Rocuronium-specific antibodies drive perioperative anaphylaxis but can also function as reversal agents in preclinical models.

Neuromuscular blocking agents (NMBAs) relax skeletal muscles to facilitate surgeries and ease intubation but can lead to adverse reactions, including complications because of postoperative residual neuromuscular blockade (rNMB) and, in rare cases, anaphylaxis. Both adverse reactions vary between types of NMBAs, with rocuronium, a widely used nondepolarizing NMBA, inducing one of the longest rNMB durations and highest anaphylaxis incidences. rNMB induced by rocuronium can be reversed by the synthetic γ-cyclodextrin sugammadex. However, in rare cases, sugammadex can provoke anaphylaxis. Thus, additional therapeutic options are needed. Rocuronium-induced anaphylaxis is proposed to rely on preexisting rocuronium-binding antibodies. To understand the pathogenesis of rocuronium-induced anaphylaxis and to identify potential therapeutics, we investigated the memory B cell antibody repertoire of patients with suspected hypersensitivity to rocuronium. We identified polyclonal antibody repertoires with a high diversity among V(D)J genes without evidence of clonal groups. When recombinantly expressed, these antibodies demonstrated specificity and low affinity for rocuronium without cross-reactivity for other NMBAs. Moreover, when these antibodies were expressed as human immunoglobulin E (IgE), they triggered human mast cell activation and passive systemic anaphylaxis in transgenic mice, although their affinities were insufficient to serve as reversal agents. Rocuronium-specific, high-affinity antibodies were thus isolated from rocuronium-immunized mice. The highest-affinity antibody was able to reverse rocuronium-induced neuromuscular blockade in nonhuman primates with kinetics comparable to that of sugammadex. Together, these data support the hypothesis that antibodies cause anaphylactic reactions to rocuronium and pave the way for improved diagnostics and neuromuscular blockade reversal agents.

Neuromuscular blocking agent drug challenge: a literature review and protocol proposal with biological evaluation.

BACKGROUND: Drug challenge is the gold standard for identifying causative agents of drug allergies. Although clinical guidelines have recently been published, they do not recommend neuromuscular blocking agent (NMBA) drug challenges. NMBA challenges are rendered difficult by the lack of homogeneity of routine allergy work-ups and the necessity of a specialised setting. Several scenarios support NMBA challenges, such as an ambiguous allergy work-up, a high suspicion of a false-positive skin test or identification of a well tolerated alternative NMBA strategy. Furthermore, routine allergy work-ups may not recognise non-IgE mechanisms, such as IgG or MRGPRX2, whereas drug challenges may reveal them. Finally, if the culprit NMBA is not identified, subsequent anaesthesia regimens will be challenging to implement, resulting in increased risk. OBJECTIVES: This literature review discusses the indications, strategies, doses, monitoring methods, limitations, and unresolved issues related to drug challenges for NMBAs. DESIGN: The literature review included randomised controlled trials, observational studies, reviews, case reports, series, and comments on humans. DATA SOURCES: Studies were retrieved from databases (PubMed) and electronic libraries (OVID, EMBASE, Scopus, etc.). ELIGIBILITY CRITERIA: All studies that referred to the NMBA challenge were included without publication date limitations. RESULTS: NMBA challenge may be considered in NMBA anaphylaxis patients with inconclusive or ambivalent IgE diagnostic work-up under controlled conditions (presence of anaesthetists and allergists with continuous monitoring in a secured environment). To illustrate its utility, a case report of a double NMBA challenge in a patient with NMBA cross-reactivity is presented, along with biological explorations to detect subclinical cellular activation, a novel aspect of this procedure. CONCLUSION: Drug challenges could be implemented during the NMBA allergy work-up under strict safety conditions at specialised centres with close collaboration between anaesthetists and allergists. This could decrease uncertainty and contribute to defining a safer strategy for subsequent anaesthetic drug regimens.

Anti-mutated citrullinated vimentin antibodies are increased in IPF patients.

INTRO: An increased prevalence of serum anti-MCV antibody is observed in the serum of patients with idiopathic pulmonary fibrosis (IPF) but the clinical relevance of these antibodies is unknown. METHODS: Patients from our center with a diagnosis of IPF according to the 2018 ATS/ERS/JRS/ALAT guidelines and at least one anti-MCV assay available were selected. All patients were part of the prospective cohort European IPF registry and selected between 03/2010 and 03/2018. We constituted two groups of patients according to the anti-MCV status at baseline to compare their characteristics at baseline and the evolution of lung function, survival and/or transplantation status. RESULTS: Anti-MCV data were available for 101 patients, of whom 86 had complete clinical data available. Twenty-nine (34 %) patients had a positive anti-MCV assay (MCV+), at a low level in most patients (29 UI/mL [IQR 25-40]), and 57 (66 %) patients a negative assay (MCV-). MCV+ patients were 20 men and 9 women, with a median age of 73 years [IQR 67-78]. MCV- patients were 49 men and 8 women with a median age of 72 years [IQR 64-77]. Sixty-two (75 %) patients were ex-smokers and 5 (6 %) were active smokers. Median cumulative tobacco smoke exposure was 22.5 (15.0-38.6) and was similar in both groups. Lung function test results and HRCT pattern distribution was similar in both groups at baseline. The median duration of follow-up was 3.5 years [IQR 2.1-5.0]. Lung function decline was similar in both groups. During the study period, 31 (36 %) patients died or have been transplanted with no difference in transplant-free survival status between the two groups. CONCLUSION: Low level anti-MCV autoimmunity was prevalent in IPF patients.

Impact of BNT162b2 mRNA anti-SARS-CoV-2 vaccine on interferon-alpha production by plasmacytoid dendritic cells and autoreactive T cells in patients with systemic lupus erythematosus: The COVALUS project.

OBJECTIVE: To evaluate the specific response of SLE patients to BNT162b2 vaccination and its impact on autoimmunity defined as in vivo production of interferon-alpha (IFNα) by plasmacytoid dendritic cells (pDCs) and autoreactive immune responses. METHODS: Our prospective study included SLE patients and healthy volunteers (HV) who received 2 doses of BNT162b2 vaccine 4 weeks apart. Subjects under immunosuppressive drugs or with evidence of prior COVID-19 were excluded. IgG anti-Spike SARS-CoV-2 (anti-S) antibodies, anti-S specific-B cells, anti-S specific T cells, in vivo INF-α production by pDCs, activation marker expression by pDCs and autoreactive anti-nuclear T cells were quantified before first injection, before second injection, and 3 and 6 months after first injection. RESULTS: Vaccinated SLE patients produced significantly lower IgG antibodies and specific B cells against SARS-CoV-2 as compared to HV. In contrast, anti-S T cell response did not significantly differ between SLE patients and HV. Following vaccination, the surface expression of HLA-DR and CD86 and the in vivo production of IFNα by pDCs significantly increased in SLE patients. The boosted expression of HLA-DR on pDCs induced by BNT162b2 vaccine correlated with the overall immune responses against SARS-CoV-2 (anti-S antibodies: r = 0.27 [0.05-0.46], p = 0.02; anti-S B cells: r = 0.19 [-0.03-0.39], p = 0.09); anti-S T cells: r = 0.28 [0.05-0.47], p = 0.016). Eventually, anti-SARS-CoV-2 vaccination was associated with an overall decrease of autoreactive T cells (slope = - 0.00067, p = 0.015). CONCLUSION: BNT162b2 vaccine induces a transient in vivo activation of pDCs in SLE that contributes to the immune responses against SARS-CoV-2. Unexpectedly BNT162b2 vaccine also dampens the pool of circulating autoreactive T cells, suggesting that vaccination may have a beneficial impact on SLE disease.

Immediate hypersensitivity to COVID-19 vaccines: Focus on biological diagnosis.

Soon after the release of the new anti-COVID mRNA vaccines, reports came in from the US and the UK of anaphylactic reactions. Fueled by the necessary caution toward these new vaccine platforms, these reports had a great impact and were largely commented upon in the scientific literature and global media. The current estimated frequency is of 5 cases per million doses. Very little biological data are presented in the literature to support the anaphylaxis diagnosis in these patients in addition to skin tests. Allergic reactions to vaccines are rare and mostly due to vaccine excipient. Therefore, the poly-ethylene-glycol (PEG) present in both mRNA formulation, and already known to be immunogenic, was soon suspected to be the potential culprit. Several hypersensitivity mechanisms to PEG or to other vaccine components can be suspected, even if the classical IgE-dependent anaphylaxis seems to be one of the most plausible candidates. In the early 2022, the international guidelines recommended to perform skin prick tests and basophil activation tests (BAT) in people experiencing allergic reaction to the first dose of COVID-19 vaccine or with a history of PEG allergy. The aim of this review is to discuss the main potential mechanisms of immediate allergy to COVID19 vaccines based on published data, together with the various techniques used to confirm or not sensitization to one component.

Autoantibodies against IFNα in patients with systemic lupus erythematosus and susceptibility for infection: a retrospective case-control study.

IFNα and anti-IFNα autoantibodies have been implicated in susceptibility both for systemic lupus erythematosus (SLE) and viral infection. We aimed to analyze the SLE disease phenotype and risk for infection associated with anti-IFN-α IgG autoantibodies in SLE patients In this multidisciplinary retrospective single referral center study, all consecutive patients with SLE admitted between January 1st and November 30th 2020 were considered. All subjects fulfilled the ACR/EULAR 2019 criteria for SLE. Anti-IFNα IgG autoantibodies were quantified at admission by ELISA. Demographic, medical history, laboratory, treatment, and outcome data were extracted from electronic medical records using a standardized data collection form. 180 patients [female 87.2%, median age of 44.4 (34-54.2) years] were included. The median disease duration was 10 years [4-20] with a median SLEDAI score of 2 [0-4] at study time. Fifty-four (30%) patients had a past-history of lupus nephritis. One hundred and forty-four (80%) had received long-term glucocorticoids and 99 (55%) immunosuppressive drugs. Overall, 127 infections-mostly bacterial and viral-were reported in 95 (52.8%) patients. Twenty SLE patients (11.1%) had positive anti-IFNα IgG autoantibodies with a titer ranging from 10 to 103 UA/mL. Age, sex, SLE phenotype and treatment did not significantly differ between SLE patients with or without anti-IFNα. Infection rate was similar in both groups except for tuberculosis which was more frequent in patients with anti-IFNα (20% vs. 3.1%, p = 0.01). The prevalence of autoantibodies against IFNα is high in SLE and associated with a higher frequency of tuberculosis.

Netherton syndrome subtypes share IL-17/IL-36 signature with distinct IFN-α and allergic responses.

BACKGROUND: Netherton syndrome (NS) is a rare recessive skin disorder caused by loss-of-function mutations in SPINK5 encoding the protease inhibitor LEKTI (lymphoepithelial Kazal-type-related inhibitor). NS patients experience severe skin barrier defects, display inflammatory skin lesions, and have superficial scaling with atopic manifestations. They present with typical ichthyosis linearis circumflexa (NS-ILC) or scaly erythroderma (NS-SE). OBJECTIVE: We used a combination of several molecular profiling methods to comprehensively characterize the skin, immune cells, and allergic phenotypes of NS-ILC and NS-SE patients. METHODS: We studied a cohort of 13 patients comprising 9 NS-ILC and 4 NS-SE. RESULTS: Integrated multiomics revealed abnormal epidermal proliferation and differentiation and IL-17/IL-36 signatures in lesion skin and in blood in both NS endotypes. Although the molecular profiles of NS-ILC and NS-SE lesion skin were very similar, nonlesion skin of each disease subtype displayed distinctive molecular features. Nonlesion and lesion NS-SE epidermis showed activation of the type I IFN signaling pathway, while lesion NS-ILC skin differed from nonlesion NS-ILC skin by increased complement activation and neutrophil infiltration. Serum cytokine profiling and immunophenotyping of circulating lymphocytes showed a TH2-driven allergic response in NS-ILC, whereas NS-SE patients displayed mainly a TH9 axis with increased CCL22/MDC and CCL17/TARC serum levels. CONCLUSIONS: This study confirms IL-17/IL-36 as the predominant signaling axes in both NS endotypes and unveils molecular features distinguishing NS-ILC and NS-SE. These results identify new therapeutic targets and could pave the way for precision medicine of NS.

Arterial Thrombotic Events in Adult Inpatients With COVID-19.

OBJECTIVE: To evaluate the clinical course of and risk factors for arterial thrombotic events in adult inpatients with coronavirus disease 2019 (COVID-19). METHODS: All consecutive adult patients admitted for COVID-19 infection in a referral center in France and discharged from the hospital between April 1 and April 30, 2020, were included. All arterial thrombotic events that occurred through discharge were considered for analysis. Epidemiologic, demographic, clinical, laboratory, treatment, and outcome data were extracted from electronic medical records with use of a standardized data collection form. RESULTS: Overall, 531 COVID-19+ patients were analyzed. Among them, 30 (5.6%) experienced arterial thrombotic events. Arterial thrombotic events in the setting of COVID-19 infection happened at a median of 11 (5-20) days after the first symptoms of infection; occurred in high-risk patients according to traditional cardiovascular risk factors; had an atypical pattern, such as thrombosis of the aorta, upper limb, or renal arteries or cerebral microvasculopathy in 7 (23.3%) cases; and were associated with an in-hospital mortality rate of 40%. Arterial thrombotic events increased the risk of death by 3-fold in COVID-19+ patients (hazard ratio, 2.96; 95% CI, 1.4 to 4.7; P=.002). A subdistribution survival hazard model showed that a concentration of D-dimer above 1250 ng/mL increased the risk of arterial thrombotic events in COVID-19+ patients by more than 7 (subdistribution hazard ratio, 7.68; 95% CI, 2.9 to 20.6; P<.001). CONCLUSION: A dramatically high rate of in-hospital death was observed in patients who suffered arterial thrombotic events in the setting of COVID-19 infection. A D-dimer level above 1250 ng/mL at entry may identify COVID-19+ patients at risk for arterial thrombotic events.

Obstetrical outcome and treatments in seronegative primary APS: data from European retrospective study.

OBJECTIVE: To compare characteristics, pregnancies and treatments during pregnancies of seronegative and seropositive antiphospholipid syndrome (APS), to analyse factors associated with obstetrical outcome. PATIENTS AND METHODS: Inclusion criteria were: (1) thrombotic and/or obstetrical APS (Sydney criteria); (2) absence of conventional antiphospholipid antibodies (APL); (3) at least one persistent non-conventional APL among IgA anticardiolipin antibodies, IgA anti-B2GPI, anti-vimentin G/M, anti-annexin V G/M, anti-phosphatidylethanolamine G/M and anti-phosphatidylserine/prothrombin G/M antibodies. The exclusion criteria were: (1) systemic lupus erythematosus ( SLE) or SLE-like disease; and (2) other connective tissue disease. RESULTS: A total of 187 women (mean 33±5 years) with seronegative APS were included from 14 centres in Austria, Spain, Italy, Slovenia and France and compared with 285 patients with seropositive APS. Seronegative APS has more obstetrical rather than thrombotic phenotypes, with only 6% of venous thrombosis in comparison to seropositive APS. Cumulative incidence of adverse obstetrical events was similar in seronegative and seropositive APS patients, although higher rates of intrauterine deaths (15% vs 5%; p=0.03), of preeclampsia (7% vs 16%, p=0.048) and lower live birth term (36±3 vs 38±3 weeks of gestation; p=0.04) were noted in seropositive APS. The cumulative incidence of adverse obstetrical events was significantly improved in treated versus untreated seronegative APS (log rank<0.05), whereas there was no difference between patients who received aspirin or aspirin-low-molecular weighted heparin combination. CONCLUSION: Several non-criteria APL can be detected in patients with clinical APS features without any conventional APL, with various rates. The detection of non-criteria APL and thus the diagnosis of seronegative APS could discuss the therapeutic management similar to seropositive APS, but well-designed controlled studies are necessary.

[Performance criteria for the verification of IgE and tryptase assay methods: recommendations from the AllergoBioNet network]. / Critères de performance pour la vérification des méthodes de dosages des IgE et de la tryptase : recommandations du réseau AllergoBioNet.

Accreditation of an in vitro diagnostic assay according to the NF/EN/ISO 15189 standard requires to analyze its technical performance before implementation for routine use, and annually when reviewing effectiveness of quality controls. Performance is evaluated through repeatability, intermediate fidelity, accuracy and uncertainty of measurement. The coefficients of variation (CV) of the intra-assay and inter-assay precision tests must be compared with those of "peers" (results from laboratories employing the same method) and also with those obtained with "all methods", i.e., results from all laboratories performing the same assay, irrespective of the method. To our best knowledge, there is currently no French or international recommendation on what the acceptable limits of performance for specific IgE and tryptase assays should be. Therefore, the AllergoBioNet network of hospital allergy laboratories set out to characterize the performance of their current methods as a basis for the development of recommendations. The results provided by 24 centers were analyzed and led to consensus recommendations for specific IgE, total IgE and tryptase assays.

An IgG-induced neutrophil activation pathway contributes to human drug-induced anaphylaxis.

Anaphylaxis is a systemic acute hypersensitivity reaction that is considered to depend on allergen-specific immunoglobulin E (IgE) antibodies and histamine release by mast cells and basophils. Nevertheless, allergen-specific IgG antibodies have been proposed to contribute when the allergen is an abundant circulating large molecule, e.g., after infusions of therapeutic antibodies or dextran. Data from animal models demonstrate a pathway involving platelet-activating factor (PAF) release by monocytes/macrophages and neutrophils activated via their Fc gamma receptors (FcγRs). We hypothesized that such a pathway may also apply to small drugs and could be responsible for non-IgE-mediated anaphylaxis and influence anaphylaxis severity in humans. We prospectively conducted a multicentric study of 86 patients with suspected anaphylaxis to neuromuscular-blocking agents (NMBAs) during general anesthesia and 86 matched controls. We found that concentrations of anti-NMBA IgG and markers of FcγR activation, PAF release, and neutrophil activation correlated with anaphylaxis severity. Neutrophils underwent degranulation and NETosis early after anaphylaxis onset, and plasma-purified anti-NMBA IgG triggered neutrophil activation ex vivo in the presence of NMBA. Neutrophil activation could also be observed in patients lacking evidence of classical IgE-dependent anaphylaxis. This study supports the existence of an IgG-neutrophil pathway in human NMBA-induced anaphylaxis, which may aggravate anaphylaxis in combination with the IgE pathway or underlie anaphylaxis in the absence of specific IgE. These results reconcile clinical and experimental data on the role of antibody classes in anaphylaxis and could inform diagnostic approaches to NMBA-induced acute hypersensitivity reactions.