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Abstract Effective approaches are needed to conserve the planet's remaining wildlife and wilderness landscapes, especially concerning global biodiversity conservation targets. Here, we present a new software system called EarthRanger: an open‐source platform built to help monitor, research and manage ecosystems. EarthRanger consists of seven main components (Core Server, API, Storage, Gundi, Web App, Mobile App, Ecoscope) that provide functionality for data (i) aggregation & collection, (ii) storage & management, (iii) real‐time and post hoc analysis, (iv) visualisation and (v) dissemination. The mobile application provides field‐based data recording and visualisation tools. EarthRanger may be deployed for single project use or can aggregate across multiple geographies as a centralised hub. EarthRanger can be used to collect standardised tracking data (e.g. from wildlife collars, vehicles and ranger patrols) and configurable event information (e.g. a singular recording with associated user‐defined attribute information such as a wildlife sighting or encounter with a poacher). Since development began in 2015, the platform has (at the time of writing) been deployed at over 500 sites across 70 countries and with myriad configurations and objectives. EarthRanger has improved the ability to monitor data feeds and manage conservation‐related operations in real time. For instance, the deployment of EarthRanger by African Parks has led to the removal of over 50,000 snares, steady population growth of key species of concern and near cessation of poaching. In Liwonde's protected area, enhanced mitigation efforts supported by EarthRanger reduced the number of deaths from wildlife conflict by more than 91%. EarthRanger is also providing a platform to enhance standardisation, aggregation, transfer and long‐term storage of ecological information and promote collaboration between groups conducting protected area management and ecology and biodiversity research.

Abstract Background Penicillin allergy adversely impacts patient care, yet most cases do not have true allergies. Clinicians require efficient, reliable clinical tools to identify low risk patients who can be safely de-labeled. Our center implemented the FIRSTLINE electronic point-of-care decision support tool to help non-allergist practitioners risk stratify patients with penicillin allergy. We sought to explore the reliability and validity of this tool in relation to allergist assessment and actual patient outcomes. We additionally compared it with two other published stratification tools, JAMA and PENFAST, to assess ability to accurately identify low risk patients appropriate for direct oral challenge. Methods In this single-center, retrospective, observational study, 181 pregnant females with self-reported penicillin allergy between July 2019 to June 2021 at BC Women’s Hospital, Vancouver, Canada were used to assess the reliability and validity of all three tools. Physician-guided history of penicillin use and symptoms were used for scoring. Results and recommendations were compared to actual patient outcomes after clinician decision for direct oral challenge or intradermal tests. We compared the performance of JAMA, PENFAST and FIRSTLINE. Results 181 patients were assessed. 176/181 (97.2%) patients were deemed not allergic. Each risk stratification tool labelled majority of patients as low risk with 88.4% of patients PENFAST 0–2, 60.2% of patients JAMA low risk, 86.7% of patients FIRSTLINE very low risk. Conclusion We demonstrate that our point-of-care electronic algorithm is reliable in identifying low risk pregnant patients, as compared to an allergist assessment. To our knowledge, this is the first study to provide direct comparison between multiple decision support tools using the same population, minimizing participant bias. Providing clinical algorithms to risk stratify patients, can enable healthcare professionals to safely identify individuals who may be candidates for direct penicillin oral challenges versus needing referral to specialists. This increases the generalizability and efficiency of penicillin allergy de-labeling.

Abstract Background Food ladders are tools designed to facilitate home-based dietary advancement in children with food allergies through stepwise exposures to increasingly allergenic forms of milk and egg. Several studies have now documented safety and efficacy of food ladders. In 2021, we published a Canadian adaptation of the previously existing milk and egg ladders originating in Europe using foods more readily available/consumed in Canada. Our study adds to the growing body of evidence supporting food ladder use and provides safety and effectiveness data for our Canadian adaptation of the milk and egg ladders. Methods Surveys were distributed to families of children using the Canadian Milk Ladder and/or the Canadian Egg Ladder at baseline, with follow up surveys at 3 months, 6 months, and 12 months. Data were analyzed using REDCap and descriptive and inferential statistics are presented. Results One hundred and nine participants were started on milk/egg ladders between September 2020 and June 2022. 53 participants responded to follow up surveys. Only 2 of 53 (3.8%) participants reported receiving epinephrine during the study. Severe grade 4 reactions (defined according to the modified World Allergy Organization grading system) were not reported by any participants. Minor cutaneous adverse reactions were common, with about 71% (n = 10/14) of respondents reporting cutaneous adverse reactions by 1 year of food ladder use. An increasing proportion of participants could tolerate most foods from steps 2–4 foods after 3, 6, and 12 months of the food ladder compared to baseline. Conclusion The Canadian food ladders are safe tools for children with cow’s milk and/or egg allergies, and participants tolerated a larger range of foods with food ladder use compared to baseline.

Abstract Background Current management of food protein-induced enterocolitis syndrome (FPIES) involves strict avoidance of the offending food for 12–18 months, followed by oral food challenge (OFC) under physician supervision. OFCs are resource-intensive and there is a lack of a universal standardized protocol for FPIES. Prolonged avoidance may increase the risk of IgE-mediated allergy, particularly in atopic patients. Food ladders have shown success in promoting accelerated tolerance in patients with IgE-mediated allergy. Our case series evaluated the safety of use of the Canadian Egg Ladder in patients with mild-to-moderate FPIES to egg. Methods From May 2020 to November 2021, patients with mild-to-moderate FPIES to egg, defined as no history of lethargy or intravenous fluid administration, were started on the Canadian Egg Ladder. Instructions for advancing up the ladder were identical to using the Canadian Egg Ladder in patients with IgE-mediated allergy. Patients were followed every 3–6 months, at which time information was collected regarding progression up the ladder, symptoms while on treatment and interventions required. Treating allergists completed a survey to capture baseline demographic characteristics and prior tolerance to egg. Descriptive statistics were analyzed using MS Excel. Results Twenty-one patients with mild-to-moderate FPIES were started on the Canadian Egg Ladder. Median age at initiation of the ladder was 10 months (IQR, 9–11). Nineteen (90.5%) patients completed the ladder, tolerating a serving size amount of cooked egg, over a median duration of 7 month (IQR, 4–9 months). Four patients (19.0%) had mild symptoms including vomiting (9.5%), pallor (9.5%), belching (4.8%), irritability (4.8%) and small spit up (4.8%). In three of the four patients, symptoms were the result of accidental exposure to a higher step of the ladder. There were no reports of lethargy. No patients required health care presentation or intravenous fluid administration. No patients discontinued the ladder. Conclusions The Canadian Egg Ladder can safely guide the dietary advancement of egg-containing foods in patients with mild-to-moderate FPIES to egg, without the need for prolonged avoidance and resource-intensive OFCs.

Background: Oral immunotherapy is an effective treatment for food allergies; however, its use in clinical practice is limited by resources and lack of standardized protocols for foods other than peanut. Previous studies have suggested that shrimp has a higher threshold for reaction than other allergenic foods, suggesting it may be safe to directly administer maintenance doses of immunotherapy. Methods: Children aged 3–17 years who had 1) skin prick test ≥3 mm and/or specific IgE level ≥0.35 kU/L and convincing objective IgE-mediated reaction to shrimp, or 2) no ingestion history and specific IgE level ≥5 kU/L, underwent a low-dose oral food challenge to 300 mg shrimp protein, with the goal of continuing daily ingestion of the 300 mg maintenance dose as oral immunotherapy. Results: Between January 2020 and April 2023, 17 children completed the low-dose oral food challenge. Nine (53%) tolerated this amount with no reaction, and 8 (47%) had a mild reaction (isolated oral pruritis or redness on chin). Sixteen (94%) continued maintenance low-dose oral immunotherapy eating 300 mg shrimp protein daily. None of the patients developed anaphylaxis related to the immunotherapy. Conclusion: Our case series suggests that some shrimp allergic patients being considered for oral immunotherapy should be offered a low-dose oral food challenge, to potentially bypass the build-up phase of immunotherapy.

Abstract Background Allergic disease is on the rise. Waitlists for specialists are long, and many referred patients have already received prior allergic assessment, either by a certified Allergist, Primary Care Provider, or other Specialist. It is important to understand the prevalence and motivating factors for multiple-opinion referrals, to deliver timely assessment for patients with allergic disease. Methods A retrospective chart review of demographic information, number of previous consultations, and motivation for new consults and multiple-opinion referrals, of pediatric patients aged 8 months–17 years to BC Children’s Hospital Allergy Clinic from September 1, 2016–August 31, 2017, was performed. Referral data including reason for referral or multiple-opinion, primary allergic concerns, and others, from referral forms and consult notes were accessed through local Electronic Medical Records and subsequently analyzed for trends in categorical variables to assess the rationale for and impact of multiple-opinion referrals to our clinic. Results Of 1029 new referrals received, 210 (20.4%) were multiple-opinion referrals. Food allergy was the predominant allergic concern prompting further opinion (75.7%). The main rationale for seeking further opinions was wanting an assessment by a certified allergist in cases where prior consultation was performed by non-allergist specialist, primary care provider, or alternative health care provider. Of second-opinion referrals generated, 70 (33.3%) initial consultations were performed by an Allergist, whereas 140 (66.7%) were performed by a non-allergist. Conclusions Many new consults at the BCCH Allergy Clinic are multiple-opinion assessments, contributing to long waitlists. Advocacy at the systems level through standardized referral guidelines, centralized triaging systems, and stronger support for Primary Care Providers is needed to provide better access in Canada for children needing a specialized Allergist. Trial registration UBC/BCCH Research Ethics Board

Abstract Background Inaccurate penicillin allergy labels lead to inappropriate antibiotic prescriptions and harmful patient consequences. System-wide efforts are needed to remove incorrect penicillin allergy labels, but more health services research is required on how to best deliver these services. Methods Data was extracted from five hospitals in Vancouver, British Columbia, Canada from October 2018-May 2022. The primary outcomes of this study were to outline de-labelling protocol designs, identify the roles of various healthcare professionals in de-labelling protocols and identify rates of de-labelling penicillin allergies and associated adverse events at various institutions. Our secondary outcome was to describe de-labelling rates for special populations, including pediatric, obstetric and immunocompromised subpopulations. To achieve these outcomes, participating institutions provided their de-labelling protocol designs and data on program participants. Protocols were then compared to find common themes and differences. Furthermore, adverse events were reviewed and percentages of patients de-labelled at each institution and in total were calculated. Results Protocols demonstrated a high level of variability, including different methods of participant identification, risk-stratification and roles of providers. All protocols used oral and direct oral challenges, heavily involved pharmacists and had physician oversight. Despite the differences, of the 711 patients enrolled in all programs, 697 (98.0%) were de-labelled. There were 9 adverse events (1.3%) with oral challenges with mainly minor symptoms. Conclusions Our data demonstrates that de-labelling programs effectively and safely remove penicillin allergy labels, including pediatric, obstetric and immunocompromised patients. Consistent with current literature, most patients with a penicillin allergy label are not allergic. De-labelling programs could benefit from increasing clinician engagement by increasing accessibility of resources to providers, including guidance for de-labelling of special populations.

Abstract Background Penicillin allergy is a commonly listed medication allergy despite rare overall incidence. Many patients erroneously have this label, which has personal, health, and societal costs. Penicillin allergy delabelling requires an oral challenge, which can be a rate limiting step in the de-labeling process; this is even more relevant with the reduction of in-person visits during the COVID-19 pandemic. Objective To identify the utility and broader applicability of using a virtually supported platform, initially adopted given COVID-19 restrictions, to expedite penicillin oral provocation challenge and penicillin de-labeling in patients at low to moderate risk of immediate hypersensitivity reaction and based on shared decision making. Methods Patients in Vancouver catchment area were referred for penicillin allergy and virtually assessed by the consulting allergist between July 2020 and April 2021. Those deemed appropriate for oral challenge based on the allergist consultant were offered the option of a virtual oral provocation challenge to oral amoxicillin in a subsequent virtual visit. Patients who agreed and were consented underwent a virtually supervised oral amoxicillin challenge during the second virtual visit. Findings are summarized in this case series. Results Twenty-three patients, both adult and pediatric, ranging from no to significant co-morbidities were consented and underwent the virtual challenge. One hundred percent of patients were successful with no reaction after an hour post virtual oral provocation challenge with amoxicillin. Conclusion Virtual medicine is likely to remain in the allergist’s practice. Virtually supported penicillin allergy delabelling, based on shared decision making and risk stratification, presents another pathway for penicillin allergy delabelling.

Hepatocellular carcinoma (HCC) is a common malignancy with high mortality rates. While surgery can be curative in early-stage disease, 80% of patients cannot undergo surgical resection. Stereotactic body radiotherapy (SBRT), an emerging, non-invasive, precision treatment, has shown promising results across various stages of HCC and has thus been adopted in practice to varying degrees around the world. This article aims to review current guideline recommendations on SBRT, clinical evidence, and outcome comparisons with other local treatment modalities. Attempts are also made to compare the differences in clinical trials between Asian and Western countries.

Background: An understanding of how patient characteristics such as age, baseline peanut-specific IgE, and atopic comorbidities may influence potential safety outcomes during peanut oral immunotherapy (P-OIT) could aid in shared decision making between clinicians and patient families. Objective: This study explored the relationship between baseline patient characteristics and reactions during P-OIT using a large sample size to better understand potential risk factors influencing P-OIT safety. Methods: Data were obtained from the Food Allergy Immunotherapy (FAIT) registry, which collects real-world OIT data from community and academic allergy clinics across Canada. Multivariable logistic regression modeling was performed to examine the relationship between baseline patient characteristics and reactions during P-OIT. Multiple imputation was applied to reduce potential bias caused by missingness and to maximize the use of available information to preserve statistical power. Results: Between April 2017 and June 2021, a total of 653 eligible patients initiated P-OIT. Multivariable regression analysis showed pre-OIT grade 2+ initial reaction (odds ratio [OR] = 1.33, 95% confidence interval [CI] 1.10, 1.61), allergic rhinitis (OR = 1.60, 95% CI 1.08, 2.38), older age (OR = 1.01, 95% CI 1.00, 1.02), and higher baseline peanut-specific IgE (OR = 1.02, 95% CI 1.02, 1.03) were associated with grade 2+ reaction during P-OIT after adjusting for potential risk factors. Conclusion: Our study identified several clinically important risk factors for grade 2+ reactions during P-OIT: pre-OIT grade 2+ initial reaction, allergic rhinitis, older age, and higher baseline peanut-specific IgE. These results highlight the need for individualized risk stratification for OIT.

Abstract A food ladder is a form of home-based dietary advancement therapy that gradually increases exposure to an allergenic food through the gradual introduction of egg or milk containing food with increasing quantity and allergenicity from extensively heated forms, such as baked goods, to less processed products. While widely considered safe, the food ladder is not risk-free and most of the egg and milk ladder studies only included preschoolers with mild egg and milk allergies, and with no or well-controlled asthma. We propose a Food Ladder Safety Checklist to assist with patient selection using “4 A's” based on available evidence for food ladders, including Age, active or poorly controlled Asthma, history of Anaphylaxis, and Adherence.

Abstract Background Over the past decade, human Interleukin 33 (hIL-33) has emerged as a key contributor to the pathogenesis of numerous inflammatory diseases. Despite the existence of several commercial hIL-33 assays spanning multiple platform technologies, their ability to provide accurate hIL-33 concentration measurements and to differentiate between active (reduced) and inactive (oxidized) hIL-33 in various matrices remains uncertain. This is especially true for lower sample volumes, matrices with low hIL-33 concentrations, and matrices with elevated levels of soluble Interleukin 1 Receptor-Like 1 (sST2), an inactive form of ST2 that competes with membrane bound ST2 for hIL-33 binding. Results We tested the performance of several commercially available hIL-33 detection assays in various human matrices and found that most of these assays lacked the sensitivity to accurately detect reduced hIL-33 at biologically relevant levels (sub-to-low pg/mL), especially in the presence of human sST2 (hsST2), and/or lacked sufficient target specificity. To address this, we developed and validated a sensitive and specific enzyme-linked immunosorbent assay (ELISA) capable of detecting reduced and total hIL-33 levels even in the presence of high concentrations of sST2. By incorporating the immuno-polymerase chain reaction (iPCR) platform, we further increased the sensitivity of this assay for the reduced form of hIL-33 by ~ 52-fold. Using this hIL-33 iPCR assay, we detected hIL-33 in postmortem human vitreous humor (VH) samples from donors with age-related macular degeneration (AMD) and found significantly increased hIL-33 levels when compared to control individuals. No statistically significant difference was observed in aqueous humor (AH) from AMD donors nor in plasma and nasosorption fluid (NF) from asthma patients compared to control individuals. Conclusions Unlike existing commercial hIL-33 assays, our hIL-33 bioassays are highly sensitive and specific and can accurately quantify hIL-33 in various human clinical matrices, including those with high levels of hsST2. Our results provide a proof of concept of the utility of these assays in clinical trials targeting the hIL-33/hST2 pathway.

Abstract Food ladders are clinical tools already widely used in Europe for food reintroduction in milk- and egg-allergic children. Previously developed milk and egg ladders have limited applicability to Canadian children due to dietary differences and product availability. Herein we propose a Canadian version of cow’s milk and egg food ladders and discuss the potential role that food ladders may have in the care of children with IgE-mediated allergies to cow’s milk and/or egg, as either a method of accelerating the acquisition of tolerance in those who would outgrow on their own, or as a form of modified oral immunotherapy in those with otherwise persistent allergy.

Abstract Background Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare but serious delayed hypersensitivity reaction that can be caused by antibiotic exposure. The reaction typically develops in 2 to 6 weeks. The pathophysiology is thought to involve toxic drug metabolites acting as a hapten, triggering a systemic response. The diagnosis is made clinically but can be confirmed using assays such as the lymphocyte toxicity assay (LTA), which correlates cell death upon exposure to drug metabolites with susceptibility to hypersensitivity reactions. Case presentations Case 1 involves a previously healthy 11-month-old male with first exposure to amoxicillin-clavulanate, prescribed for seven days to treat a respiratory infection. The patient developed DRESS fourteen days after starting the drug and was successfully treated with corticosteroids. LTA testing confirmed patient susceptibility to hypersensitivity reactions with amoxicillin-clavulanate. Parental samples were also tested, showing both maternal and paternal susceptibility. Neither parent reported prior hypersensitivity reactions. Lifelong penicillin avoidance for the patient was advised along with the notation in medical records of penicillin allergy. The parents were advised to avoid penicillin class antibiotics and be monitored closely for DRESS if they are exposed. Case 2 involves an 11-year-old female with atopic dermatitis with first exposure to amoxicillin-clavulanate, prescribed for ten days to treat a secondary bacterial skin infection. She developed DRESS eleven days after starting antibiotics and was successfully treated with corticosteroids. LTA testing confirmed patient susceptibility to hypersensitivity reactions with amoxicillin-clavulanate. Maternal samples were also tested and showed sensitivity. The mother reported no prior hypersensitivity reactions. Lifelong penicillin avoidance for the patient was advised along with the notation in medical records of penicillin allergy. Conclusions Amoxicillin-clavulanate is a commonly used antibiotic and the cases we have described suggest that it should be recognized as a potential cause of DRESS in pediatric patients. Furthermore, these cases contribute to current literature supporting that there may be a shorter latent period in DRESS induced by antibiotics. We have also shown that the LTA can be a helpful tool to confirm DRESS reactions, and that testing may have potential implications for family members.

Abstract Beta-lactam allergy is reported in 5–10% of children in North America, but up to 94–97% of patients are deemed not allergic after allergist assessment. The utility of standardized skin testing for penicillin allergy in the pediatric population has been recently questioned. Oral drug challenges when appropriate, are preferred over skin testing, and can definitively rule out immediate, IgE-mediated drug allergy. To our knowledge, this is the only pediatric study to assess the reliability of a penicillin allergy stratification tool using a paper and electronic clinical algorithm. By using an electronic algorithm, we identified 61 patients (of 95 deemed not allergic by gold standard allergist decision) as low risk for penicillin allergy, with no false negatives and without the need for allergist assessment or skin testing. In this study, we demonstrate that an electronic algorithm can be used by various pediatric clinicians when evaluating possible penicillin allergy to reliably identify low risk patients. We identified the electronic algorithm was superior to the paper version, capturing an even higher percentage of low risk patients than the paper version. By developing an electronic algorithm to accurately assess penicillin allergy risk based on appropriate history, without the need for diagnostic testing or allergist assessment, we can empower non-allergist health care professionals to safely de-label low risk pediatric patients and assist in alleviating subspecialty wait times for penicillin allergy assessment.

Abstract The vast majority of individuals labelled as allergic are not deemed truly allergic upon appropriate assessment by an allergist. A label of beta-lactam allergy carries important risks for individual and public health. This article provides an overview of beta-lactam allergy, implications of erroneous beta-lactam allergy labels and the impact that can be provided by structured allergy assessment. We provide recommendations on how to stratify risk of beta-lactam allergy, beta lactam challenge protocols as well as management of patients at high risk of beta-lactam allergy.

Abstract Drug allergy encompasses a spectrum of immunologically-mediated hypersensitivity reactions with varying mechanisms and clinical presentations. This type of adverse drug reaction not only affects patient quality of life, but may also lead to delayed treatment, unnecessary investigations, and even mortality. Given the myriad of symptoms associated with the condition, diagnosis is often challenging. Therefore, referral to an allergist experienced in the identification, diagnosis and management of drug allergy is recommended if a drug-induced allergic reaction is suspected. Diagnosis relies on a careful history and physical examination and, in some instances, skin testing and graded challenges. Induction of drug tolerance procedures may also be required. The most effective strategy for the management of drug allergy is avoidance or discontinuation of the offending drug. When available, alternative medications with unrelated chemical structures should be substituted. Cross-reactivity among drugs should be taken into consideration when choosing alternative agents. Additional therapy for drug hypersensitivity reactions is largely supportive and may include topical corticosteroids, oral antihistamines and, in severe cases, systemic corticosteroids. In the event of anaphylaxis, the treatment of choice is injectable epinephrine. If a particular drug to which the patient is allergic is indicated and there is no suitable alternative, induction of drug tolerance procedures may be considered to induce temporary tolerance to the drug. This article provides a background on drug allergy and strategies for the diagnosis and management of some of the most common drug-induced allergic reactions, such as penicillin, sulfonamides, cephalosporins, radiocontrast media, local anesthetics, general anesthetics, acetylsalicylic acid and non-steroidal anti-inflammatory drugs, and therapeutic monoclonal antibodies.

Abstract Background Ginseng is a perennial herb used in traditional Chinese medicine, which has become increasingly popular world-wide due to its proposed medicinal effects. There are two major species of ginseng, Panax ginseng (Korean or Asian ginseng), and Panax quinquefolius (American ginseng). Although cases of allergy due to Korean ginseng have been reported in adults, there are no reported cases of allergy to American ginseng, and no reported cases of ginseng allergy in pediatric patients. Case presentation We present two unique cases of pediatric patients with suspected allergic reactions to American ginseng. The first patient is a 6-year-old girl who presented to the emergency department in anaphylaxis (urticaria and respiratory symptoms) minutes after inhaling powdered American ginseng. There was evidence of sensitization to American ginseng on skin prick testing (SPT) (13 × 12 mm wheal) and evidence of allergy to American ginseng on basophil activation testing, with a dose-dependent increase in expression of CD63 on basophils in response to American ginseng extract. The second patient is a 3-year-old boy who presented with recurrent allergic conjunctivitis upon exposure to aerosolized powdered ginseng, with evidence of sensitization to American ginseng on SPT (13 × 7 mm wheal), but with no evidence of IgE-mediated allergic reaction during oral challenge with American ginseng powder. Conclusions These cases highlight two different allergic responses to American ginseng in pediatric patients. To our knowledge, these are the first reported cases of allergy to American ginseng, in addition to the first reported cases of allergy to ginseng in pediatric patients.

Antibodies against cell surface antigens may be internalized through their specific interactions with these proteins and in some cases may induce or perturb antigen internalization. The anti-cancer efficacy of antibody-drug conjugates is thought to rely on their uptake by cancer cells expressing the surface antigen. Numerous techniques, including microscopy and flow cytometry, have been used to identify antibodies with desired cellular uptake rates. To enable quantitative measurements of internalization of labeled antibodies, an assay based on internalized and quenched fluorescence was developed. For this approach, we generated novel anti-Alexa Fluor monoclonal antibodies (mAbs) that effectively and specifically quench cell surface-bound Alexa Fluor 488 or Alexa Fluor 594 fluorescence. Utilizing Alexa Fluor-labeled mAbs against the EphA2 receptor tyrosine kinase, we showed that the anti-Alexa Fluor reagents could be used to monitor internalization quantitatively over time. The anti-Alexa Fluor mAbs were also validated in a proof of concept dual-label internalization assay with simultaneous exposure of cells to two different mAbs. Importantly, the unique anti-Alexa Fluor mAbs described here may also enable other single- and dual-label experiments, including label detection and signal enhancement in macromolecules, trafficking of proteins and microorganisms, and cell migration and morphology.