Hypersensitivity Research Articles

Adverse Impacts of PEGylated Protein Therapeutics: A Targeted Literature Review.

The beneficial effects of polyethylene glycol (PEG)-conjugated therapeutics, such as increased half-life, solubility, stability, and decreased immunogenicity, have been well described. There have been concerns, however, about adverse outcomes with their use, but understanding of those adverse outcomes is still relatively limited. The present study aimed to characterize adverse outcomes associated with PEGylation of protein-based therapeutics on immunogenicity, pharmacologic properties, and safety. A targeted review of English language articles published from 1990 to September 29, 2023, was conducted. Of the 29 studies included in this review, 18 reported adverse safety outcomes such as hematologic complications, hepatic toxicity, injection site reactions, arthralgia, nausea, infections, grade 3 or 4 adverse events (AEs), and AE-related discontinuations and dose modifications. Fifteen studies reported immunogenicity-related outcomes, such as the prevalence of pre-existing antibodies to PEG, treatment-emergent antibody response, and hypersensitivity reactions to PEGylated drugs. Seven studies reported pharmacological outcomes such as increased clearance and reduced activity in response to PEGylated drugs. This review aims to contribute to a balanced view of PEGylated therapies by summarizing the adverse outcomes or lack of benefit associated with PEGylated therapeutics reported in the literature. We identified several studies characterizing adverse outcomes, pharmacological effects, and immunogenicity associated with the use of PEGylated therapeutics. Our findings suggest that using PEGylated therapeutics may require careful monitoring for adverse safety outcomes, including screening and monitoring for pre-existing antibodies and those induced in response to PEGylated therapy, as well as monitoring and adjusting the dosing of PEGylated therapeutics.

In vitro diagnostics of drug allergies.

In vitro diagnostics for drug hypersensitivity reactions distinguish between serological and cellular-based tests. A serological test used for the diagnosis of immediate type reactions is the detection of specific IgE antibodies. The cellular tests include the basophil activation test for immediate type reactions and the lymphocyte transformation test, which is mainly used to detect delayed type hypersensitivity reactions. Further cellular-based tests are the CAST-ELISA and the mast cell activation test. None of the above-mentioned tests can definitively exclude an allergy if the result is negative. In addition, it is important to note that even a positive test result is not necessarily associated with an allergy but has to be interpreted in the clinical context.

First Report of Fire Blight Caused by Erwinia amylovora on Pear in Saudi Arabia.

In the spring of 2020 and 2021, pear trees (Pyrus communis cv. Williams) in orchards (27°46'36.0"N 42°29'44.7"E, 30°00'00.2"N 40°15'11.8"E, and 28°44'52.9"N 36°18'47.8" E) in Hail, Al Jouf, and Tabuk regions exhibited fire blight symptoms. After removing bark, the affected trees showed shoot blight, brown-blighted shoot tips and blossom blight, dead flowers on the stems, and reddish-colored cankers. The disease incidence varied from 10% to 25%. Pathogen was isolated from 21 symptomatic samples including fruits, flowers, and shoots. Bacteria were isolated from washed tissues on King's B (KB) and semi-selective CCT media (Ishimaru and Klos, 1984). After 48 hours, colonies resembling Erwinia amylovora on KB media were 1.5-2 mm in diameter, white, circular, slightly convex, with a smooth surface, and exhibited no fluorescence under ultraviolet light. Colonies on CCT after 72 h were 3-4 mm in diameter, mucoid with shiny surfaces, semitransparent, speckled with craters, and slightly violet. All isolates were purified by subculturing on KB. All isolates were Gram-negative and rod-shaped, fermentative of glucose, positive for catalase and negative for oxidase, and potato rot. They induced a hypersensitive reaction when infiltrated in tobacco leaves (cv. Xanthi). Based on morphology and biochemical tests (EPPO, 2004), the strains were identified as Erwinia sp. Twenty-six strains from Saudi Arabia (SA) and the reference strain (NCPPB 683T) hydrolyzed gelatin and formed white, highly mucous colonies on the levan medium. These strains could not reduce nitrate to nitrite and tested negative for urease and indole production. All the isolates and the reference strain were confirmed to be E. amylovora based on a PCR 0.9-kb DNA fragment amplification with a species-specific primer set, A/B targets pEA29 (Bereswill et al. 1992). 16S-rDNA fragments from Saudi isolates were amplified with 27F and 1492R primers (Lane, 1991). Purified amplicons from PCR were sequenced (OR717505 and OR743536-OR743560), and a BLAST search of the GenBank database revealed 100% (927/927) homology with E. amylovora strain CP066796.1. The housekeeping gene rpoB was PCR amplified with primers CM7-F and CM31b-R (Rezzonico et al. 2012), and the products were sequenced (PP465516-PP465541). BLAST analysis showed 100% (944/944 nt) and 96.19% (908/944 nt) identities with the sequences of E. amylovora ATCC 15580 CP066796.1 and E. pyrifoliae CP201486 CP103445.1, respectively. To fulfill Koch's postulates, SA strains were inoculated on five healthy 3-month-old clones of apple (Malus domestica cv. Gala) per strain with a 10-μl bacterial suspension containing 107 colony-forming units per milliliter by injecting directly in the veins of the upper second leaf plus 5 healthy plants injected with sterile distilled water as control. Plants were incubated at 28°C for six days under a 12-hour light regime. Observed symptoms were similar to the ones observed in the field. The experiment was replicated twice. Bacterial colonies on CCT media were re-isolated from the inoculated apple rootstocks and confirmed by the A/B primer set. To our knowledge, this is the first peer-reviewed report of E. amylovora in SA since the fire blight-like symptoms were observed in SA in 2013 (Alhudaib, 2013). Further research will identify new host plants for the fire blight pathogen within SA which is important due to the importation of pome fruit seedlings (quince, apple, and pear) from neighboring Jordan where E. aylovora was reported (Tehabsim et al. 1992).

Host-Driven Selection, Revealed by Comparative Analysis of Xanthomonas Type III Secretion Effectoromes, Unveils Novel Recognized Effectors.

Xanthomonas species are specialized plant pathogens, often exhibiting a narrow host range. They rely on the translocation of effector proteins through the type III secretion system to colonize their respective hosts. The effector arsenal varies among Xanthomonas spp., typically displaying species-specific compositions. This species-specific effector composition, collectively termed the effectorome, is thought to influence host specialization. We determined the plant host-derived effectoromes of more than 300 deposited genomes of Xanthomonas species associated with either Solanaceae or Brassicaceae hosts. Comparative analyses revealed clear species-specific effectorome signatures. However, Solanaceae or Brassicaceae host-associated effectorome signatures were not detected. Nevertheless, host biases in the presence or absence of specific effector classes were observed. To assess whether host-associated effector absence results from selective pressures, we introduced effectors unique to Solanaceae pathogens to X. campestris pv. campestris and effectors unique to Brassicaceae pathogens to X. euvesicatoria pv. euvesicatoria (Xeue) and evaluated if these introductions hindered virulence on their respective hosts. Introducing the effector XopI into X. campestris pv. campestris reduced virulence on white cabbage leaves without affecting localized or systemic colonization. Introducing the XopAC or XopJ5 effectors into Xeue reduced virulence and colonization on tomato but not on pepper. Additionally, XopAC and XopJ5 induced a hypersensitive response on tomato leaves when delivered by Xeue or through Agrobacterium-mediated transient expression, confirming recognition in tomato. This study demonstrates the role of host-derived selection in establishing species-specific effectoromes, identifying XopAC and XopJ5 as recognized effectors in tomato.

Oxaliplatin triggered hypersensitivity reactions in colorectal cancer patients: Case report

Colorectal cancer stands as a significant global health concern, encompassing adenocarcinoma of both the colon and rectum. Recognized risk factors include advancing age and medical history of inflammatory bowel conditions like Crohn's disease or ulcerative colitis. Oxaliplatin, a platinum-based chemotherapy agent, serves as the frontline treatment for colorectal cancer due to its cytotoxic effects on cancerous cells. However, its use is not without complications, as hypersensitivity reactions can occur, posing challenges in patient management. This case report discusses two instances where patients undergoing chemotherapy for colorectal cancer developed grade two hypersensitivity reactions following oxaliplatin administration, the Naranjo probability scale was used to analyze the causation of the adverse drug reactions (ADRs), and a score of 6 was obtained, indicating oxaliplatin as a probable cause of the hypersensitivity reactions. In both cases, treatment was promptly halted upon manifestation of symptoms, and patients were administered intravenous steroids along with anti-histamines. This intervention resulted in significant improvement in the patients' conditions. Both genders are equally susceptible to such reactions, emphasizing the need for gender-neutral awareness and precautionary measures among medical practitioners. This case report serves as a reminder of the potential adverse effects associated with oxaliplatin therapy in colorectal cancer patients. Heightened awareness among healthcare professionals regarding the risk of hypersensitivity reactions is imperative to ensure timely detection and appropriate management, thereby optimizing patient outcomes. Consequently, while giving oxaliplatin to cancer patients, healthcare professionals need to use extreme caution.

A five-year-old boy with anaphylaxis reaction to gadolinium-based MR contrast medium: a case report

Magnetic resonance imaging (MRI) is one of the most widely used tests in orthopedic areas. Gadolinium-based magnetic resonance (MR) contrast media are commonly used for MRI tests. They are known to be safe with little side effects and low incidence of acute adverse reactions. Although not common, immediate hypersensitivity reaction can occur in some patients after administration of gadolinium-based MR contrast media, causing skin rash, vascular edema, dyspnea, abdominal pain, hypotension, altered mental status, cardiopulmonary arrest, and even death. During a knee joint MRI test in a 5-year-old boy, anaphylaxis, a serious symptom, occured after injecting gadolinium-based MR contrast medium. Here we report this case along with a literature review.

Intensive Care for Anaphylaxis in Children: Current Trends

Anaphylaxis is an acute allergic reaction with rapid clinical development and risk of death. This article provides an analysis of literary sources devoted to intensive care of anaphylaxis in childhood. It was revealed that the prevalence of anaphylaxis is increasing, in children and adolescents as well. The main triggers of anaphylaxis in pediatric practice include food products, insect bites and drugs. Anaphylaxis is an IgE-mediated hypersensitivity reaction of type 1, characterized by the release of chemical mediators that lead to smooth muscle contraction, increased permeability and vasodilation and vagal activation. Clinically, anaphylaxis is manifested by allergic skin rash, angioedema, obstruction of the upper respiratory tract (URT), broncho-obstructive syndrome (BOS), arterial hypotension, tachycardia. Intensive care for anaphylaxis in children begins with stabilization of the condition: stopping the entry of a possible allergen into the body, hospitalization in the anesthesiology and intensive care unit, restoring patency of the URT, conducting oxygen therapy, monitoring vital functions. The first-line drug for the treatment of anaphylaxis in children is adrenaline at a dose of 0.01 mg/kg, which stops all the main pathophysiological links of anaphylaxis. Adrenaline autoinjectors are not used in the Russian Federation. Second-line drugs for intensive care for anaphylaxis in children include glucocorticosteroids (GCS), antihistamines, bronchodilators and infusion therapy. The effectiveness of GCS in anaphylaxis in children has not been proven, antihistamines can relieve skin manifestations of an allergic reaction, but do not affect vital disorders. Bronchodilators reduce BOS and are an additional treatment, while infusion therapy eliminates hypovolemia. Knowledge and timely implementation of modern care algorithms for anaphylaxis in children and adolescents will improve the quality of emergency care and reduce the risk of fatal outcomes in this pathology.

Reporting a Rare HLA Allele with Sequence Analysis Prevents Potentially Lethal Allopurinol Hypersensitivity Reaction

Abstract Introduction/Objective In addition to their essential role in histocompatibility testing, human leukocyte antigen (HLA) alleles have informative pharmacogenomic and disease associations. For example, HLA-B*58:01 carriers have 100- fold greater risk of allopurinol hypersensitivity syndrome (AHS), a lethal T-cell mediated Type IV reaction with a 20- 25% mortality rate. To prevent AHS, patients are tested for carrier status before treatment. Methods/Case Report Patient presented for workup of intermittently flaring right knee pain and uricemia. Uric acid is elevated, plain film imaging is ordered, arthrocentesis is planned, and HLA testing is performed to inform uricemia treatment. Next generation sequencing (NGS) typing reveals the patient carries HLA-B*58:11. Sequence analysis demonstrates the allele’s open reading frame differs from HLA-B*58:01 by a single I194V substitution. Amino acid sequences of peptide binding regions (PBR) encoded by these alleles are identical. Presentation of allopurinol/oxypurinol peptides to T-cells by B*58:01 is the putative mechanism underlying AHS pathogenesis. Identical protein sequence in the PBR of B*58:11 favors similar function. Findings are reported and treatment with allopurinol foregone. Results (if a Case Study enter NA) NA Conclusion High resolution HLA testing is essential to appropriately interpret and report results for disease risk and pharmacogenomics assessments. However, NGS detects rare alleles that have yet to be associated with a disease process. When pathogenesis is thought to be linked to the PBR, rare HLA alleles with identical or similar PBR to disease associated alleles may confer similar risk. In this case, NGS identified PBR similarity between the patient’s allele and an established AHS risk allele. Although B*58:11 has not been shown to be associated with AHS, likely due to low prevalence, the risk was deemed sufficient to select an alternative therapy and potentially prevent a lethal drug reaction.

Implementation of HLA-related genotype-guided prescribing in Singapore.

In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. To describe the implementation of human leukocyte antigen (HLA)-related genotype-guided prescribing in Singapore. Various HLA alleles have been implicated in drug hypersensitivity syndromes (DHS). These include HLA-B*15:02, which has been associated with carbamazepine-induced Stevens-Johnson syndrome/toxic epidermal necrolysis, HLA-B*58:01, which has been associated with increased risk of severe cutaneous adverse reactions with allopurinol use, and HLA-B*57:01, which has been associated with increased risk of hypersensitivity reactions with abacavir use. Integrating pharmacogenomics into patient care through genotype-guided prescribing potentially optimizes use of these drugs by reducing DHS-related and healthcare costs. We describe the prevalence of HLA-related DHS in Singapore, the cost-effectiveness of genotype-guided prescribing, and local policies and guidelines, as well as the impact of genotype-guided prescribing where available. HLA-related genotype-guided prescribing has the potential to reduce the incidence of DHS and decrease healthcare costs, as seen in the success with carbamazepine. However, not all genotype-guided prescribing is cost-effective when implemented across the population, as was evident from local studies for allopurinol and abacavir. The cost-effectiveness of such measures may change over time with new data (eg, allele frequencies, test costs, drug prices, genotyping approach) and should be evaluated periodically and locally. Implementation of preemptive pharmacogenomics panel testing as part of routine clinical care may shift the threshold for cost-effectiveness and brings promise of further optimization of pharmacotherapy through precision medicine.

Intranasal Trans-Sialidase Vaccine Mitigates Acute and Chronic Pathology in a Preclinical Oral Chagas Disease Model

Chagas disease, caused by Trypanosoma cruzi, leads to severe complications in 30% of infected individuals, including acute myocarditis and chronic fibrosing cardiomyopathy. Despite the significant burden of this disease, there is currently no licensed vaccine available to prevent it. This study aimed to evaluate the mucosal and systemic immunogenicity as well as the prophylactic efficacy of a mucosal vaccine candidate and its impact on both acute and chronic cardiomyopathy. The results showed that the nasal administration of trans-sialidase (TS) plus c-di-AMP (TS+A) vaccine elicited a NALT expression of IFN-γ, IL-17a and IL-4 mRNA as well as a nasal-specific production of IgA. An in vivo challenge with TS also triggered increased proliferation of lymphocytes from the NALT, sentinel cervical lymph node, and spleen. TS+A immunization increased the plasma levels of Th1/Th2/Th17 cytokines and elicited an evident cellular response by which to judge enhanced delayed-type hypersensitivity responses following a TS footpad challenge. After oral infection, TS+A-vaccinated mice showed significantly reduced parasitemia and parasite load in the heart, muscles and intestines, while markers of hepatic and muscle damage as well as clinical manifestations of acute infection were strongly diminished. TS+A also attenuated acute myocarditis and the expression of inflammatory markers in the heart. The protection conferred by TS+A extended into the chronic phase, where it resulted in a clear reduction in chronic myocarditis, fibrosis and functional electrocardiographic abnormalities, associated with a decreased expression of the pro-fibrotic TGF-β. These results revealed that it is possible to develop a mucosal vaccine against T. cruzi based on TS and c-di-AMP that is capable of reducing the development of Chagas cardiomyopathy, the hallmark of Chagas disease.

An epinephrine nasal spray (neffy) for anaphylaxis.

The FDA has approved an epinephrine nasal spray (neffy – ARS Pharma) for emergency treatment of type 1 hypersensitivity reactions including anaphylaxis in patients who weigh ≥30 kg. It is the first noninjectable epinephrine product to be approved for this indication.

Hypersensitivity myocarditis induced by isoniazid overdose in a 15-year-old girl: a case report.

Myocarditis represents a diverse group of inflammatory diseases affecting the heart muscle, with both infectious and non-infectious etiologies. Among the non-infectious causes, drug-induced hypersensitivity reactions are rare but serious. Isoniazid, a cornerstone in tuberculosis treatment, is known for its hepatotoxicity but has rarely been documented to cause hypersensitivity myocarditis. We present a case of a 15-year-old girl from Eastern Turkmenistan who was admitted to our emergency department with altered consciousness and seizure activity. She was diagnosed with status epilepticus and treated accordingly. The patient, with no prior medical history, was found to have hypotensive shock and myocarditis upon further examination. A detailed history revealed she had ingested 45 tablets of expired isoniazid in a suicide attempt. She was treated with pyridoxine and supportive therapies, resulting in a gradual recovery. This case underscores the critical need to consider drug-induced hypersensitivity myocarditis in the differential diagnosis of myocarditis, especially in patients with recent medication use. Prompt recognition and appropriate treatment with pyridoxine, steroid, and supportive cardiac care can be lifesaving. This case also highlights the importance of awareness regarding the potential cardiotoxic effects of isoniazid overdose.

Protocol for a systematic review and meta-analysis of interventions aimed at delabeling low-risk penicillin allergies with consideration for sex and gender

BackgroundApproximately, 10% of people report a penicillin allergy; however, more than 90% can safely undergo delabeling after a detailed history, oral challenge, or other investigations such as penicillin skin testing (PST). Although PST is the gold standard, the results can be heterogeneous, and awaiting specialist assessment may take an inordinate amount of time. Therefore, oral provocation challenge has become acceptable for individuals with low-risk penicillin allergy histories. There also appears to be an association with increased prevalence of adverse drug reaction reporting in female individuals, which may translate to penicillin allergy prevalence; however, the evidence has not been assessed through a sex and gender lens. This systematic review will identify and synthesize the findings from studies that report measures of effectiveness and safety of interventions aimed at delabeling penicillin allergies in low-risk individuals. Information related to sex and gender will be extracted, where available, to understand potential differences in allergy reporting and patient outcomes.MethodsThe Cochrane Handbook for Systematic Reviews of Interventions and the Centre for Review and Dissemination’s Guidance for Undertaking Reviews in Health Care will be used as frameworks for conducting this systematic review. The literature search will be conducted by a medical librarian (B. M. M.) and will consist of a search strategy to identify and retrieve published studies that meet our inclusion criteria. Studies that require penicillin skin testing (PST) as a step prior to other interventions will be excluded. Integrated knowledge translation involving co-design was carried out for this systematic review protocol creation. Data extraction will be conducted at four levels: (1) study level, (2) patient level, (3) intervention level, and (4) outcome level. A narrative descriptive synthesis of results and risk of bias of all included studies will be provided, and, if relevant, a meta-analysis will be performed.DiscussionThe dissemination of findings from this knowledge synthesis to various stakeholders is intended to inform on options for evidence-based interventions to aid in delabeling penicillin allergies in individuals with a low risk of experiencing a hypersensitivity reaction. Detailed reporting on the characteristics of delabeling interventions as well as the effectiveness of similar interventions will benefit policy makers considering the implementation of a penicillin allergy delabeling protocol. Additionally, findings from this systematic review will report on the current evidence regarding the role of sex and gender in both the prevalence and outcomes associated with the presence of penicillin allergies.Systematic review registrationPROSPERO CRD42022336457.

Population pharmacokinetics and pharmacodynamics of L-asparaginase and its impact on the development of pancreatitis and hypersensitivity reactions in children with leukemia under treatment

L-asparaginase (L-Asp) is an essential enzyme in the treatment of patients with Acute Lymphoblastic Leukemia (ALL), commonly associated with adverse events (AE). Knowing the pharmacokinetic and pharmacodynamic (PK/PD) parameters of L-Asp as well as its relationship with the development of AE is an important strategy in the search to improve the efficacy and safety of the treatment. Seventy-four children with ALL that were being treated with L-Asp, were included. One to three blood samples were randomly obtained from each patient, at times from 0 to 30 hours, until completing a total of 211 samples. The L-Asp activity and the Asparagine (Asp) concentration were quantified, in addition, the presence of anti-L-Asp antibodies (Anb) was determined. A population PK/PD model of L-Asp was developed to determine the association of covariates with PK/PD parameters. The presence of Anb was associated with the increase in L-Asp clearance (CL) and with the decrease of volume of distribution 1 (V1). On the other hand, female sex was significantly associated with the increase of V1, while the age from 1 to 6 years was significantly associated with the increase of V1. The presence of Anb as well as the female sex were related to the increase IC50 (concentration-needed to deplete-50% of Asp). Patients who presented Asp depletion before the first 24 hours after administration presented pancreatitis, this could be a risk marker. Significant results were found in this study, use of these results may contribute to the safe and effective use of L-Asp.

Mechanisms of Electroacupuncture in Alleviating Visceral Hypersensitivity in Post-Infectious Irritable Bowel Syndrome Mice: The Role of GDNF Signaling Pathway and Gut Microbiota.

Post-infectious irritable bowel syndrome (PI-IBS) is a functional bowel disease that develops following an acute gastrointestinal infection. Electroacupuncture (EA) can regulate the gut microbiota and alleviate visceral hypersensitivity. Glial cell-derived neurotrophic factor (GDNF) is a potential factor in visceral hypersensitivity reactions. The aim of this study was to explore whether EA could alleviate visceral hypersensitivity in PI-IBS by regulating gut microbiota through GDNF signaling. 2,4,6-trinitrobenzene sulfonic acid (TNBS) was used to induce visceral hypersensitivity in PI-IBS mice. Assessment of intestinal visceral sensitivity using the abdominal withdrawal reflex (CRD). 16S ribosomal RNA (16S rRNA) sequencing to profile the gut microbiome community. GDNF can exacerbate the imbalances of the gut microbiota and increase visceral hypersensitivity compared with the model group. Whereas EA treatment increases the richness and diversity of the gut microbiota, decreases differences among species and alleviates visceral sensitivity. EA can alleviate visceral hypersensitivity in PI-IBS by regulating the gut microbiota via GDNF signaling, providing new insights for mechanistic research on EA in PI-IBS treatment.

Predictors of immediate and delayed cutaneous hypersensitivity reactions to paclitaxel.

Paclitaxel is one of the first-line treatments for breast, ovarian, and lung cancers. However, its use is limited by the high frequency of hypersensitivity reactions. In this retrospective chart review at Memorial Sloan Kettering Cancer Center, we assess clinical factors associated with immediate and delayed hypersensitivity reactions to paclitaxel and characterize delayed hypersensitivity reactions to paclitaxel in patients with breast cancer. 12,274 patients were treated with paclitaxel. 6,165 had breast cancer and 1,233 were seen by a dermatologist. 734 patients (11.9%) developed an immediate hypersensitivity reaction. Age (p < 0.001), race (p < 0.001), and prior history of allergy (p = 0.05) were associated with immediate hypersensitivity reactions. 147 patients (4.0%) had a rash of interest. The most common phenotypes were maculopapular (52%) and urticaria (36%). Race (p < 0.001) and history of allergy (p < 0.001) were associated with development of a cutaneous reaction. Patients with an immediate hypersensitivity reaction were more likely to have developed a delayed cutaneous reaction (OR = 1.80). Risk factors for development of immediate hypersensitivity reactions in this study were younger age, race, and history of allergy. Patients who developed an immediate hypersensitivity reaction were more likely to develop a delayed hypersensitivity reaction. Risk factors for development of the rash included Asian race and history of allergy. Identification of risk factors is critical to guide care coordination. Awareness of these clinical factors which are associated with development of a rash could guide providers in choosing treatment with paclitaxel or nab-paclitaxel. If the cutaneous reactions are bothersome to the patient, the transition of treatment from paclitaxel to nab-paclitaxel may be warranted, or a consideration of re-challenge or desensitization may be discussed.

Differential MRGPRX2-dependent activation of human mast cells by polymyxins and octapeptins

The emergence of multi-drug resistant Gram-negative bacteria has led to renewed interest in the antimicrobial activity of polymyxins and novel polymyxin analogues (e.g. nonapeptides and octapeptin). In some individuals, clinically used polymyxins can cause acute hypersensitivity reactions through mast cell activation, with a recent study attributing this effect to activation of the MAS-related G protein-coupled receptor X2 (MRGPRX2). In the present study, HEK293 cells expressing human MRGPRX2 and the human mast cell line LAD2 were used to characterize the activity of the broader family of polymyxins. Octapeptin C4, polymyxin B and colistin produced concentration-dependent calcium mobilization, degranulation, and CCL-2 (MCP-1) release in LAD2 mast cells, with the former being highly potent. CRISPR-Cas9 knockdown of MRGPRX2 in LAD2 cells and a MRGPRX2 inverse agonist caused a significant reduction in calcium mobilization, degranulation, and CCL-2 release, demonstrating dependency on MRGPRX2 expression. In contrast, polymyxin nonapeptides were far less potent calcium mobilisers and failed to induce functional degranulation in LAD2 cells. Our results confirm that activation of mast cells induced by polymyxin-related antibiotics is MRGPRX2-dependent and reveal that octapeptin C4 might be more liable, whilst nonapeptides are less liable, to trigger immediate hypersensitivity reactions clinically. The mechanism underpinning the difference in MRGPRX2 activation between polymyxin-related antibiotics is important to better understand as it may help design new, safer polymyxins and guide the optimal clinical use of existing polymyxin drugs.

Serum metabolomics analysis reveals potential biomarkers of penicillins-induced fatal anaphylactic shock in rats

Immunoglobulin E (IgE)-mediated immediate hypersensitivity reactions are the most concerning adverse events after penicillin antibiotics (PENs) administration because of their rapid progression and potential for fatal outcome. However, the diagnosis of allergic death is a forensic challenge because it mainly depends on nonspecific characteristic morphological changes, as well as exclusion and circumstantial evidence. In this study, an untargeted metabolomics approach based on liquid chromatography-mass spectrometry (LC-MS) was used to screen potential forensic biomarkers of fatal anaphylactic shock induced by four PENs (benzylpenicillin (BP), amoxicillin (AMX), oxacillin (OXA), and mezlocillin (MEZ)), and analyzed the metabolites, metabolic pathway and the mechanism which were closely related to the allergic reactions. The metabolomics results discovered that a total of 24 different metabolites in all four anaphylactic death (AD) groups, seven of which were common metabolites. A biomarker model consisting of six common metabolites (linoleic acid, prostaglandin D2, lysophosphatidylcholine (18:0), N-acetylhistamine, citric acid and indolelactic acid) AUC value of Receiver Operating Characteristic (ROC) curve was 0.978. Metabolism pathway analysis revealed that the pathogenesis of PENs-induced AD is closely related to linoleic acid metabolism. Our results revealed that the metabolomic profiling has potential in PENs-induced AD post-mortem diagnosis and metabolic mechanism investigations.

Antioxidant and immunomodulatory activities of ethanol extracts from Syzygium cumini L. Skeels and Pogostemon cablin Benth

Syzygium cumini and Pogostemon cablin are mostly cultivated in tropical climates for culinary and perfumery purposes, yet their potential medicinal properties remain underreported. The aim of this study was to examine the antioxidant and immunomodulatory activities of ethanol extracts from S. cumini (EESC) and P. cablin (EEPC). Reflux extraction was carried out using 96% ethanol on the collected plant specimens to produce EESC and EEPC. Secondary metabolites of each extract were identified using gas chromatography-mass spectrometry (GC-MS). The extracts were measured for total phenol and flavonoid levels and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. The immunomodulatory activity test was carried out in vivo by assessing several parameters, including the phagocytic index via the carbon clearance method, organ indices, antibody titers, and delayed-type hypersensitivity (DTH) response, using sheep red blood cells (SRBC) as antigens. The extracts were also examined for their anti-inflammatory activity in acute and chronic inflammation models. In the DPPH antioxidant test, EESC and EEPC had IC50 values of 12.33 µg/mL and 182.17 µg/mL, respectively. Both extracts showed immunosuppressant activity, marked by a phagocytic index of &lt;1. EESC yielded lower organ indices for the liver (p=0.025 at 200 mg/kg BW), spleen (p=0.028 at 100 mg/kg BW), and thymus (p=0.032 at 200 mg/kg BW) compared to the control group. For EEPC, lower organ indices were observed in the liver at 100 mg/kg BW (p=0.005) and 200 mg/kg BW (p=0.031). In the primary antibody titer and DTH tests, both EESC and EEPC showed immunosuppressant activity at 200 and 400 mg/kg BW (p&lt;0.05). The extracts suppressed both the innate and adaptive immune systems. Both EEPC (p=0.004) and EESC at 100 mg/kg BW (p=0.03) significantly reduced serum TNF-α levels. In conclusion, EESC and EEPC have the potential as immunosuppressive and anti-inflammatory agents.

Evaluation of long-term stability of L-asparaginase encapsulated PLL-g-PEG nanoparticles in solution to aid in therapeutic delivery

Abstract L-asparaginase (L-ASNase) is a therapeutic enzyme that is widely used for the treatment of hematopoietic diseases such as acute lymphoblastic leukemia and lymphomas. L-ASNase destroys asparagine dependent tumors by degrading circulating L-asparagine and thereby destroying malignant cells. As a protein drug, L-ASNase carries a few inherent drawbacks including short circulating half-life, low stability, and low catalytic activity under physiological conditions. Moreover, due to the bacterial origin of L-ASNase used in treatments, there have been reports with high frequency of hypersensitivity reactions in patients. The use of this drug in adult cancer populations has largely been hindered not only due to its immunological side effects but also due to non-immunogenic toxicities such as pancreatitis, liver toxicities, coagulopathy, and neurotoxicity. Therefore, it is vital to find new methods to decrease its immunogenic/toxicity profile while increasing the stability and half-life. The purpose of this study is to achieve a new L-ASNase polymer nanocarrier to improve stability of the enzyme while masking it from the immune system of the host. We designed and characterized a nanoparticle (NP) where a poly-L-lysine-grafted-poly(ethylene) glycol co-polymer was used to encapsulate L-ASNase. The primary focus of the study was to evaluate the stability and encapsulation efficiency of this NP construct over time. There was no aggregation of NPs observed during the study period of 6 months in solution and NPs had a 0.436 mV surface charge. L-ASNase NPs showed a percent asparaginase activity of 31% compared to free L-ASNase. Under physiological conditions NPs were found to be intact and retained the encapsulated proteins for up to 6 months in solution. Together, these results demonstrate that L-ASNase loaded PLL-g-PEG NPs may serve as a fundamental platform to design nanocarriers to prolong stability in solution.