Dual effect of tacrolimus on mast cell-mediated allergy and inflammation through Mas-related G protein-coupled receptor X2.

BACKGROUND: Topical tacrolimus, although widely used in the treatment of dermatoses, presents with an immediate irritation on initial application resembling a pseudo-allergic reaction. Mas-related G protein-coupled receptor X2 (MRGPRX2) in mast cells (MCs) mediates drug-induced pseudo-allergic reaction and immunoglobulin E (IgE)-independent pruritis in chronic skin diseases. However, the immunosuppression mechanism of tacrolimus on MCs via MRGPRX2 has not been reported. OBJECTIVE: To investigate the role of MRGPRX2 and the mechanism of action of tacrolimus on its short-term and long-term applications. METHODS: Wild-type mice, KitW-sh/W-sh mice, and MrgprB2-deficient (MUT) mice were used to study the effect of tacrolimus on in vivo anaphylaxis model. LAD2 cells and MRGPRX2-knockdown LAD2 cells were specifically used to derive the associated mechanism of the tacrolimus effect. RESULTS: Short-term application of tacrolimus triggers IgE-independent activation of MCs via MRGPRX2/B2 in both in vivo and in vitro experiments. Tacrolimus binds to MRGPRX2, which was verified by fluorescently labeled tacrolimus in cells. On long-term treatment with tacrolimus, the initial allergic reaction fades away corresponding with the downregulation of MRGPRX2, which leads to decreased release of inflammatory cytokines (P < 0.05 to P < 0.001). CONCLUSION: Short-term treatment with tacrolimus induces pseudo-allergic reaction via MRGPRX2/B2 in MCs, whereas long-term treatment downregulates expression of MRGPRX2/B2, which may contribute to its potent immunosuppressive effect in the treatment of various skin diseases.

Propolis Silver Nanoparticles as an Adjuvant in Immunization of Rats with Citrobactor Freundii Antigens.

This study aimed to examine the impact of Citrobacter freundii killed whole cell sonicated antigen (KWCSAg) alone and in combination with propolis nanoparticles on humoral immunoglobulin (IgG) and cellular immune responses of rats. The ELISA interleukin 4 (IL4) and IgG, delayed-type hypersensitivity (DTH) skin test, and phagocytosis activity tests were used in this study. In total, 45 rats were divided into five groups of 9 rats. The first group received a 1,000 µg\ml dose of KWCSAg-CF. The second group received an injection of 1,000 µg/ml of KWCSAg-CF antigen and 30 mg/ml of propolis AgNPs. The third group received an injection of 1,000 µg/ml of KWCSAg-CF antigen along with 10 mg/ml of propolis AgNPs. The fourth group was subjected to 30 mg/ml of propolis AgNPs. One ml of phosphate-buffered saline (pH 7.2) was injected into the fifth group (the negative control group). The rats received booster injections of the same antigens after 14 days. Blood was obtained from them to detect immunoglobulin and interleukin 4 (IL-4) on days 21, 28, 32, 46, 50, and 60 following the injection. The second group showed the most significant rise in IL-4 and IgG concentration, followed by the third group, the first group, and the fourth group, compared to the negative control group (fifth group). In all immunized groups, the DTH test results demonstrated an increase in the means of induration with significant differences (P<0.05) of the concentrated antigen after 24 and 48 h, and subsequently a decrease after 72 h, compared to the negative control group. At 48 h after the concentrated antigen was indurated, the second group displayed the most significant increase in diameter.

Sulfasalazine-Induced Delayed Hypersensitivity Reaction Presenting as Fever, Aseptic Meningitis, and Mesenteric Panniculitis in a Patient with Seronegative Arthritis.

BACKGROUND An 82-year-old woman presented with acute pyrexial illness and mesenteric panniculitis and developed biochemical aseptic meningitis (cerebrospinal fluid pleocytosis with no identifiable pathogen). Investigation determined her illness was likely a delayed hypersensitivity reaction caused by sulfasalazine. Sulfasalazine-induced aseptic meningitis is a rare condition often diagnosed late in a patient's admission owing to initial non-specific illness symptomatology requiring the exclusion of more common "red flag" etiologies, such as infection and malignancy. CASE REPORT An 82-year-old woman with a history of recurrent urinary tract infections and seronegative arthritis presented with a 3-day history of fatigue, headache, dyspnea, and lassitude. On admission, she was treated as presumed sepsis of uncertain source owing to pyrexia and tachycardia. Brain computer tomography (CT) revealed no acute intracranial abnormality. Furthermore, CT of the chest, abdomen, and pelvis did not reveal any source of sepsis or features of malignancy. After excluding infective etiologies with serological and cerebrospinal fluid testing, sulfasalazine-induced aseptic meningitis (SIAM) was diagnosed. The patient was then commenced on intravenous steroids, resulting in immediate defervescence and symptom resolution. CONCLUSIONS SIAM remains a diagnostic challenge since patients present with non-specific signs and symptoms, such as pyrexia, headaches, and lassitude. These patients require a thorough investigative battery starting with anamnesis, physical examination, biochemical testing, and radiologic imaging. This case illustrates the need for a high suspicion index of drug-induced hypersensitivity reaction in a rheumatological patient with pyrexial illness where infective etiologies have been confidently excluded. Prompt initiation of intravenous steroids in SIAM provides a dramatic recovery and resolution of symptoms.

Melittin as a safe compound to BALB/c mice immune system; a tiered approach immunotoxicity screening.

BACKGROUND: Maintenance of immune system integrity is a vital requirement to protect human body against pathogens/cancers. Natural compounds have long been used due to their benefits for the immune system. One of which is bee venom that contains a peptide called melittin having antimicrobial and anticancer effects. Since a limited number of studies regarding the effects of melittin on the immune system have been carried out, we aimed to evaluate the effects of melittin on BALB/c mice immune system parameters. METHODS: Female BALB /c mice were treated intraperitoneally (i.p) with 0.75 and 1.5 mg/kg doses of melittin for 14 days (5 doses per week). The negative control group received i.p normal saline whereas the positive controls received i.p 20 mg/kg cyclophosphamide (CYP). Immunological parameters such as hematological parameters, delayed-type hypersensitivity (DTH), hemagglutination titer (HA), spleen cellularity, splenocytes proliferation, as well as spleen and bone marrow histopathological assessment were evaluated. RESULTS: Our findings showed that melittin has no gross pathological effect on the spleen and bone marrow. It was also demonstrated that melittin has no any significant effect on hematological parameters. Melittin did not cause any significant changes to proliferation response of splenocytes to PHA and LPS, spleen cellularity, DTH response, as well as the production of anti-SRBC antibodies. According to our results, melittin at 0.75 and 1.5 mg/kg doses could not induce significant changes on immune parameters and as a result, melittin was found to be safe for the mice immune system.

Clinical Application of In Vitro Tests for COVID-19 Vaccine Delayed Hypersensitivity Diagnostics.

Drug hypersensitivity reactions can be classified as immediate or delayed. While diagnostic options for immediate reactions are well developed and standardized, delayed reactions (in many cases type IV according to Gell and Coombs) are a challenge for allergy work-up. In recent years, some in vitro markers have been proposed and used for delayed reactions, such as contact dermatitis. Primary strategy: Avoidance is difficult to achieve, especially for COVID-19 vaccinations, when immunity against infection is extremely important. The aim of our study was to evaluate the application of in vitro delayed hypersensitivity tests in COVID-19 vaccines. Seven patients with a positive history of severe delayed drug allergy were enrolled. Vein blood was collected to stimulate cells with the tested vaccines (Comirnaty, Janssen, Spikevax) and excipients with the assessment of CD40L, CD69, IL-2, IL-4, IL-6, IL-10, IFNgamma, TNFalfa, and intracellular markers: granulysin and INFgamma. In addition, basophile activation tests, patch tests, skin prick tests, and intradermal tests were performed with the tested vaccine. Finally, the decision was made to either administer a vaccine or resign. Two out of seven patients were considered positive for drug hypersensitivity in the in vitro test according to the high vaccine stimulation index measured with CD69 (6.91 and 12.18) and CD40L (5.38 and 15.91). All patch tests, BATs, and skin tests were negative. Serum interleukin measurements were inconclusive as the impact of the vaccine itself on the immunity system was high. Intracellular markers gave uncertain results due to the lack of stimulation on the positive control. CD69 and CD40L could be reliable in vitro markers for delayed hypersensitivity to COVID-19 vaccines. Patch tests, skin tests, BATs, and serum interleukins did not confirm their usefulness in our study.

Drug Hypersensitivity Reactions.

Drug hypersensitivity reactions are a diverse group of reactions mediated by the immune system after exposure to a drug. The Gell and Coombs classification divides immunologic DHRs into 4 major pathophysiologic categories based on immunologic mechanism. Anaphylaxis is a Type I hypersensitivity reaction that requires immediate recognition and treatment. Severe cutaneous adverse reactions (SCARs) are a group of dermatologic diseases that result from a Type IV hypersensitivity process and include drug reaction with eosinophilia and systemic symptom (DRESS) syndrome, Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP). Other types of reactions are slow to develop and do not always require rapid treatment. Emergency physicians should have a good understanding of these various types of drug hypersensitivity reactions and how to approach the patient regarding evaluation and treatment.

Delayed hypersensitivity reactions to iodinated contrast media: A diagnostic approach by skin tests.

BACKGROUND: Adverse drug reactions to iodinated contrast media (ICM) have risen due to their increasing use in x-ray-based imaging modalities. Delayed hypersensitivity reactions are mainly caused by nonionic monomeric compounds and represent an issue impacting the diagnostic-therapeutic pathways of cancer, cardiology and surgery patients. OBJECTIVES: To prospectively evaluate the usefulness of skin tests in delayed hypersensitivity reactions to ICM and to evaluate the tolerability of iobitridol, a monomeric nonionic low osmolality compound, as a possible safe alternative. METHODS: Patients with delayed hypersensitivity reactions to ICM referred to us from 2020 to 2022 were prospectively enrolled in the study. All patients underwent patch test and, if negative, intradermal test with the culprit ICM and iobitridol as alternative. RESULTS: A total of 37 patients (females 24, 64.9%) were enrolled in the study. Iodixanol and iomeprol were the most frequently involved ICM (48.5% and 35.2%, respectively); 62.2% of patients presented maculopapular eruption, while 37.8% reported delayed urticaria-like rash. Skin tests resulted positive to the culprit ICM in 19 patients (51.4%), 16 to patch test and 3 to intradermal test. Skin tests with iobitridol, tested as alternative, resulted positive in 3/19 patients (15.8%). All 16 patients with negative results to iobitridol were administered this ICM and tolerated it. CONCLUSIONS: In at least half of patients, delayed-type hypersensitivity was demonstrated by skin tests, particularly by patch test. This diagnostic approach resulted simple, cost-effective and safe, not only to confirm the culprit ICM but also to identify iobitridol as feasible alternative.

Hypersensitivity reactions to anti-SARS-CoV-2 vaccines: Basophil reactivity to excipients.

Basophil activation test (BAT) can tackle multiple mechanisms underlying acute and delayed hypersensitivity to drugs and vaccines and might complement conventional allergy diagnostics but its role in anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine-related hypersensitivity is ill-defined. Therefore, 89 patients with possible hypersensitivity (56 % with delayed mucocutaneous manifestations) to anti-SARS-CoV-2 vaccines were tested with BAT for Macrogol 3350, DMG-PEG 2000, PEG 20000, polysorbate-80 and trometamol and compared to 156 subjects undergoing pre-vaccine BAT. A positive BAT was associated with delayed reaction onset (p = 0.010) and resolution (p = 0.011). BAT was more frequently positive to DMG-PEG 2000 than to other excipients in both groups (p < 0.001). DMG-PEG 2000 reactivity was less frequent in vaccine-naïve (6 %) than vaccinated subjects (35 %, p < 0.001) and associated with mRNA-1273 vaccination. DMG-PEG 2000 BAT might therefore have a diagnostic role in subjects with delayed hypersensitivity reactions. Natural immunity might be a key player in basophil activation.

Type IV Hypersensitivity Reaction after Cyanoacrylate Venous Closure.

BACKGROUND: Nonthermal endovenous closure techniques are routinely utilized to treat superficial axial venous reflux. Cyanoacrylate closure is a safe and effective modality implemented for truncal closure. However, an adverse reaction of type IV hypersensitivity (T4H), unique to cyanoacrylate, is a known risk. This study aims to evaluate the real-world incidence of T4H and examine risk factors that may predispose its development. METHODS: A retrospective review between 2012- and 2022 was performed at four tertiary US institutions to examine patients who underwent cyanoacrylate vein closure of their saphenous veins. Patient demographics, comorbidities, CEAP (Clinical [C], Etiological [E], Anatomical [A], and Pathophysiological [P]) classification, and periprocedural outcomes were included. The primary endpoint was development of T4H post procedure. Logistic regression analysis for risk factors predictive of T4H was performed. Variables with a P-value of <0.05 were deemed significant. RESULTS: 595 patients underwent 881 cyanoacrylate venous closures. Mean age was 66.2 ± 14.9, and 66% of patients were female. There were 92 (10.4%) T4H events in 79 (13%) patients. Oral steroids were administered to 23% for persistent and/or severe symptoms. There were no systemic allergic reactions to cyanoacrylate. Multivariate analysis revealed younger age (P = 0.015), active smoking status (P = 0.033), and CEAP 3 (P < 0.001) and 4 (P = 0.005) classifications as independent risk factors associated with development of T4H. CONCLUSIONS: This real-world multicenter study shows the overall incidence of T4H to be 10%. CEAP 3 and 4 patients of younger age and smokers predicted a higher risk of T4H to cyanoacrylate.

Delayed Severe Gingivitis After Placement of Orthodontic Braces in an Atopic Teenager: A Case Report and Literature Review.

We report a case of a 15-year-old atopic patient presenting with delayed, severe ulcerative hypertrophic gingivitis after placement of orthodontic braces, which required removal of braces and restorative laser surgical procedures. Patch testing to multiple metals and chemicals showed weak positive reactions to steel bands and formaldehyde. The patient experienced urticarial, gingivitis, and other intraoral symptoms after patch testing and re-exposure to nickel-containing products. In contrast, nickel, cobalt, and cobalt-chromium (Co-Cr) bracket patch testing sites were negative. Nickel-caused contact dermatitis is Type IV delayed hypersensitivity reaction occurring at least 24 h after exposure. This reaction can result in intraoral blisters, ulcerations, eczematous and urticarial reactions of the face and more distant skin areas. This case illustrates the intraoral delayed response, symptom resolution after removing the braces, and brackets and local reactions upon subsequent nickel exposure, despite negative patch testing and lymphocyte stimulation test to nickel. This case further illustrates the difficulty associated with diagnosing nickel allergy.

The role of lymphocyte transformation tests (LTT) in suspected severe delayed hypersensitivity reactions following COVID-19 vaccination.

Coronavirus (COVID-19) vaccines have proved to be effective in the pandemic response but can cause adverse events such as delayed hypersensitivity reactions (DHRs). Delayed-reading intradermal tests (IDT) to vaccines are limited by false-positive results and may reflect a cell-mediated rather than IgE-mediated immune response. Lymphocyte transformation test (LTT), which has been utilized in the diagnosis of drug allergy, may be helpful in suspected COVID-19 vaccine and/or its excipient-related DHRs. To investigate the use of LTT in two suspected cases of COVID-19 vaccine-induced DHRs, two patients with suspected DHRs to COVID-19 vaccination were tested by delayed-reading IDT and LTT against vaccines and their excipients. A 47-year-old man developed acute mixed-pattern hepatitis after the second dose of ChAdOx1 vaccine. LTT performed at 2 months post-vaccination revealed reactivity to the ChAdOx1 vaccine, polysorbate 80 and mildly to PEG 2050 but not BNT162b2 vaccine. Delayed-reading IDT returned negative to both vaccines and excipients. He tolerated BNT162b2 vaccination with no adverse events. A 36-year-old woman presented with subacute morbilliform eruption and hepatitis after the first dose of BNT162b2 vaccine. LTT performed 3 months later revealed reactivity to the BNT162b2 but not PEG 2050. Repeat LTT following subsequent natural Severe Acute Respiratory Coronavirus-2 (SARS-CoV-2) infection revealed reactivity to ChAdOx1 and NVX-CoV2373 vaccines but not polysorbate 80. Delayed-reading IDT remained negative. She proceeded with NVX-CoV2373 vaccination with no symptom recurrence. LTT may be a useful tool in suspected COVID-19 vaccine-related DHRs. Further evaluation with a larger patient cohort is required.