8 research outputs found
Development of a modified lymphocyte transformation test for diagnosing drug-induced liver injury associated with an adaptive immune response
Drug-induced liver injury (DILI) is a growing problem. Diagnostic methods to differentiate DILI caused by an adaptive immune response from liver injury of other causes or to identify the responsible drug in patients receiving multiple drugs, herbals and/or dietary supplements (polypharmacy) have not yet been established. The lymphocyte transformation test (LTT) has been proposed as a diagnostic method to determine if a subject with an apparent hypersensitivity reaction has become sensitized to a specific drug. In this test, peripheral blood mononuclear cells (PBMC) collected from a subject are incubated with drug(s) suspected of causing the reaction. Cell proliferation, measured by the incorporation of [3H]-thymidine into new DNA, is considered evidence of a drug-specific immune response. The objectives of the current studies were to: (1) develop and optimize a modified version of the LTT (mLTT) and (2) investigate the feasibility of using the mLTT for diagnosing DILI associated with an adaptive immune response and identifying the responsible drug. PBMC collected from donors with a history of drug hypersensitivity reactions to specific drugs (manifested as skin rash) were used as positive controls for assay optimization. Following optimization, samples collected from 24 subjects enrolled in the U.S. Drug-Induced Liver Injury Network (DILIN) were tested in the mLTT. Using cytokine and granzyme B production as the primary endpoints to demonstrate lymphocyte sensitization to a specific drug, most samples from the DILIN subjects failed to respond. However, robust positive mLTT responses were observed for two of four samples from three DILIN subjects with hepatitis due to isoniazid (INH). We conclude that the mLTT, as performed here on frozen and thawed PBMC, is not a reliable test for diagnosing DILI caused by all drugs, but that it may be useful for confirming the role of the adaptive immune response in DILI ascribed to INH
Development of a modified lymphocyte transformation test for diagnosing drug-induced liver injury associated with an adaptive immune response
New approaches to investigate drug-induced hypersensitivity
The workshop on “New approaches to investigate drug-induced hypersensitivity” was held on June 5 2014 at the Foresight centre, University of Liverpool. The aims of the workshop were to (1) discuss our current understanding of the genetic, clinical and chemical basis of small molecule drug hypersensitivity (2) highlight the current status of assays that might be developed to predict potential drug immunogenicity, (3) identify the limitations, knowledge gaps and challenges that limit the use of these assays and utilise the knowledge gained from the workshop to develop a pathway to establish new and improved assays that better predict drug-induced hypersensitivity reactions during the early stages of drug development. This perspective article reviews the clinical and immunological bases of drug hypersensitivity and summarises various experts’ views on the different topics covered during the meeting
Development and partial validation of a mouse model for predicting drug hypersensitivity reactions
Development of a screening assay to evaluate the potential of drugs to cause immune-mediated hypersensitivity reactions
Discovery and Characterization of (<i>R</i>)‑6-Neopentyl-2-(pyridin-2-ylmethoxy)-6,7-dihydropyrimido[2,1‑<i>c</i>][1,4]oxazin-4(9<i>H</i>)‑one (PF-06462894), an Alkyne-Lacking Metabotropic Glutamate Receptor 5 Negative Allosteric Modulator Profiled in both Rat and Nonhuman Primates
We
previously observed a cutaneous type IV immune response in nonhuman
primates (NHP) with the mGlu<sub>5</sub> negative allosteric modulator
(NAM) <b>7</b>. To determine if this adverse event was chemotype-
or mechanism-based, we evaluated a distinct series of mGlu<sub>5</sub> NAMs. Increasing the sp<sup>3</sup> character of high-throughput
screening hit <b>40</b> afforded a novel morpholinopyrimidone
mGlu<sub>5</sub> NAM series. Its prototype, (<i>R</i>)-6-neopentyl-2-(pyridin-2-ylmethoxy)-6,7-dihydropyrimidoÂ[2,1-<i>c</i>]Â[1,4]Âoxazin-4Â(9<i>H</i>)-one (PF-06462894, <b>8</b>), possessed favorable properties and a predicted low clinical
dose (2 mg twice daily). Compound <b>8</b> did not show any
evidence of immune activation in a mouse drug allergy model. Additionally,
plasma samples from toxicology studies confirmed that <b>8</b> did not form any reactive metabolites. However, <b>8</b> caused
the identical microscopic skin lesions in NHPs found with <b>7</b>, albeit with lower severity. Holistically, this work supports the
hypothesis that this unique toxicity may be mechanism-based although
additional work is required to confirm this and determine clinical
relevance
Discovery and Characterization of (<i>R</i>)‑6-Neopentyl-2-(pyridin-2-ylmethoxy)-6,7-dihydropyrimido[2,1‑<i>c</i>][1,4]oxazin-4(9<i>H</i>)‑one (PF-06462894), an Alkyne-Lacking Metabotropic Glutamate Receptor 5 Negative Allosteric Modulator Profiled in both Rat and Nonhuman Primates
We
previously observed a cutaneous type IV immune response in nonhuman
primates (NHP) with the mGlu<sub>5</sub> negative allosteric modulator
(NAM) <b>7</b>. To determine if this adverse event was chemotype-
or mechanism-based, we evaluated a distinct series of mGlu<sub>5</sub> NAMs. Increasing the sp<sup>3</sup> character of high-throughput
screening hit <b>40</b> afforded a novel morpholinopyrimidone
mGlu<sub>5</sub> NAM series. Its prototype, (<i>R</i>)-6-neopentyl-2-(pyridin-2-ylmethoxy)-6,7-dihydropyrimidoÂ[2,1-<i>c</i>]Â[1,4]Âoxazin-4Â(9<i>H</i>)-one (PF-06462894, <b>8</b>), possessed favorable properties and a predicted low clinical
dose (2 mg twice daily). Compound <b>8</b> did not show any
evidence of immune activation in a mouse drug allergy model. Additionally,
plasma samples from toxicology studies confirmed that <b>8</b> did not form any reactive metabolites. However, <b>8</b> caused
the identical microscopic skin lesions in NHPs found with <b>7</b>, albeit with lower severity. Holistically, this work supports the
hypothesis that this unique toxicity may be mechanism-based although
additional work is required to confirm this and determine clinical
relevance