Idiosyncratic adverse drug reactions are unpredictable, dose independent and potentially life threatening; this makes them a major factor contributing to the cost and uncertainty of drug development. Clinical data suggests that many such reactions involve immune mechanisms, and genetic association studies have identified strong linkage between drug hypersensitivity reactions to several drugs and specific HLA alleles. One of the strongest such genetic associations has been found for the antiviral drug abacavir, which causes severe adverse reactions exclusively in patients expressing the HLA molecular variant B*57:01. The mechanism by which abacavir induces this pathologic T cell response remains unclear. We have strong preliminary data that systemic adverse drug reactions can be caused by the formation of an altered peptide repertoire that triggers T cell immunity in HLA associated drug hypersensitivity. Using in vitro binding assays, MHC ligand elution and X- ray crystallography, we have shown that abacavir binds inside the F-pocket of HLA B*57:01, thereby altering its specificity. This supports a novel hypothesis that systemic adverse drug reactions are due to the formation of an altered peptide repertoire that triggers T cell immunity in HLA associated drug hypersensitivity. The objective is to utilize this approach to define the roles of three drugs in altering peptide binding to HLA and to guide development of drug variants that have a reduced likelihood of causing HLA linked drug hypersensitivity.
Our specific aims are: 1) Identify peptides that bind to HLA-B molecules in a drug dependent manner. We will perform affinity measurements of a combinatorial peptide library in the presence or absence of the drug to the relevant HLA-B molecule and confirm drug effects detected in the MHC binding assays using MHC ligand elution experiments with live cells. 2) Determine structures of drugs complexed to HLA-B molecules associated with hypersensitivity. We will determine the structure of drug/peptide/HLA complexes by X-ray crystallography. As available, we will utilize the peptides identified in Aim 1 for crystallization, which we have foun to facilitate drug/peptide/HLA complex formation in the case of abacavir. 3) a. Characterization of functional consequences of the drug-induced altered peptide repertoire. b. Characterization of the functional effects of drug variation on HLA associated drug recognition. We will utilize the structural information from Aim 2 to design drug variants that do not bind HLA molecules and are therefore predicted to not cause T cell immune responses. We will test the drug variants for T recognition using samples from hypersensitive patients. The ability to test specific drug HLA combinations in molecular binding assays for effects on the self repertoire could drastically improve the ability to detect HLA linked drug hypersensitivities. Moreover, the drug variation approach may be attractive to global healthcare endeavors where a potentially small change in a proven therapy would simplify treatment.

Public Health Relevance

The proposed research is relevant to public health because drug related morbidity and mortality is a significant health problem estimated to cost $136 billion annually. Moreover, the discovery of drug interaction mechanisms is ultimately expected to increase understanding of why HLA alleles are associated with human diseases. Thus, the proposed research is relevant to the part of the NIHs mission that pertains to developing fundamental knowledge that will help enhance health and reduce the burdens of illness.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
4R01AI103348-04
Application #
9096713
Study Section
Cellular and Molecular Immunology - A Study Section (CMIA)
Program Officer
Davidson, Wendy F
Project Start
2013-07-01
Project End
2017-06-30
Budget Start
2016-07-01
Budget End
2017-06-30
Support Year
4
Fiscal Year
2016
Total Cost
Indirect Cost
Name
University of Florida
Department
Pathology
Type
Schools of Medicine
DUNS #
969663814
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Norton, Allison Eaddy; Konvinse, Katherine; Phillips, Elizabeth J et al. (2018) Antibiotic Allergy in Pediatrics. Pediatrics 141:
Trubiano, Jason A; Grayson, M Lindsay; Phillips, Elizabeth J et al. (2018) Antibiotic allergy testing improves antibiotic appropriateness in patients with cancer. J Antimicrob Chemother 73:3209-3211
Phillips, Elizabeth J; Sukasem, Chonlaphat; Whirl-Carrillo, Michelle et al. (2018) Clinical Pharmacogenetics Implementation Consortium Guideline for HLA Genotype and Use of Carbamazepine and Oxcarbazepine: 2017 Update. Clin Pharmacol Ther 103:574-581
Derrick, Michael Ian; Williams, Kristina Blis; Shade, Lincoln Morris Payne et al. (2018) A survey of drug allergy training opportunities in the United States. J Allergy Clin Immunol Pract 6:302-304
Stone Jr, Cosby A; Liu, Yiwei; Relling, Mary V et al. (2018) Immediate Hypersensitivity to Polyethylene Glycols and Polysorbates: More Common Than We Have Recognized. J Allergy Clin Immunol Pract :
Trubiano, Jason A; Strautins, Kaija; Redwood, Alec J et al. (2018) The Combined Utility of Ex Vivo IFN-? Release Enzyme-Linked ImmunoSpot Assay and In Vivo Skin Testing in Patients with Antibiotic-Associated Severe Cutaneous Adverse Reactions. J Allergy Clin Immunol Pract 6:1287-1296.e1
Stone Jr, Cosby A; Hemler, Jonathan A; Commins, Scott P et al. (2018) Reply. J Allergy Clin Immunol 141:1957-1958
Cook, Kathryn M; Gillon, Jessica; Grisso, Alison G et al. (2018) Incidence of Nephrotoxicity Among Pediatric Patients Receiving Vancomycin With Either Piperacillin-Tazobactam or Cefepime: A Cohort Study. J Pediatric Infect Dis Soc :
Trubiano, Jason A; Grayson, M Lindsay; Thursky, Karin A et al. (2018) How antibiotic allergy labels may be harming our most vulnerable patients. Med J Aust 208:469-470
Phillips, Elizabeth J (2018) NEW STRATEGIES TO PREDICT AND PREVENT SERIOUS IMMUNOLOGICALLY MEDIATED ADVERSE DRUG REACTIONS. Trans Am Clin Climatol Assoc 129:74-87

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