Drug hypersensitivity reactions (DHRs) are a type of adverse drug reaction that can occur with different classes of drugs and affect multiple organ systems and patient populations. DHRs can be classified as allergic or non-allergic based on the cellular mechanisms involved. Whereas nonallergic reactions rely mainly on the innate immune system, allergic reactions involve the generation of an adaptive immune response. Consequently, drug allergies are DHRs for which an immunological mechanism, with antibody and/or T cell, is demonstrated. Despite decades of research, methods to predict the potential for a new chemical entity to cause DHRs or to correctly attribute DHRs to a specific mechanism and a specific molecule are not well-established. This review will focus on allergic reactions induced by systemically administered low-molecular weight drugs with an emphasis on drug- and patient-specific factors that could influence the development of DHRs. Strategies for predicting and diagnosing DHRs, including potential tools based on the current state of the science, will also be discussed.

HepatologyVolume 73, Issue 1 p. 452-455 Clinical Observations in Hepatology Biopsy Pathology and Immunohistochemistry of a Case of Immune-Mediated Drug-Induced Liver Injury With Atabecestat Sandra De Jonghe, Corresponding Author sdjonghe@its.jnj.com A Division of Janssen Pharmaceutica NV, Janssen Research & Development, Beerse, Belgium ADDRESS CORRESPONDENCE AND REPRINT REQUESTS TO: Sandra De Jonghe, D.V.M. Janssen Research & Development, a Division of Janssen Pharmaceutica NV Turnhoutseweg 30, B-2340 Beerse, Belgium E-mail: sdjonghe@its.jnj.com Tel.: +32 (0)14606732Search for more papers by this authorDaniel Weinstock, Janssen Research & Development, LLC, Spring House, PASearch for more papers by this authorJason Aligo, Janssen Research & Development, LLC, Spring House, PASearch for more papers by this authorKay Washington, Department of Pathology, Vanderbilt University Medical Center, Nashville, TNSearch for more papers by this authorDean Naisbitt, MRC Centre for Drug Safety Science, Department of Molecular & Clinical Pharmacology, University of Liverpool, Liverpool, United KingdomSearch for more papers by this author Sandra De Jonghe, Corresponding Author sdjonghe@its.jnj.com A Division of Janssen Pharmaceutica NV, Janssen Research & Development, Beerse, Belgium ADDRESS CORRESPONDENCE AND REPRINT REQUESTS TO: Sandra De Jonghe, D.V.M. Janssen Research & Development, a Division of Janssen Pharmaceutica NV Turnhoutseweg 30, B-2340 Beerse, Belgium E-mail: sdjonghe@its.jnj.com Tel.: +32 (0)14606732Search for more papers by this authorDaniel Weinstock, Janssen Research & Development, LLC, Spring House, PASearch for more papers by this authorJason Aligo, Janssen Research & Development, LLC, Spring House, PASearch for more papers by this authorKay Washington, Department of Pathology, Vanderbilt University Medical Center, Nashville, TNSearch for more papers by this authorDean Naisbitt, MRC Centre for Drug Safety Science, Department of Molecular & Clinical Pharmacology, University of Liverpool, Liverpool, United KingdomSearch for more papers by this author First published: 02 June 2020 https://doi.org/10.1002/hep.31403Citations: 3 Potential conflict of interest: Dr. Weinstock, Dr. Aligo and S. De Jonghe are employed and own stock in Johnson & Johnson. Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Citing Literature Volume73, Issue1January 2021Pages 452-455 This article also appears in:Clinical Observations in Hepatology RelatedInformation

The pathogenesis of Staphylococcus aureus is thought to depend on the production of pore-forming leukocidins that kill leukocytes and lyse erythrocytes. Two leukocidins, Leukocidin ED (LukED) and γ-Hemolysin AB (HlgAB), are necessary and sufficient to kill mice upon infection and toxin challenge. We demonstrate that LukED and HlgAB cause vascular congestion and derangements in vascular fluid distribution that rapidly cause death in mice. The Duffy antigen receptor for chemokines (DARC) on endothelial cells, rather than leukocytes or erythrocytes, is the critical target for lethality. Consistent with this, LukED and HlgAB injure primary human endothelial cells in a DARC-dependent manner, and mice with DARC-deficient endothelial cells are resistant to toxin-mediated lethality. During bloodstream infection in mice, DARC targeting by S. aureus causes increased tissue damage, organ dysfunction, and host death. The potential for S. aureus leukocidins to manipulate vascular integrity highlights the importance of these virulence factors.

The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP), and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative changes in rats and mice. The purpose of this publication is to provide a standardized nomenclature for classifying changes observed in the hematolymphoid organs, including the bone marrow, thymus, spleen, lymph nodes, mucosa-associated lymphoid tissues, and other lymphoid tissues (serosa-associated lymphoid clusters and tertiary lymphoid structures) with color photomicrographs illustrating examples of the lesions. Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. The nomenclature for these organs is divided into 3 terminologies: descriptive, conventional, and enhanced. Three terms are listed for each diagnosis. The rationale for this approach and guidance for its application to toxicologic pathology are described in detail below.

The cytokines TNF-α and IL-17A are elevated in a variety of autoimmune diseases, including rheumatoid arthritis. Both cytokines are targets of several biologic drugs used in the clinic, but unfortunately many patients are refractory to these therapies. IL-17A and TNF-α are known to mediate signaling synergistically to drive expression of inflammatory genes. Hence, combined blockade of TNF-α and IL-17A represents an attractive treatment strategy in autoimmune settings where monotherapy is not fully effective. However, a major concern with this approach is the potential predisposition to opportunistic infections that might outweigh any clinical benefits. Accordingly, we examined the impact of individual versus combined neutralization of TNF-α and IL-17A in a mouse model of rheumatoid arthritis (collagen-induced arthritis) and the concomitant susceptibility to infections that are likely to manifest as side effects of blocking these cytokines (oral candidiasis or tuberculosis). Our findings indicate that combined neutralization of TNF-α and IL-17A was considerably more effective than monotherapy in improving collagen-induced arthritis disease even when administered at a minimally efficacious dose. Encouragingly, however, dual cytokine blockade did not cooperatively impair antimicrobial host defenses, as mice given combined IL-17A and TNF-α neutralization displayed infectious profiles and humoral responses comparable to mice given high doses of individual anti–TNF-α or anti–IL-17A mAbs. These data support the idea that combined neutralization of TNF-α and IL-17A for refractory autoimmunity is likely to be associated with acceptable and manageable risks of opportunistic infections associated with these cytokines.

Molecular pathology is a rapidly progressing field. As members of a multidisciplinary investigational team, pathologists are increasingly being asked to have a basic understanding of molecular techniques, their usefulness, and their limitations. The correlation of the morphologic phenotype with the cellular and gene based pathogenesis of disease lies within this realm. This chapter will focus on appropriate sample collection for molecular pathology as well as the utility of various molecular techniques as tools from for use in drug discovery and through development.

An important component of safety assessment of new pharmaceuticals is evaluation of their potential to increase the risk of developing cancer in humans. The traditional 2-year rodent bioassay often is not feasible or scientifically applicable for evaluation of biotherapeutics. Additionally, it has poor predictive value for non-genotoxic immunosuppressive compounds. Thus, there is a need for alternative testing strategies. A novel 3-stage tumor model in syngeneic C3H/HeN mice was evaluated here to study the effects of immunosuppressive drugs on tumor promotion and progression in vivo. The model employed a skin squamous cell carcinoma cell line (SCC VII) due to the increased prevalence of squamous cell carcinoma (SCC) in humans associated with immunosuppression after transplants. Local invasion, colonization and tumor progression were evaluated. The validation set of immunosuppressive drugs included: Cyclosporin (CSA), cyclophosphamide (CTX), azathioprine, etanercept, abatacept and prednisone. Local invasion was evaluated by histological assessment as well as fluorescence trafficking from Qdot®-labeled tumor cells from the site of inoculation to the draining lymph node. Colonization was evaluated by lung colony counts following intravenous inoculation. Tumor progression was assessed by morphometric analysis of lesion area, angiogenesis and growth fraction of established metastatic neoplasia. Immunosuppressive drugs in the validation set yielded mixed results, including decreased progression. The methods and results described herein using an in vivo syngeneic mouse tumor model can provide insight about the assessment of immunosuppressive drugs in carcinogenicity risk assessment.

Over the past 30 years, the world of pharmaceutical toxicology has seen an explosion in the area of cytokines. An overview of the many aspects of cytokine safety evaluation currently in progress and evolving strategies for evaluating these important entities was presented at this symposium. Cytokines play a broad role to help the immune system respond to diseases, and drugs which modulate their effect have led to some amazing therapies. Cytokines may be good when stimulating the immune system to fight a foreign pathogen or attack tumors. Other good cytokine effects include reduction of an immune response, for example interferon reduction of neuron inflammation in patients with multiple sclerosis. They may be bad when their expression causes inflammatory diseases, such as the role of tumor necrosis factor alpha in rheumatoid arthritis or asthma and Crohn's disease. Therapeutic modulation of cytokine expression can help the good cytokines to generate or quench the immune system and block the bad cytokines to prevent damaging inflammatory events. However, care must be exercised, as some antibody therapeutics can cause ugly cytokine release which can be deadly. Well-designed toxicology studies should incorporate careful assessment of cytokine modulation that will allow effective therapies to treat unmet needs. This symposium discussed lessons learned in cytokine toxicology using case studies and suggested future directions.

Abstract The discovery of targeted therapies against tumors offers promise of therapeutic benefit to patients however, it poses challenges in assessing immunologic and toxicologic risk during drug development. We determined that early safety assessment of combination therapy, prior to later stage toxicology studies, can be used to support Go/No-Go NME decision and thereby reduce time, efficiency, and resources used to choose and develop lead candidates. The rodent T-cell-dependent antibody response (TDAR) assay is used to assess the effect of candidate therapeutic agents on the immune system by measuring primary and secondary IgM and IgG antibody responses to exogenous antigen challenge. TDAR responses require intact function of multiple immune cells including antigen presenting cells and T and B lymphocytes, as well as a cytokine-dependent isotype class switch from IgM to IgG, resulting in production of an antigen-specific antibody response. Alterations in the amount of antibody produced therefore can reflect effects on any or all cell populations involved in TDAR. TDAR is commonly used in preclinical drug development especially where increased cause for concern exists (ICH guideline S8). Development of combination therapy that engages multiple targets impacting the immune system poses unique opportunity for increased efficacy but also unique risk for increased immunotoxicity including immune stimulation. For this work, a mouse TDAR evaluating primary and secondary KLH antibody responses in a KLH-Specific IgM and IgG sandwich enzyme-linked immunosorbent assay (ELISA) was first validated and then used to assess immunotoxicologic potential of multiple single immunosuppressive agents (cyclophosphamide (CTX), abatacept, azathioprine (AZT), etanercept, cyclosporine (CsA), and prednisone) and biological therapies (A, B, C, D, E, and F) and combination biologic therapies ( A+B, C+D, E+F). Doses of 100 mg/kg CsA, 250 mg/kg abatacept, 125 mg/kg etanercept, 100 mg/kg AZT, 20 mg/kg prednisone administered subcutaneously (s.c.) on Days 1 and 3 had mild immunosuppressive effects. 200 mg/kg of CTX administered s.c. had an expected robust immunosuppressive effect that was statistically significant than control. Combination of biologic therapies did not result in enhanced TDAR immunotoxicity compared to single biologic therapy alone for the molecules evaluated. Tier 1 immunotoxicology assessments similar to those in standard toxicity studies were added to the TDAR assessment. Together, these data support the use of the TDAR assay for early safety assessment of potential combination therapies against tumors. Citation Format: Amy L. Volk, Mindi Walker, Kerry Brosnan, Dorie Capaldi, Patricia Rafferty, Daniel Weinstock, Eva Emmell. Early safety assessment of single and combination therapy using TDAR. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr B58.

Immunosuppressive agents are used for treatment of a variety of autoimmune diseases including rheumatoid arthritis (RA), systemic lupus erythematosis (SLE), and psoriasis, as well as for prevention of tissue rejection after organ transplantation. Recrudescence of herpesvirus infections, and increased risk of carcinogenesis from herpesvirus-associated tumors are related with immunosuppressive therapy in humans. Post-transplant lymphoproliferative disorder (PTLD), a condition characterized by development of Epstein Barr Virus (EBV)-associated B-lymphocyte lymphoma, and Kaposi's Sarcoma (KS), a dermal tumor associated with Kaposi Sarcoma-associated virus (KSHV), may develop in solid organ transplant patients. KS also occurs in immunosuppressed Acquired Immunodeficiency (AIDS) patients. Kaposi Sarcoma-associated virus (KSHV) is a herpes virus genetically related to EBV. Murine gammaherpes-virus-68 (MHV-68) is proposed as a mouse model of gammaherpesvirus infection and recrudescence and may potentially have relevance for herpesvirus-associated neoplasia. The pathogenesis of MHV-68 infection in mice mimics EBV/KSHV infection in humans with acute lytic viral replication followed by dissemination and establishment of persistent latency. MHV-68-infected mice may develop lymphoproliferative disease that is accelerated by disruption of the immune system. This manuscript first presents an overview of gammaherpesvirus pathogenesis and immunology as well as factors involved in viral recrudescence. A description of different types of immunodeficiency then follows, with particular focus on viral association with lymphomagenesis after immunosuppression. Finally, this review discusses different gammaherpesvirus animal models and describes a proposed MHV-68 model to further examine the interplay of immunomodulatory agents and gammaherpesvirus-associated neoplasia.

The possible onset of Cytokine Release Syndrome (CRS) is an important consideration in the development of monoclonal antibody (mAb) therapeutics. In this study, several machine learning approaches are used to analyze CRS data. The analyzed data come from a human blood in vitro assay which was used to assess the potential of mAb-based therapeutics to produce cytokine release similar to that induced by Anti-CD28 superagonistic (Anti-CD28 SA) mAbs. The data contain 7 mAbs and two negative controls, a total of 423 samples coming from 44 donors. Three (3) machine learning approaches were applied in combination to observations obtained from that assay, namely (i) Hierarchical Cluster Analysis (HCA); (ii) Principal Component Analysis (PCA) followed by K-means clustering; and (iii) Decision Tree Classification (DTC). All three approaches were able to identify the treatment that caused the most severe cytokine response. HCA was able to provide information about the expected number of clusters in the data. PCA coupled with K-means clustering allowed classification of treatments sample by sample, and visualizing clusters of treatments. DTC models showed the relative importance of various cytokines such as IFN-γ, TNF-α and IL-10 to CRS. The use of these approaches in tandem provides better selection of parameters for one method based on outcomes from another, and an overall improved analysis of the data through complementary approaches. Moreover, the DTC analysis showed in addition that IL-17 may be correlated with CRS reactions, although this correlation has not yet been corroborated in the literature.

Murine gammaherpesvirus-68 (MHV-68), a natural pathogen of mice, is being evaluated as a model of Epstein Barr Virus (EBV) infection for use in investigation of the effects of immunomodulatory therapy on herpesvirus pathogenesis in humans. Immunosuppressive agents are used for treatment of a variety of autoimmune diseases as well as for prevention of tissue rejection after organ transplantation and can result in recrudescence of latent herpesvirus infections. Prior to examination of MHV-68 as a suitable model for EBV, better characterization of the MHV-68 model was desirable. Characterization of the MHV-68 model involved development of assays for detecting virus and for demonstration of safety when present in murine colonies. Limited information is available in the literature regarding MHV-68 transmission, although recent reports indicate the virus is not horizontally spread in research facilities. To further determine transmission potential, immunocompetent and immunodeficient mice were infected with MHV-68 and co-habitated with naïve animals. Molecular pathology assays were developed to characterize the MHV-68 model and to determine viral transmission. Horizontal transmission of virus was not observed from infected animals to naïve cagemates after fluorescence microscopy assays and quantitative PCR (qPCR). Serologic analysis complemented these studies and was used as a method of monitoring infection amongst murine colonies. Overall, these findings demonstrate that MHV-68 infection can be controlled and monitored in murine research facilities, and the potential for unintentional infection is low.