Project description:Background:Antivenoms are the only validated treatment against snakebite envenoming. Numerous drawbacks pertaining to their availability, safety and efficacy are becoming increasingly evident due to low sustainability of current productions. Technological innovation of procedures generating therapeutics of higher purity and better physicochemical characteristics at acceptable cost is necessary. The objective was to develop at laboratory scale a compact, feasible and economically viable platform for preparation of equine F(ab')2 antivenom against Vipera ammodytes ammodytes venom and to support it with efficiency data, to enable estimation of the process cost-effectiveness. Methods:The principle of simultaneous caprylic acid precipitation and pepsin digestion has been implemented into plasma downstream processing. Balance between incomplete IgG breakdown, F(ab')2 over-digestion and loss of the active drug's protective efficacy was achieved by adjusting pepsin to a 1:30 substrate ratio (w/w) and setting pH at 3.2. Precipitation and digestion co-performance required 2 h-long incubation at 21 °C. Final polishing was accomplished by a combination of diafiltration and flow-through chromatography. In vivo neutralization potency of the F(ab')2 product against the venom's lethal toxicity was determined. Results:Only three consecutive steps, performed under finely tuned conditions, were sufficient for preservation of the highest process recovery with the overall yield of 74%, comparing favorably to others. At the same time, regulatory requirements were met. Final product was aggregate- and pepsin-free. Its composition profile was analyzed by mass spectrometry as a quality control check. Impurities, present in minor traces, were identified mostly as IgG/IgM fragments, contributing to active drug. Specific activity of the F(ab')2 preparation with respect to the plasma was increased 3.9-fold. Conclusion:A highly streamlined mode for production of equine F(ab')2 antivenom was engineered. In addition to preservation of the highest process yield and fulfillment of the regulatory demands, performance simplicity and rapidity in the laboratory setting were demonstrated. Suitability for large-scale manufacturing appears promising.
Project description:Backgroundβ-lactam antibiotics are associated with a variety of immune-mediated or hypersensitivity reactions, including immediate (type I) reactions mediated by antigen-specific IgE.ObjectiveWe sought to identify genetic predisposing factors for immediate reactions to β-lactam antibiotics.MethodsPatients with a clinical history of immediate hypersensitivity reactions to either penicillins or cephalosporins, which were immunologically confirmed, were recruited from allergy clinics. A genome-wide association study was conducted on 662 patients (the discovery cohort) with a diagnosis of immediate hypersensitivity and the main finding was replicated in a cohort of 98 Spanish cases, recruited using the same diagnostic criteria as the discovery cohort.ResultsGenome-wide association study identified rs71542416 within the Class II HLA region as the top hit (P = 2 × 10-14); this was in linkage disequilibrium with HLA-DRB1∗10:01 (odds ratio, 2.93; P = 5.4 × 10-7) and HLA-DQA1∗01:05 (odds ratio, 2.93, P = 5.4 × 10-7). Haplotype analysis identified that HLA-DRB1∗10:01 was a risk factor even without the HLA-DQA1∗01:05 allele. The association with HLA-DRB1∗10:01 was replicated in another cohort, with the meta-analysis of the discovery and replication cohorts showing that HLA-DRB1∗10:01 increased the risk of immediate hypersensitivity at a genome-wide level (odds ratio, 2.96; P = 4.1 × 10-9). No association with HLA-DRB1∗10:01 was identified in 268 patients with delayed hypersensitivity reactions to β-lactams.ConclusionsHLA-DRB1∗10:01 predisposed to immediate hypersensitivity reactions to penicillins. Further work to identify other predisposing HLA and non-HLA loci is required.
Project description:The European continent is inhabited by medically important venomous Viperinae snakes. Vipera ammodytes, Vipera berus, and Vipera aspis cause the greatest public health problems in Europe, but there are other equally significant snakes in specific regions of the continent. Immunotherapy is indicated for patients with systemic envenoming, of which there are approximately 4000 annual cases in Europe, and was suggested as an indication for young children and pregnant women, even if they do not have systemic symptoms. In the present study, the safety and venom-neutralizing efficacy of Inoserp Europe-a new F(ab')₂ polyvalent antivenom, designed to treat envenoming by snakes in the Eurasian region-were evaluated. In accordance with World Health Organization recommendations, several quality control parameters were applied to evaluate the safety of this antivenom. The venom-neutralizing efficacy of the antivenom was evaluated in mice and the results showed it had appropriate neutralizing potency against the venoms of several species of Vipera, Montivipera, and Macrovipera. Paraspecificity of the antivenom was demonstrated as well, since it neutralized venoms of species not included in the immunization schemes and contains satisfactory levels of total proteins and F(ab')₂ fragment concentration. Therefore, this new polyvalent antivenom could be effective in the treatment of snake envenoming in Europe, including Western Russia and Turkey.
Project description:Kovax® antivenom is the main treatment for toxins produced by the Gloydius species. However, research on adverse reactions after Kovax® antivenom administration is scarce. We aimed to identify the incidence and characteristics of adverse reactions after Kovax® antivenom administration. We conducted a retrospective review of the medical records of snakebite patients in Korea between January 2008 and September 2019. We identified the frequency, characteristics, and treatments of adverse reactions to Kovax® antivenom. There were 150 patients with snakebites, of whom 121 (80.7%) patients received Kovax® antivenom. Adverse reactions occurred in five patients (4.1%). Acute adverse reactions within 24 h of antivenom administration occurred in two patients (1.7%). The symptoms of patients with acute adverse reactions were nausea, diaphoresis, dizziness, and hypotension. Delayed adverse reactions that occurred 24 h after antivenom administration were reported in three patients (2.5%). One patient had a skin rash after 10 days, and two patients had fever 37 and 48 h after antivenom use. In conclusion, most patients were managed safely after Kovax® antivenom, and the incidence of adverse reactions was low. Severe adverse reactions occurred in a small percentage of patients, and there were no deaths.
Project description:IntroductionAlpha-gal syndrome (AGS) is characterized by delayed hypersensitivity to non-primate mammalian meat in people having specific immunoglobulin E (sIgE) to the oligosaccharide galactose-alpha-1,3-galactose. AGS has been linked to tick bites from Amblyomma americanum (Aa) in the U.S. A small animal model of meat allergy is needed to study the mechanism of alpha-gal sensitization, the effector phase leading to delayed allergic responses and potential therapeutics to treat AGS.MethodsEight- to ten-weeks old mice with a targeted inactivation of alpha-1,3-galactosyltransferase (AGKO) were injected intradermally with 50 μg of Aa tick salivary gland extract (TSGE) on days 0, 7, 21, 28, 42, and 49. Total IgE and alpha-gal sIgE were quantitated on Day 56 by enzyme-linked immunosorbent assay. Mice were challenged orally with 400 mg of cooked pork kidney homogenate or pork fat. Reaction severity was assessed by measuring a drop in core body temperature and scoring allergic signs.ResultsCompared to control animals, mice treated with TSGE had 190-fold higher total IgE on Day 56 (0.60 ± 0.12 ng/ml vs. 113.2 ± 24.77 ng/ml; p < 0.001). Alpha-gal sIgE was also produced in AGKO mice following TSGE sensitization (undetected vs. 158.4 ± 72.43 pg/ml). Further, sensitized mice displayed moderate clinical allergic signs along with a drop in core body temperature of ≥2°C as an objective measure of a systemic allergic reaction. Interestingly, female mice had higher total IgE responses to TSGE treatment but male mice had larger declines in mean body temperature.ConclusionTSGE-sensitized AGKO mice generate sIgE to alpha-gal and demonstrate characteristic allergic responses to pork fat and pork kidney. In keeping with the AGS responses documented in humans, mice reacted more rapidly to organ meat than to high fat pork challenge. This mouse model establishes the central role of tick bites in the development of AGS and provides a small animal model to mechanistically study mammalian meat allergy.
Project description:BACKGROUND:Dentine hypersensitivity (DH) can occur after gum recession or enamel loss and may impact quality of life. Treatments include toothpastes that decrease DH by occluding dentine tubules. One effective occluding ingredient used in toothpastes is stannous fluoride (SnF2), but this can be unstable in aqueous formulation. These three studies aimed to characterise the short-term effects of an experimental, anhydrous SnF2 dentifrice on DH. METHODS:Three examiner-blind, parallel-group studies evaluated DH in participants with the condition after a single brushing and after 3d brushing with an experimental anhydrous 0.454% SnF2/polyphosphate toothpaste (Test) or a toothpaste containing 0.76% sodium monofluorophosphate (Control). Test treatment participants brushed two pre-identified sensitive teeth first, then their remaining dentition for ?1?min ('focused brushing'). Control treatment participants brushed their whole dentition for ?1?min. DH was measured after single brushing and after 3d twice-daily use, via evaporative (air) (Schiff Sensitivity Scale) and tactile (Yeaple probe) stimuli and analysed using an ANCOVA model. RESULTS:In all studies, after 3d treatment, the Test toothpaste/brushing regimen significantly reduced DH compared to the Control regimen by both evaporative and tactile stimuli assessment (p <?0.0001 for all). The Test regimen also significantly reduced DH from baseline at both time-points by both measures in all studies (p?<?0.0001 for all). Mean Schiff sensitivity score differences (95% confidence intervals) between Test and Control regimens after 3d were: Study 1: -?0.45 (-?0.577, -?0.319); Study 2: -?0.40 (-?0.505, -?0.300); Study 3: -?1.31 (-?1.500, -?1.128). Mean tactile score differences were: Study 1: 11.30 (7.927, 14.662); Study 2: 3.57 (2.531, 4.614); Study 3: 24.54 (20.349, 28.736). After single use, in Studies 2 and 3, the Test toothpaste/brushing regimen significantly reduced DH versus Control by both measures (p <?0.001 for all); in Study 1, treatment differences were not significant. Toothpastes were generally well-tolerated. CONCLUSIONS:Taken together, these studies indicated focused brushing with an experimental anhydrous 0.454% SnF2/polyphosphate toothpaste reduces DH compared to brushing with a conventional toothpaste after single use, with greater reduction after 3d. TRIAL REGISTRATION:Registrations at ClinicalTrials.gov : Study 1: NCT02832375 (registered 26.July.2016); Study 2: NCT02731833 (registered 26.April.2016); Study 3: NCT02923895 (registered 5.October.2016).
Project description:Diagnosing and treating acute severe and recurrent antivenom-related anaphylaxis (ARA) is challenging and reported experience is limited. Herein, we describe our experience of severe ARA in patients with neurotoxic snakebite envenoming in Nepal. Patients were enrolled in a randomised, double-blind trial of high vs. low dose antivenom, given by intravenous (IV) push, followed by infusion. Training in ARA management emphasised stopping antivenom and giving intramuscular (IM) adrenaline, IV hydrocortisone, and IV chlorphenamine at the first sign/s of ARA. Later, IV adrenaline infusion (IVAI) was introduced for patients with antecedent ARA requiring additional antivenom infusions. Preantivenom subcutaneous adrenaline (SCAd) was introduced in the second study year (2012). Of 155 envenomed patients who received ≥ 1 antivenom dose, 13 (8.4%), three children (aged 5-11 years) and 10 adults (18-52 years), developed clinical features consistent with severe ARA, including six with overlapping signs of severe envenoming. Four and nine patients received low and high dose antivenom, respectively, and six had received SCAd. Principal signs of severe ARA were dyspnoea alone (n=5 patients), dyspnoea with wheezing (n=3), hypotension (n=3), shock (n=3), restlessness (n=3), respiratory/cardiorespiratory arrest (n=7), and early (n=1) and late laryngeal oedema (n=1); rash was associated with severe ARA in 10 patients. Four patients were given IVAI. Of the 8 (5.1%) deaths, three occurred in transit to hospital. Severe ARA was common and recurrent and had overlapping signs with severe neurotoxic envenoming. Optimising the management of ARA at different healthy system levels needs more research. This trial is registered with NCT01284855.