A baixa seletividade dos métodos convencionais para diagnóstico e terapia de neoplasias, bem como o fato de nem sempre alcançarem o sucesso terapêutico desejado, configuram dificuldades para a prática oncológica. Diante disso, os anticorpos monoclonais (AcMs) radiomarcados, aplicados em técnicas diagnósticas, têm se destacado, visto que permitem a entrega seletiva da radiação ao alvo de interesse. A metodologia Radioimunodiagnóstico (RID), utilizando AcM anti-EGFR radiomarcado, possibilita triagem prévia, avaliando a resistência ao tratamento e estratificando pacientes que possam apresentar benefícios à imunoterapia com cetuximabe. Além disso, permite monitorar a progressão da terapia, visando tratamento mais efetivo e direcionado, promulgando a abordagem da medicina personalizada. No Brasil, ainda não há radioimunoconjugado disponível para diagnóstico e seguimento do câncer. Nesse contexto, o objetivo com este trabalho foi o de desenvolver uma formulação farmacêutica para padronizar uma rotina de produção dos radiofármacos para radioimunodiagnóstico de câncer de cabeça e pescoço e de câncer colorretal: cetuximabe-DTPA-111In e cetuximabe-DFO-89Zr. Em adição, corroborar na elucidação dos mecanismos de resistência das células tumorais à terapia com o cetuximabe, através da realização de estudos de ligação do radioimunoconjugado à receptores celulares. Em relação aos radiofármacos estudados, destaca-se que os processos de conjugação do cetuximabe com os quelantes DTPA, na razão molar 1:20, e com o DFO, 1:5, foram bem-sucedidos e otimizados, demonstrando boa reprodutibilidade. Os imunoconjugados apresentaram preservação da imunorreatividade e alta estabilidade quando armazenados a -20°C por até seis meses. Esses imunoconjugados, quando radiomarcado com 111In e 89Zr, exibiram pureza radioquímica superior a 95%, sem necessidade de purificação pós-marcação, e estabilidade por tempo que possibilita seu transporte às clínicas distantes do centro produtor. As análises in vitro do cetuximabe-DTPA-111In em células FaDu-C10 (linhagem resistente) demonstraram percentual inexpressivo de ligação e internalização do radioimunoconjugado, congruindo na explanação do modelo de resistência conferido à linhagem. O estudo de corpo inteiro em MicroPET/TC revelou redução no perfil de captação no grupo de bloqueio, com excesso de cetuximabe não marcado, e intensa captação do cetuximabe-DFO-89Zr pelo tumor de células escamosas no grupo sem bloqueador, confirmando a especificidade in vivo do radioimunoconjugado. Os estudos de biodistribuição dos radiofármacos foram compatíveis com os descritos em literatura e validaram os resultados obtidos por imagens em MicroSPECT/TC e MicroPET/TC, além de apresentarem apreciável captação tumoral, considerando os tempos analisados. A estabilidade alta in vivo e a eficácia da marcação foram confirmadas pela baixa captação óssea e em tecidos não alvos. O melhor intervalo pós-injeção do radiofármaco para avaliação in vivo foi após cinco dias da administração. Conclui-se, portanto, que os radioimunoconjugados para imuno-SPECT e imuno-PET, cetuximabe-DTPA-111In e cetuximabe-DFO-89Zr, são ferramentas promissoras para diagnóstico e monitoramento de câncer receptor específico (EGFR) e para estratificação de pacientes à terapia anti-EGFR, encorajando a continuidade deste projeto para futuros estudos clínicos. / The low selectivity of conventional methods for cancer diagnosis and therapy, as well as the fact that these methods could not achieve the desired therapeutic success, constitute difficulties for the oncological practice. In this regard, radiolabeled monoclonal antibodies (mAbs) applied in diagnostic techniques have been highlighted, since they allow the selective delivery of the radiation to the specific target. The radioimmunodiagnosis methodology (RID), using radiolabeled anti-EGFR mAbs, enables previous screening, evaluating resistance to treatment and stratifying patients who may present benefits to cetuximab immunotherapy. In addition, it allows monitoring the progression of the therapy, aiming for a more effective and directed treatment, leading the personalized medicine approach. A radioimmunoconjugate is not yet available for diagnosis and management of cancer in Brazil. In this context, this research was carried out to develop a pharmaceutical formulation to standardize a routine production of radiopharmaceuticals for diagnosis and monitoring head and neck cancer and colorectal carcinoma: 111In-DTPA-cetuximab and 89Zr-DFO-cetuximab. In addition, corroborate in the elucidation of the tumor cells resistance mechanisms to EGFR-targeted therapy, through in vitro and in vivo radioimmunoconjugate binding studies to cellular receptors. Regarding to the radiopharmaceuticals studied, cetuximab was conjugated to DTPA chelator at 1:20 molar ratio and to DFO at 1: 5, and these processes were successful and optimized, showing good reproducibility. Immunoconjugates showed preservation of immunoreactivity and high stability when stored at -20 °C for up to 6 months. These immunoconjugates when radiolabeled with 111In and 89Zr have exhibited radiochemical purity above 95%, without any post-labeling purification, and the radioimmunoconjugates have demonstrated stability for a time that allows them to be transported to clinics far from the producer center. 111In-DTPA-cetuximab in vitro analyzes in FaDu-C10 cells (resistant cell line) has presented an inexpressive percentage of binding and internalization of the radioimmunoconjugate, ensuring the resistance model conferred to this cell line. The MicroPET/CT imaging study has revealed a reduction in uptake profile for \"Blocking\" group, with an excess of unlabeling cetuximab, and an intense 89Zr-DFO-cetuximab uptake in squamous cell tumor for \"Non-blocking\" group, that evidenced the in vivo radioimmunoconjugate specificity. The biodistribution studies of the radiopharmaceuticals were well-matched with those described in the literature and they validated the results obtained through the MicroSPECT/CT and MicroPET/ CT images. In addition, these studies in vivo have displayed a substantial tumor uptake, according with the analyzed time points. The radioimmunoconjugate showed high in vivo stability and labeling procedures efficiency, which were confirmed by low bone and non-target tissues uptake. The best post-injection interval for in vivo evaluation is after 5 days of radioimmunoconjugate administration. In conclusion, the radioimmunoconjugates for immuno-SPECT and immuno-PET, 111In-DTPA-cetuximab and 89Zr-DFO-cetuximab, are promising tools for diagnosis and monitoring of specific receptor cancer (EGFR), as well as for stratification of patients to anti-EGFR therapy, and thus encourages the continuity of this project for future clinical trials.

Purpose: Cetuximab is a monoclonal antibody with a known risk of hypersensitivity reactions. Early studies showed hypersensitivity reaction rates of 3%, but there appears to be a higher incidence in the southeastern United States. To confirm the findings from nearby institutions that cetuximab-associated hypersensitivity reactions occur in approximately 20% of patients in the southeastern United States. Methods: A retrospective chart review was conducted at Johnson City Medical Center in Johnson City, Tennessee. Each patient’s first infusion was analyzed for hypersensitivity reaction, as well as for demographic information such as allergy and smoking history, pre-medications, and malignancy type. Results: Data from the first infusion of cetuximab were collected for a total of 71 patients with various malignancies. The overall rate of grade 3 or higher hypersensitivity reaction was 1.4%, and total rate of hypersensitivity reaction was 8.5%. These findings more closely correlate to the early clinical trials and package insert. Both severe (p = 0.001) and any-grade (p = 0.002) hypersensitivity reaction occurred less frequently in one Southeastern Appalachian medical center compared to academic medical centers directly to the east and west. Conclusions: Patients in southern Appalachia may be less likely to develop cetuximab hypersensitivity reactions compared to surrounding areas in the Southeastern U.S. These results lend support to the theory that exposure to lonestar ticks (Amblyomma americanum) may be responsible for the development of IgE antibodies to cetuximab that cause hypersensitivity reactions. The development of quick and reliable bedside predictors of cetuximab hypersensitivity reactions may aid clinicians considering the use of cetuximab.

Title: Inhibition of interleukin-6 trans-signaling by sgp130Fc is anti-tumorigenic in head and neck squamous cell carcinoma. Background: Head and neck squamous cell carcinoma (HNSCC) is a highly inflammatory cancer type, and interleukin-6 (IL-6) is associated with this phenotype. Elevated expression of IL-6 is linked to tumor progression, recurrence, metastasis, and resistance to therapy in HNSCC. However, targeting IL-6 or IL-6 receptor (IL-6R) has demonstrated little to no clinical efficacy. IL-6 signals through a classical signaling pathway via membrane IL-6R or a trans-signaling pathway via soluble IL-6R (sIL-6R). Recent evidence suggests that classical signaling induces acute, transient inflammation, eventually resulting in homeostasis; whereas trans-signaling may induce chronic, pro-tumorigenic inflammation. Therefore we propose that IL-6 trans-signaling is associated with the pro-inflammatory phenotype observed in HNSCC. We wanted to determine whether inhibition of IL-6 trans-signaling by sgp130Fc would better demonstrate anti-tumor efficacy and increase HNSCC tumor response to radiation, chemotherapy, and targeted therapy (cetuximab) compared to global IL-6 pathway inhibition. Method/Results: Baseline levels of IL-6, IL-6R, sIL-6R, and sgp130 proteins in HNSCC cells were determined using ELISA and flow cytometry. Cisplatin, radiation, and cetuximab treatments each induced HNSCC cell secretion of IL-6 and sIL-6R in vitro, yet adding sgp130Fc to those treatments did not further reduce clonogenic survival. Sgp130Fc treatment significantly suppressed SQ20B tumor growth in nude mice, whereas global IL-6 pathway inhibition by IL-6R antagonist tocilizumab did not; however, cetuximab reduced the efficacy of sgp130Fc in this animal model. Sgp130Fc also sensitized SQ20B xenograft tumors to radiation and chemotherapy in nude mice and suppressed SCCVII tumor growth in male but not female C3H/HeJ mice. Conclusion: Inhibition of IL-6 trans-signaling by sgp130Fc displayed significant anti-tumor effects as a single therapy and sensitized resistant HNSCC tumors to radiation and chemotherapy in vivo; however, sgp130Fc did not reduce survival of HNSCC cells in vitro. These results suggest that the efficacy of sgp130Fc relies on targeting another part of the microenvironment instead of tumor cells directly. Sgp130Fc has promise both as a single therapy and potentially as combined therapy with radiation and chemotherapy in HNSCC.

Le cancer colorectal représente un défi thérapeutique compte tenu de sa fréquence (38 000 nouveaux cas annuels dans notre pays), et de sa gravité (moins de 10 % de survie à 5 ans en situation métastatique). Sa prise en charge adéquate est avant tout multidisciplinaire associant les nouvelles techniques de chirurgie et de radiologie à la chimiothérapie. Celle-ci est représentée par trois cytotoxiques majeurs : le 5-Fluorouracile, pierre angulaire du traitement, l'oxaliplatine (L-OHP) et enfin l'irinotecan (CPT-11), auxquels se sont ajoutées ces dernières années les biothérapies ciblant le facteur angiogénique VEGF (bevacizumab) ou le récepteur épithélial de surface EGFR (cetuximab, panitumumab). Notre travail de Thèse d'Université a cherché à explorer, chez des patients atteints d'un cancer colorectal métastatique, le retentissement sur les taux de réponses, les survies et les toxicités, de génotypes enzymatiques impliqués dans les métabolismes des trois cytotoxiques principalement utilisés dans cette indication. Nos études translationnelles montrent l'optimisation des traitements à base de 5-FU par l'approche pharmacocinétique associée au dépistage préthérapeutique d'une population à haut risque de toxicité (DPYD mutés et/ou rapport UH2/U abaissé). Par ailleurs apparaissent de mauvais pronostic sur la survie globale et en cas de monochimiothérapie par 5-FU, les patients 3R/3R pour TYMS et homozygote sauvage pour MTHFR 1298 A>C ou 677 C>T, facteurs de risques génotypiques disparaissant avec l'adjonction de CPT-11. Concernant ce dernier, un schéma de traitement adapté au statut UGT 1A1, et combiné au cetuximab, aboutit à des taux de maladie contrôlée et de survie sans progression inégalés en deuxième ligne de traitement. Enfin, les patients homozygotes T/T pour ERCC1 118 C>T et C/C XPD 751 A>C apparaissent à risque de neurotoxicité chroniques à l'oxaliplatine. Considérant le génome tumoral, outre Kras et Braf, PI3KCA muté apparaît pour la première fois comme un facteur possible de résistance aux traitements anti-EGFR. En conclusion, la prise en compte des facteurs pharmacogénétiques et pharmacogénomiques devrait permettre à l'avenir une meilleure rationalisation des traitements de chimiothérapies en optimisant leurs efficacités tout en limitant leurs toxicités.

Current methods to diagnose and treat cancer often involve expensive, time-consuming equipment and materials that may lead to unwanted side effects and may not even increase a patient’s chance of survival. Thus, for a while now, a large part of the research community has focused on developing improved methods to detect, diagnose, and treat cancer on the molecular scale. One of the most recently discovered methods of cancer therapy is targeted therapy. These targeted therapies have potential to provide a patient with a form of personalized medicine because these therapies are biological molecules that specifically target other molecules involved with a cancer’s growth. Past trials using these therapeutic molecules, however, have led to controversial results, where certain patients responded better than others to the therapy for unknown reasons. Elucidating the reason behind these mixed results can be accomplished using metal nanoparticle technologies which could provide a bright signal to monitor the path that these therapeutic molecules take in vivo as well as enhance the molecule’s efficacy. Literature has shown that presenting targeting molecules in a dense manner to their target will increase these molecules’ binding affinity. This concept has been explored here to increase binding affinity of therapeutic molecules by attaching these molecules in a dense manner on the surface of gold nanoparticles, and correlating this increased affinity with therapeutic efficacy. Additionally, gold nanoparticles provide an easy surface for molecules to be functionalized on and have shown to be effective imaging, x-ray, and photothermal therapy agents. A major roadblock to using these gold nanoparticles clinically is their non-degradability and thus potential to cause long-term negative side effects in vivo. A platform for developing biodegradable gold nanoparticles is also explored here to take advantage of the gold nanoparticles’ excellent imaging and drug delivery capabilities while still allowing them to be used safely in the long term. / text

Orientador: Marlus Chorilli / Resumo: O câncer de próstata (CP) é a segunda neoplasia mais frequente entre homens no Brasil e é caracterizado por não apresentar sintomas em seus estágios iniciais, sendo diagnosticado em seu estágio avançado, o que muitas vezes dificulta o tratamento. Alguns fatores relacionados podem intensificar sua agressividade como, por exemplo, a superexpressão do receptor do fator de crescimento epidérmico (EGFR) em alguns subtipos de tumores de próstata. Neste contexto, a inibição do EGFR auxilia no combate da neoplasia, função essa que pode ser atribuída ao anticorpo monoclonal quimérico IgG1 (cetuximabe-CTX) que se liga à porção externa do EGFR, inibindo a proliferação celular, angiogênese e metástase, além de promover a apoptose. Dentre as formas de tratamento destacam-se a braquiterapia, a radioterapia e a quimioterapia utilizando o docetaxel (DTX), o qual apresenta vantagem de prolongar a sobrevivência em pacientes com CP metastático resistentes à terapia antiandrogênica. No entanto, a formulação comercial (Taxotere®) causa efeitos colaterais, como febre, anemia, retenção de líquidos, hipersensibilidades, mialgias, mucosite, neuropatias periféricas e toxidade a pele e unhas, tornando necessário o estudo de novas formas de veiculação para este fármaco Deste modo, o objetivo deste trabalho foi desenvolver uma nanodispersão de cristal líquido (NCL) de fase cúbica baseada em álcool cetílico etoxilado 20 e propoxilado 5 como tensoativo (T), ácido oleico, DSPE-PEG-MAL e fosfatidilcolina de ... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

Le cancer de la prostate, premier cancer chez l’homme en France, a bénéficié largement des avancées thérapeutiques de la chirurgie, de la chimiothérapie, de la radiothérapie et, depuis une dizaine d’années, de l’hormonothérapie. Lorsque le cancer devient hormono-résistant, la chimiothérapie par docetaxel et prednisone est désormais le traitement de référence. Actuellement les traitements de deuxième ligne sont décevants et tout reste à faire. Notre travail a eu pour but d’évaluer l’impact de thérapies ciblées visant EGFR et VEGFR dans cette situation clinique actuellement très défavorable, données seules ou en association au docetaxel. Nous avons pour celà utilisé un modèle cellulaire PC3 xénogreffé sur la souris nude. Matériels et méthodesUn premier travail a consisté à tester l’efficacité anti-tumorale du sunitinib (agent anti-angiogénique), du cetuximab (agent anti-EGFR) et du docetaxel en monothérapies, bithérapies ou trithérapie in vivo, à partir d’une lignée cellulaire PC3 xénogreffée à la souris nude. Un deuxième travail a consisté à tester l’efficacité anti-tumorale du vandetanib (agent anti-VEGFR et anti-EGFR) associé ou non au docetaxel in vivo, à partir de deux lignées PC3 xénogreffées à la souris nude. Une lignée sauvage sensible au docetaxel, et une lignée résistante au docetaxel.Résultats :Dans notre premier travail, nous avons montré un effet supra-additif de l’association sunitinib – docetaxel et sunitinib - cetuximab, avec une bonne tolérance du traitement évaluée sur le poids des souris. Dans notre deuxième travail, le vandetanib n’a pas montré d’efficacité sur la souche sauvage, et même un effet activateur de croissance tumorale à faible dose. Sur la souche résistante, il n’a pas montré d’effet de resensibilisation au docetaxel. In vitro, il n’a pas montré d’effet modulateur sur MDR1.ConclusionSi le sunitinib a présenté des résultats intéressants dans le cadre de notre modèle préclinique pour le cancer de prostate hormono-résistant, il semble que le vandetanib soit à réserver éventuellement aux cancers de prostate hormono-résistants devenus docetaxel résistants, en deuxième ligne et en monothérapie, dans le cadre d’essais cliniques à venir. / Prostate cancer is the first male cancer men in France. Clinical benefits were realized during the ten last year’s concerning surgery, cytotoxic chemotherapy, hormonotherapy and radiotherapy. The reference treatment for homone-refractory prostate cancer combines docetaxel and prednisone. The current responses to second-line treatments are disappointing and considerable progress remains to be made. The aim of our studies was to test novel therapeutics approaches by combining docetaxel with EGFR and VEGFR targeting agents. Mice bearing well-established PC3 prostate tumors were used.MethodsThe aim of our first study was to test a rational therapeutic approach by combining docetaxel with an EGFR-targeting agent (cetuximab) and with an anti-angiogenic agent (sunitinib), using mice bearing PC3 prostate tumors.The aim of our second study was to test a novel therapeutic approach by combining docetaxel with vandetanib, a dual EGFR and VEGFR targeting agent. Mice bearing docetaxel-sensitive-or-resistant PC3 were used.ResultsIn our first study, supra-additive effects were observed with the sunitinib-docetaxel combination. Stable mean mouse weight suggested that no drug-induced toxicity was evident.In our second study, vandetanib had growth-stimulation effects at the smallest concentration on PC3 wild type, and no effect concerning the other conditions on PC3 wild type. MDR1 was expressed in PC3 resistant only, but was neither modulated nor its action inhibited, by vandetanib in vitro.ConclusionUse of sunitinib might support innovative strategies in the management of hormone-refractory prostate cancer, in our preclinical model. Concerning vandetanib, it would be use for hormone-refractory prostate cancer only after relapse under docetaxel, as a second-line treatment.

Einleitung: Die zielgerichtete Therapie von Plattenepithelkarzinomen der Kopf-Hals-Region (HNSCC) durch simultanes Targeting von EGFR (epidermal growth factor-receptor) mit Cetuximab (E) und αVβ3 und αVβ5-Integrinen mit Cilengitide (Cil) könnte wegen dessen geringen Nebenwirkungen attraktiv sein. Wir analysierten die Koloniebildung epithelialer Zellen (CFec) und die Produktion pro-angiogener and pro-inflammatorischer Zytokine im Kurzzeit-Chemoresponsetest (FLAVINO). Methoden: Kollagenase-IV-verdaute Proben von 43 histopathologisch gesicherter HNSCC wurden in Laminin-beschichtete 96-well-Platten eingesät, die in Triplikaten E, Cil oder CilE in Endkonzentrationen von 66,7 µg/ml, 10 µM, und 66,7 µg/ml+10 µM enthielten. Kulturüberstände (KÜS) wurden nach 3 Tagen entnommen und adhärente Zellen Ethanol-fixiert. 39 HNSCC hatten CFec≥4/well. Interleukin 6 (IL-6), MCP-1 (monocyte chemoattractant protein 1) und VEGF (vascular endothelial growth factor A) in KÜS wurden mit ELISA quantifiziert. Ergebnisse: CFec auf Laminin wurde durch Cil, E und CilE signifikant unterdrückt. Die Produktion von MCP-1, IL-6 und VEGF wurde ebenfalls vermindert. CilE bewirkte die stärkste Suppression von CFec, MCP-1 und VEGF. Die Wirksamkeit von CilE überstieg dabei diejenige von E oder Cil allein. Der überwiegend additiv gesteigerte aber bei manchen HNSCC ausbleibende Effekt zeigt starke Heterogenität in der Response verschiedener HNSCC auf. Die IL-6-Freisetzung wurde durch E und verstärkt durch CilE, aber nicht durch Cil allein signifikant supprimiert. Schlussfolgerung: Kombiniertes Targeting von EGFR und Integrinen mit CilE erhöht die suppressiven Effekte auf CFec und pro-angiogene und pro-inflammatorische Zytokine, welche potentielle Bedeutung als Biomarker für Response erlangen.:1 Einleitung 3 1.1 Integrine – multifunktionale Transmembranproteine 4 1.1.1 Erkennungsmerkmal RGD-Sequenz 5 1.1.2 Integrine αVβ3 und αVβ5 sowie deren Rolle in Tumorangiogenese und Metastasierung 5 1.2 Cilengitide – ein Integrin-Inhibitor 6 1.3 Epidermaler Wachstumsfaktorrezeptor 8 1.3.1 Die Rolle des EGFR bei Tumoren 9 1.3.2 Cetuximab - ein EGFR-Inhibitor 10 1.4 Tumore der Kopf-Hals-Region und deren Biomarker 11 1.4.1 Therapie von Kopf-Hals-Tumoren 12 1.4.2 Klinische Erprobungen von Cilengitide 12 1.4.3 Targeted Therapie mit Cetuximab bei Kopf-Hals-Tumoren 13 1.4.4 Biomarker bei HNSCC 15 1.4.5 Interleukin 6 16 1.4.6 Vaskulärer endothelialer Wachstumsfaktor A – VEGF-A 17 1.4.7 Monozyten-Chemoattraktor Protein 1 – MCP-1 19 1.5 Chemoresponsetestung ex vivo 21 1.5.1 Der koloniebildende Kurzzeit-Chemoresponsetest FLAVINO 22 1.5.2 Flavin-induzierte photodynamische Degeneration 22 1.5.3 Ablauf des FLAVINO-Chemoresponsetests 23 1.6 Aufgabenstellung und neue Erkenntnisse 24 2 Publikationen 26 2.1 Abstract zum Vortrag zur 84. Jahrestagung der Deutschen Gesellschaft für Hals-, Nasen-, Ohrenheilkunde und Kopf- und Hals-Chirurgie 27 2.2 Publikation bei Anticancer Research 28 2.3 Abstract zum Beitrag zur 88. Jahrestagung der deutschen Gesellschaft für Hals-, Nasen-, Ohrenheilkunde und Kopf- und Hals-Chirurgie 36 3 Zusammenfassung 37 4 Literaturverzeichnis 41 5 Anlagen 49 5.1 Erklärung über die eigenständige Verfassung der Arbeit 49 5.2 Darstellung des Eigenanteils 50 5.3 Lebenslauf 52 5.4 Danksagung 53

Objective: While most allergic responses to food are directed against protein epitopes and occur within 30 minutes of ingesting the allergen, recent studies suggest that delayed reactions may occur, sometimes mediated by IgE antibodies directed against carbohydrate moieties. The objective of this review is to summarize the clinical features and management of delayed hypersensitivity reactions to mammalian meat mediated by IgE antibodies to galactose-alpha 1,3-galactose (alpha-gal), an oligosaccharide.Methods: A PubMed search was conducted with MeSH terms: galactosyl-(1,3) galactose, oligosaccharides, cetuximab, allergy/hypersensitivity, and anaphylaxis. Reported cases with alpha-gal-mediated reactions were reviewed. This research study was approved by the Institutional Review Board of East Tennessee State University.Results: Thirty-two cases of adults presenting with red-meat induced allergy thought to be related to oligosaccharides have been reported in the literature so far, making this a rare and evolving syndrome. Most of these patients demonstrated delayed reactions to beef, as was seen in the case reported by us in this manuscript. IgE specific to alpha-gal was identified in most patients with variable response to skin testing with beef and pork. Inhibition studies in some cases showed that the IgE antibodies to beef were directed towards alpha-gal in the meat rather than the protein. The patients often reported history of tick bites, the significance of which is unclear at present. Reactions to cetuximab, a monoclonal antibody, are mediated by a similar mechanism, with IgE antibodies directed against an alpha-gal moiety incorporated in the drug structure.Conclusion: Alpha-gal is an oligosaccharide recently incriminated in delayed anaphylactic reactions to mammalian meats such as to beef, pork, and lamb. It appears that anaphylactic reactions to the anti-cancer biological agent, cetuximab, may be linked mechanistically to the same process. More studies are required to understand the underlying molecular basis for these delayed reactions in specific, and their broader implications for host defense in general.

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