS-GPA is a user-friendly tool that may facilitate clinical decision making and appropriate stratification of future clinical trials.

The Effect of Gene Alterations and Tyrosine Kinase Inhibition on Survival and Cause of Death in Patients With Adenocarcinoma of the Lung and Brain Metastases.

PURPOSE: Lung cancer remains the most common cause of both cancer mortality and brain metastases (BM). The purpose of this study was to assess the effect of gene alterations and tyrosine kinase inhibition (TKI) on median survival (MS) and cause of death (CoD) in patients with BM from lung adenocarcinoma (L-adeno). METHODS: A multi-institutional retrospective database of patients with L-adeno and newly diagnosed BM between 2006 and 2014 was created. Demographics, gene alterations, treatment, MS, and CoD were analyzed. The treatment patterns and outcomes were compared with those in prior trials. RESULTS: Of 1521 L-adeno patients, 816 (54%) had known alteration status. The gene alteration rates were 29%, 10%, and 26% for EGFR, ALK, and KRAS, respectively. The time from primary diagnosis to BM for EGFR-/+ was 10/15 months (P=.02) and for ALK-/+ was 10/20 months (P<.01), respectively. The MS for the group overall (n=1521) was 15 months. The MS from first treatment for BM for EGFR and ALK-, EGFR+, ALK+ were 14, 23 (P<.01), and 45 (P<.0001) months, respectively. The MS after BM for EGFR+ patients who did/did not receive TKI before BM was 17/30 months (P<.01), respectively, but the risk of death was not statistically different between TKI-naïve patients who did/did not receive TKI after the diagnosis of BM (EGFR/ALK hazard ratios: 1.06 [P=.84]/1.60 [P=.45], respectively). The CoD was nonneurologic in 82% of patients with known CoD. CONCLUSION: EGFR and ALK gene alterations are associated with delayed onset of BM and longer MS relative to patients without these alterations. The CoD was overwhelmingly nonneurologic in patients with known CoD.

Extended Survival and Prognostic Factors for Patients With ALK-Rearranged Non-Small-Cell Lung Cancer and Brain Metastasis.

PURPOSE: We performed a multi-institutional study to identify prognostic factors and determine outcomes for patients with ALK-rearranged non-small-cell lung cancer (NSCLC) and brain metastasis. PATIENTS AND METHODS: A total of 90 patients with brain metastases from ALK-rearranged NSCLC were identified from six institutions; 84 of 90 patients received radiotherapy to the brain (stereotactic radiosurgery [SRS] or whole-brain radiotherapy [WBRT]), and 86 of 90 received tyrosine kinase inhibitor (TKI) therapy. Estimates for overall (OS) and intracranial progression-free survival were determined and clinical prognostic factors were identified by Cox proportional hazards modeling. RESULTS: Median OS after development of brain metastases was 49.5 months (95% CI, 29.0 months to not reached), and median intracranial progression-free survival was 11.9 months (95% CI, 10.1 to 18.2 months). Forty-five percent of patients with follow-up had progressive brain metastases at death, and repeated interventions for brain metastases were common. Absence of extracranial metastases, Karnofsky performance score ≥ 90, and no history of TKIs before development of brain metastases were associated with improved survival (P = .003, < .001, and < .001, respectively), whereas a single brain metastasis or initial treatment with SRS versus WBRT were not (P = .633 and .666, respectively). Prognostic factors significant by multivariable analysis were used to describe four patient groups with 2-year OS estimates of 33%, 59%, 76%, and 100%, respectively (P < .001). CONCLUSION: Patients with brain metastases from ALK-rearranged NSCLC treated with radiotherapy (SRS and/or WBRT) and TKIs have prolonged survival, suggesting that interventions to control intracranial disease are critical. The refinement of prognosis for this molecular subtype of NSCLC identifies a population of patients likely to benefit from first-line SRS, close CNS observation, and treatment of emergent CNS disease.

Survival Outcomes of Dose-Escalated External Beam Radiotherapy versus Combined Brachytherapy for Intermediate and High Risk Prostate Cancer Using the National Cancer Data Base.

PURPOSE: We evaluated survival outcomes between dose-escalated EBRT (external beam radiotherapy) vs EBRT plus brachytherapy for intermediate and high risk prostate cancer using NCDB (National Cancer Data Base). MATERIALS AND METHODS: Patients with cN0M0 prostate cancer treated from 2004 to 2006 were divided into radiotherapy comparison groups, including EBRT alone (75.6 to 81 Gy) and EBRT (40 to 50.4 Gy) plus brachytherapy with EBRT delivered at 1.8 to 2.0 Gy per fraction. Brachytherapy data were limited to yes/no with no information on modality, dose or schedule. Eligible patients were known to have received androgen deprivation therapy. Overall survival was evaluated using multivariate Cox regression and propensity score matched analyses. RESULTS: Of the 20,279 study patients with prostate cancer, including 12,617 at intermediate risk and 7,662 at high risk, 71.3% received EBRT alone and 28.7% received EBRT plus brachytherapy. Median followup was 82 months (range 3 to 120) and median age was 70 years (range 36 to 90). On multivariate analysis compared to EBRT alone (75.6 to 81 Gy) EBRT plus brachytherapy was associated with improved survival (HR 0.75, p <0.001). This significance remained consistent for intermediate and high risk when analyzed separately (HR 0.73 and 0.76, respectively, each p <0.001). However on subset analysis compared to very high dose EBRT alone (79.2 to 81 Gy) in all patients combined EBRT plus brachytherapy was not associated with improved survival (HR 0.91, p = 0.083). CONCLUSION: Compared to EBRT (75.6 to 81 Gy) we observed an association of EBRT plus brachytherapy with a decreased risk of death in men with intermediate and high risk prostate cancer. However this association was no longer significant when EBRT doses of 79.2 to 81 Gy were used.

Survival Outcomes of Whole-Pelvic Versus Prostate-Only Radiation Therapy for High-Risk Prostate Cancer Patients With Use of the National Cancer Data Base.

PURPOSE/OBJECTIVES: The addition of whole pelvic (WP) compared with prostate-only (PO) radiation therapy (RT) for clinically node-negative prostate cancer remains controversial. The purpose of our study was to evaluate the survival benefit of adding WPRT versus PO-RT for high-risk, node-negative prostate cancer, using the National Cancer Data Base (NCDB). METHODS AND MATERIALS: Patients with high-risk prostate cancer treated from 2004 to 2006, with available data for RT volume, coded as prostate and pelvis (WPRT) or prostate alone (PO-RT) were included. Multivariate analysis (MVA) and propensity-score matched analysis (PSM) were performed. Recursive partitioning analysis (RPA) based on overall survival (OS) using Gleason score (GS), T stage, and pretreatment prostate-specific antigen (PSA) was also conducted. RESULTS: A total of 14,817 patients were included: 7606 (51.3%) received WPRT, and 7211 (48.7%) received PO-RT. The median follow-up time was 81 months (range, 2-122 months). Under MVA, the addition of WPRT for high-risk patients had no OS benefit compared with PO-RT (HR 1.05; P=.100). On subset analysis, patients receiving dose-escalated RT also did not benefit from WPRT (HR 1.01; P=.908). PSM confirmed no survival benefit with the addition of WPRT for high-risk patients (HR 1.05; P=.141). In addition, RPA was unable to demonstrate a survival benefit of WPRT for any subset. Other prognostic factors for inferior OS under MVA included older age (HR 1.25; P<.001), increasing comorbidity scores (HR 1.46; P<.001), higher T stage (HR 1.17; P<.001), PSA (HR 1.81; P<.001), and GS (HR 1.29; P<.001), and decreasing median county household income (HR 1.15; P=.011). Factors improving OS included the addition of androgen deprivation therapy (HR 0.92; P=.033), combination external beam RT plus brachytherapy boost (HR 0.71; P<.001), and treatment at an academic/research institution (HR 0.84; P=.002). CONCLUSION: In the largest reported analysis of WPRT for patients with high-risk prostate cancer treated in the dose-escalated era, the addition of WPRT demonstrated no survival advantage compared with PO-RT.

Radiation Therapy for Oligometastatic Non-Small Cell Lung Cancer: Theory and Practice.

Management paradigms for metastatic non-small cell lung cancer (mNSCLC) are evolving. Locally ablative therapies are now being increasingly integrated into combined-modality treatment strategies for mNSCLC patients with limited burdens of metastatic foci, termed oligometastases. Concurrently, techniques allowing for precise high-dose radiotherapy delivered over 1 to 5 total treatments, termed stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy (SABR), have emerged as a powerful means of noninvasive tumor ablation with broad patient candidacy. Strong rationale exists for ablative therapy in the setting of oligometastatic NSCLC, including patterns-of-failure analyses and data supporting local ablation of oligoprogressive disease for patients with oncogene-addicted mNSCLC treated with tyrosine kinase inhibitors. In this article, we examine the theoretical basis for ablation of oligometastatic NSCLC and review the growing clinical literature of mNSCLC patients treated with ablative radiation therapy.

Stereotactic body radiation therapy (SBRT) for lung cancer patients previously treated with conventional radiotherapy: a review.

Lung cancer continues to be one of the most prevalent malignancies worldwide and is the leading cause of death in both men and women. Presently, local control rates are quite poor. Improvements in imaging and radiation treatment delivery systems however have provided radiation oncologists with new tools to better target these tumors. Stereotactic body radiation therapy (SBRT) is one such technique that has shown efficacy as upfront treatment for lung cancer. In addition, more recent studies have demonstrated some effectiveness in recurrent tumors in prior irradiated fields as well. This review summarizes seven recent studies of re-irradiation with SBRT in patients with thoracic recurrences treated previously with conventionally fractionated radiation therapy. Combined, 140 patients were included. The median initial thoracic radiation doses ranged from 50-87.5 Gy and median re-irradiation dose ranged from 40-80 Gy. Local control rates varied from 65-92%. Re-irradiation was well tolerated with few grade 4 and 5 complications (observed in one study). Currently, based on these published reports, re-irradiation with SBRT appears feasible for in-field thoracic recurrences, though caution must be taken in all cases of retreatment.

The prognostic significance of Gleason scores in metastatic prostate cancer.

PURPOSE: Although the majority of metastatic prostate cancer (mPCa) will arise from tumors with Gleason scores (GS) of 8 to 10 existing tumor grade analyses for mPCa have been almost uniformly limited to comparisons of ≤7 vs. ≥8. In this analysis, we comprehensively evaluate the GS as a prognostic factor for mPCa in the era of the updated Gleason grading system. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was queried for patients with mPCa, GS 6 to 10, diagnosed from 2006 to 2008. GS and primary-secondary Gleason pattern variations were analyzed for overall survival and prostate cancer-specific survival (PCSS). RESULTS: A total of 4,654 patients were evaluable. At 4 years, the overall survival rates were 51%, 45%, 34%, 25%, and 15% and PCSS rates were 69%, 57%, 44%, 33%, and 21% for GS 6, 7, 8, 9, and 10, respectively. Survival differences for GS 7 vs. 8, 8 vs. 9, and 9 vs. 10 were highly significant on both univariate and multivariate analyses accounting for age, prostate-specific antigen level, and T stage (all P<0.001). Gleason pattern 5 was an independent prognostic factor, both overall for patients with GS 6 to 10 and on primary-secondary Gleason pattern comparisons within the GS 8 (4+4 vs. 3+5 and 5+3) and GS 9 (4+5 vs. 5+4) subgroups. No survival differences were observed between 3+4 vs. 4+3. Overall, lower prostate-specific antigen level, younger age, and lower GS were associated with improved survival, with GS being the strongest prognostic factor for PCSS. CONCLUSIONS: In this large population-based cohort, stratified survival outcomes were observed for GS 6 to 10, with sequential comparisons of GS 7 to 10, and the presence and extent of Gleason pattern 5 representing independent prognostic factors in the metastatic setting.

The impact of adjuvant radiation therapy for high-grade gliomas by histology in the United States population.

PURPOSE: To compare the survival impact of adjuvant external beam radiation therapy (RT) for malignant gliomas of glioblastoma (GBM), anaplastic astrocytoma (AA), anaplastic oligodendroglioma (AO), and mixed anaplastic oligoastrocytoma (AOA) histology. METHODS AND MATERIALS: The Surveillance, Epidemiology, and End Results (SEER) database was queried from 1998 to 2007 for patients aged ≥18 years with high-grade gliomas managed with upfront surgical resection, treated with and without adjuvant RT. RESULTS: The primary analysis totaled 14,461 patients, with 12,115 cases of GBM (83.8%), 1312 AA (9.1%), 718 AO (4.9%), and 316 AOA (2.2%). On univariate analyses, adjuvant RT was associated with significantly improved overall survival (OS) for GBMs (2-year OS, 17% vs 7%, p<.001), AAs (5-year OS, 38% vs 24%, p<.001), and AOAs (5-year OS, 55% vs 44%, p=.026). No significant differences in OS were observed for AOs (5-year OS, with RT 50% vs 56% without RT, p=.277). In multivariate Cox proportional hazards models accounting for extent of resection, age, sex, race, year, marital status, and tumor registry, RT was associated with significantly improved OS for both GBMs (HR, 0.52; 95% CI, 0.50-0.55; P<.001) and AAs (HR, 0.57; 95% CI, 0.48-0.68; P<.001) but only a trend toward improved OS for AOAs (HR, 0.70; 95% CI, 0.45-1.09; P=.110). Due to the observation of nonproportional hazards, Cox regressions were not performed for AOs. A significant interaction was observed between the survival impact of RT and histology overall (interaction P<.001) and in a model limited to the anaplastic (WHO grade 3) histologies. (interaction P=.024), characterizing histology as a significant predictive factor for the impact of RT. Subgroup analyses demonstrated greater hazard reductions with RT among patients older than median age for both GBMs and AAs (all interaction P≤.001). No significant interactions were observed between RT and extent of resection. Identical patterns of significance were observed for cause-specific survival and OS across analyses. CONCLUSIONS: In this large population-based cohort, glioma histology represented a significant predictor for the survival impact of RT. Adjuvant RT was associated with improved survival for AAs, with benefits comparable to those observed for GBMs over the same 10-year interval. No survival advantage was observed with adjuvant RT for AOs.

STAT3-dependent IL-21 production from T helper cells regulates hematopoietic progenitor cell homeostasis.

The contribution of specific cell types to the production of cytokines that regulate hematopoiesis is still not well defined. We have previously identified T cell-dependent regulation of hematopoietic progenitor cell (HPC) numbers and cycling. In this report, we demonstrated that HPC activity is decreased in mice with STAT3-deficient T cells, a phenotype that is not because of decreased expression of IL-17 or RORγt. STAT3 expression in T cells was required for IL-21 production by multiple T helper subsets, and neutralization of IL-21 resulted in decreased HPC activity identical to that in mice with STAT3-deficient T cells. Importantly, injection of IL-21 rescued HPC activity in mice with STAT3-deficient T cells. Thus, STAT3-dependent IL-21 production in T cells is required for HPC homeostasis.

Tc17 cells are capable of mediating immunity to vaccinia virus by acquisition of a cytotoxic phenotype.

CD8 T cells can acquire cytokine-secreting phenotypes paralleling cytokine production from Th cells. IL-17-secreting CD8 T cells, termed Tc17 cells, were shown to promote inflammation and mediate immunity to influenza. However, most reports observed a lack of cytotoxic activity by Tc17 cells. In this study, we explored the anti-viral activity of Tc17 cells using a vaccinia virus (VV) infection model. Tc17 cells expanded during VV infection, and TCR transgenic Tc17 cells were capable of clearing recombinant VV infection. In vivo, adoptively transferred Tc17 cells lost the IL-17-secreting phenotype, even in the absence of stimulation, but they did not acquire IFN-gamma-secreting potential unless stimulated with a virus-encoded Ag. However, examination of cells following infection demonstrated that these cells acquired cytotoxic potential in vivo, even in the absence of IFN-gamma. Cytotoxic potential correlated with Fasl expression, and the cytotoxic activity of postinfection Tc17 cells was partially blocked by the addition of anti-FasL. Thus, Tc17 cells mediate VV clearance through expression of specific molecules associated with cytotoxicity but independent of an acquired Tc1 phenotype.

Temporal induction pattern of STAT4 target genes defines potential for Th1 lineage-specific programming.

STAT4 is a critical component in the development of inflammatory adaptive immune responses. It has been extensively characterized as a lineage-determining factor in Th1 development. However, the genetic program activated by STAT4 that results in an inflammatory cell type is not well defined. In this report, we use DNA isolated from STAT4-chromatin immunoprecipitation to perform chromatin immunoprecipitation-on-chip analysis of over 28,000 mouse gene promoters to identify STAT4 targets. We demonstrate that STAT4 binds multiple gene-sets that program distinct components of the Th1 lineage. Although many STAT4 target genes display STAT4-dependent IL-12-inducible expression, other genes displayed IL-12-induced histone modifications but lack induction, possibly due to high relative basal expression. In the subset of genes that STAT4 programs for expression in Th1 cells, IL-12-induced mRNA levels remain increased for a longer time than mRNA from genes that are not programmed. This suggests that STAT4 binding to target genes, while critical, is not the only determinant for STAT4-dependent gene programming during Th1 differentiation.

Signal transducer and activator of transcription 4 is required for the transcription factor T-bet to promote T helper 1 cell-fate determination.

Transcriptional regulatory networks direct the development of specialized cell types. The transcription factors signal tranducer and activator of transcription 4 (Stat4) and T-bet are required for the interleukin-12 (IL-12)-stimulated development of T helper 1 (Th1) cells, although the hierarchy of activity by these factors has not been clearly defined. In this report, we show that these factors did not function in a linear pathway and that each factor played a unique role in programming chromatin architecture for Th1 gene expression, with subsets of genes depending on Stat4, T-bet, or both for expression in Th1 cells. T-bet was not able to transactivate expression of Stat4-dependent genes in the absence of endogenous Stat4 expression. Thus, T-bet requires Stat4 to achieve complete IL-12-dependent Th1 cell-fate determination. These data provide a basis for understanding how transiently activated and lineage-specific transcription factors cooperate in promoting cellular differentiation.

IL-23 promotes maintenance but not commitment to the Th17 lineage.

IL-23 plays a critical role establishing inflammatory immunity and enhancing IL-17 production in vivo. However, an understanding of how it performs those functions has been elusive. In this report, using an IL-17-capture technique, we demonstrate that IL-23 maintains the IL-17-secreting phenotype of purified IL-17(+) cells without affecting cell expansion or survival. IL-23 maintains the Th17 phenotype over multiple rounds of in vitro stimulation most efficiently in conjunction with IL-1beta. However, in contrast to Th1 and Th2 cells, the Th17 phenotype is not stable and when long-term IL-23-stimulated Th17 cultures are exposed to Th1- or Th2-inducing cytokines, the Th17 genetic program is repressed and cells that previously secreted IL-17 assume the cytokine secreting profile of other Th subsets. Thus, while IL-23 can maintain the Th17 phenotype, it does not promote commitment to an IL-17-secreting lineage.

Vaccinia virus blocks Stat1-dependent and Stat1-independent gene expression induced by type I and type II interferons.

Blocking the function of Stat (signal transducer and activator of transcription) proteins, which are critical for antiviral responses, has evolved as a common mechanism for pathogen immune evasion. The poxvirus-encoded phosphatase H1 is critical for viral replication, and may play an additional role in the evasion of host defense by dephosphorylating Stat1 and blocking interferon (IFN)-stimulated innate immune responses. Vaccinia virus (VACV) H1 can inhibit the phosphorylation of the transcription factor Stat1 after IFN-gamma stimulation of epithelial cells, greatly attenuating IFN-induced biological functions. In this study, we demonstrate that VACV infection is capable of inhibiting the phosphorylation of Stat1 and Stat2 after stimulation of fibroblasts or bone marrow-derived macrophages with either type I or type II IFNs, but did not inhibit the activation of Stat3 or Stat5 in either cell type. By using recombinant proteins for in vitro assays, we observe that variola virus H1 is more active than VACV H1, although it has similar selectivity for Stat targets. Differential effects of VACV infection were observed on the induction of IFN-stimulated genes, with complete inhibition of some genes by VACV infection, while others were less affected. Despite the IFN-gamma-induced expression of some genes in VACV-infected cells, IFN-gamma was unable to rescue the VACV-mediated inhibition of MHC class II antigen presentation. Moreover, VACV infection can affect the IFN-induced expression of Stat1-dependent and Stat1-independent genes, suggesting that the virus may target additional IFN-activated pathways. Thus, VACV targets multiple signaling pathways in the evasion of antiviral immune responses.

Thymic selection pathway regulates the effector function of CD4 T cells.

Recently, a new developmental pathway for CD4 T cells that is mediated by major histocompatibility complex class II-positive thymocytes was identified (Choi, E.Y., K.C. Jung, H.J. Park, D.H. Chung, J.S. Song, S.D. Yang, E. Simpson, and S.H. Park. 2005. Immunity. 23:387-396; Li, W., M.G. Kim, T.S. Gourley, B.P. McCarthy, D.B. Sant'angelo, and C.H. Chang. 2005. Immunity. 23:375-386). We demonstrate that thymocyte-selected CD4 (T-CD4) T cells can rapidly produce interferon gamma and interleukin (IL) 4 upon in vivo and in vitro T cell receptor stimulation. These T-CD4 T cells appear to be effector cells producing both T helper type 1 (Th1) and Th2 cytokines, and they maintain a potential to produce Th2 cytokines under Th1-skewing conditions in a signal transducer and activator of transcription 6-independent manner. The IL-4 mRNA level is high in CD4 single-positive thymocytes if they are selected on thymocytes, which is at least partly caused by enhanced histone acetylation of the IL-4 locus. However, mice that can generate T-CD4 T cells showed attenuated immune responses in an allergen-induced airway inflammation model, suggesting a protective role for T-CD4 T cells during an airway challenge. Our results imply that this thymic selection pathway plays an important role in determining the effector function of the resulting CD4 cells and in regulating immune response.