At-home compounding preparation of slow desensitization of elexacaftor/tezacaftor/ivacaftor for delayed hypersensitivity rash.

As elexacaftor/tezacaftor/ivacaftor has proven to have robust clinical efficacy for eligible persons with cystic fibrosis, desensitization should be offered to those with maculopapular eruption hypersensitivity reactions to achieve tolerance. As presented in this case, if provided with tools for crushing and mixing the medication, a successful escalation protocol can be completed at home without coordinating the help of a compound pharmacy.

Pyruvate enhances oral tolerance via GPR31.

CX3CR1high myeloid cells in the small intestine mediate the induction of oral tolerance by driving regulatory T (Treg) cells. Bacterial metabolites, e.g. pyruvate and lactate, induce a dendrite extension of CX3CR1high myeloid cells into the intestinal lumen via GPR31. However, it remains unclear whether the pyruvate-GPR31 axis is involved in the induction of oral tolerance. Here, we show that pyruvate enhances oral tolerance in a GPR31-dependent manner. In ovalbumin (OVA)-fed Gpr31-deficient mice, an OVA-induced delayed-type hypersensitivity response was substantially induced, demonstrating the defective induction of oral tolerance in Gpr31-deficient mice. The percentage of RORγt+ Treg cells in the small intestine was reduced in Gpr31-deficient mice. In pyruvate-treated wild-type mice, a low dose of OVA efficiently induced oral tolerance. IL-10 production from intestinal CX3CR1high myeloid cells was increased by OVA ingestion in wild-type mice, but not in Gpr31-deficient mice. CX3CR1high myeloid cell-specific IL-10-deficient mice showed a defective induction of oral tolerance to OVA and a decreased accumulation of OVA-specific Treg cells in the small intestine. These findings demonstrate that pyruvate enhances oral tolerance through a GPR31-dependent effect on intestinal CX3CR1high myeloid cells.

Iodixanol activation of mast cells: Implications in the pathogenesis of iodixanol-induced delayed cutaneous adverse reactions.

Iodinated contrast media (ICM) is widely used in radiological examination and interventional therapy. In the commonly used ICM, iodixanol is considered to be the safer one. However, compared with other ICMs, it has a higher incidence of delayed cutaneous adverse reactions. The underlying mechanisms are unclear. In this study, mice with positive allergic reactions were selected based on the mouse clinical allergy symptom score and skin and blood samples taken 1, 6, 24, 48, and 72 h after ICMs (6 g iodine/kg) injection for histological and blood analyses. ICMs-induced pseudo-allergic reactions were investigated through in vivo intravital vascular imaging and passive cutaneous anaphylaxis (PCA) not mediated by IgE and through, calcium imaging degranulation of mast cells (MCs), and western blot assays in vitro. Results shows iodixanol-induced systemic anaphylaxis caused severe extravasation of plasma proteins and degranulation of skin MCs, and increased levels of plasma histamine, cytokines and inflammatory chemokines. Mechanistically, iodixanol increases degranulation of MCs and promotes the synthesis of inflammatory factors by activating PLC-γ and PI3K-related pathways. Trigonelline inhibit iodixanol-induced MC-related pseudo-allergic reactions in vitro and in vivo. These results suggest that mice in the iodixanol group had a higher incidence of delayed cutaneous reactions, characterized by cytokine release over time and delayed cutaneous MC degranulation. Iodixanol's delayed cutaneous adverse reactions may be due to a delayed phase of MC-related pseudo-allergic reactions. Trigonelline revealed anti-allergic activity in iodixanol-induced MC-related pseudo-allergic reactions.

The Ability of AhR Ligands to Attenuate Delayed Type Hypersensitivity Reaction Is Associated With Alterations in the Gut Microbiota.

Aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor that regulates T cell function. The aim of this study was to investigate the effects of AhR ligands, 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), and 6-Formylindolo[3,2-b]carbazole (FICZ), on gut-associated microbiota and T cell responses during delayed-type hypersensitivity (DTH) reaction induced by methylated bovine serum albumin (mBSA) in a mouse model. Mice with DTH showed significant changes in gut microbiota including an increased abundance of Bacteroidetes and decreased Firmicutes at the phylum level. Also, there was a decrease in Clostridium cluster XIV and IV, which promote anti-inflammatory responses, and an increase in Prevotella copri that facilitates pro-inflammatory responses. Interestingly, treatment of mice with TCDD attenuated the DTH response, induced Tregs, suppressed Th17 cells in the mesenteric lymph nodes (MLNs), and reversed the gut microbiota composition toward normalcy. In contrast, FICZ exacerbated the DTH response, induced heightened Th17 cells, and failed to cause a major shift in gut microbiota. Furthermore, TCDD but not FICZ caused an increase in the levels of short-chain fatty acids (SCFA), n-butyric acid, and acetic acid. Administration of sodium butyrate into mice with DTH suppressed the response, increased Tregs, and reduced Th17 cells IL17. Butyrate also caused an increase in the abundance of Clostridium and a decrease in Prevotella. Lastly, TCDD, as well as butyrate but not FICZ, were able to inhibit proinflammatory Histone deacetylases (HDACs) class I and II. Together, our data suggest that AhR ligands, such as TCDD that suppress DTH response, may mediate this effect by reversing the gut dysbiosis induced during this inflammatory response, while FICZ may fail to suppress the DTH response because of its inability to overturn the dysbiosis.

miR-155 Contributes to the Immunoregulatory Function of Human Mesenchymal Stem Cells.

Objectives: Mesenchymal stem/stromal cells (MSCs) are widely investigated in regenerative medicine thanks to their immunomodulatory properties. They exert their anti-inflammatory function thanks to the secretion of a number of mediators, including proteins and miRNAs, which can be released in the extracellular environment or in the cargo of extracellular vesicles (EVs). However, the role of miRNAs in the suppressive function of MSCs is controversial. The aim of the study was to identify miRNAs that contribute to the immunomodulatory function of human bone marrow-derived MSCs (BM-MSCs). Methods: Human BM-MSCs were primed by coculture with activated peripheral blood mononuclear cells (aPBMCs). High throughput miRNA transcriptomic analysis was performed using Human MicroRNA TaqMan® Array Cards. The immunosuppressive function of miRNAs was investigated in mixed lymphocyte reactions and the delayed type hypersensitivity (DTH) murine model. Results: Upon priming, 21 out of 377 tested miRNAs were significantly modulated in primed MSCs. We validated the up-regulation of miR-29a, miR-146a, miR-155 and the down-regulation of miR-149, miR-221 and miR-361 in additional samples of primed MSCs. We showed that miR-155 significantly reduced the proliferation of aPBMCs in vitro and inflammation in vivo, using the DTH model. Analysis of miRNA-mRNA interactions revealed miR-221 as a potential target gene that is down-regulated by miR-155 both in primed MSCs and in aPBMCs. Conclusion: Here, we present evidence that miR-155 participates to the immunosuppressive function of human BM-MSCs and down-regulates the expression of miR-221 as a possible inflammatory mediator.

AhR Ligands Differentially Regulate miRNA-132 Which Targets HMGB1 and to Control the Differentiation of Tregs and Th-17 Cells During Delayed-Type Hypersensitivity Response.

Aryl hydrocarbon receptor (AhR), is a transcription factor and an environmental sensor that has been shown to regulate T cell differentiation. Interestingly, AhR ligands exert varying effects from suppression to exacerbation of inflammation through induction of Tregs and Th-17 cells, respectively. In the current study, we investigated whether the differential effects of AhR ligands on T cell differentiation are mediated by miRNA during delayed-type hypersensitivity (DTH) reaction against methylated Bovine Serum Albumin (mBSA). Treatment of C57BL/6 mice with TCDD attenuated mBSA-mediated DTH response, induced Tregs, decreased Th-17 cells, and caused upregulation of miRNA-132. TCDD caused an increase in several Treg subsets including inducible peripheral, natural thymic, and Th3 cells. Also, TCDD increased TGF-ß and Foxp3 expression. In contrast, treating mice with FICZ exacerbated the DTH response, induced inflammatory Th17 cells, induced IL-17, and RORγ. Analysis of miRNA profiles from draining lymph nodes showed that miR-132 was upregulated in the TCDD group and downregulated in the FICZ group. Transfection studies revealed that miRNA-132 targeted High Mobility Group Box 1 (HMGB1). Downregulation of HMGB1 caused an increase in FoxP3+ Treg differentiation and suppression of Th-17 cells while upregulation of HMGB1 caused opposite effects. Moreover, TCDD was less effective in suppressing DTH response and induction of Tregs in mice that were deficient in miR-132. In summary, this study demonstrates that TCDD and FICZ have divergent effects on DTH response and T cell differentiation, which is mediated through, at least in part, regulation of miRNA-132 that targets HMGB1.

Evaluation of the immunomodulatory and anti-inflammatory activity of Bakuchiol using RAW 264.7 macrophage cell lines and in animal models stimulated by lipopolysaccharide (LPS).

Bakuchiol (BAK) has been reported to have a diverse pharmacological property as an antibiotic, anti-cancer, anti-hypolipidemic, anti-inflammatory and anti-convulsant agent. This study aimed to elucidate the immunomodulation and anti-inflammatory mechanism of bakuchiol using lipopolysaccharide stimulated RAW 264.7 macrophages and various animal models. The present study has shown that BAK significantly suppressed the pro-inflammatory cytokine expression in a dose-dependent manner and its oral administration significantly decreased delayed hypersensitivity responses as compared to control group. The assessment of immunomodulatory activity was carried out by the testing Hemagglutinating antibody (HA) titer, delayed type hypersensitivity (DTH) responses and phagocytic index by carbon clearance test. On the other hand, it showed significant decrease in circulating antibody titer and carbon clearance assay in a concentration-dependent manner. BAK has significantly potentiated the cellular immunity as well as humoral immunity by facilitating the footpad thickness responses in sheep RBCs in sensitized mice by significantly decreasing circulating antibody titer. Molecular studies revealed that BAK inhibited the activation of upstream mediator nuclear factor-κB by suppressing the phosphorylation of IκBα and p65. The responses were statistically significant as compared with the control (*p < 0.05, **p < 0.01).

Germinated black soybean fermented with Lactobacillus pentosus SC65 alleviates DNFB-induced delayed-type hypersensitivity in C57BL/6N mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Rhynchosia nulubilis (black soybean) has many applications in oriental medicine. It is traditionally used to treat disease related with high blood pressure, diabetes, inflammation, and osteoporosis. Furthermore, fermented soybean foods have traditionally been used for immunity enhancement in East Asia. However, the anti-inflammatory effects of germinated R. nulubilis (GR) against delayed-type hypersensitivity (DTH) are not fully understood. AIM OF STUDY: This study aimed to investigate the anti-inflammatory effects of germinated Rhynchosia nulubilis (GR) fermented with the lactic acid bacterium Lactobacillus pentosus SC65 (GR-SC65) isolated from pickled burdock. MATERIALS AND METHODS: We investigated the effects of GR-SC65 (300 mg/kg/day) on ear thickness and immune cell infiltration in DNFB-induced DTH in mice. We used dexamethasone (3 mg/kg) as a reference drug. Changes in infiltration of CD4+ and CD8+ T cells and NK cells were examined by immunohistochemistry. In addition, we investigated cytokine and chemokine production related to DTH using reverse transcription-polymerase chain reaction. We also investigated DTH-related cytokine production using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. RESULTS: Two lactic acid bacterial strains (Lactobacillus pentosus SC65 and Pediococcus pentosaceus ON81A) were selected for fermenting GR due to their high 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity. The total polyphenol contents (TPCs) in GR-SC65 and GR-ON81A were higher than that in unfermented GR (∗∗∗P < 0.001 vs. GR). Content of daidzein, glycitein, and genistein, the deglycosylated form of isoflavonoids, was higher in GR-SC65 than in unfermented GR. The ethanol extracts of GR-SC65 exerted a stronger anti-inflammatory activity than GR by inhibiting pro-inflammatory cytokines, such as tumor necrosis factor (TNF), interleukin-6 (IL-6), and interleukin-1ß (IL-1ß) in LPS-induced RAW264.7 macrophages. GR-SC65 reduced 1-fluoro-2,4-dinitrofluorobenzene (DNFB)-induced ear swelling and hyperplasia as well as vascular permeability. Fewer infiltrated CD4+ and CD8+ T cells were observed in the ear tissue of the GR-SC65-treated mice than those of the unfermented GR-treated mice. Furthermore, fewer infiltrated NK cells were observed in the GR-SC65 treated mice, than in the GR-treated mice. GR-SC65 significantly diminished the levels of CCL5 and COX-2 mRNAs and increased the level of IL-10 mRNA. CONCLUSIONS: These data suggest that GR-SC65 can be used as a health supplement or a prophylactic against delayed-type hypersensitive inflammatory disease.

Purification, structural elucidation and in vivo immunity-enhancing activity of polysaccharides from quinoa (Chenopodium quinoa Willd.) seeds.

Quinoa crude polysaccharides (QPS) were extracted from Chenopodium quinoa Willd. The soluble non-starch polysaccharide fraction (QPS1) was subsequently purified by DEAE-52 cellulose and Sephadex G-50 gel chromatography, using QPS as raw materials. Its chemical structure was identified using FT-IR, NMR, AFM, SEM and Congo red staining. High performance gel permeation chromatography (HPGPC) was used to determine molecular weight, and composition by HPLC. QPS1, with a molecular weight of 34.0 kDa, was mainly composed of mannose, rhamnose, galacturonic acid, glucose, galactose, xylose and arabinose at a molar ratio of 2.63:2.40:1.64:6.28:1.95:2.48:5.01. In addition, we evaluated the ameliorative effects of QPS1 on the improvement of anti-cyclophosphamide (CTX)-induced immunosuppression in ICR mice. The result exhibited significantly immune-enhancing activity: QPS1 successfully improved the content of IFN-γ, IL-6, IFN-ɑ, IgM and lysozyme (LYSO) in serum for three weeks, enhanced the phagocytic function of mononuclear macrophages and ameliorated delayed allergy in mice.

Successful Graded Dose Challenge to Iodixanol Radiocontrast Media in a Patient With Delayed Anaphylaxis to Iohexol.

We present a case of an 82-year-old male with known radiocontrast media (RCM) hypersensitivity who was admitted to our hospital with gangrene of his right toe. The plan for revascularization of his lower extremity required an angiogram. This presented a management challenge as the patient had experienced 2 episodes of delayed anaphylaxis to Omnipaque (iohexol) RCM, and based on a literature review, there was no known or established precedent on a safe procedure in these situations. The patient was premedicated and given a graded dose challenge of an alternative RCM (iodixanol) prior to the radiographic study. He was given 1% of the total expected dose 1 hour before to the procedure and an additional 10% for the 30 minutes prior. He was then given the final dose in the operating room. Following angiogram, the patient was monitored for 18 hours in the postanesthesia care unit, with no adverse reactions. He was placed on a prednisone taper for 1 week, with daily diphenhydramine. The patient remained asymptomatic throughout the hospital course. This novel approach to RCM hypersensitivity management lends itself to a hope that graded dose challenges may play a greater role in the management of these patients.

Polymorphous Light Eruption.

Polymorphous light eruption (PLE) is the commonest immuno-mediated photodermatosis. It occurs after solar or artificial UV-light exposure and affects only the sun-exposed areas with preference of the V-area of the chest, of arms and forearms, legs, upper part of the back, and rarely the face. The lesions are itching or burning, and vary morphologically from erythema to papules, vesico-papules and occasionally blisters, plaques, sometimes erythema multiforme-like, insect bite-like wheals and purpura. The clinical manifestations befall within a few hours to days from light exposure, last a few days, and subside in about a week without sequelae. Its diagnosis is based on history, morphology and phototests. PLE is considered as a delayed hypersensitivity response to newly UV induced, but still unidentified, antigen(s). Usually, MED is normal, but the provocative phototests with UVA or UVB reproduce the spontaneous lesions in about 50% of the patients. Broad spectrum sunscreens and antioxidants, photohardening with PUVA or narrow band UVB may be beneficial to prevent the disease. Therapy is based mainly on topical or systemic corticosteroids.

Positive Skin Test or Specific IgE to Penicillin Does Not Reliably Predict Penicillin Allergy.

INTRODUCTION: According to guidelines, patients are diagnosed with penicillin allergy if skin test (ST) result or specific IgE (s-IgE) to penicillin is positive. However, the true sensitivity and specificity of these tests are presently not known. OBJECTIVE: To investigate the clinical relevance of a positive ST result and positive s-IgE and to study the reproducibility of ST and s-IgE. METHODS: A sample of convenience of 25 patients with positive penicillin ST results, antipenicillin s-IgE results, or both was challenged with their culprit penicillin. Further 19 patients were not challenged, but deemed allergic on the basis of a recent anaphylactic reaction or delayed reactions to skin testing. Another sample of convenience of 18 patients, 17 overlapping with the 25 challenged, with initial skin testing and s-IgE (median, 25; range, 3-121), months earlier (T-1), was repeat skin tested and had s-IgE measured (T0), and then skin tested and had s-IgE measured 4 weeks later (T1). RESULTS: Only 9 (36%) of 25 were challenge positive. There was an increased probability of being penicillin allergic if both ST result and s-IgE were positive at T0. Positive ST result or positive s-IgE alone did not predict penicillin allergy. Among the 18 patients repeatedly tested, 46.2% (12 of 25) of positive ST results at T-1 were reproducibly positive at T0. For s-IgE, 54.2% (14 of 24) positive measurements were still positive at T0 and 7 converted to positive at T1. CONCLUSIONS: The best predictor for a clinically significant (IgE-mediated) penicillin allergy is a combination of a positive case history with simultaneous positive ST result and s-IgE or a positive challenge result.

Patients Taking Amoxicillin-Clavulanic Can Become Simultaneously Sensitized to Both Drugs.

BACKGROUND: Patients can react to amoxicillin (AX) and clavulanic acid (CLV) taken in combination because of selective reactions to either drug. However, scant information exists concerning patients who react simultaneously to both compounds. OBJECTIVE: To analyze the mechanisms involved in 4 patients who developed allergic reactions to AX-CLV administration (3 with immediate IgE-mediated reaction and 1 with nonimmediate T-cell-mediated reaction) and who responded specifically to both AX and CLV. METHODS: Skin tests with benzylpenicillin (BP), AX, and CLV were done and, if necessary, drug provocation tests with BP/penicillin V, AX, and AX-CLV were carried out. In immediate reactors, serum specific IgE to benzylpenicilloyl and amoxicilloyl was determined by using the CAP-FEIA system (Pharmacia Diagnostics, Uppsala, Sweden), and basophil activation test to BP, AX, CLV, and AX-CLV was done. In nonimmediate reactors, immunohistochemistry of skin biopsy and analysis of dendritic cell maturation and T-cell-specific response to BP, AX, CLV, and AX-CLV at both acute and resolution phases of the reaction were conducted. RESULTS: All patients with immediate reactions (N = 3) had good tolerance to BP and penicillin V. Two cases also had specific IgE to AX and all had a basophil activation test positive to AX, CLV, and AX-CLV. The patient with a nonimmediate reaction exhibited dendritic cell and T-lymphocyte responses specific to both AX and CLV. Finally, the analysis of the cells infiltrating the skin and peripheral blood during the acute phase indicated a TH1 pattern response. CONCLUSIONS: Our study provides evidence that reactions to both AX and CLV can appear in the same patient.

A novel preservative-free seasonal influenza vaccine safety and immune response study in the frame of preclinical research.

The paper describes the results of preclinical testing of the preparation "Vaccine allantoic split-virus inactivated against seasonal influenza." Acute toxicity and local irritating effect, anaphylactic reactions to different antigens (vaccine and ovalbumin), delayed-type hypersensitivity to ram erythrocytes, humoral immune response in hemaggtination reaction, immunogenic activity was studied in laboratory animals of various species (mice, rats, guinea pigs). Comparative analysis of the results from testing immunogenic activity of the preparation under study and the commercial influenza vaccines was performed. The preclinical testing has demonstrated safety and immune response of the seasonal split influenza vaccine, so it may be recommended for clinical study on limited contingent of volunteers.

[Triggers of exanthematous drug eruptions: Stop intake, treat through or desensitization?] / Auslöser von Arzneiexanthemen: Absetzen, durchbehandeln oder desensibilisieren?

Drug hypersensitivity reactions affect over 7% of the population and are problematic both for patients and doctors. They frequently occur in the form of exanthematous drug eruptions. The clinical manifestation of delayed hypersensitivity reactions is very variable ranging from localized fixed drug eruptions to life-threatening, severe bullous mucocutaneous eruptions or systemic drug hypersensitivity syndromes. In the case of suspicion of an exanthematous drug eruption, the causality should initially be assessed according to the proposed algorithm. If both the chronology and the clinical symptoms are indicative of a delayed drug hypersensitivity reaction, the suspected drug should be avoided. Only in cases of urgent therapeutic indications and if alternative drugs are not available, the options of "treating through" and temporary tolerance induction by "desensitization" should be considered after an individual risk-benefit analysis.

Immunomodulatory activity of Buchholzia coriacea seed methanol extract on Trypanosoma brucei brucei infected mice.

CONTEXT: The seeds of Buchholzia coriacea Engler (Capparaceae) are used in Eastern Nigeria to treat feverish conditions, and to treat malaria and sleeping sickness that cause fever. OBJECTIVE: The current study assesses the immunomodulatory activity of Buchholzia coriacea seed extract on Trypanosoma brucei brucei infected mice. MATERIALS AND METHODS: Delayed hypersensitivity reaction, humoral antibody response and in-vivo leucocyte mobilization tests were assessed in three different experiments to determine the effect of the extract on immune response. Seventy-five (75) mice (25 mice per experiment) were used for the study and were each infected with 1.00 × 106 trypanosomes intra-peritoneally. Groups A, B and C were given 250, 500 and 1000 mg/kg of the extract, respectively, group D received 7.5 mg/kg body weight of levamisole and group E was the control. Sheep RBCs were used as antigen. RESULTS: The acute toxicity tests did not cause clinical signs or death within 24 h post treatment at all the doses tested. The extract inhibited delayed hypersensitivity reaction by 20.9 and 20.8% at 250 and 500 mg/kg, respectively, while at 1000 mg/kg, the paw size increased (-101.9%) when compared with the control. The extract elevated the antibody titre from 1.60 ± 0.40 for control to 8.00 ± 3.58 for 500 mg/kg group. The extract increased in total leucocytes counts. DISCUSSION AND CONCLUSION: The extract has a very wide safety margin and was able to improve immune response. The results of the present study showed that Buchholzia coriacea seed methanol extract possesses immunostimulatory activity on trypanosome-infected mice.

Aged garlic extract ameliorates immunotoxicity, hematotoxicity and impaired burn-healing in malathion- and carbaryl-treated male albino rats.

Malathion and carbaryl are the most widely used organophosphate and carbamate insecticides, respectively, especially in developing countries; they pose a potential health hazard for both humans and animals. Here, we evaluated the protective effects of an odorless (free from allicin) Kyolic aged garlic extract (AGE, containing 0.1% S-allylcysteine; 200 mg/kg body weight) on the toxicity induced by 0.1 LD50 of malathion (89.5 mg/kg body weight) and/or carbaryl (33.9 mg/kg body weight) in male Wistar rats. Doses were orally administered to animals for four consecutive weeks. The present study showed that AGE completely modulated most adverse effects induced by malathion and/or carbaryl in rats including the normocytic normochromic anemia, immunosuppression, and the delay in the skin-burning healing process through normalizing the count of blood cells (erythrocytes, leucocytes and platelets), hemoglobin content, hematocrit value, blood glucose-6-phosphodehydrogenase activity, weights and cellularity of lymphoid organs, serum γ-globulin concentration, and the delayed type of hypersensitivity response to the control values, and accelerating the inflammatory and proliferative phases of burn-healing. In addition, AGE completely modulated the decrease in serum reduced glutathione (GSH) concentration and the increase in clotting time in malathion alone and carbaryl alone treated rats. Moreover, AGE induced a significant increase (P < 0.001) in serum GSH concentration (above the normal value) and accelerating burn-healing process in healthy rats. In conclusion, AGE was effective in modulating most adverse effects induced in rats by malathion and carbaryl, and hence may be useful as a dietary adjunct for alleviating the toxicity in highly vulnerable people to insecticides intoxication. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 789-798, 2017.

Immunoregulatory effects of 4-(4-chlorophenyl)-1-(5-amino-3-methylisoxazole-4-carbonyl)-thiosemicarbazide (06K) in non-immunized and SRBC-immunized mice.

OBJECTIVES: Immunoregulatory properties of 06K derivative (4-(4-chlorophenyl)-1-(5-amino-3-methylisoxazole-4-carbonyl)-thiosemicarbazide) in mouse in vivo models were investigated. METHODS: Several in vivo models were used: humoral and cellular immune response, carrageenan inflammatory reaction and determination of lymphocyte subsets in non-immunized mice. KEY FINDINGS: The compound administered before or after immunization with sheep erythrocytes (sheep red blood cell (SRBC)) elevated the number of plaque-forming cells (PFC), and this effect was stronger at lower doses. Although total haemagglutinin titres to SRBC decreased upon postimmunization treatment, IgG titre increased. In the model of delayed-type hypersensitivity (DTH) to ovalbumin (OVA), the compound, applied intraperitoneally before an eliciting dose of an antigen but not before immunization, inhibited the magnitude of a cutaneous reaction. Further, 06K significantly diminished carrageenan-induced foot pad inflammation when administered 1 h before carrageenan. The compound, administered intraperitoneally to naïve mice, elicited changes in weight, cell number in lymphoid organs and content of lymphocyte subsets, depending on the dose and number of applications. Phenotypic changes included increased turnover of thymocytes, changes in B-cell distribution in spleens and lymph nodes, increased percentage of CD8+ cells and regulatory CD4+ CD25+ Foxp3+ T cells. CONCLUSIONS: Immunoregulatory properties of 06K involve mobilization of lymphopoiesis and generation of regulatory T cells.

Patients with breakthrough reactions to iodinated contrast media have low incidence of positive skin tests.

BACKGROUND: The term "breakthrough reactions" designates repeated hypersensitivity reactions to iodinated contrast media (ICM) despite premedication with glucocorticoids and antihistamines. We aimed to retrospectively evaluate the rate of positive skin test (STs) in our cohort of patients with previous breakthrough reactions to different ICMs. METHODS: A series of 35 patients, who experienced at least one breakthrough reaction to ICM and who underwent STs within 6 months from the reaction were studied, and results were compared to a control group of patients with a first hypersensitivity reaction occurred without premedication. Skin prick tests (SPT), intradermal tests (IDT) and patch tests (PT) at different dilutions, with a set of three to four ICM were performed. RESULTS: Of the 35 patients with prior breakthrough reactions, 57% had an immediate reaction (IR) and 43% had a non-immediate reaction (NIR). Patients who experienced the first hypersensitivity IR or NIR, later had one or more breakthrough IR or NIR, respectively. Overall, 29% (10/35) of patients with prior breakthrough reactions resulted positive to STs compared to 57% (16/28) of the control group (p < 0.05). No significant difference in allergy history, age, sex, other clinical / demographic features nor chronic use of ACE-inhibitor, beta-blockers or NSAIDs was observed. CONCLUSION: This preliminary finding suggests that patients with prior breakthrough reactions have significantly lower immunologically proven ICM reactions (positive STs) if compared to non-breakthrough patients. According to that, a considerable number of breakthrough reactions seems to be non-allergic hypersensitivity reactions or reactions which could be mostly prevented by a proper, well-timed skin testing. Larger prospective studies are needed to confirm these results, with a more careful analysis of patients' risk factors, a laboratory assessment that includes an in vitro allergy diagnostics, and hopefully a drug provocation test for selected cases.