Effective in vitro evaluation of the risk of histamine release related to valemetostat tosylate using MRGPRX2-expressing cells.

Mas-related G-protein-coupled receptor X2 (MRGPRX2), expressed on mast cells, is associated with drug-induced pseudo-allergic reactions. Although it is well known that there are differences of sensitivity between species in the pseudo-allergic reactions, no platform for evaluating a human risk of the pseudo-allergic reactions observed in nonclinical studies has been established. Valemetostat tosylate, developed as an anti-cancer drug, induced histamine release in a nonclinical study with dogs. The purpose of the current study was to identify the mechanism and assess the human risk of valemetostat-tosylate-induced histamine release using dog and human MRGPRX2-expressing cells. In an experiment with human or dog MRGPRX2-expressing cells, valemetostat tosylate caused activation of human and dog MRGPRX2. Importantly, the EC50 for dog MRGPRX2 was consistent with the Cmax value at which histamine release was observed in dogs. Furthermore, the EC50 for human MRGPRX2 was ca. 27-fold higher than that for dog MRGPRX2, indicating a species difference in histamine-releasing activity. In a clinical trial, histamine release was not observed in patients receiving valemetostat tosylate. In conclusion, an in vitro assay using human and animal MRGPRX2-expressing cells would be an effective platform to investigate the mechanism and predict the human risk of histamine release observed in nonclinical studies.

Study on the potential allergen and mechanism of pseudo-allergic reactions induced by combined using of Reduning injection and penicillin G injection based on metabolomics and bioinformatics / 药学学报

Based on the strategy of metabolomics combined with bioinformatics, this study analyzed the potential allergens and mechanism of pseudo-allergic reactions (PARs) induced by the combined use of Reduning injection and penicillin G injection. All animal experiments and welfare are in accordance with the requirements of the First Affiliated Experimental Animal Ethics and Animal Welfare Committee of Henan University of Chinese Medicine (approval number: YFYDW2020002). Based on UPLC-Q-TOF/MS technology combined with UNIFI software, a total of 21 compounds were identified in Reduning and penicillin G mixed injection. Based on molecular docking technology, 10 potential allergens with strong binding activity to MrgprX2 agonist sites were further screened. Metabolomics analysis using UPLC-Q-TOF/MS technology revealed that 34 differential metabolites such as arachidonic acid, phosphatidylcholine, phosphatidylserine, prostaglandins, and leukotrienes were endogenous differential metabolites of PARs caused by combined use of Reduning injection and penicillin G injection. Through the analysis of the "potential allergen-target-endogenous differential metabolite" interaction network, the chlorogenic acids (such as chlorogenic acid, neochlorogenic acid, cryptochlorogenic acid, and isochlorogenic acid A) and β-lactam allergens in the combination of the two may be mainly regulated by PLD1, PLA2G12A and CYP1A1. The three upstream signal target proteins mainly activate the arachidonic acid metabolic pathway, promote the degranulation of mast cells, release downstream endogenous inflammatory mediators, and induce PARs.

Inhibitory effect of daphnetin on the C48/80-induced pseudo-allergic reaction.

Pseudo-allergic reaction is an allergic reaction mediated by nonimmunoglobulin E (IgE), which does not require prior contact with antigen sensitization and directly leads to mast cell degranulation. Daphnetin (DAP) is known for its anti-inflammatory effects, but there are few studies on the effect of DAP on pseudo-allergy and its mechanism. To investigate the effect of DAP on pseudo-allergy and its mechanism, we inflicted pseudo-allergy on RBL-2H3 cells using C48/80 in vitro. Moreover, to assess the antipseudo-allergy effect of C48/80 in vivo, mouse models of local anaphylaxis, systemic anaphylaxis, and itch were used. The in vitro results show that DAP inhibits degranulation and chemokine release; furthermore, DAP reduced the activation of the PLC-IP3R and MAPK signaling pathways induced by C48/80. Additionally, our in vivo results showed that DAP inhibited C48/80-induced local anaphylaxis and inhibited eosinophil aggregation, vasodilation and mast cell degranulation. In systemic anaphylaxis, DAP inhibits the decrease in body temperature and reduces the release of His, TNF-a and IL-8. In C48/80-induced itch, the number of scratches in mice was reduced. Our results demonstrate that DAP can play a suppressive role in the pseudo-allergy induced by C48/80, providing information for the cure of disorders linked to pseudo-allergic reactions.

Screening potential anaphylactoid components in vinpocetine injection using a high expression Mas-related G-protein-coupled receptor X2 cell membrane chromatography.

Vinpocetine injection is often used in clinical treatment of acute cardiovascular and cerebrovascular diseases. However, it was reported that vinpocetine injection caused allergic reactions in clinical use; therefore, its safety needs urgent attention. Until now, research on its sensitization is rarely reported. Here, the components contained in three vinpocetine injections were examined. It was found that besides vinpocetine, the synthetic raw material vincamine, the excipients benzyl alcohol and ethyl p-toluenesulfonate, and the impurities A, B, C, and D, which are excipients specified in the European Pharmacopoeia, were also present in them. Then the Mas-related G-protein-coupled receptor X2 (MRGPRX2)-HEK293 cell membrane chromatography was used to investigate the affinity of them with MRGPRX2 and found that vinpocetine, vincamine, and impurities A, B, C, and D bind to MRGPRX2. Afterwards, these compounds were further used to investigate the local sensitization ability in vivo. The results showed that vinpocetine, vincamine, and impurity C could induce swelling of the paw and decrease body temperature in mice, but only impurity C could cause local skin mast cell degranulation and serum histamine release increase. In vitro, the results also indicated that impurity C could increase intracellular [Ca2+ ] in MRGPRX2-HEK293 cells, whereas vinpocetine and vincamine did not. Therefore, the impurity C was the potential anaphylactoid component in vinpocetine injection, which may be one of the reasons for the occurrence of allergic reactions in the clinical use of vinpocetine injection. This work provides evidence on the sensitization of impurity C and also contributes to promoting the clinical safety of vinpocetine injection.

Synthetic imperatorin derivatives alleviate allergic reactions via mast cells.

Anaphylaxis is a severe systemic allergic reaction that exhibits multiple clinical symptoms. The Mas-related G protein-coupled receptor X2 (MRGPRX2) is recognized as a key cell receptor mediating allergic diseases and drug-induced anaphylactoid reactions. Thus, it has been a promising target for preventing and treating these reactions. Based on the potential activity of imperatorin and active structural feature of MRGPRX2, we first demonstrated that the synthetic imperatorin derivatives (IDs) could significantly inhibit MRGPRX2 agonist-induced degranulation and cytokine release in LAD2 cells, as well as alleviate local and systemic anaphylaxis in mice. The IC50 value of the most promising compound is an order of magnitude lower than that of imperatorin. IDs were further identified to display anti-pseudo-allergic activity by binding MRGPRX2 with the tertiary nitrogen substructures, just liking the reported MRGPRX2-ligand. These results would propose evidence for discovery of agents for treating MCs-dependent allergic disorders.

Clinical features of adverse events associated with Xiyanping-Ribavirin combination: A systematic review.

ETHNOPHARMACOLOGICAL RELEVANCE: In China, Xiyanping (XYP) has been widely used in combination with Ribavirin (RB) for the treatment of infectious diseases. It has been found that this combination may change the severity of XYP-associated adverse events (AEs). AIM: To provide a comprehensive review about the clinal features of AEs of XYP-RB combination from randomized controlled trials, cohort studies, case-control studies, case reports, case series, and data from the National Adverse Drug Reaction Monitoring Information System (NADRMIS). MATERIALS AND METHODS: Seven electronic databases were searched in March 2021. Articles on AEs associated with XYP published from January 2004 to December 2020 in the NADRMIS were included. Data on the incidence of AEs, distribution of AEs, occurrence time of AEs, type and possible signal of AEs, primary diseases, allergic history, family history of allergies, dosage, and combination interval were extracted. RESULTS: We included 228 cases of AEs with XYP-RB combination (63 cases from randomized controlled trials, 1 from a cohort study, and 164 from the NADRMIS). The most common primary disease was hand-foot-and-mouth disease. The main age distribution was 0-6 years (118 cases, 72%) and 8 cases (6.8%) experienced serious AEs. The combination group showed a significant reduction than the RB group in the incidence of AEs in those with hand-foot-and-mouth disease (risk ratio = 0.54, 95% confidence interval = 0.38-0.78, P = 0.0008) and children with viral pneumonia (risk ratio = 0.36, 95% confidence interval = 0.14-0.95, P = 0.04). Allergic history and infusion interval were not described in the randomized controlled trials. AEs were reported in 57.9% of cases in the first combination (XYP-RB were combined for the first time) (NADRMIS), 56.4% of which were skin and appendage reactions, and the risk signal of skin and appendage reactions was a maximum (Information Component = 6.21). CONCLUSION: The major AE associated with XYP-RB combination was skin and appendage reactions. Most of the combination AEs were pseudo-allergic reactions. These findings suggest that we should increase awareness about the safety of XYP-RB combination treatment and standardize medication protocol, especially for children. Unless absolutely necessary, children should avoid combination therapy. More rigorous high-quality studies are needed to obtain more evidence.

Auriculotemporal Frey syndrome not associated with surgery or diabetes: systematic review.

Patients who undergo salivary gland, neck, or facelift surgery or suffer from diabetes mellitus often develop Frey syndrome (also known as auriculotemporal syndrome or gustatory sweating). Frey syndrome has been occasionally reported to occur in subjects without history of surgery or diabetes but this variant of Frey syndrome has not been systematically investigated. We searched for original articles of Frey syndrome unrelated to surgery or diabetes without date and language restriction. Article selection and data extraction were performed in duplicate. Our systematic review included 76 reports describing 121 individual cases (67 males and 54 females) of Frey syndrome not associated with surgery or diabetes. The age at onset of symptoms was ≤ 18 years in 113 (93%) cases. The time to diagnosis was 12 months or more in 55 (45%) cases. On the other hand, an allergy evaluation was performed in half of the cases. A possible cause for Frey syndrome was detected in 85 (70%) cases, most frequently history of forceps birth (N = 63; 52%). The majority of the remaining 22 cases occurred after a blunt face trauma, following an auriculotemporal nerve neuritis or in association with a neurocutaneous syndrome. The cause underlying Frey syndrome was unknown in 36 cases.   Conclusion: Frey syndrome not associated with surgery or diabetes almost exclusively affects subjects in pediatric age and is uncommon and underrecognized. Most cases occur after forceps birth. There is a need to expand awareness of this pseudo-allergic reaction among pediatricians and allergists. What is Known: • Pre-auricular reddening, sweating, and warmth in response to mastication or a salivary stimulus characterize Frey syndrome. • It usually occurs after salivary gland surgery and in diabetes. What is New: • In children, Frey syndrome is rare, and most cases occur after a forceps-assisted birth. • In childhood, this condition is often erroneously attributed to food allergy.

Chrysin Inhibits Pseudo-allergic Reaction by Suppressing Mitochondrial STAT3 Activation via MAS-Related GPR Family Member X2.

Chrysin, one of the most pharmacologically active natural flavonoids, has been extracted from various plants. Mast cells are an important part of innate immunity-mediating anaphylaxis. Pseudo-allergic reactions are currently believed to be associated with the MAS-related GPR family member X2 (MrgX2). In this study, the anti-pseudo allergy effect of chrysin and its underlying mechanisms were studied in vitro and in vivo. Chrysin inhibited passive cutaneous anaphylaxis and systemic pseudo-allergy in vivo. LAD2 cell degranulation, calcium ion (Ca2+) influx, and adenosine 5'-triphosphate (ATP) content were significantly suppressed in a dose-dependent manner. Chrysin suppressed pseudo-allergic reactions through the PLC/IP3/Ca2+ and ERK/STAT3 serine 727 pathways downstream of MrgX2. Therefore, mitochondrial ATP, but not glycolysis, is vital for pseudo-allergic reactions mediated by MrgX2. This study provides new insights for the treatment of pseudo-allergy.

[Research progress on adverse reactions and pseudo-allergic reactions of traditional Chinese medicine injections].

Since the safety re-evaluation of traditional Chinese medicine(TCM) injections began in 2009, some TCM injection companies and research institutes have done a lot of work. And with the increase of drug development and drug production technology levels in China, the safety of some TCM injections has been greatly improved. There are safety risks in TCM injections, which are mainly reflected in unclear basis of medicinal materials, simple production process, poor controllability of quality standards, nonstan-dard drug instructions and irrational medication in the use process. This paper describes the research progress of the above-mentioned aspects of TCM injections. In addition, the author team found that adverse reactions of TCM injections are mainly pseudo-allergic reactions. Therefore, a lot of work has been done in detection of pseudo-allergic reactions, mechanism research and risk control. This part of the work is also described in this article.

Research progress on adverse reactions and pseudo-allergic reactions of traditional Chinese medicine injections / 中国中药杂志

Since the safety re-evaluation of traditional Chinese medicine(TCM) injections began in 2009, some TCM injection companies and research institutes have done a lot of work. And with the increase of drug development and drug production technology levels in China, the safety of some TCM injections has been greatly improved. There are safety risks in TCM injections, which are mainly reflected in unclear basis of medicinal materials, simple production process, poor controllability of quality standards, nonstan-dard drug instructions and irrational medication in the use process. This paper describes the research progress of the above-mentioned aspects of TCM injections. In addition, the author team found that adverse reactions of TCM injections are mainly pseudo-allergic reactions. Therefore, a lot of work has been done in detection of pseudo-allergic reactions, mechanism research and risk control. This part of the work is also described in this article.

Discovery and analysis the anti-pseudo-allergic components from Perilla frutescens leaves by overexpressed MRGPRX2 cell membrane chromatography coupled with HPLC-ESI-IT-TOF system.

OBJECTIVES: Screen and identify the anti-pseudo-allergic activity components of Perilla frutescens leaves that interacted with MRGPRX2 (a new reported pseudo-allergic reaction-related receptor). METHODS: An overexpressed MRGPRX2 cell membrane chromatography (CMC) coupled with HPLC-ESI-IT-TOF system has been established to screen and identify the effective components from P. frutescens leaves. A frontal analysis method was performed to investigate the binding affinity between ligands and MRGPRX2. Their activity of relieving pseudo-allergic reaction was evaluated in vitro by histamine release assay, ß-hexosaminidase release assay and intracellular Ca2+ mobilization assay. KEY FINDINGS: Extract of P. frutescens leaves was proved to be effective in anti-pseudo-allergic reaction by inhibiting MRGPRX2. Apigenin (API) and rosmarinic acid (ROS) were confirmed to be the potential anti-allergy compounds that could bind with MRGPRX2. The binding affinity (KD ) of ROS and API with MRGPRX2 was (8.79 ± 0.13) × 10-8  m and (6.54 ± 1.69) × 10-8  m, respectively. The IC50 of API inhibiting laboratory of allergic disease 2 cells degranulation was also determined to be (51.96 ± 0.18) µm. CONCLUSIONS: A MRGPRX2/CMC coupled with HPLC-ESI-IT-TOF system was successfully established and applied to discover the effective components from P. frutescens leaves.

Thimerosal induces skin pseudo-allergic reaction via Mas-related G-protein coupled receptor B2.

BACKGROUND: Thimerosal has been used as a preservative in many products which may cause contact dermatitis. It is the second most common allergen in positive patch test reactions, though being a clinical irrelevant allergen. Thimerosal-induced contact dermatitis is generally considered to be a delayed-type hypersensitivity reaction, but it is difficult to explain the fact that most patients develop an allergic reaction upon first encounter with thimerosal. Recent studies have demonstrated the association between Mas-related G protein coupled receptor X2 (MRGPRX2) and pseudo-allergic reactions which occur at the first contact with stimulation. This suggests the possibility that thimerosal may cause contact dermatitis via MRGPRX2 mediated mechanism. OBJECTIVES: To investigate the role of Mas-related G-protein coupled receptor B2 (MrgprB2)/MRGPRX2 in contact dermatitis induced by thimerosal. METHODS: Thimerosal induced pseudo-allergic reactions via MrgprB2/ MRGPRX2 were investigated using a novel skin pseudo-allergic reaction mouse model, footpad swelling and extravasation assays in vivo and mast cell degranulation assay in vitro. RESULTS: Thimerosal induced contact dermatitis in dorsal skin and footpad swelling in wild-type mice, but had no significant effect in MrgprB2-knockout mice. Thimerosal-induced dermatitis is characterized by infiltration of inflammatory cells and elevation of serum histamine and inflammatory cytokines, rather than elevation of serum IgE level. Thimerosal increased the intracellular Ca2+ concentration in HEK293 cells overexpressing MrgprB2/MRGPRX2. Downregulation of MRGPRX2 resulted in the reduced degranulation of LAD2 human mast cells. CONCLUSIONS: MrgprB2 mediates thimerosal-induced mast cell degranulation and pseudo-allergic reaction in mice. MRGPRX2 may be a key contributor to human contact dermatitis.

Preliminary study on the mechanism of anaphylactoid reaction induced by natural product germacrone / 药学学报

The Chinese medicine injections prepared by the natural products containing sesquiterpenoids caused various adverse reactions in clinical use, among which skin allergic reactions are the most common. However, whether the reason of allergic reaction was related to the three isoprene units contained in the sesquiterpenoids is not clear, so the evaluation of drug safety has important guiding significance. The sesquiterpenoids are small molecular substances, and they are not antigens or haptens. They may induce anaphylaxis reactions by acting mast cells directly. Current research confirmed that Mas-related G protein-coupled receptor-X2 (MRGPRX2) which is a 7-transmembrane G protein coupled receptor on mast cells was a key target mediated allergic reactions induced by many small molecular drugs. Unlike IgE-mediated allergic reactions, pseudo-allergic reaction is related to dosage and dosing rate, and occurs in the first exposure to the sensitizer. In this paper, a series of experiments in vitro found that not all sesquiterpenoids caused anaphylactoid reactions. Ginsenoside Re, ginsenoside Rb1 and germacrone were selected as representative of sesquiterpenoids for calcium imaging assay. The data confirmed that only germacrone activated calcium mobilization through MRGPRX2, causing an increase in intracellular calcium ion concentration in mast cells. Furthermore, the release rate of β-hexosaminidase and the release amount of histamine analysis confirmed that germacrone induced mast cells degranulation directly. Knockdown of MRGPRX2 expression by siRNA and competitive binding experiments against ciprofloxacin were used to prove the target of germacrone was MRGPRX2. The results indicated that germacrone could activate mast cells directly to induce anaphylactoid reaction via MRGPRX2, which might be the reason of skin allergic reactions caused by injections containing germacrone.

[Safety of animal traditional Chinese medicine (TCM) injections].

Animal medicine injection is an important part of traditional Chinese medicine (TCM) injections. All or part of animals with a significant curative effect and little side reactions as raw materials as well as modern technology are used to produce traditional Chinese medicine injections with a reliable and rapid drug efficacy and high bioavailability. Due to the complex composition of traditional Chinese medicine injections, imperfect quality standards, and unreasonable clinical use, the incidence of adverse reactions of traditional Chinese medicine injections has been significantly higher than that of traditional Chinese medicine for oral use. Animal medicine injections contain rich protein and fat, and heteroproteins are the main sensitization source in animal medicine injections. At present, the adverse reactions of animal medicine injections are mainly manifested in the anaphylaxis-like reactions at skin, mucous membranes and organ systems. The adverse reactions that occur during the first medication are more common. Specific causes for allergic-like adverse reactions in animal injections and related substances in traditional Chinese medicine injections made of animals that induce allergies or anaphylactoid reactions are currently not specifically reported. This article reviews the current adverse reactions of animal TCM injections, allergies and pseudoallergic reactions of animal TCM injections, the pharmacokinetics of animal TCM injections, and the combined use of drugs, in order to improve the quality standards of Chinese medicine injections for animals and provide reference for further safety related research.

Safety of animal traditional Chinese medicine (TCM) injections / 中国中药杂志

Animal medicine injection is an important part of traditional Chinese medicine (TCM) injections. All or part of animals with a significant curative effect and little side reactions as raw materials as well as modern technology are used to produce traditional Chinese medicine injections with a reliable and rapid drug efficacy and high bioavailability. Due to the complex composition of traditional Chinese medicine injections, imperfect quality standards, and unreasonable clinical use, the incidence of adverse reactions of traditional Chinese medicine injections has been significantly higher than that of traditional Chinese medicine for oral use. Animal medicine injections contain rich protein and fat, and heteroproteins are the main sensitization source in animal medicine injections. At present, the adverse reactions of animal medicine injections are mainly manifested in the anaphylaxis-like reactions at skin, mucous membranes and organ systems. The adverse reactions that occur during the first medication are more common. Specific causes for allergic-like adverse reactions in animal injections and related substances in traditional Chinese medicine injections made of animals that induce allergies or anaphylactoid reactions are currently not specifically reported. This article reviews the current adverse reactions of animal TCM injections, allergies and pseudoallergic reactions of animal TCM injections, the pharmacokinetics of animal TCM injections, and the combined use of drugs, in order to improve the quality standards of Chinese medicine injections for animals and provide reference for further safety related research.