Fuente: PubMed "hive" Pol Arch Intern Med. 2026 Jan 7:17187. doi: 10.20452/pamw.17187. Online ahead of print.ABSTRACTINTRODUCTION: Mas-related G protein-coupled receptor X2 (MRGPRX2) has emerged as a mediator of mast-cell activation in acute and chronic conditions. Exogenous ligands, such as neuromuscular blocking agents (NMBAs) and fluoroquinolones (FQs), can trigger MRGPRX2-dependent activation and may augment immunoglobulin E (IgE)-mediated pathways. Although investigators have measured serum MRGPRX2 in asthma, mastocytosis, and chronic urticaria, its role in immediate hypersensitivity reactions (IHRs) to FQs or NMBAs remains unclear.OBJECTIVES: We conducted this study to determine whether increased serum MRGPRX2 concentration is a risk factor for IHRs to NMBAs or FQs and whether concentration relate to reaction severity, causative agent, or serum tryptase.PATIENTS AND METHODS: We studied 43 patients with a history of IHRs to NMBAs or FQs and compared them with 50 patients with IHRs to Hymenoptera venom and 40 control individuals. Participants underwent a diagnostic evaluation that included skin testing, specific IgE measurement, and basophil activation test when indicated. We measured serum MRGPRX2 by enzyme-linked immunosorbent assay.RESULTS: The median serum MRGPRX2 values with interquartile ranges for the drug-induced reactions group, the Hymenoptera venom-induced reactions group, and the control group were 7.50 (3.73-15.64), 7.00 (3.96-10.62), and 5.89 (2.43-9.98) ng/mL, respectively (P = 0.32). Serum MRGPRX2 concentration showed no relationship with reaction severity, specific causative agents, or serum tryptase.CONCLUSIONS: In this cohort, serum MRGPRX2 was not a risk factor for the investigated drug- and venom-induced IHRs. These findings do not support using serum MRGPRX2 as a predictor of reaction occurrence or severity in these settings.PMID:41498153 | DOI:10.20452/pamw.17187