Dual inhibition of airway inflammation and fibrosis by common ß cytokine receptor blockade.

BACKGROUND: Patients with severe asthma can present with eosinophilic type 2 (T2), neutrophilic, or mixed inflammation that drives airway remodeling and exacerbations and represents a major treatment challenge. The common ß (ßc) receptor signals for 3 cytokines, GM-CSF, IL-5, and IL-3, which collectively mediate T2 and neutrophilic inflammation. OBJECTIVE: To determine the pathogenesis of ßc receptor-mediated inflammation and remodeling in severe asthma and to investigate ßc antagonism as a therapeutic strategy for mixed granulocytic airway disease. METHODS: ßc gene expression was analyzed in bronchial biopsy specimens from patients with mild-to-moderate and severe asthma. House dust mite extract and Aspergillus fumigatus extract (ASP) models were used to establish asthma-like pathology and airway remodeling in human ßc transgenic mice. Lung tissue gene expression was analyzed by RNA sequencing. The mAb CSL311 targeting the shared cytokine binding site of ßc was used to block ßc signaling. RESULTS: ßc gene expression was increased in patients with severe asthma. CSL311 potently reduced lung neutrophils, eosinophils, and interstitial macrophages and improved airway pathology and lung function in the acute steroid-resistant house dust mite extract model. Chronic intranasal ASP exposure induced airway inflammation and fibrosis and impaired lung function that was inhibited by CSL311. CSL311 normalized the ASP-induced fibrosis-associated extracellular matrix gene expression network and strongly reduced signatures of cellular inflammation in the lung. CONCLUSIONS: ßc cytokines drive steroid-resistant mixed myeloid cell airway inflammation and fibrosis. The anti-ßc antibody CSL311 effectively inhibits mixed T2/neutrophilic inflammation and severe asthma-like pathology and reverses fibrosis gene signatures induced by exposure to commonly encountered environmental allergens.

IgE receptor of mast cells signals mediator release and inflammation via adaptor protein 14-3-3ζ.

BACKGROUND: Mast cells (MCs) are tissue-resident immune cells that mediate IgE-dependent allergic responses. Downstream of FcεRI, an intricate network of receptor-specific signaling pathways and adaptor proteins govern MC function. The 14-3-3 family of serine-threonine phosphorylation-dependent adapter proteins are known to organize intracellular signaling. However, the role of 14-3-3 in IgE-dependent activation remains poorly defined. OBJECTIVE: We sought to determine whether 14-3-3 proteins are required for IgE-dependent MC activation and whether 14-3-3 is a viable target for the treatment of MC-mediated inflammatory diseases. METHODS: Genetic manipulation of 14-3-3ζ expression in human and mouse MCs was performed and IgE-dependent mediator release assessed. Pharmacologic inhibitors of 14-3-3 and 14-3-3ζ knockout mice were used to assess 14-3-3ζ function in a MC-dependent in vivo passive cutaneous anaphylaxis (PCA) model of allergic inflammation. Expression and function of 14-3-3ζ were assessed in human nasal polyp tissue MCs. RESULTS: IgE-dependent mediator release from human MCs was decreased by 14-3-3ζ knockdown and increased by 14-3-3ζ overexpression. Deletion of the 14-3-3ζ gene decreased IgE-dependent activation of mouse MCs in vitro and PCA responses in vivo. Furthermore, the 14-3-3 inhibitor, RB-11, which impairs dimerization of 14-3-3, inhibited cultured MC and polyp tissue MC activation and signaling downstream of the FcεRI receptor and dose-dependently attenuated PCA responses. CONCLUSION: IgE/FcεRI-mediated MC activation is positively regulated by 14-3-3ζ. We identify a critical role for this p-Ser/Thr-binding protein in the regulation of MC FcεRI signaling and IgE-dependent immune responses and show that this pathway may be amenable to pharmacologic targeting.

Translating the biology of ß common receptor-engaging cytokines into clinical medicine.

The family of cytokines that comprises IL-3, IL-5, and GM-CSF was discovered over 30 years ago, and their biological activities and resulting impact in clinical medicine has continued to expand ever since. Originally identified as bone marrow growth factors capable of acting on hemopoietic progenitor cells to induce their proliferation and differentiation into mature blood cells, these cytokines are also recognized as key mediators of inflammation and the pathobiology of diverse immunologic diseases. This increased understanding of the functional repertoire of IL-3, IL-5, and GM-CSF has led to an explosion of interest in modulating their functions for clinical management. Key to the successful clinical translation of this knowledge is the recognition that these cytokines act by engaging distinct dimeric receptors and that they share a common signaling subunit called ß-common or ßc. The structural determination of how IL-3, IL-5, and GM-CSF interact with their receptors and linking this to their differential biological functions on effector cells has unveiled new paradigms of cell signaling. This knowledge has paved the way for novel mAbs and other molecules as selective or pan inhibitors for use in different clinical settings.

Targeting the Human ßc Receptor Inhibits Contact Dermatitis in a Transgenic Mouse Model.

Allergic contact dermatitis (ACD) is a prevalent and poorly controlled inflammatory disease caused by skin infiltration of T cells and granulocytes. The beta common (ßc) cytokines GM-CSF, IL-3, and IL-5 are powerful regulators of granulocyte function that signal through their common receptor subunit ßc, a property that has made ßc an attractive target to simultaneously inhibit these cytokines. However, the species specificity of ßc has precluded testing of inhibitors of human ßc in mouse models. To overcome this problem, we developed a human ßc receptor transgenic mouse strain with a hematopoietic cell‒specific expression of human ßc instead of mouse ßc. Human ßc receptor transgenic cells responded to mouse GM-CSF and IL-5 but not to IL-3 in vitro and developed tissue pathology and cellular inflammation comparable with those in wild-type mice in a model of ACD. Similarly, Il3-/- mice developed ACD pathology comparable with that of wild-type mice. Importantly, the blocking anti-human ßc antibody CSL311 strongly suppressed ear pinna thickening and histopathological changes typical of ACD and reduced accumulation of neutrophils, mast cells, and eosinophils in the skin. These results show that GM-CSF and IL-5 but not IL-3 are major mediators of ACD and define the human ßc receptor transgenic mouse as a unique platform to test the inhibitors of ßc in vivo.

Understanding mast cell heterogeneity at single cell resolution.

Mast cells (MC)s are evolutionarily conserved, tissue-resident immune cells with diverse roles in allergy, cancer, and protection from infection by helminths and microorganisms. The significant diversity in MC development and tissue-specific functional characteristics has recently begun to be understood. Exciting developments in single-cell-based RNA, protein, and chromatin profiling technologies offer new opportunities to characterize MC heterogeneity and to uncover novel MC functions and subtypes; these developments might lead to new and clinically effective therapies for certain pathologies. In this review, we provide an overview of the current understanding of MC development and heterogeneity and discuss new insights gained from single-cell-based studies that may lead to future research directions and therapeutic opportunities.

AIM2 nuclear exit and inflammasome activation in chronic obstructive pulmonary disease and response to cigarette smoke.

INTRODUCTION: The role inflammasomes play in chronic obstructive pulmonary disease (COPD) is unclear. We hypothesised that the AIM2 inflammasome is activated in the airways of COPD patients, and in response to cigarette smoke. METHODS: Lung tissue, bronchoscopy-derived alveolar macrophages and bronchial epithelial cells from COPD patients and healthy donors; lungs from cigarette smoke-exposed mice; and cigarette smoke extract-stimulated alveolar macrophages from healthy controls and HBEC30KT cell line were investigated. AIM2 inflammasome activation was assessed by multi-fluorescence quantitative confocal microscopy of speck foci positive for AIM2, inflammasome component ASC and cleaved IL-1ß. Subcellular AIM2 localization was assessed by confocal microscopy, and immunoblot of fractionated cell lysates. Nuclear localization was supported by in-silico analysis of nuclear localization predicted scores of peptide sequences. Nuclear and cytoplasmic AIM2 was demonstrated by immunoblot in both cellular fractions from HBEC30KT cells. RESULTS: Increased cytoplasmic AIM2 speck foci, colocalized with cleaved IL-1ß, were demonstrated in COPD lungs (n = 9) vs. control (n = 5), showing significant positive correlations with GOLD stages. AIM2 nuclear-to-cytoplasmic redistribution was demonstrated in bronchiolar epithelium in cigarette-exposed mice and in HBEC30KT cells post 24 h stimulation with 5% cigarette smoke extract. Alveolar macrophages from 8 healthy non-smokers responded to cigarette smoke extract with an > 8-fold increase (p < 0.05) of cytoplasmic AIM2 and > 6-fold increase (p < 0.01) of colocalized cleaved IL-1ß speck foci, which were also localized with ASC. CONCLUSION: The AIM2 inflammasome is activated in the airway of COPD patients, and in response to cigarette smoke exposure, associated with a nuclear to cytoplasmic shift in the distribution of AIM2.

Short-term Oral Steroids Significantly Improves Chronic Rhinosinusitis Without Nasal Polyps.

OBJECTIVES/HYPOTHESIS: The efficacy of short-term oral corticosteroids in chronic rhinosinusitis without nasal polyps (CRSsNP) is unknown. The aim of this controlled study was to assess the immediate and long-term outcomes from a short course of a commonly used oral corticosteroid, prednisolone, in well-defined CRSsNP patients. STUDY DESIGN: Prospective, observational controlled study. METHODS: A prospective-controlled study of CRSsNP patients treated with prednisolone at 0.5 mg/kg tapered over 10 days and non-prednisolone treated CRSsNP patients (controls) and follow-up at 2, 6, and 12 months. Baseline and follow-up SinoNasal Outcome Test (SNOT)-22, nasal endoscopy (Lund-Kennedy), and sinus CT scan scores (Lund-Mackay) were compared. RESULTS: At 2 months, there was a significant improvement in the SNOT-22, nasal endoscopy, and sinus CT scan scores in the prednisolone group (P < .0001) compared with controls (p = ns, Mann-Whitney U test). 52.5% of prednisolone-treated CRSsNP patients had improved symptoms and did not require sinus surgery at 12 months compared with 14.3% of controls (P < .001). Side-effects were reported in 8.9% of prednisolone-treated patients. Patients who benefited from prednisolone had a median symptom duration of 7.25 (99% confidence, upper limit of 11) months compared with 18 months in those requiring surgery. CONCLUSIONS: Short-term oral prednisolone significantly improved all three clinical measures of disease in CRSsNP patients and avoided surgical intervention in 52.5% patients in the first 12 months. Patients with symptoms for less than 11 months were most likely to benefit. The side-effects of oral steroids require careful consideration and further studies are needed to ascertain appropriate dosage and treatment duration. LEVEL OF EVIDENCE: 3 Laryngoscope, 131:E2618-E2626, 2021.

Hemostasis in Endoscopic Sinus Surgery.

Intraoperative bleeding during endoscopic sinus surgery poses an additional dimension to an already technically challenging surgical approach because of the narrow sinonasal surgical field, single working hand, and the use of endoscopic instruments. Poor visualization is one of the most important factors that increase the risk of intraoperative complications such as inadvertent injury to major vessels and nerves, and incomplete surgery. This article provide a logical approach to improving the surgical field, minimizing risk of inadvertent vascular injury, and managing intraoperative bleeding.

Endoscopic Management of Vascular Sinonasal Tumors, Including Angiofibroma.

The greatest challenge in the surgical treatment of angiofibromas is dealing with the hypervascularity of these tumors. Staging systems that take into account the vascularity of the tumor may be more prognostic. A variety of treatment strategies are used to deal with the vascularity of angiofibromas, including preoperative embolization, segmentation of the tumor into vascular territories, use of hemostatic tools, and staging of surgery. Even large angiofibromas with intracranial extension and residual vascularity can be successfully managed by a skull base team using endoscopic techniques.

CD4(+) and CD8(+) regulatory T cells in chronic rhinosinusitis mucosa.

BACKGROUND: Chronic rhinosinusitis (CRS) mucosal inflammation is characterized by an accumulation of effector-memory T cells, but their immune regulatory potential has not been adequately examined. Coexpression of transcription factor, forkhead box P3 (Foxp3), and interleukin-2 receptor, CD25, in CD4(+) and CD8(+) T cells is linked with regulatory function in humans. The aim of this study was to investigate the regulatory T cell (Treg) phenotype of CD4(+) (CD4Treg) and CD8(+) (CD8Treg) T cells in peripheral blood (PB) and sinus mucosa of CRS patients. METHODS: Prospective study was performed involving 32 CRS with nasal polyp (CRSwNP), 14 CRS without nasal polyp (CRSsNP), and 8 control patients. Sinus and PB T lymphocytes were stained with CD3, CD4, CD8, CD25, and Foxp3 and analyzed using flow cytometry. Relevant clinical characteristics, sinus bacterial culture results, and eosinophilic mucus were examined. RESULTS: Sinus mucosa had a higher percentage of CD4Treg (CD3(+)CD4(+)CD25(+)Foxp3(+)) population compared with PB in all patients. The percentage of PB CD4Treg and CD8Treg (CD3(+)CD8(+)CD25(+)Foxp3(+)) was not significantly different between the study groups. CRS mucosal tissue had a higher percentage of CD4Treg and activated T-helper cells than controls. There was no significant difference in PB and mucosal CD4Treg populations in CRS patients based on the presence of allergy, sinus culture results, or eosinophilic mucus. In controls, increased mucosal CD4Treg correlated with coexisting allergy. Although overall CD4Treg numbers were higher, the regulatory potential of activated CD4(+) T cells (CD4Treg/activated T-helper cell ratio) was significantly lower in CRS mucosa compared with controls. The CD8Treg subset was also significantly reduced in CRSwNP mucosa compared with controls. CONCLUSION: A higher percentage of CD4Treg and activated T-helper cells in CRS mucosa suggests increased inflammation in CRS, independent of the presence of allergy, microbial culture results, or eosinophilic mucus. However, the decreased ratio of CD4Treg versus activated T-helper cells in CRS and reduced CD8Treg population in CRSwNPs indicates an inflammatory bias and the inability to control mucosal disease.

CD8(+) T cells implicated in the pathogenesis of allergic fungal rhinosinusitis.

Fungi in paranasal sinuses are characteristic and considered a major pathogenic factor in a subset of chronic rhinosinusitis (CRS) patients, known as allergic fungal rhinosinusitis (AFRS). CD8(+) T cells are enriched in AFRS sinuses but their role in fungal-specific responses is unknown. Alternaria alternata- and Aspergillus fumigatus-specific T lymphocyte responses were investigated in 6 AFRS patients, 10 eosinophilic mucus CRS (EMCRS) patients, 10 CRS with nasal polyps (CRSwNPs) patients, 6 allergic rhinitis with fungal allergy (ARFA) patients, and five controls. Fungal-specific proliferation of human peripheral blood mononuclear cells (PBMCs) was studied prospectively. Proliferating cells were examined for CD3, CD4, CD8, and CD25 expression. Relevant clinical characteristics, fungal allergy, detection of fungi in sinuses, and CD4(+) and CD8(+) composition of sinus T cells were also examined. CD4(+) T-cell division to fungi occurred in all samples, regardless of fungal allergy or CRS. Fungal-specific CD8(+) T-cell division occurred in all ARFA and control samples and the majority of CRSwNP patients; however, CD8(+) T cells failed to proliferate in AFRS and EMCRS patients. The CD8(+) T cells from AFRS patients also did not up-regulate the activation marker, CD25, with fungal antigen exposure. Presence of A. alternata- and A. fumigatus-specific CD4(+) and CD8(+) T-cell proliferation in healthy individuals, ARFA, and CRSwNP patients suggests that both T-cell subsets may be important in immune responses to these fungi. In AFRS and EMCRS patients, only fungal-specific CD4(+) T-cell proliferation occurred; hence, a lack of CD8(+) T-cell proliferation and activation in the presence of sinus eosinophilic mucus in these patients, regardless of fungal allergy, is a novel finding. This raises the question whether a dysfunctional CD8(+) T-cell response predisposes to ineffective clearance and accumulation of fungi in the sinuses of susceptible patients.

CD4+ and CD8+ regulatory T cells in chronic rhinosinusitis mucosa.

BACKGROUND: Chronic rhinosinusitis (CRS) mucosal inflammation is characterized by an accumulation of effector-memory T cells, but their immune regulatory potential has not been adequately examined. Coexpression of transcription factor, forkhead box P3 (Foxp3), and interleukin-2 receptor, CD25, in CD4+ and CD8+ T cells is linked with regulatory function in humans. The aim of this study was to investigate the regulatory T cell (Treg) phenotype of CD4+ (CD4Treg) and CD8+ (CD8Treg) T cells in peripheral blood (PB) and sinus mucosa of CRS patients. METHODS: Prospective study was performed involving 32 CRS with nasal polyp (CRSwNP), 14 CRS without nasal polyp (CRSsNP), and 8 control patients. Sinus and PB T lymphocytes were stained with CD3, CD4, CD8, CD25, and Foxp3 and analyzed using flow cytometry. Relevant clinical characteristics, sinus bacterial culture results, and eosinophilic mucus were examined. RESULTS: Sinus mucosa had a higher percentage of CD4Treg (CD3+CD4+CD25+Foxp3+) population compared with PB in all patients. The percentage of PB CD4Treg and CD8Treg (CD3+CD8+CD25+Foxp3+) was not significantly different between the study groups. CRS mucosal tissue had a higher percentage of CD4Treg and activated T-helper cells than controls. There was no significant difference in PB and mucosal CD4Treg populations in CRS patients based on the presence of allergy, sinus culture results, or eosinophilic mucus. In controls, increased mucosal CD4Treg correlated with coexisting allergy. Although overall CD4Treg numbers were higher, the regulatory potential of activated CD4+ T cells (CD4Treg/activated T-helper cell ratio) was significantly lower in CRS mucosa compared with controls. The CD8Treg subset was also significantly reduced in CRSwNP mucosa compared with controls. CONCLUSION: A higher percentage of CD4Treg and activated T-helper cells in CRS mucosa suggests increased inflammation in CRS, independent of the presence of allergy, microbial culture results, or eosinophilic mucus. However, the decreased ratio of CD4Treg versus activated T-helper cells in CRS and reduced CD8Treg population in CRSwNPs indicates an inflammatory bias and the inability to control mucosal disease.

Accumulation of effector memory CD8+ T cells in nasal polyps.

BACKGROUND: T lymphocytes are prevalent in sinus mucosa and are implicated in chronic rhinosinusitis (CRS) pathogenesis. However, the major T-cell subpopulations, helper (CD4+) and cytotoxic (CD8+), have not been adequately examined in CRS. This study was designed to characterize human sinus mucosa and peripheral blood (PB) CD4+ and CD8+ T cells and their level of differentiation in CRS with nasal polyps (NPs), CRS without NPs, and control patients. METHODS: A prospective study was performed. Percentages of CD4+ and CD8+ T cells and their levels of differentiation were analyzed in sinus mucosa and PB by flow cytometry. Cell populations were defined as naive, central memory, effector memory, and effector T cells using cell surface markers CD45RA, CD62L, and CD27. The influence of coexisting allergy, sinus eosinophilic mucus (EM), and culture results were examined. RESULTS: In all patients, sinus mucosa had a lower percentage of CD4+ and a higher percentage of CD8+ T cells compared with PB. However, CRS with NPs (n = 86) had a significantly higher percentage of mucosal CD8+ T cells compared with CRS without NPs (n = 40) in control (n = 13) patients (p < 0.0001). Effector memory T cells were increased in sinuses compared with PB in all patients; however, the percentage of effector memory CD8+ T cells was greatest in CRS with NP mucosa (p = 0.002). Surprisingly coexisting allergy or culture results did not influence the mucosal T-cell phenotype. CRS with NP patients with sinus EM had a significantly higher percentage of mucosal CD8+ T cells. CONCLUSION: Sinus mucosa in CRS with NPs is characterized by a significant enrichment of CD8+ T cells and a relative deficiency of CD4+ T cells. The majority of NP CD8+ T cells had a terminally differentiated, mature, effector memory phenotype, which raises the question, whether these cells are pathogenic or appear as a consequence of inflammation, independent of the presence of allergy or positive microbial culture.

Carotid artery injury during endoscopic endonasal skull base surgery: incidence and outcomes.

BACKGROUND: Injury to the internal carotid artery (ICA) during endoscopic endonasal skull base surgery is a feared complication that is not well studied or reported. OBJECTIVE: To evaluate the incidence, to identify potential risk factors, and to present management strategies and outcomes of ICA injury during endonasal skull base surgery at our institution. METHODS: We performed a retrospective review of all endoscopic endonasal operations performed at our institution between 1998 and 2011 to examine potential factors predisposing to ICA injury. We also documented the perioperative management and outcomes after injury. RESULTS: There were 7 ICA injuries encountered in 2015 endonasal skull base surgeries, giving an incidence of 0.3%. Most injuries (5 of 7) involved the left ICA, and the most common diagnosis was chondroid neoplasm (chordoma, chondrosarcoma; 3 of 7 [2% of 142 cases]). Two injuries occurred during 660 pituitary adenoma resections (0.3%). The paraclival ICA segment was the most commonly injured site (5 of 7), and transclival and transpterygoid approaches had a higher incidence of injury, although neither factor reached statistical significance. Four of 7 injured ICAs were sacrificed either intraoperatively or postoperatively. No patient suffered a stroke or neurological deficit. There were no intraoperative mortalities; 1 patient died postoperatively of cardiac ischemia. One of the 3 preserved ICAs developed a pseudoaneurysm over a mean follow-up period of 5 months that was treated endovascularly. CONCLUSION: ICA injury during endonasal skull base surgery is an infrequent and manageable complication. Preservation of the vessel remains difficult. Chondroid tumors represent a higher risk and should be resected by surgical teams with significant experience.

Confounding factors in rhinological research.

PURPOSE OF REVIEW: Basic science studies directed at understanding the inflammatory mechanisms in chronic rhinosinusitis (CRS) are increasing, yet their relevance to the underlying disease process is often conflicting and confounded by the enrollment of a heterogeneous CRS population. This review is aimed at exploring the issues affecting the basic science mucosal studies of CRS patients, with special attention to the inclusion criteria for CRS and the control group, and the site from which the mucosal tissue sample is obtained. RECENT FINDINGS: A common confounding factor is an inadequate documentation of selection criteria for patients, controls, and tissue sites examined. Inconsistent definitions for CRS and for maximum medical therapy, and a lack of histopathology confirmation of mucosal inflammation (eosinophilic or neutrophilic) can bias the disease population entering a given study. Further confounding factors include the influence of coexisting diseases, pollution and cigarette smoke, and a need for same-site tissue comparisons, meticulous selection of relevant controls, and consensus on 'nondiseased' mucosal inflammatory cell populations and microbiology. SUMMARY: Documentation of well defined patient and control groups, standardized specimen collection methods, and detection assays are critical in minimizing the bias and conflicting findings among investigators. With standardized sampling of tissue sites and tight controls on subcategories of CRS patients enrolled, studies will more likely identify the findings that can increase our understanding of the disparate group of CRS patients and identify new therapeutic targets in the CRS subcategories.

Rhinitis medicamentosa as a cause of increased intraoperative bleeding.

Rhinitis medicamentosa occurs with repeated and prolonged use of topical decongestants. The resultant reduced ability to respond to decongestants mediated via enlarged capillary endothelial gaps can lead to profuse bleeding during turbinate surgery. We recommend that patients with rhinitis medicamentosa be weaned off topical decongestants prior to elective turbinate surgery to minimize this complication. The management of rhinitis medicamentosa and a case of intraoperative hemorrhage are presented.

Quality of life following endonasal skull base surgery.

The importance of quality of life (QOL) outcomes following treatments for head and neck tumors are now increasingly appreciated and measured to improve medical and surgical care for these patients. An understanding of the definitions in the setting of health care and the use of appropriate QOL instruments and measures are critical to obtain meaningful information that guides decision making in various aspects of patient health care. QOL outcomes following cranial base surgery is only recently being defined. In this article, we describe the current published data on QOL outcomes following cranial base surgery and provide preliminary prospective data on QOL outcomes and sinonasal morbidity in patients who underwent endonasal cranial base surgery for management of various skull base tumors at our institution. We used a disease-specific multidimensional instrument to measure QOL outcomes in these patients. Our results show that although sinonasal morbidity is increased, this is temporary, and the vast majority of patients have a very good QOL by 4 to 6 months after endonasal approach to the cranial base.

A new endoscopic staging system for angiofibromas.

OBJECTIVE: To develop a new staging system for juvenile nasopharyngeal angiofibroma that reflects changes in surgical approaches (endonasal), route of intracranial extension, and the extent of vascular supply from the internal carotid artery. DESIGN: Retrospective review of case series. SETTING: Academic medical center. PATIENTS: Patients undergoing endoscopic endonasal surgery for juvenile nasopharyngeal angiofibroma at the University of Pittsburgh Medical Center (UPMC), Pittsburgh, Pennsylvania, from 1998 through 2008. INTERVENTION: Patients were staged according to current systems and compared with a new staging system that also incorporated the route of skull base extension and tumor vascularity. MAIN OUTCOME MEASURES: Estimated blood loss, number of operations, and tumor recurrence. RESULTS: Skull base erosion was observed in 74% of cases. Following embolization of external carotid artery tributaries, residual vascularity from the internal carotid artery was seen in 51% of patients. Residual vascularity, classified as UPMC stage IV and V, strongly correlated with blood loss, requirement for multiple procedures, and residual or recurrent tumor. CONCLUSIONS: Tumor size and extent of sinus disease are less important in predicting complete tumor removal with endonasal surgical techniques. The UPMC staging system for juvenile nasopharyngeal angiofibroma accounts for 2 important prognostic factors, route of cranial base extension, and vascularity and is applicable to endoscopic or open approaches. Compared with other staging systems, the UPMC staging system provides a better prediction of immediate morbidity (including blood loss and need for multiple operations) and tumor recurrence.