Primary retroperitoneal lymph node dissection for metastatic non-seminomatous germ cell tumours: outcomes and adjuvant chemotherapy.

OBJECTIVES: To compare the outcomes and treatment burden of primary retroperitoneal lymph node dissection (pRPLND) alone versus pRPLND + adjuvant chemotherapy (AC) in patients with pathological stage II (PSII) non-seminomatous germ cell tumours (NSGCT). PATIENTS AND METHODS: Retrospective review of the Princess Margaret Cancer Center eTestes cancer database identified patients with PSII NSGCT after pRPLND between 1995 and 2020. The primary outcome was relapse-free survival (RFS). Secondary outcomes included disease-specific survival (DSS), burden of relapse treatment, and factors associated with relapse. RESULTS: A total of 109 PSII patients were included in the study. There were 96 patients treated with pRPLND alone and 13 treated with pRPLND + AC. The median follow-up was 61 months. The 5-year RFS was 72% for the pRPLND-only group vs 92% for the pRPLND + AC group (hazard ratio [HR] 4.372, 95% confidence interval [CI] 0.59-32.36; P = 0.11). Within the pRPLND-only group the 5-year RFS differed by pN stage (pN1 = 94% vs pN2/N3 = 67%, P = 0.03). Despite a higher relapse rate within the pRPLND-only group, the DSS was similar at 5 years (98% pRPLND only vs 100% pRPLND + AC, P = 0.48). Only 24 (25%) of the patients in the pRPLND-only group required any subsequent chemotherapy. Despite achieving similar survival, the cumulative post-RPLND treatment burden was less for the pRPLND-only group than the pRPLND+AC group overall (average 1.23 vs 2.46 cycles of chemotherapy per patient in group). CONCLUSION: The majority of patients with PSII NSGCT treated with pRPLND alone do not experience a recurrence or require chemotherapy. Despite a lower relapse risk when AC is given, no difference in survival was seen but higher chemotherapy burden was entertained. AC may constitute overtreatment for most patients with PSII NSGCT treated with pRPLND.

Sterol-like drugs potentiate statin-triggered prostate cancer cell death by inhibiting SREBP2 nuclear translocation.

There is an urgent need to provide immediate and effective options for the treatment of prostate cancer (PCa) to prevent progression to lethal castration-resistant PCa (CRPC). The mevalonate (MVA) pathway is dysregulated in PCa, and statin drugs commonly prescribed for hypercholesterolemia, effectively target this pathway. Statins exhibit anti-PCa activity, however the resulting intracellular depletion of cholesterol triggers a feedback loop that restores MVA pathway activity, thus diminishing statin efficacy and contributing to resistance. To identify drugs that block this feedback response and enhance the pro-apoptotic activity of statins, we performed a high-content image-based screen of a 1508 drug library, enriched for FDA-approved compounds. Two of the validated hits, Galeterone (GAL) and Quinestrol, share the cholesterol-related tetracyclic structure, which is also evident in the FDA-approved CRPC drug Abiraterone (ABI). Molecular modeling revealed that GAL, Quinestrol and ABI not only share structural similarity with 25-hydroxy-cholesterol (25HC) but were also predicted to bind similarly to a known protein-binding site of 25HC. This suggested GAL, Quinestrol and ABI are sterol-mimetics and thereby inhibit the statin-induced feedback response. Cell-based assays demonstrated that these agents inhibit nuclear translocation of sterol-regulatory element binding protein 2 (SREBP2) and the transcription of MVA genes. Sensitivity was independent of androgen status and the Fluva-GAL combination significantly impeded CRPC tumor xenograft growth. By identifying cholesterol-mimetic drugs that inhibit SREBP2 activation upon statin treatment, we provide a potent "one-two punch" against CRPC progression and pave the way for innovative therapeutic strategies to combat additional diseases whose etiology is associated with SREBP2 dysregulation.

Cardiovascular Outcomes in Fontan Patients With Right vs Left Univentricular Morphology: A Multicenter Study.

Background: There is a paucity of data on long-term outcomes after Fontan palliation in patients with a dominant morphological univentricular right (uRV) vs left (uLV) ventricle. Objectives: The purpose of this study was to compare the incidence of atrial arrhythmias, thromboembolic events, cardiac transplantation, and death following Fontan palliation in patients with uRV vs uLV. Methods: The Alliance for Adult Research in Congenital Cardiology conducted a multicenter retrospective cohort study on patients with total cavopulmonary connection Fontan palliation across 12 centers in North America. All components of the composite outcome, that is, atrial arrhythmias, thromboembolic events, cardiac transplantation, and death, were reviewed and classified by a blinded adjudicating committee. Time-to-event analyses were performed that accounted for competing risks. Results: A total of 384 patients were followed for 10.5 ± 5.9 years. The composite outcome occurred in 3.7 vs 1.7 cases per 100 person-years for uRV (N = 171) vs uLV (N = 213), respectively (P < 0.001). In multivariable analyses, uRV conferred a >2-fold higher risk of the composite outcome (HR: 2.17, 95% CI: 1.45-3.45, P < 0.001). In secondary analyses of components of the primary outcome, uRV was significantly associated with a greater risk of cardiac transplantation or death (HR: 9.09, 95% CI: 2.17-38.46, P < 0.001) and atrial arrhythmias (HR: 2.17, 95% CI: 1.20-4.00, P = 0.010) but not thromboembolic events (HR: 1.64, 95% CI: 0.86-3.16, P = 0.131). Conclusions: Fontan patients with uRV vs uLV morphology have a higher incidence of adverse cardiovascular events, including atrial arrhythmia, cardiac transplantation, and all-cause mortality.

MicroRNA for Prediction of Teratoma and Viable Germ Cell Tumor after Chemotherapy.

MicroRNAs (miRNAs) are emerging as highly sensitive and specific markers for testicular germ cell tumors (GCTs) across the spectrum of disease. However, their utility in specific clinical scenarios requires further study. Here, we review the current evidence for miRNAs as tumor markers for the evaluation of treatment response in patients undergoing chemotherapy for the treatment of advanced testicular GCT.

Cardiac arrhythmia and epilepsy genetic variants in sudden unexpected death in epilepsy.

Introduction: Sudden Unexpected Death in Epilepsy (SUDEP) is the leading epilepsy-related cause of death, affecting approximately 1 per 1,000 individuals with epilepsy per year. Genetic variants that affect autonomic function, such as genes associated with cardiac arrhythmias, may predispose people with epilepsy to greater risk of both sudden cardiac death and SUDEP. Advances in next generation sequencing allow for the exploration of gene variants as potential biomarkers. Methods: Genetic testing for the presence of cardiac arrhythmia and epilepsy gene variants was performed via genetic panels in 39 cases of SUDEP identified via autopsy by the Ontario Forensic Pathology Service. Variants were summarized by in-silico evidence for pathogenicity from 4 algorithms (SIFT, PolyPhen-2, PROVEAN, Mutation Taster) and allele frequencies in the general population (GnomAD). A maximum credible population allele frequency of 0.00004 was calculated based on epilepsy prevalence and SUDEP incidence to assess whether a variant was compatible with a pathogenic interpretation. Results: Median age at the time of death was 33.3 years (range: 2, 60). Fifty-nine percent (n=23) were male. Gene panels detected 62 unique variants in 45 genes: 19 on the arrhythmia panel and 26 on the epilepsy panel. At least one variant was identified in 28 (72%) of decedents. Missense mutations comprised 57 (92%) of the observed variants. At least three in silico models predicted 12 (46%) cardiac arrhythmia panel missense variants and 20 (65%) epilepsy panel missense variants were pathogenic. Population allele frequencies were <0.00004 for 11 (42%) of the cardiac variants and 10 (32%) of the epilepsy variants. Together, these metrics identified 13 SUDEP variants of interest. Discussion: Nearly three-quarters of decedents in this SUDEP cohort carried variants in comprehensive epilepsy or cardiac arrhythmia gene panels, with more than a third having variants in both panels. The proportion of decedents with cardiac variants aligns with recent studies of the disproportionate cardiac burden the epilepsy community faces compared to the general population and suggests a possible cardiac contribution to epilepsy mortality. These results identified 13 priority targets for future functional studies of these genes potential role in sudden death and demonstrates the necessity for further exploration of potential genetic contributions to SUDEP.

Reduced kinase function in two ultra-rare TNNI3K variants in families with congenital junctional ectopic tachycardia.

Genetic missense variants in TNNI3K, encoding troponin-I interacting kinase, have been associated with dilated cardiomyopathy (DCM) and observed in families with supraventricular tachycardias (SVT). Previously, a family harboring the TNNI3K-c.1615A > G (p.Thr539Ala) variant presented with congenital junctional ectopic tachycardia (CJET), an arrhythmia that arises from the atrioventricular (AV) node and His bundle. However, this was a relatively small four-generational family with limited genetic testing (N = 3). We here describe a multigenerational family with CJET harboring a novel ultra-rare TNNI3K variant: TNNI3K-c.1729C > T (p.Leu577Phe). Of all 18 variant carriers, 13 individuals presented with CJET, resulting in a genetic penetrance of 72%. In addition, CJET is reported in another small family harboring TNNI3K-c.2225C > T (p.Pro742Leu). Similar to the previously published CJET family, both TNNI3K variants demonstrate a substantial reduction of kinase activity. Our study contributes novel evidence supporting the involvement of TNNI3K genetic variants as significant contributors to CJET, shedding light on potential mechanisms underlying this cardiac arrhythmia.

Addressing controversial areas in the management of advanced prostate cancer in Canada Areas of consensus and controversy from the third Canadian consensus forum.

INTRODUCTION: The management of prostate cancer (PCa) is rapidly evolving. Treatment and diagnostic options grow annually, however, high-level evidence for the use of new therapeutics and diagnostics is lacking. In November 2022, the Genitourinary Research Consortium held its 3rd Canadian Consensus Forum (CCF3) to provide guidance on key controversial areas for management of PCa. METHODS: A steering committee of eight multidisciplinary physicians identified topics for discussion and adapted questions from the Advanced Prostate Cancer Consensus Conference 2022 for CCF3. Questions focused on management of metastatic castration-sensitive prostate cancer (mCSPC); use of novel imaging, germline testing, and genomic profiling; and areas of non-consensus from CCF2. Fifty-eight questions were voted on during a live forum, with threshold for "consensus agreement" set at 75%. RESULTS: The voting panel consisted of 26 physicians: 13 urologists/uro-oncologists, nine medical oncologists, and four radiation oncologists. Consensus was reached for 32 of 58 questions (one ad-hoc). Consensus was seen in the use of local treatment, to not use metastasis-directed therapy for low-volume mCSPC, and to use triplet therapy for synchronous high-volume mCSPC (low prostate-specific antigen). Consensus was also reached on sufficiency of conventional imaging to manage disease, use of germline testing and genomic profiling for metastatic disease, and poly (ADP-ribose) polymerase (PARP) inhibitors for BRCA-positive prostate cancer. CONCLUSIONS: CCF3 identified consensus agreement and provides guidance on >30 practice scenarios related to management of PCa and nine areas of controversy, which represent opportunities for research and education to improve patient care. Consensus initiatives provide valuable guidance on areas of controversy as clinicians await high-level evidence.

Impact of Fontan Fenestration on Adverse Cardiovascular Outcomes: A Multicentre Study.

BACKGROUND: Fenestrating a Fontan baffle has been associated with improved perioperative outcomes in patients with univentricular hearts. However, longer-term potential adverse effects remain debated. We sought to assess the impact of a fenestrated Fontan baffle on adverse cardiovascular events including all-cause mortality, cardiac transplantation, atrial arrhythmias, and thromboemboli. METHODS: A multicentre North American retrospective cohort study was conducted on patients with total cavopulmonary connection Fontan baffle, with and without fenestration. All components of the composite outcome were independently adjudicated. Potential static and time-varying confounders were taken into consideration, along with competing risks. RESULTS: A total of 407 patients were followed for 10.4 (7.1-14.4) years; 70.0% had fenestration of their Fontan baffle. The fenestration spontaneously closed or was deliberately sealed in 79.9% of patients a median of 2.0 years after Fontan completion. In multivariable analysis in which a persistent fenestration was modelled as a time-dependent variable, an open fenestration did not confer a higher risk of the composite outcome (hazard ratio, 1.18; 95% confidence interval, 0.71-1.97; P = 0.521). In secondary analyses, an open fenestration was not significantly associated with components of the primary outcome: that is, mortality or transplantation, atrial arrhythmias, or thromboemboli. However, sensitivity analyses to assess the possible range of error resulting from imprecise dates for spontaneous fenestration closures could not rule out significant associations between an open fenestration and atrial arrhythmias or thromboemboli. CONCLUSIONS: In this multicentre study, no significant association was identified between an open fenestration in the Fontan baffle and major adverse cardiovascular events.

Screening asthmatics for atopic status using the ALergy EXplorer (ALEX2) macroarray.

BACKGROUND: Screening asthma patients for atopy facilitates management. Since 2010, the core biomarker for screening asthma subjects for atopic status has been the qualitative Phadiatop. multi-aeroallergen screen. A more quantitative macroarray, the Allergy Explorer (ALEX2), shows promise as an alternative. OBJECTIVE: The study's goal was to examine the pros and cons of the use of ALEX2 in the screening of asthma patients for atopic status. METHODS: We evaluated the atopic (IgE-sensitization) status in asthmatic Amish and Hutterite farm children using the ImmunoCAP and ALEX2 assays in Phadiatop equivocal and positive subjects. RESULTS: All 42 asthmatic children were analyzed by Phadiatop and total serum IgE. Of these, 22 had a negative Phadiatop (<0.1 kUa/L) and total IgE <100 kU/L which defined them as non-atopic and they were excluded from ALEX2 testing. Of six children with equivocal Phadiatops (0.1-0.2 kUa/L-Group 1) and three children with a negative Phadiatop but total IgE >100 kUa/L (group 3), 44% (n = 4) had detectable IgE antibody by ALEX2 to mite, tree pollen, and other allergens not detected by Phadiatop, but confirmed by allergen-specific ImmunoCAP testing. In 11 Phadiatop positive subjects (>0.2 kUa/L-group 2), all but one were positive by ALEX2. IgE antibody specific for mold and rabbit aeroallergens matched their agricultural and pet exposure history. Three children were positive for IgE antibody to allergens in the profilin, nsLTP, or PR-10 cross-reactive protein families. CONCLUSION: Judicious use of ALEX2's enhanced specificity data not provided by the Phadiatop can aid in the interpretation of sensitization patterns and planning management of atopic asthmatics, but sensitization relevance must be confirmed by the patient's clinical history.

Vitellin/Vitellogenin Is an Important Allergen in German Cockroach.

INTRODUCTION: German cockroach (GCr) aeroallergens are associated with allergic rhinitis and asthma. Vitellogenin (Vg) and vitellin (Vn) are abundant proteins in GCr blood and eggs (including egg cases), respectively, and are possible high molecular mass allergens. Prior efforts to purify Vg/Vn yielded amounts too small for subsequent studies. In this study, we report the affinity purification of Vg/Vn from whole-body defatted GCr powder and determination of the binding of Vg/Vn to anti-GCr IgE. METHOD: New Zealand white rabbits were immunized with pure Vg/Vn in Freund's adjuvant, and IgG was purified from the rabbit sera and conjugated to cyanogen bromide (CNBr)-activated Sepharose. Aqueous extracts from GCr powder were passed over the column. After extensive washing, putative Vg/Vn was eluted in low-pH buffer, neutralized, and analyzed by SDS-PAGE and liquid chromatography high-resolution mass spectrometry (LC-HRMS). IgE binding of Vg/Vn was evaluated by inhibition of IgE binding to GCr-ImmunoCAP(I6) in sera from 10 GCr-allergic individuals. In addition, Vg/Vn was biotinylated and bound to ImmunoCAP-streptavidin, and direct IgE antibody binding to the immobilized Vg/Vn was determined in sera from 26 GCr-allergic individuals. RESULTS: Vg/Vn isolated by affinity chromatography was 91% pure by LC-HRMS; contaminants included Bla g 3 (0.9%), human keratin (6%), and rabbit IgG. Vg/Vn inhibited IgE binding to GCr-ImmunoCAP(I6) in 8 of 10 sera. In direct-binding experiments, 21/26 (80%) sera had anti-Vg/Vn IgE at >0.10 kUA/L, while 11/26 (42%) sera were >0.35 kUA/L. CONCLUSIONS: We affinity-purified Vg/Vn and demonstrated that Vg/Vn-specific IgE antibody is a major component of GCr-specific IgE.

Propensity-matched Analysis of Open Versus Robotic Primary Retroperitoneal Lymph Node Dissection for Clinical Stage II Testicular Cancer.

BACKGROUND: Open retroperitoneal lymph node dissection (O-RPLND) is the accepted standard surgical approach to treat retroperitoneal nodal disease in testis cancer. Increasingly, robotic RPLND (R-RPLND) is being performed due to the potential for lower blood loss, shorter length of stay, and accelerated recovery. OBJECTIVE: We have performed a propensity score matching (PSM) analysis comparing the survival and perioperative outcomes of O- and R-RPLND. DESIGN, SETTING, AND PARTICIPANTS: Analyzing the data from all patients who underwent primary RPLND at our center between 1990 and 2022, we used PSM to create a 2:1 (O-RPLND:R-RPLND) matched cohort. INTERVENTION: Primary O-RPLND versus R-RPLND. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary endpoint was time to relapse. The secondary endpoints included operating time, length of stay, estimated blood loss (EBL), and surgical complications. Relapse-free survival rates were calculated using the Kaplan-Meier method, and log-rank tests were used to compare perioperative outcomes of O-RPLND versus R-RPLND. KEY FINDINGS AND LIMITATIONS: A total of 178 patients underwent primary RPLND: 137 O-RPLND and 41 R-RPLND. After PSM, 26 patients in the R-RPLND group were matched with 38 in the O-RPLND group. After matching, no significant baseline differences were noted. After a median follow-up of 23.5 mo (interquartile range 4.4-59.2), one (3.8%) relapse was noted in the R-RPLND group versus three (7.8%) in the O-RPLND group; however, this was not significant (hazard ratio 0.65, 95% confidence interval 0.07-6.31, p = 0.7097). No in-field relapses occurred in either cohort. R-RPLND was associated with a shorter length of stay (1 vs 5 d, p < 0.0001) and lower EBL (200 vs 300 ml, p = 0.032), but longer operative time (8.8 vs 4.3 h, p < 0.0001). CONCLUSIONS: R-RPLND offers low morbidity and improved perioperative outcomes, while maintaining oncologic efficacy of the open approach. PATIENT SUMMARY: To the best of our knowledge, this is the first study to compare open and robotic retroperitoneal lymph node dissection (R-RPLND) using a propensity score-matched system. We encourage the discussion and inclusion of primary R-RPLND into the standard of care algorithm for patients with de novo clinical stage (CS) II and relapsed CS I with CS II equivalent disease.

Prognostic Factor Risk Groups for Clinical Stage I Seminoma: An Individual Patient Data Analysis by the European Association of Urology Testicular Cancer Guidelines Panel and Guidelines Office.

BACKGROUND: The relapse rate in patients with clinical stage I (CSI) seminomatous germ cell tumor of the testis (SGCTT) who were undergoing surveillance after radical orchidectomy is 4-30%, depending on tumor size and rete testis invasion (RTI). However, the level of evidence supporting the use of both risk factors in clinical decision-making is low. OBJECTIVE: We aimed to identify the most important prognostic factors for relapse in CSI SGCTT patients. DESIGN, SETTING, AND PARTICIPANTS: Individual patient data for 1016 CSI SGCTT patients diagnosed between 1994 and 2019 with normal postorchidectomy serum tumor marker levels and undergoing surveillance were collected from nine institutions. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Multivariable Cox proportional hazard regression models were fit to identify the most important prognostic factors. The primary endpoint was the time to first relapse by imaging and/or markers. Relapse probabilities were estimated by the Kaplan-Meier method. RESULTS AND LIMITATIONS: After a median follow-up of 7.7 yr, 149 (14.7%) patients had relapsed. Categorical tumor size (≤2, >2-5, and >5 cm), presence of RTI, and lymphovascular invasion were used to form three risk groups: low (56.4%), intermediate (41.3%), and high (2.3%) risks with 5-yr cumulative relapse probabilities of 8%, 20%, and 44%, respectively. The model outperformed the currently used model with tumor size ≤4 versus >4 cm and presence of RTI (Harrell's C index 0.65 vs 0.61). The low- and intermediate-risk groups were validated successfully in an independent cohort of 285 patients. CONCLUSIONS: The risk of relapse after radical orchidectomy in CSI SGCTT patients under surveillance is low. We propose a new risk stratification model that outperformed the current model and identified a small subgroup with a high risk of relapse. PATIENT SUMMARY: The risk of relapse after radical orchidectomy in patients with clinical stage I seminomatous germ cell tumor of the testis is low. We propose a new risk stratification model that outperformed the current model and identified a small subgroup with a high risk of relapse.

Patterns of Electrocardiographic Abnormalities in Children with Hypertrophic Cardiomyopathy.

Hypertrophic cardiomyopathy (HCM), a common cardiomyopathy in children, is an important cause of morbidity and mortality. Early recognition and appropriate management are important. An electrocardiogram (ECG) is often used as a screening tool in children to detect heart disease. The ECG patterns in children with HCM are not well described.ECGs collected from an international cohort of children, and adolescents (≤ 21 years) with HCM were reviewed. 482 ECGs met inclusion criteria. Age ranged from 1 day to 21 years, median 13 years. Of the 482 ECGs, 57 (12%) were normal. The most common abnormalities noted were left ventricular hypertrophy (LVH) in 108/482 (22%) and biventricular hypertrophy (BVH) in 116/482 (24%) Of the patients with LVH/BVH (n = 224), 135 (60%) also had a strain pattern (LVH in 83, BVH in 52). Isolated strain pattern (in the absence of criteria for hypertrophy) was seen in 43/482 (9%). Isolated pathologic Q waves were seen in 71/482 (15%). Pediatric HCM, 88% have an abnormal ECG. The most common ECG abnormalities were LVH or BVH with or without strain. Strain pattern without hypertrophy and a pathologic Q wave were present in a significant proportion (24%) of patients. Thus, a significant number of children with HCM have ECG abnormalities that are not typical for "hypertrophy". The presence of the ECG abnormalities described above in a child should prompt further examination with an echocardiogram to rule out HCM.

Clinical presentation of calmodulin mutations: the International Calmodulinopathy Registry.

AIMS: Calmodulinopathy due to mutations in any of the three CALM genes (CALM1-3) causes life-threatening arrhythmia syndromes, especially in young individuals. The International Calmodulinopathy Registry (ICalmR) aims to define and link the increasing complexity of the clinical presentation to the underlying molecular mechanisms. METHODS AND RESULTS: The ICalmR is an international, collaborative, observational study, assembling and analysing clinical and genetic data on CALM-positive patients. The ICalmR has enrolled 140 subjects (median age 10.8 years [interquartile range 5-19]), 97 index cases and 43 family members. CALM-LQTS and CALM-CPVT are the prevalent phenotypes. Primary neurological manifestations, unrelated to post-anoxic sequelae, manifested in 20 patients. Calmodulinopathy remains associated with a high arrhythmic event rate (symptomatic patients, n = 103, 74%). However, compared with the original 2019 cohort, there was a reduced frequency and severity of all cardiac events (61% vs. 85%; P = .001) and sudden death (9% vs. 27%; P = .008). Data on therapy do not allow definitive recommendations. Cardiac structural abnormalities, either cardiomyopathy or congenital heart defects, are present in 30% of patients, mainly CALM-LQTS, and lethal cases of heart failure have occurred. The number of familial cases and of families with strikingly different phenotypes is increasing. CONCLUSION: Calmodulinopathy has pleiotropic presentations, from channelopathy to syndromic forms. Clinical severity ranges from the early onset of life-threatening arrhythmias to the absence of symptoms, and the percentage of milder and familial forms is increasing. There are no hard data to guide therapy, and current management includes pharmacological and surgical antiadrenergic interventions with sodium channel blockers often accompanied by an implantable cardioverter-defibrillator.

Evolution Toward Chip-Based Arrays in the Laboratory Diagnosis of Human Allergic Disease.

Multiplex-based specific IgE antibody assays have emerged into the clinical immunology laboratory through the combined use of pure, recombinant allergenic molecules and new methods to simultaneously and accurately analyze specific IgE antibodies to hundreds of allergens. This review traces the historical development and examines outstanding questions related to the strengths and limitations of these new molecular allergen multipex technologies for the assessment of human allergic sensitization. Multiplexed technologies are poised to provide the most cost-effective and comprehensive evaluation of patients with suspected allergy as compared with the commonly used singleplex autoanalyzers. How analytically sensitive and quantitative are the multiplex technologies, down to 0.1 kUA/L? Because each allergen is viewed as a unique assay, how will analytical and clinical performance be documented at the manufacturing and clinical laboratory levels to guarantee reproducibility and obtain government regulatory clearance? Will interference by naturally occurring allergen-specific IgG compromise analytical performance? Successful resolution of these and other questions covered in this review will position multiplex technologies to become the single most-effective means of screening patients for allergic sensitization, assessing IgE antibody cross-reactivity, and planning therapy directed at the patient with allergy.