IgE-mediated Allergy Research Articles

Epitope-specific IgE, IgG4, and IgG1 antibodies for clinical phenotyping of IgE-mediated wheat allergy

Epitope-specific IgE, IgG4, and IgG1 antibodies for clinical phenotyping of IgE-mediated wheat allergy

Abrogation and homeostatic restoration of IgE responses by a universal IgE allergy CTL vaccine-The three signal self/non-self/self (S/NS/S) theory.

Natural IgE cytotoxic peptides (nECPs), which are derived from the constant domain of the heavy chain of human IgE producing B cells via endoplasmic reticulum (ER) stress, are decorated onto MHC class 1a molecules (MHCIa) as unique biomarkers for CTL (cytotoxic T lymphocyte)-mediated immune surveillance. Human IgE exhibits only one isotype and lacks polymorphisms; IgE is pivotal in mediating diverse, allergen-specific allergies. Therefore, by disrupting self-IgE tolerance via costimulation, the CTLs induced by nECPs can serve as universal allergy vaccines (UAVs) in humans to dampen IgE production mediated by diverse allergen-specific IgE-secreting B cells and plasma cells expressing surface nECP-MHCIa as targets. The study herein has enabled the identification of nECPs, A32 and SP-1/SP-2 nonameric natural peptidesproduced through the correspondence principle. Vaccination using nECP induced nECP-specific CTL that profoundly suppressed human IgE production in vitro as well as chimeric human IgE production in human IgE/HLA-A2.01/HLA-B7.02 triple transgenic rodents. Furthermore, nECP-tetramer-specific CTLs were found to be converted into CD4 Tregs that restored IgE competence via the homeostatic principle, mediatepred by SREBP-1c suppressed DCs. Thus, nECPs showed causal efficacy and safety as UAVs for treating categorically type I hypersensitivity IgE-mediated allergies. The applied vaccination concept presented provides the foundation to unify, integrate through a singular class of tetramer-specific TCR clonotypes for regulaing human IgE production. The three signal theory pertains to mechanisms of three cells underlying central tolerance (S), breaking self tolerance (NS) and regaining peripheral tolerance (S) via homeostasisconcerning nECP as an efficacious and safe UAV to treat type I IgE-mediated hypersensitivity. The three signal theory impirically extended, may be heuritic for immuno-regulation of adaptive immune repertoire in general.

DIA-based quantitative proteomics analysis of plasma exosomes in rat model of allergic rhinitis

Allergic rhinitis (AR) is a common chronic inflammatory disease characterized by symptoms such as itching, rhinorrhea, sneezing, and nasal obstruction. Despite being classified as an IgE-mediated typeⅠ allergy for many years, the complex pathophysiological mechanism of AR continues to present a challenge in clinical management. The objective of this study was to quantify the proteomics of plasma exosomes using data independent acquisition (DIA) in combination with liquid chromatography-mass spectrometry (LC-MS/MS) to identify the key proteins involved in the development and progression of AR. In the AR rat model, a total of 41 proteins demonstrated significant up-regulation, while 51 proteins were found to be significantly down-regulated. Gene ontology (GO) analysis results indicated that the altered proteins were highly enriched in cellular regulatory processes and enzymatic activity in AR rats. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and protein-protein interaction (PPI) network results revealed that the pivotal proteins C4b, C1qa, C1qc, and Mbl1 might be involved in the metabolic pathways of the immune system in AR through the activation of the complement and coagulation cascades pathway. These proteins could serve as diagnostic markers and therapeutic targets for AR, which is of great significance in understanding the role of exosome proteins in AR.

Allergenicity and Conformational Diversity of Allergens

Allergens are substances that cause abnormal immune responses and can originate from various sources. IgE-mediated allergies are one of the most common and severe types of allergies, affecting more than 20% of the population in Western countries. Allergens can be subdivided into a limited number of families based on their structure, but this does not necessarily indicate the origin or the route of administration of the allergen, nor is the molecular basis of allergenicity clearly understood. This review examines how understanding the allergenicity of proteins involves their structural characterization and elucidates the study of conformational diversity by nuclear magnetic resonance spectroscopy. This article also discusses allergen cross-reactivity and the mechanisms by which IgE antibodies recognize and bind to allergens based on their conformational and linear epitopes. In addition, we outline how the pH, the proteolytic susceptibility and the endosomal degradation affect the outcome of allergic reactions, and how this is correlated with conformational changes and secondary structure rearrangement events. We want to emphasize the importance of considering structural diversity and dynamics, proteolytic susceptibility and pH-dependent factors to fully comprehend allergenicity.

IgG in the control of FcεRI activation: a battle on multiple fronts.

The rising global incidence of IgE-mediated allergic reactions poses a significant challenge to the quality of life of affected individuals and to healthcare systems, with current treatments being limited in effectiveness, safety, and disease-modifying capabilities. IgE acts by sensitizing the high-affinity IgE receptor FcεRI expressed by mast cells and basophils, tuning these cells for inflammatory degranulation in response to future allergen encounters. In recent years, IgG has emerged as an essential negative regulator of IgE-dependent allergic inflammation. Mechanistically, studies have proposed different pathways by which IgG can interfere with the activation of IgE-mediated inflammation. Here, we briefly summarize the major proposed mechanisms of action by which IgG controls the IgE-FcεRI inflammatory axis and how those mechanisms are currently applied as therapeutic interventions for IgE-mediated inflammation.

Integrated gut metabolome and microbiome fingerprinting reveals that dysbiosis precedes allergic inflammation in IgE-mediated pediatric cow's milk allergy.

IgE-mediated cow's milk allergy (IgE-CMA) is one of the first allergies to arise in early childhood and may result from exposure to various milk allergens, of which β-lactoglobulin (BLG) and casein are the most important. Understanding the underlying mechanisms behind IgE-CMA is imperative for the discovery of novel biomarkers and the design of innovative treatment and prevention strategies. We report a longitudinal invivo murine model, in which two mice strains (BALB/c and C57Bl/6) were sensitized to BLG using either cholera toxin or an oil emulsion (n = 6 per group). After sensitization, mice were challenged orally, their clinical signs monitored, antibody (IgE and IgG1) and cytokine levels (IL-4 and IFN-γ) measured, and fecal samples subjected to metabolomics. The results of the murine models were further extrapolated to fecal microbiome-metabolome data from our population of IgE-CMA (n = 22) and healthy (n = 23) children (Trial: NCT04249973), on which polar metabolomics, lipidomics and 16S rRNA metasequencing were performed. Invitro gastrointestinal digestions and multi-omics corroborated the microbial origin of proposed metabolic changes. During mice sensitization, we observed multiple microbially derived metabolic alterations, most importantly bile acid, energy and tryptophan metabolites, that preceded allergic inflammation. We confirmed microbial dysbiosis, and its associated effect on metabolic alterations in our patient cohort, through invitro digestions and multi-omics, which was accompanied by metabolic signatures of low-grade inflammation. Our results indicate that gut dysbiosis precedes allergic inflammation and nurtures a chronic low-grade inflammation in children on elimination diets, opening important new opportunities for future prevention and treatment strategies.

Treatment Difficulties in Wheat Oral Immunotherapy and the Predictive Value of Wheat-Specific IgE.

Factors associated with wheat oral immunotherapy (OIT) difficulties in patients with IgE-mediated wheat allergy have not been well studied. We aimed to assess factors associated with difficulties in wheat OIT. We retrospectively collected data from children under 18 years of age with history of IgE-mediated wheat allergy who underwent wheat OIT. The initial specific IgE (sIgE) of wheat and omega-5-gliadin, wheat skin prick test (SPT) sizes, eliciting doses, and adverse reactions during the OIT were evaluated. A total of 81 children were enrolled, with a mean age of 7.0 ± 2.7 years at the initiation of wheat OIT. The median follow-up duration was 2 years (IQR 1.2 -3.0 years). Difficulties in wheat OIT included patients who experienced frequent reactions (at least grade 2 or exercise-induced reactions) or deviated from the up-dosing protocol, which we defined as 'Complicated cases.' Twenty-six patients (32.1%) were complicated cases. Initial wheat-sIgEs were significantly higher in complicated cases than in noncomplicated cases (median of 192.3 kUA/L (IQR 30.4-590.0) vs 6.9 kUA/L (IQR 1.9-100.0) (p = 0.001)). Initial omega-5-gliadin-sIgEs in the complicated group were also significantly higher, with a median of 15.0 kUA/L (IQR 6.3-69.8) vs 1.6 kUA/L (IQR 0.2-11.4) (p < 0.001). The risk factors for complicated cases include higher omega-5-gliadin-sIgEs and anaphylaxis during the oral food challenge test (aOR 1.035 and 5.684, respectively). The initial wheat and omega-5-gliadin-sIgEs were significant risk factors for complicated OIT patients and could be used to monitor these patients carefully during the OIT period.

Hay diseases in Iceland

Diseases due to work in hay dust have long been known in Iceland and the first written records of them appear in the beginning of the 17th century. At the end of the 18th century, a district doctor alleges that they cause many deaths in the country. In the latter part of the 20th century, research was started to investigate the causes and nature of hay diseases in Iceland. Studies of allergens showed high levels of storage mites in hay. Highest levels were of Tarsonemus sp., Acarus farris and Lepidoglyphus destructor. A several micro-fungi were also found, most commonly Rhizopus sp., Penicillium sp. and Aspergillus sp. Micropolyspora faeni was also found in all hay samples. A study was done on people aged 6-50 years in two districts in Iceland. In one district farmers used almost exclusively dry hay and in the other they used 80-90% silage. There was no difference in IgE-mediated allergy between the provinces, but most had positive skin tests for L. destructor and cattle. Those with symptoms connected with hay dust most often reported nasal symptoms (79%), eye symptoms (63%), cough (41%), dyspnea (32%) and fever (21%). Those who had positive skin reaction complained most often of nose and eye symptoms. A study was also conducted on subjects aged 16-87 years from the same regions investigating precipitin tests for M. faeni, Thermoactinomyces vulgaris and Aspergillus fumigatus. Pulmonary symptoms and lung function were also investigated. Precipitin tests were almost exclusively positive for M. faeni, and 5 individuals were positive for A. fumigatus and none for T. vulgaris. The precipitin tests were significantly more often positive in those working almost exclusively with dry hay (72.9% vs. 23.9%). They had also more commonly obstructive pulmonary disease (FEV1/FVC%&lt;70: 24.8% vs. 9.5%) as well as dyspnea when walking on level ground. There was a positive correlation between positive precipitin tests for M. faeni and dyspnea walking on level ground. The sensitivity and specificity of positive precipitin tests for M. faeni were investigated to detect farmer’s lung. The sensitivity was 82% and specificity was only 49%. A survey of emphysema in patients in the only Pulmonary Clinic in the country showed that farmers had more often emphysema than the rest of the country population, and 58% of farmers with emphysema had smoked compared to 94% of other emphysema patients.

An optimized method for IgE-mediated degranulation of human lung mast cells.

Mast cells are critically involved in IgE-mediated diseases, e.g., allergies and asthma. Human mast cells are heterogeneous, and mast cells from different anatomical sites have been shown to respond differently to certain stimuli and drugs. The origin of the mast cells is therefore of importance when setting up a model system, and human lung mast cells are highly relevant cells to study in the context of asthma. We therefore set out to optimize a protocol of IgE-mediated activation of human lung mast cells. Human lung mast cells were extracted from lung tissue obtained from patients undergoing pulmonary resection by enzyme digestion and mechanical disruption followed by CD117 magnetic-activated cell sorting (MACS) enrichment. Different culturing media and conditions for the IgE-mediated degranulation were tested to obtain an optimized method. IgE crosslinking of human lung mast cells cultured in serum-free media gave a stronger response compared to cells cultured with 10% serum. The addition of stem cell factor (SCF) did not enhance the degranulation. However, when the cells were put in fresh serum-free media 30 minutes prior to the addition of anti-IgE antibodies, the cells responded more vigorously. Maximum degranulation was reached 10 minutes after the addition of anti-IgE. Both CD63 and CD164 were identified as stable markers for the detection of degranulated mast cells over time, while the staining with anti-CD107a and avidin started to decline 10 minutes after activation. The levels of CD203c and CD13 did not change in activated cells and therefore cannot be used as degranulation markers of human lung mast cells. For an optimal degranulation response, human lung mast cells should be cultured and activated in serum-free media. With this method, a very strong and consistent degranulation response with a low donor-to-donor variation is obtained. Therefore, this model is useful for further investigations of IgE-mediated mast cell activation and exploring drugs that target human lung mast cells, for instance, in the context of asthma.

Diagnostics of IgE-mediated occupational allergies: Between reality, requirements, and opportunities.

Occupational skin and respiratory allergies are among the most common occupational diseases in Germany. The identification of the allergy trigger is essential for the recognition of an occupational allergy as well as for effective individual prevention. However, occupational type I allergens are among the "rare" allergens and the possibilities of guideline-compliant diagnosis using quality-tested skin test solutions is becoming increasingly difficult due to the reduction in commercially available test allergens. In order to guarantee meaningful diagnostic workup for all affected insured persons with suspected occupational type I allergies and to ensure this in the future, a durable optimization, standardization, and availability of allergy tests for occupational allergic diseases is urgently required. The need for action has been recognized by the German Social Accident Insurance (DGUV), and steps to eliminate the diagnostic gaps have been initiated by a joint research project at the Institute for Prevention and Occupational Medicine of the DGUV (IPA) and the Paul Ehrlich Institut (PEI). The evaluation of alternative methods for the production of standardized test allergen solutions can also be used for newly emerging allergens in the workplace. New allergen sources at workplaces and thus also sensitization and allergies among employees can be expected as a result of changes in work processes and the introduction of new technologies and/or working materials, which are also introduced in connection with climate change and the concept of sustainability.

Diagnostic Decision Point for IgE-Mediated Wheat Allergy in Children.

The diagnostic decision point can help diagnose food allergies while reducing the need for oral food challenge (OFC) tests. We performed a multicenter survey of children aged 0-7 years from January 1, 2018 to March 31, 2022. A total of 231 children were recruited from 18 institutions. Wheat allergy (WA) or non-wheat allergy (NWA) was determined on the basis of OFC results and symptoms. There were no differences in age, sex, family history of allergy or allergic comorbidities between the WA and NWA groups. According to receiver operating characteristic analysis for wheat-specific immunoglobulin E (IgE), the optimal cutoff value, positive decision point, and negative decision point were 10.2, 33.5, and 0.41 kU/L, respectively. For the ω-5 gliadin-specific IgE, their values were 0.69, 3.88, and 0.01 kU/L, respectively. This new diagnostic decision point may be used to diagnose WA in Korean children.

Immunotherapy with biodegradable nanoparticles encapsulating the oligosaccharide galactose-alpha-1,3-galactose enhance immune tolerance against alpha-gal sensitization in a murine model of alpha-gal syndrome.

IgE antibodies against the mammalian oligosaccharide allergen galactose-α-1,3-galactose (αGal) can result in a severe allergic disease known as alpha-gal syndrome (AGS). This syndrome, acquired by tick bites that cause αGal sensitization, leads to allergic reactions after ingestion of non-primate mammalian meat and mammalian-derived products that contain αGal. Allergen-specific immunotherapies for this tickborne allergic syndrome are understudied, as are the immune mechanisms of allergic desensitization that induce clinical tolerance to αGal. Here, we reveal that prophylactic administration of αGal glycoprotein-containing nanoparticles to mice prior to tick protein-induced αGal IgE sensitization blunts the production of Th2 cytokines IL-4, IL-5, and IL-13 in an αGal-dependent manner. Furthermore, these effects correlated with suppressed production of αGal-specific IgE and hypersensitivity reactions, as measured by reduced basophil activation and histamine release and the systemic release of mast cell protease-1 (MCPT-1). Therapeutic administration of two doses of αGal-containing nanoparticles to mice sensitized to αGal had partial efficacy by reducing the Th2 cytokine production, αGal-specific IgE production, and MCPT-1 release without reducing basophil activation or histamine release. These data identify nanoparticles carrying encapsulated αGal glycoprotein as a potential strategy for augmenting αGal-specific immune tolerance and reveal diverse mechanisms by which αGal nanoparticles modify immune responses for established αGal-specific IgE-mediated allergic reactions.

Eosinophilic esophagitis as a side-effect of allergen immunotherapy: protocol for a systematic review and meta-analysis.

Background. Sensitization to food and airborne allergens is common in the majority of patients with eosinophilic esophagitis (EoE). Although there is not a direct cause-effect relationship of IgE-mediated allergy with the pathogenesis of EoE, there is a growing evidence that oral desensitization to food and sublingual immunotherapy (SLIT) may induce the development of EoE as an adverse effect. As part of the 'EoE and Allergen Immunotherapy (AIT)' Task Force funded by the European Academy of Allergy and Clinical Immunology (EAACI), a systematic approach will be followed to review the evidence from the published scientific literature on the development of EoE in children and adults under any type of AIT. Methods. This systematic review will be carried out following the PRISMA statement guidelines. Studies will be assessed for inclusion in the review according to the Population-Interventions-Comparators-Outcomes (PICO) criteria. Results. Expected outcomes will provide evidence on the AIT-EoE development connection. Conclusions. The findings from this review will be used as a reference to provide useful guidelines for physicians treating patients with EoE and/or are practicing AIT.

Skin test (Skin Prick Test) in food allergy

Skin tests, also known as prick tests, in food allergies are restricted to IgE-mediated food allergies, with results that barely indicate sensitization to a certain food and do not necessarily suggest food allergy. The clinical context of the patient is the decisive point before performing any type of food allergy skin test; Contextualizing and relating the patient's clinical picture with the immunological mechanism of IgE-mediated allergies will allow a better selection of the allergy test for each case. Positive tests should be interpreted more carefully, and consider that during early childhood it is common that several patients may have negative specific serum IgE tests in the blood for food allergens compared to those performed on the skin, which are positive. Skin testing can be carried out with standardized strata of foods, but they are not always available for all foods and some are very unstable. Skin tests can even be performed with raw foods, using the prick to prick technique to perform the puncture with fresh foods (especially fruits or vegetables) or other products that are not commercially available. The skin prick test is a test where, after having placed the allergenic extract in drops or with fresh food itself, the puncture must be carried out with a standardized lancet.

RAST, Inmunoblot, Immunocap and ISAC in food allergy

skin tests; Sensitization; IgE-mediated allergy; allergenic extract. After the discovery of IgE, technological advances have provided new laboratory tools for the quantification of allergen-specific IgE antibodies in serum and on the surface of basophils-mast cells. In vitro testing offers numerous advantages: accurate quantitation, lack of drug interference, safety, and long-term storage of samples. Quantitative immunoassays for IgE antibodies can be an adjunct to skin testing. The allergen reagent in solid phase (allergosorbent) or liquid is the main component of the assay that confers specificity to the IgE antibody test. It is the most complex and highly variable reagent in IgE antibody assays. The choice to use diagnostic recombinants on a single rather than multiple platforms is made on a case-by-case basis (considering prior history and clinical profile) and in an allergen-dependent manner. Although most food allergies are limited to a small number of possible triggers, these foods are very complex when evaluating their allergenic potential. The possibility of fractionating the allergen and understanding some of its components as potentially important to define the risk of clinical reaction, cross-reactivity, or persistence of allergy, opened a new era in the field of allergy, called molecular allergy. The identification of the allergenic component responsible for the reactions is an important tool to confirm the information and severity of the symptoms, natural history of the disease, possibility of cross-reactivity and clinical symptoms (allergy markers).

A Rare Case of Angioedema Face due to Fish Allergy - A Case Report

Angioedema is defined by World Allergy Organization as a transient swelling of the skin or submucosal surface due to increased vascular permeability of small venules. Most common etiologies include IgE-mediated allergic reactions (to food, drug, or environmental triggers), nonsteroidal anti-inflammatory drug (NSAID), and chemically induced histamine release (most commonly opiates, highly cationic antibiotics, and muscle relaxants). Recent publications show a global incidence of anaphylaxis between 50 and 112 episodes per 100 000 person-years while the estimated lifetime prevalence is 0.3-5.1%. Timely intubation and administration of steroids/ antihistaminic agents will prevent a catastrophic cannot intubate cannot ventilate situation. In small, resource limited environment of a field hospital which may be compared to a rural setting in India managing such emergencies is challenging. If available in a case of anticipated difficult airway like this difficult airway cart must contain a whole armamentarium of airway adjuncts and gadgets. History of consumption of fish (Nile Perch) a rare form of allergen causing airway and breathing issues leading to timely intubation saved the life of patient.

Potential honey bee (Apis mellifera) allergens associated with IgE-mediated allergy- An In-silico study.

Allergies due to honeybee venom (HBV) are reported to be the second most common form of allergy toHymenopteravenom that occurs after being stung. Indeed, 15-20% of people test IgE positive after being stung. However, accurate data on the incidence of honey bee allergens is missing and estimated to be less than 0.001%. Beekeeping is an ancient and widely practiced activity across the Kingdom of Saudi Arabia. Still, studies on the allergenic effect of the different subspecies of honey bees are very rare in Saudi Arabia. Hence, in this study, using the In-silico approach, we aimed to study and evaluate the effect of allergens from honey bees in Ha'il City, Saudi Arabia on IgE-mediated allergies. A list of potential allergens from Apis mellifera was prepared, and the 3D structure was prepared using the SWISS-MODEL web server and the PDB database was used for retrieving the structure of the immunoglobulin E- fragment antigen-binding (IgE-Fab) region. Molecular docking (clusPro webserver) and molecular dynamics (Schrödinger) results revealed that the B2D0J5 protein from Apis mellifera might be the key protein associated with IgE-mediated allergic response. Overall, the identified knowledge can be used for exploring prophylactic vaccine candidates and improving the diagnosis of allergic reactions to honey bees in the Ha'il region of Saudi Arabia.

Characteristics of clinical manifestations of allergy in correlation with cow’s milk-sIgE components in children – preliminary reports

Background: Cow’s milk, which is one of the first foods in human life, is also one of the most common causes of food allergy in infants and young children, as well as anaphylaxis in the youngest population. Thanks to component diagnostics, it is possible to accurately determine the concentrations of antibodies specific to individual milk proteins. The aim of the study was to determine the relationship between the cow’s milk component-specific IgE and the type of clinical manifestation of allergy. Materials and methods: Eighteen children with documented IgE-mediated allergy to cow’s milk proteins were enrolled in the study. Blood samples (2 mL) were collected from each patient for component diagnostics using the ALEX test. Results: The antibodies that were most frequently found among the children with cow’s milk allergy were antibodies against casein (Bos d 8). There were no statistically significant relationships between the clinical symptoms and the levels of individual components. A statistically significant relationship was observed between the concentration of α-lactalbumin (Bos d 4) and the duration of clinical symptoms of allergy to cow’s milk protein. Conclusions: The results of our study indicate that the most common component is casein (Bos d 8). The relationship between the sensitisation to other components and clinical symptoms requires further research, which is currently being conducted.

Low Prevalence of Idiopathic Mast Cell Activation Syndrome Among 703 Patients With Suspected Mast Cell Disorders

BackgroundIdiopathic mast cell activation syndrome (iMCAS) is characterised by severe, episodic systemic mast cell (MC) activation and mediator-related symptoms, event-related increase in serum tryptase levels and response to MC-targeted therapies, in the absence of underlying IgE-mediated allergy or clonal MC disorder. Studies indicating its prevalence using evidence-based diagnostic criteria are currently lacking. ObjectiveThe present study aimed to assess prevalence, as well as clinical and laboratory features of patients with iMCAS. MethodsWe conducted a retrospective evaluation of the data from 703 consecutive patients (≥18 years old) who were referred to our centre based on suspected MC disorders. Patients underwent a thorough clinical work-up including patient history, allergy tests, KIT D816V mutation analysis and/or bone marrow investigation. Disease activity was prospectively assessed during follow-up visits. ResultsThirty-one cases with confirmed iMCAS were identified. Furthermore, hereditary alpha-tryptasemia was detected in three of the cases with baseline tryptase levels >8 ng/ml. The most common clinical presentation during the MCAS episodes was mucocutaneous symptoms in patients with iMCAS, especially urticaria/angioedema. However, these symptoms were less prevalent in clonal MCAS patients (p=0.015). The duration of diagnostic delay was significantly longer in iMCAS compared to cMCAS patients (p=0.02). ConclusionOverall prevalence of iMCAS was 4.4% in the entire cohort, which indicates that iMCAS is an uncommon condition. Screening suspected patients for the three diagnostic criteria and performing a comprehensive allergy work-up including laboratory tests and ultrasensitive mutation analysis of KIT D816V followed by applying recommended diagnostic algorithms is crucial for the diagnosis of iMCAS.

Clinical characteristics, allergic response to autologous semen, and desensitization in patients with postorgasmic illness syndrome.

Postorgasmic illness syndrome (POIS) is rare and includes a cluster of physical and cognitive symptoms that occur after ejaculation. The pathogenesis and effective treatments remain unclear. This study aimed to characterize the symptomatology of POIS, study the allergic response of autologous semen in patients and controls, and evaluate the effects of desensitization therapy. The clinical characteristics of 24 Chinese patients with POIS were analyzed. Skin prick tests, intracutaneous tests, and specific IgE detection were performed with autologous semen. Five patients were desensitized via subcutaneous injections of autologous semen. Evaluated outcomes included the clinical features of POIS; scores of the Self-rating Anxiety Scale (SAS), Self-rating Depression Scale (SDS), and visual analog scale (VAS) of symptoms; skin reactions; desensitization with diluted autologous seminal fluid; and the IgE reactivity patterns of immunoblotting and enzyme-linked immunosorbent assay in vitro. The most common symptom cluster was the general cluster, and the most prevalent symptoms were extreme fatigue and inattention. A total of 66.67% (14/21) of the patients had no symptoms or milder symptoms after nocturnal emission than after intercourse or masturbation. Of the patients, 87.5% (21/24) had psychiatric symptoms and 53.85% (7/13) had abnormal sex hormone levels. The SAS and SDS scores of the high and low VAS groups were significantly higher than those of the control group. Pearson analysis showed that the correlation coefficient between the SAS and VAS was 0.607 (P < .01) and that between the SDS and VAS was 0.490 (P < .05). The patients and healthy donors all had positive intracutaneous test results with their own semen, negative skin prick test results, and no IgE specific to autologous semen. Most patients (4/5) did not achieve ideal therapeutic effects with desensitization. Allergy is not the main pathogenesis of POIS, and desensitization with autologous semen is not effective for most patients. This project included the largest number of patients with POIS in China and assessed the allergic response to autologous semen and the effect of desensitization therapy. There is no objective method for evaluating the efficacy of desensitization with autologous semen. IgE-mediated semen allergy is not the main pathogenesis of POIS, and there is a positive chance that POIS is related to psychological factors. Most patients do not respond to desensitization with autologous semen, and POIS treatment should be individualized, especially in cases with uncertain causes.