Association of a Network of Immunologic Response and Clinical Features With the Functional Recovery From Crotalinae Snakebite Envenoming.



The immunologic pathways activated during snakebite envenoming (SBE) are poorly described, and their association with recovery is unclear. The immunologic response in SBE could inform a prognostic model to predict recovery. The purpose of this study was to develop pre- and post-antivenom prognostic models comprised of clinical features and immunologic cytokine data that are associated with recovery from SBE.

Materials and methods

We performed a prospective cohort study in an academic medical center emergency department. We enrolled consecutive patients with Crotalinae SBE and obtained serum samples based on previously described criteria for the Surgical Critical Care Initiative (SC2i)( Identifier: NCT02182180). We assessed a standard set of clinical variables and measured 35 unique cytokines using Luminex Cytokine 35-Plex Human Panel pre- and post-antivenom administration. The Patient-Specific Functional Scale (PSFS), a well-validated patient-reported outcome of functional recovery, was assessed at 0, 7, 14, 21 and 28 days and the area under the patient curve (PSFS AUPC) determined. We performed Bayesian Belief Network (BBN) modeling to represent relationships with a diagram composed of nodes and arcs. Each node represents a cytokine or clinical feature and each arc represents a joint-probability distribution (JPD).


Twenty-eight SBE patients were enrolled. Preliminary results from 24 patients with clinical data, 9 patients with pre-antivenom and 11 patients with post-antivenom cytokine data are presented. The group was mostly female (82%) with a mean age of 38.1 (SD ± 9.8) years. In the pre-antivenom model, the variables most closely associated with the PSFS AUPC are predominantly clinical features. In the post-antivenom model, cytokines are more fully incorporated into the model. The variables most closely associated with the PSFS AUPC are age, antihistamines, white blood cell count (WBC), HGF, CCL5 and VEGF. The most influential variables are age, antihistamines and EGF. Both the pre- and post-antivenom models perform well with AUCs of 0.87 and 0.90 respectively.


Pre- and post-antivenom networks of cytokines and clinical features were associated with functional recovery measured by the PSFS AUPC over 28 days. With additional data, we can identify prognostic models using immunologic and clinical variables to predict recovery from SBE.





Published Version (Please cite this version)


Publication Info

Gerardo, Charles J, Elizabeth Silvius, Seth Schobel, John C Eppensteiner, Lauren M McGowan, Eric A Elster, Allan D Kirk, Alexander T Limkakeng, et al. (2021). Association of a Network of Immunologic Response and Clinical Features With the Functional Recovery From Crotalinae Snakebite Envenoming. Frontiers in immunology, 12. p. 628113. 10.3389/fimmu.2021.628113 Retrieved from

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Charles J. Gerardo

Professor of Emergency Medicine

Dr. Gerardo is Professor and Chair for the Department of Emergency Medicine.  He graduated with honors from Stanford University with a Bachelor’s of Science in Biology, and received his MD degree from University of California, Davis.  He went on to complete his residency training in Emergency Medicine at Loma Linda University Medical Center.  He completed his Masters of Health Sciences from the Duke University Clinical Research and Training Program.  In 2000, he joined Emergency Medicine faculty at Duke University and has served in numerous educational, research and administrative leadership roles. His current research focuses on US and global snake envenomation using a variety of methodologies from transitional science and clinical trials to machine learning and implementation science. He has over 90 peer reviewed publications and book chapters, and is published in JAMA, PLOS Medicine, Annals of Emergency Medicine, Academic Emergency Medicine and Clinical Toxicology. 


John C Eppensteiner

Assistant Professor of Emergency Medicine

John Eppensteiner, MD is an Assistant Professor in the Department of Emergency Medicine. He completed his emergency medicine training here at Duke University during which time he served as chief resident. He also completed the first-of-its-kind integrated research fellowship year which is now an established pathway in the Duke Emergency Medicine Residency Program. His research interests are primarily focused on the immune response to trauma and early inflammatory biomarkers used in predictive modeling after traumatic injury. Dr. Eppensteiner has also served as site PI for several clinical trials enrolling patients in the Emergency Department.


Allan Douglas Kirk

David C. Sabiston, Jr. Distinguished Professor of Surgery

I am a surgeon with interest in immune management of transplant recipients. I am particularly interested in therapies that influence T cell costimulation pathways and adjuvant therapies that facilitate costimulation blockade to prevent the rejection of transplanted organs without undue suppression of protective immunity. I am also interested in understanding how injury, such as that occurring during trauma or in elective surgery, influences immune responses and subsequent healing following injury.


Alexander Tan Limkakeng

Professor of Emergency Medicine

Dr. Alexander T. Limkakeng, Jr., MD, MHSc, FACEP is a Professor of Emergency Medicine, Vice Chair of Clinical Research, Director of the Acute Care Research Team, and Director of the Resident Research Fellowship for the Department of Emergency Medicine in the Duke University School of Medicine in Durham, North Carolina.

Dr. Limkakeng has served as chair of the American College of Emergency Physicians (ACEP) Research Committee, and been the Course Director of the ACEP Research Forum from 2016-2018, the largest emergency medical research platform in the nation. He is also the Assistant Director of ACEP’s Emergency Medicine Basic Research Skills course. He was elected to the Nominating Committee of the Society of Academic Emergency Medicine.

As a researcher, Dr. Limkakeng has led multiple clinical trials and interdepartmental sponsored projects and is author on over 100 peer-reviewed manuscripts. These include studies in emergency conditions such as COVID-19, traumatic brain injury, hypertension, heart failure, thrombosis, stroke, envenomations, and septic shock. His research has been funded by grants and contracts totaling over $9 million dollars. He has lectured internationally on acute coronary syndrome, responsible conduct of research, design of clinical trials, and precision medicine in emergency care. He has led Duke’s involvement in NIH-funded research networks and in industry-funded work that led to FDA approval for multiple high-sensitivity cardiac troponin assays and point-of-care COVID-19 diagnostic tests. He has servesd as Co-PI for the Duke U24 Hub in the NIH Early Phase Pain Investigation Clinical Network (EPPIC-Net) (1U24NS114416) and now serves as a co-PI on the Duke U24 Hub award (1U24NS129498) in the NIH Strategies to Innovate Emergency Care Clinical Trials (SIREN) Network and in the NIH NINDS Strokenet network (1U24NS135250)

His personal research interest is finding new ways to diagnose acute coronary syndrome. In particular, he is interested in novel biomarkers and precision medicine approaches to this problem. The common element throughout this work is a focus on time-sensitive health conditions.

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