While both the incidence and general awareness of food allergies is increasing, the variety and clinical availability of therapeutics remain limited. Therefore, investigations into the potential factors contributing to the development of food allergy and the mechanisms of natural tolerance or induced desensitization are required. In addition, a detailed understanding of the pathophysiology of food allergies is needed to generate compelling, enduring, and safe treatment options. New findings regarding the contribution of barrier function, the effect of emollient interventions, mechanisms of allergen recognition, and the contributions of specific immune cell subsets through rodent models and human clinical studies provide novel insights. With the first approved treatment for peanut allergy, the clinical management of food allergy is evolving towards less intensive, alternative approaches involving fixed doses, lower maintenance dose targets, co-administration of biologicals, adjuvants, and tolerance-inducing formulations. The ultimate goal is to improve immunotherapy and develop precision-based medicine via risk phenotyping allowing optimal treatment for each food-allergic patient.
Title : Distinct and mutually exclusive Ca++ flux- and adenyl cyclase-inducing gene expression profiles of G-Protein-Coupled Receptors on human antigen-specific B cellsAuthors : Iris Chang1,2†, Abhinav Kaushik, PhD1,2†, Pattraporn Satitsuksanoa PhD1, Minglin Yang1, Laura Buergi Msc1, Stephan R. Schneider Msc1, Cezmi A. Akdis, MD1, Kari Nadeau MD, PhD2, Willem van de Veen, PhD1, Mübeccel Akdis, MD, PhD1*1 Swiss Institute of Allergy and Asthma Research (SIAF), University of Zürich, Davos, Switzerland.2 Sean N. Parker Center for Allergy and Asthma Research, Department of Medicine, Stanford University, Palo Alto, CA, USA.† Contributed equally* Corresponding authorB cells play an essential role in allergies by producing allergen-specific IgE, which is a prerequisite for allergen-induced degranulation of mast cells (MCs) and basophils. MCs, basophils, dendritic cells and bacteria are capable of releasing inflammatory mediators including histamine. Histamine is a bioactive amine that exerts its function through binding to histamine receptors (HRs), which are 7-transmembrane G-protein-coupled receptors (GPCRs). There are four types of HRs (HR1-4), wherein HR1 ligation triggers Ca2+ mobilization, HR2 stimulates and increases cAMP concentrations, and HR3 and HR4 inhibit cAMP accumulation1. In the presence of histamine in the environment, high affinity HR1is triggered causing cellular activation, followed by expression of 10 times lower affinity HR2 to regulate the over-inflammatory events. These HRs trigger different intracellular events upon activation, with HR1 as a Ca2+ flux-inducing activating receptor and HR2 as an adenyl cyclase-stimulating suppressive receptor 1,2. Therefore, to explore the response of B-cells in allergic diseases, we analyzed the expression profile of HRs and other GPCRs in B cell clones. We hypothesized that the expression profile of HRs (HR1+ vs HR2+ B cell clones) is associated with significant changes in the expression profile of other GPCRs that govern the downstream cascade of pathways associated with cAMP signaling or Ca2+ mobilization.A total of 27 IgG1 and IgG4 expressing B cell clones were isolated for gene expression analysis under BCR stimulated and unstimulated conditions (Figure 1A and Online Supplementary Methods) . Interestingly, we observed B-cell clones with mutually exclusive expression profile of HRH1 and HRH2 genes (Figure 1B), with more HRH1+ B-cell clones in BCR-stimulated samples than unstimulated samples. The subsequentHRH1+ vs HRH2+ differential gene expression analysis (Figure 1C ), reveal 27 differentially expressed (DE) GPCRs in unstimulated samples, with up-regulated P2RY13 and C5AR1genes in HRH2 + B-cell clones (Figure 2A) , which are associated with the cAMP signaling and suppressive pathway3,4. To further prioritize the DE GPCRs specifically associated with Ca2+ and cAMP signaling pathways, we reconstructed the co-expression networks and performed the weighted degree analysis across HRH1+ vs HRH2+ clones. The analysis reveals that the purinergic receptor family of GPCRs (i.e. P2RY1 , P2RY13 ) and complement component 5a receptor family of genes (i.e. C5AR1 and C5AR2 ) share highest degree of interactions. These genes are up-regulated inHRH2+ samples and are well-known to affect cAMP signaling pathway3,4 (Figure S1A ). Intriguingly, we also observed upregulation of GPR35 in HRH2 + B cells, which is associated in maintaining a low baseline Ca2+ level5. Similarly, we also observed up-regulation of GPR68 and GPR171 in HRH1 + B cells; both are known to stimulate Ca2+ flux (Online Supplementary Discussion) .Similarly, 28 GPCRs were differentially expressed in BCR-stimulated samples (Figure 2B ), including higher expression of serotonin receptor type 1A (HTR1A ) and HCAR1 (or GPR81 ) inHRH2+ samples, with a cAMP-linked suppressive function. In addition, we also observed upregulation of complement component 5a receptor family of genes (i.e., C5AR1 and C5AR2 ) and GPR35 , in agreement with the trend observed in unstimulatedHRH2 + B-cell clones. Surprisingly, we observed a higher expression of prostaglandin E2 receptor subtype EP4 (PTGER4) and adenosine A2A receptor (ADORA2A ) in HRH2+ samples3,6, which are known to be associated with activation of cAMP production and share the highest strength of interactions with the cAMP signaling sub-network (Figure S1B ). Among the up-regulated genes in HRH1 + samples, we found three Ca2+ mobilizing genes, i.e., GPR34 ,P2RY10 and PTAFR .The results reported in this study provides data for a novel hypothesis suggesting investigation of co-expressed genes that may play important synergistic or antagonistic regulatory roles in B-cell function.
Direct cleavage and activation of gasdermin B by asthma trigger allergensTo the Editor:Recent fine-mapping studies have pointed to gasdermn B (GSDMB ) as a potential asthma susceptibility gene in 17q21 locus, the strongest and most highly replicated signal in genome-wide association studies1. The GSDMB protein is a member of the gasdermin family that, when cleaved, triggers an inflammatory cell death known as pyroptosis2. Caspase-1 and granzyme A have been shown to cut GSDMB at specific sites to release the N-terminal fragment of the protein (GSDMB-NT) that has the ability to induce pyroptosis in cells, including airway epithelial cells3,4. These findings suggest that the role of GSDMB in asthma lies in its ability to be activated through cleavage to induce pyroptosis; however, it remains unclear whether GSDMB cleavage and activation occur in the context of asthma.Common asthma trigger allergens often possess protease activities that cause airway epithelial injury and inflammation5,6. We thus tested whether the allergens directly cleave GSDMB. Incubation of extracts from house dust mite (HDM), a common asthma trigger, with lysates from human bronchial epithelial cells, which express endogenous GSDMB3, resulted in GSDMB cleavage as evidenced by the appearance of a smaller protein around 17kD (Figure 1A). Since the GSDMB antibody used in the Western blotting targets the C-terminus of the protein, the 17kD protein band likely represents the C-terminal GSDMB fragment. Such GSDMB cleavage was also observed when lysates from cells expressing C-terminal-FLAG-tagged GSDMB were mixed with HDM extract (Figure 1B). Furthermore, mold or cockroach extract also cleaved tagged GSDMB (Figure 1C). The cleavage of GSDMB protein by all allergen extracts resulted in a single product of similar size (about 17 kD), suggesting a specific cutting site.To identify the cleavage site, we incubated recombinant full-length GSDMB with HDM extract and resolved the cleaved protein products on SDS-PAGE (Figure 1D). We excised the putative 17 kD C-terminal fragment (GSDMB-CT, Figure 1D) and determined the N-terminal amino acid sequence of the fragment via Edman sequencing (Supplemental Figure S1, Figure 1E). Despite some ambiguities, the first ten amino acid residues of the 17 kD GSDMB-CT largely map to position 245 to 254 (SLGSEDSRNM) of the full length GSDMB protein (Figure 1E). This result indicates that GSDMB was cleaved immediately after the lysine residue at position 244 (K244). Interestingly, granzyme A also cuts GSDMB at the same K244 site4. To confirm K244 as the site of cleavage, we mutated lysine 244 to alanine (K244A) in GSDMB and tested whether the mutant protein can be cleaved by HDM. As shown by Western blotting, HDM was able to cleave wild type (WT) GSDMB but failed to cleave K244A GSDMB as evidenced by the absence of the 17 kD fragment (Figure 1F).The cleavage of GSDMB by HDM is expected to release an N-terminal fragment of 244 amino acids (GSDMB-NT-K244) (Figure 2A). We next tested whether GSDMB-NT-K244 triggers pyroptosis. Transfection of GSDMB-NT-K244 induced cell morphological changes characteristic of pyroptosis, including rounding up and detachment (Figure 2B). LDH release assay confirmed increased toxicity in these cells (~3.4 fold) as compared to cells transfected with the full-length GSDMB (Figure 2C). Consistent with our previous finding on GSDMB-NT shortened by a functional asthma-associated splice variant3, transfection of a truncated GSDMB-NT from the variant (NT-K231var) did not induce pyroptosis (Figure 2B,C).While future studies are needed to identify the specific proteases within the allergen extracts that cleave GSDMB, our current study demonstrates that asthma triggers such as HDM can directly cleave and activate GSDMB, thus providing biochemical evidence linking GSDMB-mediated pyroptosis to asthma.
The field of food allergy has seen tremendous change over the past 5-10 years with seminal studies redefining our approach to prevention and management and novel testing modalities in the horizon. Early introduction of allergenic foods is now recommended, challenging the previous paradigm of restrictive avoidance. The management of food allergy has shifted from a passive avoidance approach to active interventions that aim to provide protection from accidental exposures, decrease allergic reaction severity and improve the quality of life of food-allergic patients and their families. Additionally, novel diagnostic tools are making their way into the clinical practice with the goal to reduce the need for food challenges and assist physicians in the -- often complex -- diagnostic process. With all the new developments and available choices for diagnosis, prevention and therapy, shared decision-making has become a key part of the medical consultation, enabling patients to make the right choice for them, based on their values and preferences. Communication with patients has also become more complex over time, as patients are seeking advice online and through social media, but the information found online may be outdated, incorrect, or lacking in context. The role of the allergist has evolved to embrace all the above exciting developments and provide patients with the optimal care that fits their needs. In this review, we discuss recent developments, as well as the evolution of the field of food allergy in the next decade.
Background. Because of altered airway microbiome in asthma, we analysed the bacterial species in sputum of patients with severe asthma. Methods. Whole genome sequencing was performed on induced sputum from non-smoking (SAn) and current or ex-smoker (SAs/ex) severe asthma patients, mild/moderate asthma (MMA) and healthy controls (HC). Data was analysed by asthma severity, inflammatory status and transcriptome-associated clusters (TACs). Results. α-diversity at the species level was lower in SAn and SAs/ex, with an increase in Haemophilus influenzae and Moraxella catarrhalis, and Haemophilus influenzae and Tropheryma whipplei, respectively, compared to HC. In neutrophilic asthma, there was greater abundance of Haemophilus influenzae and Moraxella catarrhalis and in eosinophilic asthma, Tropheryma whipplei was increased. There was a reduction in α-diversity in TAC1 and TAC2 that expressed high levels of Haemophilus influenzae and Tropheryma whipplei, and Haemophilus influenzae and Moraxella catarrhalis, respectively, compared to HC. Sputum neutrophils correlated positively with Moraxella catarrhalis and negatively with Prevotella, Neisseria and Veillonella species and Haemophilus parainfluenzae. Sputum eosinophils correlated positively with Tropheryma whipplei which correlated with pack-years of smoking. α- and β-diversities were stable at one year. Conclusions. Haemophilus influenzae and Moraxella catarrhalis were more abundant in severe neutrophilic asthma and TAC2 linked to inflammasome and neutrophil activation, while Haemophilus influenzae and Tropheryma whipplei were highest in SAs/ex and in TAC1 associated with highest expression of IL-13 Type 2 and ILC2 signatures with the abundance of Tropheryma whipplei correlating positively with sputum eosinophils. Whether these bacterial species drive the inflammatory response in asthma needs evaluation.
Background: Dupilumab, a human monoclonal antibody, blocks the shared receptor component for interleukins 4/13, key and central drivers of type 2 inflammation. The LIBERTY ASTHMA TRAVERSE (NCT02134028) open-label extension study demonstrated the long-term safety and efficacy of dupilumab in patients ≥12 years who had participated in a previous dupilumab asthma study. The safety profile was consistent with that observed in the parent studies. Methods: This analysis includes patients from phase 2b (NCT01854047) or phase 3 (QUEST; NCT02414854) studies receiving high- or medium-dose inhaled corticosteroids (ICS) at parent study baseline (PSBL) and enrolled in TRAVERSE. We analyzed unadjusted annualized severe exacerbation rates, change from PSBL in pre-bronchodilator (pre-BD) FEV 1 (L), asthma control (5-item asthma control questionnaire), and type 2 biomarkers in patients with type 2 asthma at baseline (blood eosinophils ≥150 cells/µL or fractional exhaled nitric oxide [FeNO] ≥25 ppb), and subgroups defined by baseline blood eosinophils or FeNO. Results: Of patients with type 2 asthma (n=1,666) in this analysis, 891 (53.5%) were receiving high‑dose ICS at PSBL. In this subgroup, unadjusted exacerbation rates for dupilumab vs placebo were 0.517 vs. 1.883 (phase 2b) and 0.571 vs. 1.300 (QUEST) over 52 weeks of the parent study, and remained low throughout TRAVERSE (0.313–0.494). Improvements in pre-BD FEV 1 from PSBL were sustained throughout TRAVERSE. Similar clinical efficacy was observed among patients receiving medium-dose ICS at PSBL and biomarker subgroups. Conclusions: Dupilumab showed sustained efficacy for up to 3 years in patients with uncontrolled, moderate-to-severe type 2 asthma on high- or medium-dose ICS.
Background: Little is known about the ontogeny of T cell immunity during infancy in farming and urban lifestyle due to lack of immunophenotyping in such birth cohorts. Methods: Our study includes two birth cohorts (farming and urban) at differing risks and rates of allergic diseases. In this study, blood mononuclear cells were collected from infants at birth, and 6 and 12 months of age. We used full spectrum flow cytometry followed by traditional gating and the Scalable Weighted Iterative Flow-clustering Technique (SWIFT) high dimensional analysis to identify cell populations that differed between farming and urban infants. Additionally, we utilized RNAseq and Luminex to assess the function of the cell population of interest. Results: We identified several regulatory T cell (Treg) subpopulations elevated in farming lifestyle as well as in non-atopic infants. We also found a unique, recently activated effector memory CD25 +CD127 +CD161 - CCR4 +CRTH2 + Th2 population that is elevated at 6 months in urban infants as well as infants who developed atopic dermatitis and/or food allergy and allergic sensitization. Functional assays confirmed this population to be highly Th2-skewed, as evidenced by an increase in Th2 cytokines and upregulation of pathways linked to asthma and Th2 differentiation. Conclusion: We have discovered Treg subpopulations associated with farming lifestyle and protection against allergic disease. We also describe a unique, recently activated effector memory Th2 population elevated in urban high-risk infants that is similar to the pathogenic effector Th2A cells but is CD25 + and CD161 -, potentially representing pre-Th2A cells implicated in the development of allergic disease.
Drug reaction with eosinophilia and systemic symptoms (DRESS), also known as Drug-induced hypersensitivity syndrome (DIHS), is a rare but severe delayed-type drug hypersensitivity reaction [(#ref-0001)1]. Its reported incidence ranges between 2 and 5 cases per million per year and the mortality between 5 and 10% [(#ref-0002)2]. DRESS is characterized by the occurrence of an extensive rash with face edema, lymphadenopathy and fever and organ damage, all of which seems to result from massive drug-directed T cell response and associated eosinophilia. DRESS is a complex condition, its clinical presentation varies depending on the cutaneous manifestation(s), affected target organ(s) and reaction severity. The diagnosis of DRESS is further challenged by the clinical overlay with autoimmune, infectious and lymphoproliferative conditions, which have to be considered in the differential diagnosis (Table 1). Eosinophilia is detected in only 80 % of DRESS patients and can be masked by e.g. the administration of systemic glucocorticoids (GCS). Furthermore, there are various differences in the DRESS diagnostic criteria (Table 1) developed by the Japanese SCAR (JSPS) [(#ref-0003)3] and RegiSCAR [(#ref-0004)4] groups, the most notable being the inclusion of herpes viremia in the criteria developed by the JSPS. All these clinical challenges underline the importance of a systematic and comprehensive approach when encountering a patient with suspected DRESS. Based on the most recent literature and our clinical expertise, we therefore suggest the medical algorithm depicted in Figure 1. DRESS should be evoked as a differential diagnosis in patients with a rash suspected to be drug-related and associated with head-and-neck edema [(#ref-0005)5]. Clinical history-taking is a critical element to consolidate or discard a drug-related etiology: most importantly, this should explore the dynamics of both possible DRESS clinical symptoms and drug exposure(s) (date of onset, way and length of administration, previous exposures / reactions). A long drug exposure prior to disease onset, i.e. 2-8 weeks, is indicative for DRESS rather than other drug hypersensitivities – but the duration may vary depending on the causative drug. A thorough clinical examination, basic laboratory work-up, electrocardiogram, and - if a rash is present - a skin biopsy should also be performed. If the clinical presentation and drug exposure history substantiate the DRESS diagnosis, additional investigations should be performed depending on the suspected target organ damage (cf. case “complementary, patient-specific work-up”). Once the diagnosis is established, a severity assessment is warranted, since DRESS can range from mild forms with very limited organ damage to fulminant ones, e.g. characterized by (multi-)organ failure. There are no consensual severity scoring. In this algorithm, we suggest the scoring system used in France (RCT DRESSCODE, https://clinicaltrial.gov NCT01987076).
Immune modulation is a key therapeutic tool for allergic diseases and asthma. It can be achieved in an antigen-specific way via allergen immunotherapy (AIT) or in endotype-driven approach using biologicals that target the major pathways of the type 2 (T2) immune response: IgE, IL-5 and IL-4/IL-13. COVID-19 vaccine provides an excellent opportunity to tackle the global pandemics and is currently being applied in an accelerated rhythm worldwide. It works as well through immune modulation. Thus, as there is an obvious interference between these treatment modalities recommendations on how they should be applied in sequence are expected. The European Academy of Allergy and Clinical Immunology (EAACI) gathered an outstanding expert panel under its Research and Outreach Committee (ROC). This expert panel was called to evaluate the evidence and formulate recommendation on the administration of COVID-19 vaccine in patients with allergic diseases and asthma receiving AIT or biologicals. The panel also formulated recommendations for COVID-19 vaccine in association with biologicals targeting the type 1 or type 3 immune response. In formulating recommendations, the panel evaluated the mechanisms of COVID-19 infection, of COVID-19 vaccine, of AIT and of biologicals and considered the data published for other anti-infectious vaccines administered concurrently with AIT or biologicals.
Needle-free Epicutaneous For t 2 DNA Vaccine is Effective for Preventing and Treating Biting Midge (Forcipomyia taiwana) allergy in a murine modelTo the Editor,Allergen-specific immunotherapy (ASIT) remains the only treatment capable of inducing immune tolerance to the corresponding allergen and potentially treating the root cause of the allergic disease.1 As the treatment course of protein-based vaccines for ASIT is time-consuming, an easily administered epicutaneous anti-allergic DNA-based vaccine is an attractive method, especially in light of the COVID-19 pandemic.2 We established a mouse model of biting midge allergy to test the concept of the epicutaneous DNA vaccine.The biting midge, Forcipomyia taiwana , is the most prevalent cause of biting insect allergy in Taiwan. It is a tiny hematophagous midge that attacks en masse. As many as 60% of exposed individuals develop allergic reactions to the bites.3 The midge is widely distributed throughout Taiwan and southern China. Among the identified allergens, For t 2 is the most predominant, with 75% of midge-allergic patients showing specific IgE to For t 2.4E.coli -expressed For t 2 recombinant protein (rFor t 2) was used as an allergen to sensitize and challenge the mice.5For t 2-encoding fragment (GenBank accession EU678971) was amplified by PCR. The PCR products were subcloned into pVAX1 (Life Technologies, Carlsbad, CA) . The experiments were designed using two approaches: therapeutic and prophylactic (Fig 1). Twenty-five μg For t 2 DNA was determined as the optimal dose after several dose-finding experiments (Fig S1, data not shown). For each treatment, the hair of the abdominal area of the mice was removed using a depilatory, tape-stripped, then patched with 25 μg For t 2 DNA vaccine for one hour and removed. A total of three treatments were given spaced one week apart (Fig 1 and Fig S2). For t 2 proteins were detected in the patched skin and the immune organ spleen at 24 hours and had significantly increased at 48 hours (Fig S3). Scratch bouts after rFor t 2 challenge were used as a clinical surrogate of itch. We measured total IgE and For t 2-specific IgG2a in the sera as well as mRNA and proteins of IL-13, interferon-gamma, IL-10, and FOXP3 in the culture supernatants of splenocytes after stimulation with various doses of rFor t 2 at 37℃ for 3-5 days by ELISA and real-time quantitative PCR. Histopathology of the challenged skins was examined.We found that after epicutaneous DNA vaccination, the allergen-induced itch of the mice significantly improved, and For t 2-specific IgG2a increased (Fig 2). Both mRNA and protein of IL-13, and eosinophils infiltration in the targeted skin, significantly decreased. Expression of FOXP3 mRNA increased (Fig S4-S6).This is the first study to demonstrate an epicutaneous anti-allergic DNA vaccine that is effective at both treating an established allergic condition and preventing the development of an allergic disease using biting midge allergy as a model. After epicutaneous DNA vaccination, in addition to the significant improvement in allergen-induced itch, the changes of biomarkers for allergic inflammation, including IgE, allergen-specific IgG2a, allergen-challenge-induced eosinophil infiltration in the skin, Th2 cytokines from the splenocytes, and regulatory T cell-related transcription factors, suggest that immune tolerance was induced after three patches of the epicutaneous DNA vaccine.Our data show that though the molecular weight of the For t 2 DNA vaccine is as high as 4000 base pairs, it is able to penetrate the dermal barrier and translates the corresponding protein in the targeted skin as well as the spleen of the vaccinated mice. It is possible that the DNA vaccine passes the epidermis via the hair follicles as the skin is tape-stripped before epicutaneous vaccination.6The mode of this anti-allergic epicutaneous DNA vaccine may have potential for use in other specific immunotherapies for other allergens.Mey Fann Lee1Chi Sheng Wu2 Shyh Jye Lin3Yi Hsing Chen2,4*1Department of Medical Research, Taichung Veterans General Hospital, Taichung, Taiwan2Division of Allergy, Immunology and Rheumatology, Taichung Veterans General Hospital, Taichung, Taiwan3School of Medical Laboratory and Biotechnology, Chung Shan Medical University, Taichung, Taiwan4School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
Background: The impact of physical activity (PA) on immune response is a hot topic in exercise immunology, but studies involving asthmatic children are scarce. We examine the level of PA and TV attendance (TVA) in asthmatic children to assess the role on asthma control and immune response to various stimulants. Methods: Weekly PA and daily TVA were obtained from questionnaires at inclusion of the PreDicta study. PBMC cultures were stimulated with phytohemagglutinin (PHA), R848, poly I:C and zymosan. Cytokines were measured and quantified in cell culture supernatants using luminometric multiplex immunofluorescence beads-based assay. Results: Asthmatic preschoolers showed significantly more TVA than their healthy peers (58.6% vs. 41.5% 1-3h daily and only 25.7% vs. 47.2% ≤ 1h daily). Poor asthma control was associated with less frequent PA (75% no or occasional activity in uncontrolled vs. 20% in controlled asthma; 25% ≥ 3x weekly vs. 62%). Asthmatics with increased PA exhibited elevated cytokine levels in response to stimulants, suggesting a readiness of circulating immune cells for type-1, -2 and -17 cytokine release compared to low-PA and high-TVA subjects. Low PA and high TVA were associated with increased proinflammatory cytokines. Proinflammatory cytokines were correlating with each other in in-vitro immune responses of asthmatic children, but not healthy controls. Conclusion: Asthmatic children show more sedentary behavior than healthy subjects, while poor asthma control leads to a decrease in PA. Asthmatic children profit from exercise, as elevated cytokine levels in stimulated conditions indicate an immune system prepared for a strong response in case of infection.
ABBREVIATIONSCA cannabis allergyCCDs cross-reactive carbohydrate determinantsCI confidence intervalCSA cannabis sativa allergic patientsnsLTP s nonspecific lipid transfer proteinsP+LTP- controls sensitized to pollen without nsLTP sensitizationP+LTP+ controls sensitized to pollen and nsLTPs(r) recombinantsIgE specific immunoglobulin EST skin teststIgE total immunoglobulin EKEYWORDSCannabis allergy, sIgE, total IgE, allergy diagnosis, sIgE-to-total IgE ratioTo the Editor,The most important “diagnostic test” for CA is a detailed history. However, a positive history is no absolute proof of CA, mainly because of physiological effects of cannabis i.e. (rhino)conjunctivitis presence and possibly because of incorrect interpretation or recollection of symptoms by the patients under the drug’s influence. Consequently, clinical suspicion of CA requires confirmatory testing. A cannabis challenge, being excluded for obvious ethical/legal reasons, documentation of CA generally starts with skin testing (ST) or specific IgE-quantification. However, in the absence of a standardized extract for ST, many will use prick-prick tests (e.g., with buds, leaves, seeds)1 2. Crude plant parts or extracts thereof, can contain both genuine and cross-reactive allergenic components. Consequently, positive results of crude extract ST and sIgE should always be interpreted cautiously, as it might merely reflect (cross-) sensitization instead of allergy.Here, we sought to investigate whether serological diagnosis of CA could benefit from an adjustment for tIgE. For this purpose, sIgE-to-tIgE ratios were calculated for sIgE hemp (FEIA, ImmunoCAP ThermoFisher Scientific), sIgE to recombinant (r) Can s 3 and rCan s 5 (Cytometric Bead Assay) as detailed elsewhere 3. A sIgE rCan s 3-to-rPru p 3 and sIgE rCan s 5-to-rBet v 1 ratio was also calculated. Negative sIgE values were excluded, as these cannot benefit from such an adjustment. Patients were selected from our previously published data3 4; cannabis sativa allergic patients (CSA), controls with a pollen but no nsLTP sensitization (P+LTP-) and controls with both pollen and nsLTP sensitizations (P+LTP+) were enrolled.Detailed demographic information is shown in table 1 of our previously published article3. As shown in figure 1, the distribution of the sIgE hemp-to-tIgE ratio and sIgE rCan s 5-to-tIgE differed significantly between controls and CSA. Using a cut-off of 0.02 for sIgE hemp-to-tIgE, it was shown that a specificity of 93% (95% confidence interval (CI), 85-98%) could be reached (table 1). A second, lower cut-off (0.005) can benefit most of the CSA population (sensitivity 77% (95% CI 67-85%)) and retains a relatively good specificity 79% (95% CI 68-87%).For sIgE rCan s 5-to-tIgE, a cut-off of 0.01 could possibly be beneficial. However, small group numbers make it difficult to estimate its true value. The ratio of sIgE rCan s 3-to-tIgE did not show added value (p=0.86).Comparing CSA patients with and without anaphylaxis; no added value was found to identify (a risk of) cannabis related anaphylaxis for any of the explored sIgE-to-tIgE ratios (sIgE hemp-to-tIgE->p=0.104; sIgE rCan s 3-to-tIgE->p=0.416; sIgE rCan s 5-to-tIgE->p=0.84, data not shown).Finally, ratios of similar protein families i.e. sIgE rCan s 3-to-sIgE rPru p 3 and sIgE rCan s 5-to-sIgE rBet v 1 were explored, showing no additional diagnostic value (see figure E1 in the online repository).These results indicate that sIgE-to-tIgE ratios might have a place in the diagnostic approach of CA. In the case of a definite history of cannabis related symptoms we recommend (figure E2) a sIgE hemp assay (sensitivity 82% (95% CI 74-89%) and specificity 32% (95% CI 20-45%)) 3. A negative result significantly reduces the chance of IgE-mediated CA. A positive result should be followed by a sIgE hemp-to-tIgE ratio as it notably increases test specificity. Where available, it is worthwhile using cannabis component resolved diagnostics as it was shown that over two-thirds of CSA who experienced anaphylaxis are Can s 3 sensitized 3. This study is bound by certain limitations; group numbers vary between the different analyses because of insufficient patients’ sera. Additionally, we could not explore sIgE rCan s 2-to-tIgE, sIgE rCan s 4-to-tIgE and sIgE rCan s 4-to-sIgE rBet v 2, because of insufficient group numbers. Finally, there is no guarantee that these results can be extrapolated to other CSA populations or different geographical regions. The results of these study are of a preliminary nature. Repetition of our methods in other, ideally larger populations are feasible to see whether these results can be confirmed and remain intact in different CA populations.FIGURES & TABLESFIGURE 1
The coronavirus disease 2019 (COVID-19) pandemic started over one year ago and produced almost 3.5 million deaths worldwide. We have been recently overwhelmed by a wide literature on how the immune system recognizes Severe Acute Respiratory Syndrome Coronavirus 2 and contributes to COVID-19 pathogenesis. Although originally considered a respiratory viral disease, COVID-19 is recognized as a far more complex, multi-organ-, immuno-mediated-, and mostly heterogeneous disorder. Though efficient innate and adaptive immunity may control infection, when the patient fails to mount an adequate immune response, a high innate-induced inflammation can lead to different clinical outcomes through heterogeneous compensatory mechanisms. The variability of viral load and persistence, the genetic alterations of virus-driven receptors/signaling pathways and the plasticity of innate and adaptive responses may all account for the extreme heterogeneity of pathogenesis and clinical patterns. As recently done for some inflammatory disorders as asthma, rhinosinusitis with polyposis and atopic dermatitis, herein we suggest to define different endo-types and the related phenotypes along COVID-19. Patients should be stratified for evolving symptoms and tightly monitored for surrogate biomarkers of innate and adaptive immunity. This would allow to preventively identify each endo-type (and its related phenotype) and to treat patients precisely with agents targeting pathogenic mechanisms.