Immunomodulatory agents for COVID-19 treatment: possible mechanism of action and immunopathology features.

The novel coronavirus pandemic has emerged as one of the significant medical-health challenges of the current century. The World Health Organization has named this new virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since the first detection of SARS-CoV-2 in November 2019 in Wuhan, China, physicians, researchers, and others have made it their top priority to find drugs and cures that can effectively treat patients and reduce mortality rates. The symptoms of Coronavirus Disease 2019 (COVID-19) include fever, dry cough, body aches, and anosmia. Various therapeutic compounds have been investigated and applied to mitigate the symptoms in COVID-19 patients and cure the disease. Degenerative virus analyses of the infection incidence and COVID-19 have demonstrated that SARS-CoV-2 penetrates the pulmonary alveoli's endothelial cells through Angiotensin-Converting Enzyme 2 (ACE2) receptors on the membrane, stimulates various signaling pathways and causes excessive secretion of cytokines. The continuous triggering of the innate and acquired immune system, as well as the overproduction of pro-inflammatory factors, cause a severe condition in the COVID-19 patients, which is called "cytokine storm". It can lead to acute respiratory distress syndrome (ARDS) in critical patients. Severe and critical COVID-19 cases demand oxygen therapy and mechanical ventilator support. Various drugs, including immunomodulatory and immunosuppressive agents (e.g., monoclonal antibodies (mAbs) and interleukin antagonists) have been utilized in clinical trials. However, the studies and clinical trials have documented diverging findings, which seem to be due to the differences in these drugs' possible mechanisms of action. These drugs' mechanism of action generally includes suppressing or modulating the immune system, preventing the development of cytokine storm via various signaling pathways, and enhancing the blood vessels' diameter in the lungs. In this review article, multiple medications from different drug families are discussed, and their possible mechanisms of action are also described.

A Reversible Chemogenetic Switch for Chimeric Antigen Receptor T†Cells.

As a revolutionary cancer treatment, the chimeric antigen receptor (CAR) T cell therapy suffers from complications such as cytokine release syndromes and T cell exhaustion. Their mitigation desires controllable activation of CAR-T cells that is achievable through regulatory display of CARs. By embedding the hepatitis C virus NS3 protease (HCV-NS3) between the single-chain variable fragment (scFv) and the hinge domain, we showed that the display of anti-CD19 scFv on CAR-T cells was positively correlated to the presence of a clinical HCV-NS3 inhibitor asunaprevir (ASV). This novel CAR design that allows the display of anti-CD19 scFv in the presence of ASV and its removal in the absence of ASV creates a practically reversible chemical switch. We demonstrated that the intact CAR on T cells can be repeatedly turned on and off by controlling the presence of ASV in a dose dependent manner both in vitro and in vivo, which enables delicate modulation of CAR-T activation during cancer treatment.

Enabling antibiotic allergy evaluations and reintroduction of first-line antibiotics for patients with cystic fibrosis.

BACKGROUND: Patients with cystic fibrosis (CF) often have a history of antibiotic adverse drug reactions (ADRs) that pose a barrier to receiving recommended first-line treatment. Targeted antibiotic allergy evaluations are increasingly recognized as an important strategy for optimization of antimicrobial stewardship. OBJECTIVE: To improve first-line antibiotic use in patients with CF with antibiotic ADRs by streamlining access to antibiotic allergy evaluations and standardizing documentation of plans for antibiotic reintroduction. METHODS: We incorporated allergy evaluations into a multidisciplinary CF clinic and used telemedicine when allergy evaluations could not be performed during CF clinic. Standard documentation of antibiotic allergy plans was used to enable safe reintroduction of first-line antibiotics by CF providers. RESULTS: Strategies used in this study allowed 81.3% (26 of 32) of patients with CF to receive allergy evaluations and antibiotic allergy plans for prioritized antibiotics (penicillin, cephalosporin, sulfonamide), with removal of 41.0% (16 of 39) of prioritized antibiotic ADRs. Only 5.1% (2 of 39) of prioritized antibiotic ADRs evaluated required strict avoidance after evaluation. There were 9 patients who received at least 1 prioritized antibiotic, with 66.6% (6 of 9) of these patients given the antibiotic after only 1 allergy evaluation visit. Furthermore, these strategies allowed allergy evaluations of 23 nonprioritized antibiotics to occur, with removal of the ADR in 39.1% (9 of 23) and use of 77.8% (7 of 9) of nonprioritized antibiotics after removal. CONCLUSION: Incorporating allergy evaluations into a multidisciplinary CF clinic can liberalize first-line antibiotic use in patients with CF. Standard documentation of antibiotic allergy plans allowed antibiotic reintroduction to occur even before complete removal of documented antibiotic ADRs.

NOD-like receptors in autoimmune diseases.

Autoimmune diseases are chronic immune diseases characterized by dysregulation of immune system, which ultimately results in a disruption in self-antigen tolerance. Cumulative data show that nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) play essential roles in various autoimmune diseases, such as inflammatory bowel disease (IBD), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), psoriasis, multiple sclerosis (MS), etc. NLR proteins, consisting of a C-terminal leucine-rich repeat (LRR), a central nucleotide-binding domain, and an N-terminal effector domain, form a group of pattern recognition receptors (PRRs) that mediate the immune response by specifically recognizing cellular pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) and triggering numerous signaling pathways, including RIP2 kinase, caspase-1, nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK) and so on. Based on their N-terminal domain, NLRs are divided into five subfamilies: NLRA, NLRB, NLRC, NLRP, and NLRX1. In this review, we briefly describe the structures and signaling pathways of NLRs, summarize the recent progress on NLR signaling in the occurrence and development of autoimmune diseases, as well as highlight numerous natural products and synthetic compounds targeting NLRs for the treatment of autoimmune diseases.

Drug allergy is associated with the development of extraintestinal manifestations in patients with ulcerative colitis.

Summary: Drug allergies are developed by antibody or cell-mediated reactions as immunologic mechanisms. It has been demonstrated that hypersensitivity reaction to certain allergens may play a role in the pathogenesis of inflammatory bowel disease (IBD) focused on food allergies. A total of 256 patients with UC were divided in two groups: 203 patients with active UC and 53 in remission UC were included in the present study. In the present study we found that 11.7% had allergy to at least one drug distributed. The most frequent drug-allergies were sulfonamides in 2.8% and penicillin in 3.1%. Sulfonamide allergy was associated with several extraintestinal manifestations such as: peripheral arthritis/arthralgia (OR = 9.06, 95% CI 1.71 - 48.00, p = 0.002); pyoderma gangrenosum (OR = 24.10, 95% CI 3.55 - 163.48, p minor 0.0001) and uveitis (OR = 15.93, 95% CI 2.55 - 99.23, p minor 0.0001). The frequency of drug allergy was 11.7% in Mexican UC patients, most frequently to sulfonamides and penicillin drugs. The presence of sulfonamide allergy was associated with the presence of several extra-intestinal manifestations.

Production of generic monoclonal antibody and development of chemiluminescence immunoassay for determination of 32 sulfonamides in chicken muscle.

A hapten of sulfabenzamide was first synthesized to generate a monoclonal antibody that simultaneously recognized 32 sulfonamides. The computational simulation showed that the 3D conformation, molecular bend angle, molecular volume, electronic charge of core structure of these drugs all showed influences on the antibody binding. The antibody was combined with a heterologous enzyme-labeled hapten to develop a direct competitive chemiluminescence enzyme linked immunosorbent assay for determination of the 32 sulfonamides in chicken muscle sample. The CRs of the optimized method for these drugs were in the range of 7.3%-1778%, and the IC50 values were in the range of 0.038-11.2 ng/g. The limits of detection for detection of these drugs in chicken were in the range of 0.03-26 ng/g. Their recoveries from the standards fortified blank chicken samples were in the range of 60.8%-97.1%. Therefore, this method could be used as a useful tool for routine screening sulfonamides residues in meat.

Distinct immune composition in lymph node and peripheral blood of CLL patients is reshaped during venetoclax treatment.

Morbidity and mortality due to immunosuppression remain among the foremost clinical challenges in chronic lymphocytic leukemia (CLL). Although immunosuppression is considered to originate within the lymph node (LN) microenvironment, alterations in T and natural killer (NK) cells have almost exclusively been studied in peripheral blood (PB). Whereas chemoimmunotherapy further deteriorates immune function, novel targeted agents like the B-cell lymphoma 2 inhibitor venetoclax potentially spare nonmalignant lymphocytes; however, the effects of venetoclax on nonleukemic cells have not been explored. We address these unresolved issues using a comprehensive analysis of nonmalignant lymphocytes in paired LN and PB samples from untreated CLL patients, and by analyzing the effects of venetoclax-based treatment regimens on the immune system in PB samples from previously untreated and relapsed/refractory patients. CLL-derived LNs contained twice the amount of suppressive regulatory T cells (Tregs) and CLL supportive follicular T helper (Tfh) cells compared with PB. This was accompanied by a low frequency of cytotoxic lymphocytes. The expression of PD-1 by CD8+ T cells was significantly higher in LN compared with PB. Venetoclax-based treatment led to deep responses in the majority of patients, but also to decreased absolute numbers of B, T, and NK cells. Tfh cell, Treg, and PD-1+ CD8+ T cell numbers were reduced more than fivefold after venetoclax-based therapy, and overproduction of inflammatory cytokines was reduced. Furthermore, we observed restoration of NK cell function. These data support the notion that the immunosuppressive state in CLL is more prominent within the LN. Venetoclax-based regimens reduced the immunosuppressive footprint of CLL, suggesting immune recovery after the elimination of leukemic cells.

Sulfonamide Hypersensitivity: Fact and Fiction.

Sulfonamide antimicrobials are commonly reported as causing drug allergy and have been implicated in a variety of hypersensitivity reactions including immediate IgE-mediated reactions, benign T-cell-mediated rashes, and severe cutaneous adverse reactions such as Stevens-Johnson syndrome, toxic epidermal necrolysis, and drug reaction with eosinophilia and systemic symptoms. Cross-reactivity is unlikely between sulfonamide antimicrobials and sulfonamide non-antimicrobials. In patients who develop reactions to a sulfonamide non-antimicrobial, there is no evidence to suggest that sulfonamide antimicrobials and other sulfonamide non-antimicrobials would cross-react. Although immediate skin testing can be performed in patients with histories of immediate reactions, they are infrequently positive and wane over time. Delayed skin testing including patch tests to sulfonamides is rarely positive. Drug challenges are a useful tool for patients with both immediate and delayed reactions to sulfonamides. The role of sulfamethoxazole desensitization is controversial as rates of hypersensitivity reactions are similar between desensitization and drug challenge.

Antibiotic Allergy in Children: More than Just a Label.

Within the broad category of adverse drug reactions in children, there has been a recent focus specifically on the evaluation of children with antibiotic allergy, in particular, beta-lactam allergy. The potential consequences of being labeled beta-lactam allergy are increasingly recognized. Appropriate evaluation of children with suspected reactions to antibiotics is essential as it is increasingly being recognized that the label of "penicillin allergy" is associated with adverse health and economic outcomes. This review will focus on the 3 main classes of antibiotics reported to cause allergic reactions in children: beta lactams (penicillin derivatives and cephalosporins), macrolides, and sulfonamides. This article is a narrative review of the prevalence, diagnosis, and management of different types of antibiotic allergies in children. Our review reveals that antibiotic allergy is often overreported and not appropriately diagnosed in the pediatric age groups. There is a recent shift in the diagnostic paradigm from the use of skin tests and if negative challenges to the use of challenge only in the pediatric age group. Larger studies to establish the usefulness and safety of this new approach as well as updated guidelines are needed.

Drug-Induced Anaphylaxis Documented in Electronic Health Records.

BACKGROUND: Although drugs represent a common cause of anaphylaxis, few large studies of drug-induced anaphylaxis have been performed. OBJECTIVE: To describe the epidemiology and validity of reported drug-induced anaphylaxis in the electronic health records (EHRs) of a large United States health care system. METHODS: Using EHR drug allergy data from 1995 to 2013, we determined the population prevalence of anaphylaxis including anaphylaxis prevalence over time, and the most commonly implicated drugs/drug classes reported to cause anaphylaxis. Patient risk factors for drug-induced anaphylaxis were assessed using a logistic regression model. Serum tryptase and allergist visits were used to assess the validity and follow-up of EHR-reported anaphylaxis. RESULTS: Among 1,756,481 patients, 19,836 (1.1%) reported drug-induced anaphylaxis; penicillins (45.9 per 10,000), sulfonamide antibiotics (15.1 per 10,000), and nonsteroidal anti-inflammatory drugs (NSAIDs) (13.0 per 10,000) were most commonly implicated. Patients with white race (odds ratio [OR] 2.38, 95% CI 2.27-2.49), female sex (OR 2.20, 95% CI 2.13-2.28), systemic mastocytosis (OR 4.60, 95% CI 2.66-7.94), Sjögren's syndrome (OR 1.94, 95% CI 1.47-2.56), and asthma (OR 1.50, 95% CI 1.43-1.59) had an increased odds of drug-induced anaphylaxis. Serum tryptase was performed in 135 (<1%) anaphylaxis cases and 1,587 patients (8.0%) saw an allergist for follow-up. CONCLUSIONS: EHR-reported anaphylaxis occurred in approximately 1% of patients, most commonly from penicillins, sulfonamide antibiotics, and NSAIDs. Females, whites, and patients with mastocytosis, Sjögren's syndrome, and asthma had increased odds of reporting drug-induced anaphylaxis. The low observed frequency of tryptase testing and specialist evaluation emphasize the importance of educating providers on anaphylaxis management.

Class-Specific Monoclonal Antibodies and Dihydropteroate Synthase in Bioassays Used for the Detection of Sulfonamides: Structural Insights into Recognition Diversity.

Molecular recognition between a receptor and ligand is a fundamental event in bioanalytical assays, which guarantees the sensitivity and specificity of an assay for the detection of the target of interest. An intensive understanding of the interaction mechanism could be useful for desirable hapten design, directed antibody evolution in vitro, and assay improvement. To illustrate the structural information on class-specific monoclonal antibodies (mAbs) and dihydropteroate synthase (DHPS) against sulfonamides (SAs) we have previously prepared, we initially measured the kinetic parameters of mAb 4C7, 4D11, and DHPS, which showed that the affinities of 4C7 and 4D11 were in the pM to µM range, while DHPS was uniformly in the µM range. Three-dimensional quantitative structure-activity relationship analysis for 4C7 and 4D11 then revealed that the contributions from the stereochemical structure and electron density of the SAs were comparable to binding with mAb. To acquire insights into the structural basis of mAbs and DHPS during the recognition process, the crystal structures of 4C7 and its complex with sulfathiazole were determined using X-ray crystallography. The results showed the SAs orientation and hydrogen bonding interactions mainly contributed to the diverse SAs-mAb affinities. However, for DHPS, a nucleophilic substitution reaction occurred during the recognition process with the SAs, which contributed to the surprisingly uniform affinity for all the SAs tested. This study verified the previous hypotheses on antibody production against SAs and enhanced our understanding of antibody-SAs interactions, which provided useful information toward the rational design of novel haptens and directed evolution to produce class-specific antibodies as DHPS.

Combinations of BRAF inhibitor and anti-PD-1/PD-L1 antibody improve survival and tumour immunity in an immunocompetent model of orthotopic murine anaplastic thyroid cancer.

BACKGROUND: Patients with anaplastic thyroid cancer (ATC) have an extremely poor prognosis despite aggressive multimodal therapy. ATC has a high prevalence of BRAFV600E mutations and is associated with an immunosuppressive microenvironment; we previously demonstrated that the combination of BRAF inhibitor and checkpoint inhibitor immunotherapy synergistically reduce tumour volume in an immunocompetent mouse model of orthotopic ATC. METHODS: We again utilised our mouse model of ATC to assess the combination of BRAFV600E inhibitor PLX4720 and anti-PD-L1 or anti-PD-1 antibody on survival, and performed immune cell profiling of lymphoid and myeloid-lineage cells during maximal treatment response and tumour regrowth. RESULTS: Combination therapy dramatically improved mouse survival. Maximal tumour reduction was associated with increases in the number and cytotoxicity of CD8+ T cells and NK cells, as well as increases in mostly M1-polarised tumour-associated macrophages (TAM) and decreases in myeloid-derived suppressor-like cells. Regrowth of tumour occurred after 2-3 weeks of ongoing combination therapy, and was most significantly associated with decreased TAMs and a dramatic increase in M2-polarisation. CONCLUSIONS: Combination of PLX4720 and anti-PD-L1/PD-1 antibody dramatically reduced tumour volume, prolonged survival and improved the anti-tumour immune profile in murine ATC. Tumour growth inevitably recurred and demonstrated re-emergence of an immunosuppressive tumour microenvironment.

Shifting the Balance of Activating and Inhibitory Natural Killer Receptor Ligands on BRAFV600E Melanoma Lines with Vemurafenib.

Over 60% of human melanoma tumors bear a mutation in the BRAF gene. The most frequent mutation is a substitution at codon 600 (V600E), leading to a constitutively active BRAF and overactivation of the MAPK pathway. Patients harboring mutated BRAF respond to kinase inhibitors such as vemurafenib. However, these responses are transient, and relapses are frequent. Melanoma cells are efficiently lysed by activated natural killer (NK) cells. Melanoma cells express several stress-induced ligands that are recognized by activating NK-cell receptors. We have investigated the effect of vemurafenib on the immunogenicity of seven BRAF-mutated melanoma cells to NK cells and on their growth and sensitivity to NK-cell-mediated lysis. We showed that vemurafenib treatment modulated expression of ligands for two activating NK receptors, increasing expression of B7-H6, a ligand for NKp30, and decreasing expression of MICA and ULBP2, ligands for NKG2D. Vemurafenib also increased expression of HLA class I and HLA-E molecules, likely leading to higher engagement of inhibitory receptors (KIRs and NKG2A, respectively), and decreased lysis of vemurafenib-treated melanoma cell lines by cytokine-activated NK cells. Finally, we showed that whereas batimastat (a broad-spectrum matrix metalloprotease inhibitor) increased cell surface ULBP2 by reducing its shedding, vemurafenib lowered soluble ULBP2, indicating that BRAF signal inhibition diminished expression of both cell-surface and soluble forms of NKG2D ligands. Vemurafenib, inhibiting BRAF signaling, shifted the balance of activatory and inhibitory NK ligands on melanoma cells and displayed immunoregulatory effects on NK-cell functional activities. Cancer Immunol Res; 5(7); 582-93. ©2017 AACR.

[«Sulfonamide allergy¼ - which drugs must patients avoid?]. / «Sulfaallergi¼ - hvilke legemidler må pasienten unngå?

Allergic reactions to sulfonamide antibiotics are common. A number of other drugs (for example diuretics, anti-diabetic drugs, cyclooxygenase-2 inhibitors and triptans) are also chemically speaking sulphonamides, and many of these are considered to be contraindicated in patients who have experienced an allergic reaction to sulfonamide antibiotics. What is the risk of allergic cross-reactivity between different sulfonamides and to what extent must this be taken into account in clinical practice?

Sarcoidosis in Patients Treated with Vemurafenib for Metastatic Melanoma: A Paradoxical Autoimmune Activation.

BACKGROUND: Vemurafenib, a BRAF inhibitor, is a first-line treatment for inoperable melanoma. Sarcoidosis has never been reported in patients on vemurafenib. OBJECTIVES: We describe 5 cases of sarcoidosis in patients treated with vemurafenib. METHODS: Seventy patients receiving vemurafenib for a BRAF-mutated inoperable stage III or IV melanoma were treated in our centre. RESULTS: Five patients (7.1%) developed sarcoidosis or a sarcoid-like reaction on vemurafenib; 4 patients had cutaneous signs and 3 had extracutaneous disorders (bilateral hilar lymph nodes, uveitis). Histological analysis of skin lesions revealed epithelioid granulomas without necrosis, consistent with sarcoidosis. Angiotensin-converting enzyme levels were high in 2 patients. Cutaneous and ophthalmological lesions rapidly disappeared on topical corticosteroid treatment without the cessation of vemurafenib treatment. Complete remission of melanoma was observed in 3 patients and partial remission was observed in another. CONCLUSION: BRAF inhibitors probably have immune system-enhancing effects and should therefore be recognized as potential inducers of sarcoidosis.

Targeted Delivery of LXR Agonist Using a Site-Specific Antibody-Drug Conjugate.

Liver X receptor (LXR) agonists have been explored as potential treatments for atherosclerosis and other diseases based on their ability to induce reverse cholesterol transport and suppress inflammation. However, this therapeutic potential has been hindered by on-target adverse effects in the liver mediated by excessive lipogenesis. Herein, we report a novel site-specific antibody-drug conjugate (ADC) that selectively delivers a LXR agonist to monocytes/macrophages while sparing hepatocytes. The unnatural amino acid para-acetylphenylalanine (pAcF) was site-specifically incorporated into anti-CD11a IgG, which binds the α-chain component of the lymphocyte function-associated antigen 1 (LFA-1) expressed on nearly all monocytes and macrophages. An aminooxy-modified LXR agonist was conjugated to anti-CD11a IgG through a stable, cathepsin B cleavable oxime linkage to afford a chemically defined ADC. The anti-CD11a IgG-LXR agonist ADC induced LXR activation specifically in human THP-1 monocyte/macrophage cells in vitro (EC50-27 nM), but had no significant effect in hepatocytes, indicating that payload delivery is CD11a-mediated. Moreover, the ADC exhibited higher-fold activation compared to a conventional synthetic LXR agonist T0901317 (Tularik) (3-fold). This novel ADC represents a fundamentally different strategy that uses tissue targeting to overcome the limitations of LXR agonists for potential use in treating atherosclerosis.

A highly sensitive and class-specific fluorescence polarisation assay for sulphonamides based on dihydropteroate synthase.

We describe a fluorescence polarisation assay based on the use of dihydropteroate synthase (DHPS) and a fluorescence probe for multi-sulphonamide detection. Dihydropteridine pyrophosphate (DHPPP) was synthesised and acts as the first substrate for DHPS. Under optimised conditions, the half-maximal inhibitory concentrations (IC50) of the assay were less than 100 ng mL(-1) for at least 29 sulphonamides and the time needed for the detection was less than 20 min. More importantly, the assay revealed quite uniform affinities for all of the individual sulphonamides tested, which has never before been achieved in an antibody-based assay.