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 #
5R01AI103348-02
Application #
8692643
Study Section
Cellular and Molecular Immunology - A Study Section (CMIA)
Program Officer
Plaut, Marshall
Project Start
2013-07-01
Project End
2017-06-30
Budget Start
2014-07-01
Budget End
2015-06-30
Support Year
2
Fiscal Year
2014
Total Cost
Indirect Cost
Name
University of Florida
Department
Pathology
Type
Schools of Medicine
DUNS #
City
Gainesville
State
FL
Country
United States
Zip Code
32611
Pavlos, Rebecca; McKinnon, Elizabeth J; Ostrov, David A et al. (2017) Shared peptide binding of HLA Class I and II alleles associate with cutaneous nevirapine hypersensitivity and identify novel risk alleles. Sci Rep 7:8653
Peter, Jonathan Grant; Lehloenya, Rannakoe; Dlamini, Sipho et al. (2017) Severe Delayed Cutaneous and Systemic Reactions to Drugs: A Global Perspective on the Science and Art of Current Practice. J Allergy Clin Immunol Pract 5:547-563
Trubiano, Jason A; Redwood, Alec; Strautins, Kaija et al. (2017) Drug-specific upregulation of CD137 on CD8+ T cells aids in the diagnosis of multiple antibiotic toxic epidermal necrolysis. J Allergy Clin Immunol Pract 5:823-826
Trubiano, Jason A; Thursky, Karin A; Stewardson, Andrew J et al. (2017) Impact of an Integrated Antibiotic Allergy Testing Program on Antimicrobial Stewardship: A Multicenter Evaluation. Clin Infect Dis 65:166-174
Somogyi, Andrew A; Phillips, Elizabeth (2017) Genomic testing as a tool to optimise drug therapy. Aust Prescr 40:101-104
Trubiano, Jason A; Strautins, Kaija; Redwood, Alec J et al. (2017) 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 :
Pavlos, R; Redwood, A; Phillips, E (2017) AdDRESSing T-cell responses to antituberculous drugs. Br J Dermatol 176:292-293
Karnes, Jason H; Bastarache, Lisa; Shaffer, Christian M et al. (2017) Phenome-wide scanning identifies multiple diseases and disease severity phenotypes associated with HLA variants. Sci Transl Med 9:
Stone Jr, Cosby A; Hemler, Jonathan A; Commins, Scott P et al. (2017) Anaphylaxis after zoster vaccine: Implicating alpha-gal allergy as a possible mechanism. J Allergy Clin Immunol 139:1710-1713.e2
Garon, Sarah L; Pavlos, Rebecca K; White, Katie D et al. (2017) Pharmacogenomics of off-target adverse drug reactions. Br J Clin Pharmacol 83:1896-1911

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