Boiling down the cysteine-stabilized LTP fold - loss of structural and immunological integrity of allergenic Art v 3 and Pru p 3 as a consequence of irreversible lanthionine formation.

BACKGROUND: Non-specific lipid transfer proteins (LTPs) are important allergens in fruits, pollen, vegetables, nuts and latex. Due to their compact structure, LTPs are highly resistant to heat treatment. Here, Art v 3 from mugwort pollen and Pru p 3 from peach were used as model allergens to in-depth investigate structural and immunological properties upon thermal treatment at different buffer conditions. METHODS: Recombinant Art v 3 and Pru p 3 were purified from E. coli and incubated at 95 °C up to 120 min using sodium phosphate buffer pH 3.4 or 7.3. Physicochemical properties of allergens were analyzed in circular dichroism spectroscopy, Fourier transform infrared spectroscopy, dynamic light scattering, size exclusion chromatography, and mass spectrometry. The crystal structure of Art v 3.0201 was determined to 1.9 Šresolution. IgG and IgE binding was investigated in ELISA using murine and LTP allergic patients' sera. RESULTS: Highly pure and homogenous recombinant allergens were obtained from bacterial production. The crystal structure of Art v 3.0201 revealed an antiparallel four helix bundle with a C-terminal extension mediating an asymmetric, transient dimer interface and differently sized cavities. Both allergens showed high thermal stability at acidic conditions. In contrast, extensive heat treatment in neutral buffer induced irreversible structural changes due to lanthionine-based cysteine rearrangement. This fostered loss of the typical α-helical structure, increased molecular size and abrogation of IgG and IgE binding epitopes. Pru p 3 lost its structural integrity at shorter heat stress duration than Art v 3, which did however only partially affect the molecule's IgE binding epitopes. CONCLUSION: During thermal treatment, susceptibility to structural changes of the LTP-fold is highly dependent on the surrounding environment but also on intrinsic features of individual LTPs. This is a crucial fact to consider when processing LTP-containing food or food products as this will directly influence their allergenic potential.

A Case of Pantoprazole Anaphylaxis with Cross Reactivity to All Proton Pump Inhibitors: Finding a Safe Alternative.

BACKGROUND: Hypersensitivity reactions due to Proton pump inhibitors (PPIs ) are rare, and further anaphylaxis to a PPI with cross-reactivity to all commercially available PPIs is very rare. OBJECTIVE: To present a case of anaphylaxis to pantoprazole with cross-reactivity to all commercially available PPIs. METHODS: Skin prick tests (SPTs), intradermal tests (IDTs) and oral provocation tests (OPTs) were performed with available PPIs according to the method described in previous studies. RESULTS: All tested PPIs except lansoprazole were positive on skin tests either SPT or IDT. The patient was challenged with lansoprazole at increasing doses (7.5 mg, 15 mg, 30 mg capsule) every 60 minutes and she reacted with urticaria to 52.5 mg cumulative dose of lansoprazole. She could tolerate ranitidine and famotidine tablets via OPT. CONCLUSION: In our best knowledge, our case was the first case in this regard and that points the possibility of all cross-reactive pattern in patients with pantoprazole anaphylaxis and the importance of a thorough drug allergy work-up for finding safe alternatives. H2 receptor antagonists are used as safe alternatives in cases with PPI hypersensitivity.

A relevant IgE-reactive 28kDa protein identified from Salsola kali pollen extract by proteomics is a natural degradation product of an integral 47kDa polygalaturonase.

A highly prevalent IgE-binding protein band of 28kDa is observed when Salsola kali pollen extract is incubated with individual sera from Amaranthaceae pollen sensitized patients. By an immunoproteomic analysis of S. kali pollen extract, we identified this protein band as an allergenic polygalacturonase enzyme. The allergen, named Sal k 6, exhibits a pI of 7.14 and a molecular mass of 39,554.2Da. It presents similarities to Platanaceae, Poaceae, and Cupressaceae allergenic polygalacturonases. cDNA-encoding sequence was subcloned into the pET41b vector and produced in bacteria as a His-tag fusion recombinant protein. The far-UV CD spectrum determined that rSal k 6 was folded. Immunostaining of the S. kali pollen protein extract with a rSal k 6-specific pAb and LC-MS/MS proteomic analyses confirmed the co-existence of the 28kDa band together with an allergenic band of about 47kDa in the pollen extract. Therefore, the 28kDa was assigned as a natural degradation product of the 47kDa integral polygalacturonase. The IgE-binding inhibition to S. kali pollen extract using rSal k 6 as inhibitor showed that signals directed to both protein bands of 28 and 47kDa were completely abrogated. The average prevalence of rSal k 6 among the three populations analyzed was 30%, with values correlating well with the levels of grains/m3 of Amaranthaceae pollen. Sal k 6 shares IgE epitopes with Oleaceae members (Fraxinus excelsior, Olea europaea and Syringa vulgaris), with IgE-inhibition values ranging from 20% to 60%, respectively. No IgE-inhibition was observed with plant-derived food extracts.

Defensive and Offensive Cross-Reactive Antibodies Elicited by Pathogens: The Good, the Bad and the Ugly.

Understanding how immunity to pathogens develops is crucial for progress in the quest for effective vaccines. Intraspecies and interspecies cross-reacting antibodies are produced in high frequency against immune-relevant and shared microbial epitopes. It has been confirmed that cross-reactive antigens may have a crucial role in natural epidemiology to a particular infection and that cross-protection may influence the outcome of natural infections. On the other hand, the action of cross-reactive antibodies may be very harmful for the host. In this review we discuss both the defensive and offensive capabilities of cross-reactive antibodies. The defensive properties are discussed with regard to the beneficial cross-protective interaction of these antibodies against various microorganisms including viruses, bacteria, fungi and protozoan parasites. We summarize the current knowledge of numerous effector functions of these antibodies such as agglutination, neutralization of infectivity, complement activation, phagocytosis enhancement, and antibody-dependent cellular cytotoxicity. We also discuss the offensive action of cross-reactive antibodies including their detrimental effects in exacerbation of the infective diseases, as well as autoimmune diseases and allergy as a result of inappriopriate or deleterious inflammatory response associated with host tissue destruction. The factors influencing cross-protective capacity of antibodies are also presented.

Cross-Reactivity of Chloroquine and Hydroxychloroquine With DRI Amphetamine Immunoassay.

BACKGROUND: Chloroquine and hydroxychloroquine are medical drugs used to treat the chemoprophylaxis of malaria and a second-line anti-inflammatory drug. METHODS: We performed a study of cross-reactivity of chloroquine and hydroxychloroquine in the DRI Amphetamine Assay inspired by a case report of a self-ingestion of chloroquine after a family dispute, that involved the following: (1) an in vitro study with control samples of healthy subjects, (2) an in vivo study with samples of patients with rheumatoid arthritis, and (3) an evaluation of the cross-reactivity of chloroquine and hydroxychloroquine in 3 additional immunoassays. RESULTS: In the case report, the Amphetamine DRI assay resulted positive both at 1000 ng/mL cutoff (1507 and 1137 ng/mL) and at 500 ng/mL cutoff (1178 and 642 ng/mL). Chloroquine urine levels were 103,900 and 100,900 ng/mL at 5 and 9 hours after ingestion. The results with control samples showed a positive cross-reactivity of chloroquine in the DRI Amphetamine Assay (approximately 0.74% and 0.89% at cutoff of 1000 and 500 ng/mL, respectively). Hydroxychloroquine did not cross-react with the DRI Amphetamine Assay up to 1,000,000 ng/mL. In patients treated with chloroquine or hydroxychloroquine, DRI Amphetamine did not produce false-positive results. The comparative assay study showed a positive cross-reactivity of chloroquine in the Emit II Plus Amphetamines Assay with control samples. CONCLUSIONS: Chloroquine can cause false-positive results in the DRI Amphetamine Assay when it is present at high concentrations. Hydroxychloroquine did not produce false-positive results neither in the DRI Amphetamine Assay nor in the others immunoassays evaluated.

Unexplained increases in serum vancomycin concentration in a morbidly obese patient.

INTRODUCTION: To report a case of increases in vancomycin concentrations without additional vancomycin doses being given. CASE STUDY: A 64 year-old morbidly obese female received three total doses of vancomycin for surgical prophylaxis and for ventilator-associated pneumonia. Subsequent vancomycin concentrations from the patient's central venous catheter (CVC) demonstrated increasing drug levels from 27.1 to 45.9mcg/mL despite no additional vancomycin being given and proper line flushing prior to sample collection. There is no clear explanation for the increase in the patient's vancomycin concentration. Drug leaching from the CVC, enterohepatic recycling, drug redistribution from adipose or other tissues, and assay cross-reactivity with other medications are all potential explanations for the increased vancomycin concentrations. CONCLUSION: This case report describes an unexplained increase in vancomycin concentrations and reinforces both the fallibility of laboratory testing and that unusual circumstances do occur. Several potential causes are hypothesised with CVC drug leaching being the most likely. Nurses and other healthcare providers with similar scenarios should consider a peripheral blood sample to rule out the potential for CVC drug leaching as a possible explanation.

Comparison of Three Assays to Quantify Infliximab, Adalimumab, and Etanercept Serum Concentrations.

BACKGROUND: To optimize treatment of inflammatory diseases, interest in the measurement of anti-tumor necrosis factor alpha (anti-TNFα) serum drug concentrations is increasing. Preferably, assays for the detection of these drugs should be compared using the same reference material. In this study, 2 commercially available enzyme-linked immunosorbent assays (ELISAs) and a commercially available bioassay for the determination of anti-TNFα drugs are compared. METHODS: Serum samples from infliximab-, adalimumab-, and etanercept-treated patients, control samples from ustekinumab-treated patients, and healthy donors were obtained. ELISAs manufactured by Sanquin and Theradiag and the iLite reporter gene-based bioassay from Biomonitor were compared. RESULTS: Sanquin, Theradiag, and iLite assays concordantly (100%) detected infliximab, adalimumab, and etanercept in the relevant patient groups. The Sanquin ELISAs specifically detected the anti-TNFα drug they were designed for, whereas the Theradiag and iLite showed cross-reactivity with other anti-TNFα drugs. Ustekinumab was not detected in any of the assays. Sanquin, Theradiag, and iLite exhibited linear quantitative correlation for all drug concentration assays. However, there were statistically significant quantitative differences in measured concentrations. CONCLUSIONS: All 3 commercially available assays seem suitable for therapeutic drug monitoring of anti-TNFα drugs, allowing sensitive and comparable detection of infliximab, adalimumab, and etanercept concentrations, however with differences in specificity and recovery.

Effects of a higher dose of alglucosidase alfa on ventilator-free survival and motor outcome in classic infantile Pompe disease: an open-label single-center study.

BACKGROUND: Though enzyme-replacement therapy (ERT) with alglucosidase alfa has significantly improved the prospects for patients with classic infantile Pompe disease, some 50 % of treated infants do not survive ventilator-free beyond the age of 3 years. We investigated whether higher and more frequent dosing of alglucosidase alfa improves outcome. METHODS: Eight cross-reactive immunological material (CRIM) positive patients were included in the study. All had fully deleterious mutations in both GAA alleles. Four received a dose of 20 mg/kg every other week (eow) and four received 40 mg/kg/week. Survival, ventilator-free survival, left-ventricular mass index (LVMI), motor outcome, infusion-associated reactions (IARs), and antibody formation were evaluated. RESULTS: All eight patients were alive at study end, seven of them remained ventilator-free. The patient who became ventilator dependent was treated with 20 mg/kg eow. Three of the four patients receiving 20 mg/kg eow learned to walk; two of them maintained this ability at study end. All four patients receiving 40 mg/kg/week acquired and maintained the ability to walk at study end (ages of 3.3-5.6 years), even though their baseline motor functioning was poorer. There were no apparent differences between the two dose groups with respect to the effect of ERT on LVMI, the number of IARs and antibody formation. CONCLUSIONS: Our data may suggest that a dose of 40 mg/kg/week improves outcome of CRIM positive patients over that brought by the currently recommended dose of 20 mg/kg eow. Larger studies are needed to draw definite conclusions.

Valoración de anticuerpos con reactividad cruzada patógeno-huésped en pacientes con diferentes estadios de cardiopatía chagásica crónica / Assessment of cross-reactive host-pathogen antibodies in patients with different stages of chronic Chagas disease

Introducción y objetivos. La infección por Trypanosoma cruzi induce una respuesta autoinmunitaria humoral contra diferentes antígenos del huésped. En especial, los anticuerpos que presentan reactividad cruzada con antígenos del miocardio tienen un papel importante en el desarrollo de las formas graves de la cardiopatía chagásica crónica. En este trabajo se analiza la asociación del estadio clínico de la enfermedad con la presencia de autoanticuerpos en pacientes con cardiopatía chagásica crónica. Métodos. Estudio transversal con pacientes con serología positiva para enfermedad de Chagas, categorizados en tres grupos según la clasificación de cardiopatía chagásica de Storino et al. Se realizó a todas las personas incluidas un examen clínico completo y se usaron las muestras de suero para cuantificar los autoanticuerpos. Resultados. Todos los pacientes presentaron cantidades detectables de anti-p2Beta y anti B13; el anti-Na-K-ATPasa fue negativo en todos los casos. No se halló asociación significativa entre las alteraciones electrocardiográficas y los valores de autoanticuerpos. Los pacientes con cardiopatía chagásica en estadio III presentaron mayor concentración de anti-B13 y riesgo de mortalidad alto, lo que muestra una clara asociación entre el estadio de la enfermedad y la puntuación de mortalidad. Conclusiones. La concentración del autoanticuerpo anti-B13 fue significativamente mayor en los pacientes con cardiopatía chagásica en estadio III , lo que indica que este anticuerpo puede estar involucrado en la progresión de la enfermedad y podría usarse como marcador de mal pronóstico respecto a la afección cardiaca. Los resultados revelan también una importante correlación entre el anti-B13 y la insuficiencia cardiaca sintomática y la cardiomiopatía dilatada (AU)

Introduction and objectives. Trypanosoma cruzi infection has been shown to induce humoral autoimmune responses against host antigens tissues. Particularly, antibodies cross-reacting with myocardial antigens may play a role in the development of the severe forms of chronic Chagas disease. The aim of this study was to determine the association between clinical stage of the disease and the presence of autoantibodies in patients with chronic Chagasic disease. Methods. We performed a cross-sectional study in T. cruzi-seropositive patients divided into 3 groups according to the classic classification of chronic Chagas heart of Storino et al. All participants underwent complete clinical examination and their sera were used to measure autoantibody levels. Results. All patients had detectable levels of anti-p2Beta and anti-B13 autoantibodies but none had anti-Na-K-ATPase antibodies. No association was observed between electrocardiographic conduction disturbances and autoantibody levels. Patients with chronic Chagas disease stage III had the highest levels of anti-B13 antibodies and a high risk of mortality score, showing a clear association between disease stage and this score. Conclusions. Anti-B13 antibodies were significantly higher in chronic Chagas disease stage III patients, suggesting that these antibodies may be involved in disease progression and that they might be a useful marker of poor prognosis in terms of heart compromise. Our results also reveal an important correlation between the level of anti-B13 autoantibodies and symptomatic heart failure and/or dilated cardiomyopathy (AU)

Proteinaceous toxins from three species of scorpaeniform fish (lionfish Pterois lunulata, devil stinger Inimicus japonicus and waspfish Hypodytes rubripinnis): close similarity in properties and primary structures to stonefish toxins.

The crude toxins from three species of venomous fish (lionfish Pterois lunulata, devil stinger Inimicus japonicus and waspfish Hypodytes rubripinnis) belonging to the order Scorpaeniformes exhibited mouse-lethal, hemolytic, edema-forming and nociceptive activities. In view of the antigenic cross-reactivity with the stonefish toxins, the primary structures of the stonefish toxin-like toxins from the three scorpaeniform fish were determined by cDNA cloning using primers designed from the highly conserved sequences of the stonefish toxins. Based on the data obtained in gel filtration, immunoblotting and cDNA cloning, each toxin was judged to be a 160 kDa heterodimer composed of 80 kDa α- and ß-subunits. The three scorpaeniform fish toxins contain a B30.2/SPRY domain (∼200 amino acid residues) in the C-terminal region of each subunit, as reported for the toxins from two species of lionfish and two species of stonefish. With respect to the amino acid sequence similarity, the scorpaeniform fish toxins are divided into the following two groups: toxins from three species of lionfish and those from devil stinger, two species of stonefish and waspfish. The phylogenetic tree generated also clearly supports the classification of the toxins.

Improvement of shrimp allergy after sublingual immunotherapy for house dust mites: a case report.

The appropriateness of house dust mite specific immunotherapy in patients allergic to shrimps still remains unclear We present a clinical case as an immunological model for the strong sensitization to tropomyosin with symptoms of anaphylaxis due to shrimps and coexisting asthma due to house dust mite. The improvement in respiratory symptoms for house dust mite and in the food challenge for shrimps during mite immunotherapy with a known and high dosage of tropomyosin suggests the hypothesis that efficacy of mite immunotherapy in food allergy to tropomyosin may be dose dependent.

Survey results on the use of the tissue cross-reactivity immunohistochemistry assay.

A multinational pharmaceutical and biotechnology company survey was conducted to gain a better understanding of the use and value of the tissue cross-reactivity (TCR) assay in the development of biotherapeutic molecules. The majority of the molecules did not use TCR data as the only basis for determining species selection for toxicity studies (73%). For 95% of the molecules, the TCR data had no impact on the development strategy. For 2% of the molecules (1/56), TCR data was the sole source of information indicating a potential risk to patients. Unexpected or off-target binding was seen with 35% of the molecules, with the majority of this binding occurring in the CNS and reproductive organs. Tissues that were known or presumed to contain the target stained positively in 22% and 10% of molecules tested in non-human primate and human tissues, respectively. Tissues that were known or presumed to lack the target were negative for staining in 39% and 50% of molecules for non-human primate and human tissue, respectively. For 5% (6/110) of all the molecules, companies stated that toxicities would have been missed in animal studies or the clinic (i.e., not identified by clinical signs, histopathology, etc.) if the TCR studies had not been performed.

Development of a novel therapy for Lipo-oligosaccharide-induced experimental neuritis: use of peptide glycomimics.

Recent etiological studies have revealed that molecular mimicry between the lipo-oligosaccharide (LOS) component of Campylobacter jejuni and gangliosides of peripheral nervous system plays an important role in the pathogenesis of Guillain-Barré syndrome (GBS). Previously, we demonstrated GD3 ganglioside molecular mimicry in a model of GBS in Lewis rats by sensitization with GD3-like LOS (LOS(GD3)) from C. jejuni. Since the neuropathophysiological consequences were due largely to the anti-GD3-like antibodies, we subsequently focused our effort upon eliminating the pathogenic antibodies using several strategies to mimic GD3 in this model. Here, we have validated this strategy by the use of peptide glycomimics based on epitopic mimicry between carbohydrates and peptides. We treated rats by i.p. administration of phage-displayed GD3-like peptides. One GD3-like peptide (P(GD3)-4; RHAYRSMAEWGFLYS) induced in treated rats a remarkable restoration of motor nerve functions, as evidenced by improved histopathology, rotarod performance, and motor nerve conduction velocity. P(GD3)-4 effectively decreased the titer of anti-GD3/anti-LOS(GD3) antibodies and ameliorated peripheral nerve dysfunction in the sera of treated rats. The data suggest that peptide glycomimics of ganglioside may be potential powerful reagents for therapeutic intervention in GBS by neutralizing specific pathogenic anti-ganglioside antibodies.

Comparison of intravenous immunoglobulins for naturally occurring autoantibodies against amyloid-beta.

Intravenous immunoglobulins (IVIG) are currently used for therapeutic purposes in autoimmune disorders. Recently, we demonstrated the presence of naturally occurring antibodies against amyloid-beta (nAbs-Abeta) within the pool of IVIG. In this study, we compared different brands of IVIG for nAbs-Abeta and have found differences in the specificity of the nAbs-Abeta towards Abeta(1-40) and Abeta(1-42). We analyzed the influence of a pH-shift over the course of antibody storage using ELISA and investigated antibody dimerization at acidic and neutral pH as well as differences in the IgG subclass distributions among the IVIG using both HPLC and a nephelometric assay. Furthermore, we investigated the epitope region of purified nAbs-Abeta. The differences found in Abeta specificity are not directly proportionate to the binding nature of these antibodies when administered in vivo. This information, however, may serve as a guide when choosing the commercial source of IVIG for therapeutic applications in Alzheimer's disease.

Coexistence conditions for strains of influenza with immune cross-reaction.

The accumulation of cross-immunity in the host population is an important factor driving the antigenic evolution of viruses such as influenza A. Mathematical models have shown that the strength of temporary non-specific cross-immunity and the basic reproductive number are both key determinants for evolutionary branching of the antigenic phenotype. Here we develop deterministic and stochastic versions of one such model. We examine how the time of emergence or introduction of a novel strain affects co-existence with existing strains and hence the initial establishment of a new evolutionary branch. We also clarify the roles of cross-immunity and the basic reproductive number in this process. We show that the basic reproductive number is important because it affects the frequency of infection, which influences the long term immune profile of the host population. The time at which a new strain appears relative to the epidemic peak of an existing strain is important because it determines the environment the emergent mutant experiences in terms of the short term immune profile of the host population. Strains are more likely to coexist, and hence to establish a new clade in the viral phylogeny, when there is a significant time overlap between their epidemics. It follows that the majority of antigenic drift in influenza is expected to occur in the earlier part of each transmission season and this is likely to be a key surveillance period for detecting emerging antigenic novelty.

Carbohydrate epitopes as a cause of cross-reactivity in patients allergic to Hymenoptera venom.

BACKGROUND: Among patients with allergy to insect stings, double positivity in tests for IgE antibodies specific to honey bee and wasp venoms is a frequent diagnostic problem. True double sensitization and possible cross-reactivity of venom hyaluronidases and with carbohydrate determinants must be considered in such patients. We studied the frequency of sensitization to carbohydrate determinants and the role of these in double positivity in tests for specific IgE antibodies. MATERIALS AND METHODS: A group of 66 patients (41 men, 25 women; 16-66 years) with double positivity for wasp and bee venoms were tested in the FEIA inhibition test in order to distinguish true double sensitization from cross-reactivity. Patients were tested for the presence of IgE antibodies specific to oilseed rape (OSR) pollen and MUXF3 allergens, both of which are rich in cross-reacting carbohydrate epitopes. RESULTS: Inhibition tests revealed true double sensitization in 37 patients (56.1%) and cross-reactivity in 29. Among those showing cross-reactivity, five were sensitized to honey bee venom and 24 to wasp venom. The median value of IgE specific for OSR pollen in patients sensitized to honey bee venom was 4.350 IU/ml, in patients sensitized to wasp venom 0.61 IU/ml, and in patients with double sensitization 0.25 IU/ml (P = 0.028, Kruskal-Wallis test). Findings for IgE specific for MUXF3 were similar. Discordance between OSR pollen positivity and MUXF3 positivity was found in 11.1% of the patients. CONCLUSION: The values of IgE specific for OSR pollen and MUXF3 in patients with primary sensitization to either honey bee venom or wasp venom were significantly higher than in patients with double sensitization. These results confirm that IgE antibodies against carbohydrates epitopes are a frequent cause of double positivity in tests for anti-venom IgE antibodies.