{"id":6363,"date":"2026-10-19T09:48:49","date_gmt":"2026-10-19T09:48:49","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-sara-bjork-stefansdottir\/"},"modified":"2026-10-19T09:48:49","modified_gmt":"2026-10-19T09:48:49","slug":"doktorsvorn-i-lif-og-laeknavisindum-sara-bjork-stefansdottir","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-sara-bjork-stefansdottir\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed l\u00edf- og l\u00e6knav\u00edsindum – Sara Bj\u00f6rk Stef\u00e1nsd\u00f3ttir"},"content":{"rendered":"
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Fimmtudaginn 7. mars 2024 ver Sara Bj\u00f6rk Stef\u00e1nsd\u00f3ttir doktorsritger\u00f0 s\u00edna \u00ed l\u00edf- og l\u00e6knav\u00edsindum vi\u00f0 L\u00e6knadeild H\u00e1sk\u00f3la \u00cdslands. Ritger\u00f0in ber heiti\u00f0: \u00der\u00f3un \u00f3n\u00e6misme\u00f0fer\u00f0ar gegn sumarexemi \u00ed hestum. Development of Immunotherapy for Equine Insect Bite Hypersensitivity.<\/p>\n

Andm\u00e6lendur eru dr. Hans Gr\u00f6nlund, d\u00f3sent vi\u00f0 Karolinska Institutet, Department of Clinical Neuroscience, Sv\u00ed\u00fej\u00f3\u00f0 og dr. Zophon\u00edas Oddur J\u00f3nsson, pr\u00f3fessor \u00ed sameindaerf\u00f0afr\u00e6\u00f0i vi\u00f0 \u00a0L\u00edf- og umhverfisv\u00edsindadeild H\u00e1sk\u00f3la \u00cdslands.<\/p>\n

Umsj\u00f3narkennari var dr. Sigurbj\u00f6rg \u00deorsteinsd\u00f3ttir, \u00f3n\u00e6misfr\u00e6\u00f0ingur og lei\u00f0beinandi var dr. Vilhj\u00e1lmur Svansson d\u00fdral\u00e6knir. Auk \u00feeirra s\u00e1tu \u00ed doktorsnefnd dr. Arna R\u00fanarsd\u00f3ttir l\u00edfefnafr\u00e6\u00f0ingur, dr. Eliane Marti d\u00fdral\u00e6knir og dr. J\u00f3n M\u00e1r Bj\u00f6rnsson sameindal\u00edffr\u00e6\u00f0ingur.<\/p>\n

\u00de\u00f3rarinn Gu\u00f0j\u00f3nsson, pr\u00f3fessor og deildarforseti vi\u00f0 L\u00e6knadeild, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 12.00.<\/p>\n

\u00c1grip<\/strong><\/p>\n

Sumarexem er h\u00fa\u00f0ofn\u00e6mi af ger\u00f0 I \u00ed hestum me\u00f0 framlei\u00f0slu \u00e1 IgE m\u00f3tefnum gegn ofn\u00e6misv\u00f6kum. \u00dea\u00f0 orsakast af biti sm\u00e1m\u00fds\/l\u00fasm\u00fds (Culicoides spp.) sem lifir ekki \u00e1 \u00cdslandi og \u00fev\u00ed er sj\u00fakd\u00f3murinn ekki til sta\u00f0ar h\u00e9r. T\u00ed\u00f0ni sj\u00fakd\u00f3msins er aftur \u00e1 m\u00f3ti h\u00e1 \u00ed \u00fatfluttum hestum samanbori\u00f0 vi\u00f0 \u00edslenska hesta sem eru f\u00e6ddir \u00e1 flugusv\u00e6\u00f0um og f\u00e1 sumarexem me\u00f0 s\u00f6mu t\u00ed\u00f0ni og \u00f6nnur hestakyn. Einkenni sumarexems eru \u00fatbrot og kl\u00e1\u00f0i og hefur sj\u00fakd\u00f3murinn mikil \u00e1hrif \u00e1 velfer\u00f0 hrossa. Markmi\u00f0 verkefnisins var a\u00f0 \u00fer\u00f3a fyrirbyggjandi \u00f3n\u00e6misme\u00f0fer\u00f0 gegn sumarexemi.<\/p>\n

A\u00f0alofn\u00e6misvakarnir hafa veri\u00f0 skilgreindir og framleiddir en \u00fea\u00f0 er undirsta\u00f0a \u00feess a\u00f0 \u00fer\u00f3a me\u00f0fer\u00f0 gegn ofn\u00e6minu. \u00c1\u00f0ur haf\u00f0i veri\u00f0 s\u00fdnt fram \u00e1 a\u00f0 sprautun \u00ed eitla me\u00f0 ofn\u00e6misv\u00f6kum \u00ed bl\u00f6ndu af alum og MPLA (\u00f3n\u00e6misgl\u00e6\u00f0um) framkalli \u00e1kj\u00f3sanlegt \u00f3n\u00e6missvar. \u00cd \u00feessari ranns\u00f3kn voru ger\u00f0ar tv\u00e6r b\u00f3lusetningartilraunir, annars vegar samanbur\u00f0ur \u00e1 stungusta\u00f0 og hins vegar samanbur\u00f0ur \u00e1 \u00f3n\u00e6misgl\u00e6\u00f0um. Samb\u00e6rilegar ni\u00f0urst\u00f6\u00f0ur fengust \u00feegar hestar voru b\u00f3lusettir me\u00f0 ofn\u00e6misv\u00f6kum \u00ed alum\/MPLA \u00ed eitla og undir h\u00fa\u00f0. Sprautun undir h\u00fa\u00f0 g\u00e6ti \u00fev\u00ed veri\u00f0 noth\u00e6f vi\u00f0 \u00f3n\u00e6misme\u00f0fer\u00f0 gegn sumarexemi. B\u00f3lusetning me\u00f0 ofn\u00e6misv\u00f6kum \u00ed alum\/MPLA framkalla\u00f0i sterkara \u00f3n\u00e6misvar en ofn\u00e6misvakar \u00ed alum og veiru-l\u00edkum \u00f6gnum (VLP).<\/p>\n

Til a\u00f0 meta hvort b\u00f3lusetning me\u00f0 hreinsu\u00f0um ofn\u00e6misv\u00f6kum \u00ed \u00f3n\u00e6misgl\u00e6\u00f0i veiti v\u00f6rn gegn sumarexemi var framkv\u00e6md \u00e1skorunartilraun. Tuttugu og sj\u00f6 heilbrig\u00f0ir \u00edslenskir hestar voru b\u00f3lusettir \u00ed kj\u00e1lkabar\u00f0seitla me\u00f0 ofn\u00e6misv\u00f6kum \u00ed alum\/MPLA. Hestarnir voru b\u00f3lusettir \u00e1 \u00cdslandi \u00e1\u00f0ur en \u00feeir voru fluttir til Sviss \u00fear sem \u00feeim var fylgt eftir \u00ed \u00ferj\u00fa \u00e1r me\u00f0 reglulegri kl\u00edn\u00edskri sko\u00f0un, bl\u00f3\u00f0t\u00f6ku og \u00f6rvunarb\u00f3lusetningum. Einn hestur var tekinn \u00far ranns\u00f3kninni. \u00c1 fyrsta \u00e1ri h\u00f6f\u00f0u 6 hestar (23,1%) \u00fer\u00f3a\u00f0 me\u00f0 s\u00e9r sumarexem, 13 hestar (50,0%) \u00e1 \u00f6\u00f0ru \u00e1ri og 16 (61,5%) \u00e1 \u00fev\u00ed \u00feri\u00f0ja. Enginn markt\u00e6kur munur var \u00e1 IgG m\u00f3tefnasvari \u00e1 neinum t\u00edmapunkti fyrstu tv\u00f6 \u00e1rin milli b\u00f3lusettra hesta sem fengu sumarexem og \u00feeirra sem voru heilbrig\u00f0ir \u00fat t\u00edmabili\u00f0 en markt\u00e6kur munur var eftir anna\u00f0 \u00e1ri\u00f0 \u00e1 IgE svari \u00e1 milli h\u00f3panna. B\u00f3lusetningin veitti \u00fev\u00ed ekki v\u00f6rn gegn sumarexemi en frekari pr\u00f3fun \u00e1 \u00feeim s\u00fdnum sem safna\u00f0 var g\u00e6ti gefi\u00f0 inns\u00fdn \u00ed ors\u00f6k \u00feess a\u00f0 b\u00f3luefni\u00f0 var\u00f0i ekki hestana.<\/p>\n

Abstract<\/strong><\/p>\n

Insect bite hypersensitivity (IBH) is an allergic dermatitis of horses caused by IgE-mediated reactions to allergens of biting midges (Culicoides spp). Iceland is free of the causative agents but the prevalence of IBH in exported Icelandic horses is much higher than in Icelandic horses born in Culicoides rich environment. IBH can severely impact the well-being of affected horses. The aim of the study was to develop preventive immunotherapy against IBH.<\/p>\n

The major allergens of IBH have been identified and produced which opens the possibility to develop an allergen-specific immunotherapy against IBH. Prior studies showed that intralymphatic (i.l) injection of recombinant (r-) allergens with adjuvants induced a preferable immune response. In this study, two vaccination experiments were carried out, that is comparison of injection route and comparison of adjuvants. Vaccination with r-allergens in alum\/MPLA adjuvant i.l. and s.c. gave comparable results. In conclusion, s.c. injection might be option in immunotherapy against IBH. Use of alum\/VLP adjuvant instead of alum\/MPLA as an immunomodulator induced weaker immune response.<\/p>\n

To test the efficacy of a preventive allergen immunotherapy, a challenge experiment was conducted. Twenty – seven healthy Icelandic horses were vaccinated i.l. with r-allergens in alum\/MPLA. The vaccination was done in Iceland and the horses subsequently exported to Switzerland and followed for three years with regular clinical examination, blood sampling and booster vaccinations. One horse was withdrawn from the study. Six horses developed IBH (23.1%) in the first year. In the second year a total of 13 horses (50.0%) and in the third year 16 (61.5%) horses were affected with IBH. The IgG antibody response showed no difference at any time-point between horses which developed IBH and horses that remained healthy. However, at the end of the second Culicoides season IBH-affected horses had significantly higher IgE levels. In conclusion, the vaccine did not reduce the incident of IBH in exported horses based on reported prevalence. Further analysis of collected samples could provide insights on why the vaccine does not protect the horses against IBH.<\/p>\n

Um doktorsefni\u00f0<\/strong><\/p>\n

Sara Bj\u00f6rk Stef\u00e1nsd\u00f3ttir er f\u00e6dd \u00e1ri\u00f0 1990 \u00e1 Akureyri. H\u00fan lauk B.Sc. pr\u00f3fi fr\u00e1 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2013 og M.Sc. gr\u00e1\u00f0u fr\u00e1 sama sk\u00f3la \u00e1ri\u00f0 2015. Sara byrja\u00f0i \u00ed doktorsn\u00e1mi vi\u00f0 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2018 og vann doktorsverkefni\u00f0 \u00e1 Tilraunast\u00f6\u00f0 H\u00e1sk\u00f3la \u00cdslands \u00ed meinafr\u00e6\u00f0i a\u00f0 Keldum \u00ed samstarfi vi\u00f0 ORF L\u00edft\u00e6kni og Vetsuisse Faculty, H\u00e1sk\u00f3lanum \u00ed Bern, Sviss. S\u00ed\u00f0ustu tv\u00f6 \u00e1rin hefur h\u00fan einnig stunda\u00f0 vinnu me\u00f0fram doktorsn\u00e1minu, sem s\u00e9rfr\u00e6\u00f0ingur \u00ed pr\u00f3teinframlei\u00f0slu hj\u00e1 ORF L\u00edft\u00e6kni og n\u00fa sem Senior Formulation Scientist vi\u00f0 lyfja\u00fer\u00f3unardeild Alvotech. Foreldrar S\u00f6ru eru Stef\u00e1n \u00de\u00f3r P\u00e1lsson og \u00deorbj\u00f6rg D\u00f3ra Gunnarsd\u00f3ttir. Eiginma\u00f0ur S\u00f6ru er J\u00f3nas Gu\u00f0mannsson og saman eiga \u00feau tvo syni, Breka Sn\u00e6 og Aron Darra.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5683,"template":"","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"_phd_date_start":"2024-03-07T12:00:00+00:00","_phd_date_end":"2024-03-07T15:00:00+00:00","_phd_location":"A\u00f0albygging H\u00e1t\u00ed\u00f0asalur","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"\u00der\u00f3un \u00f3n\u00e6misme\u00f0fer\u00f0ar gegn sumarexemi \u00ed hestum. 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