{"id":6392,"date":"2026-10-19T09:48:51","date_gmt":"2026-10-19T09:48:51","guid":{"rendered":"https:\/\/phd.hi.is\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-hildur-sigurgrimsdottir\/"},"modified":"2026-10-19T09:48:51","modified_gmt":"2026-10-19T09:48:51","slug":"doktorsvorn-i-lif-og-laeknavisindum-hildur-sigurgrimsdottir","status":"publish","type":"phd_defence","link":"https:\/\/phd.hi.is\/en\/doktorsvorn\/doktorsvorn-i-lif-og-laeknavisindum-hildur-sigurgrimsdottir\/","title":{"rendered":"Doktorsv\u00f6rn \u00ed l\u00edf- og l\u00e6knav\u00edsindum – Hildur Sigurgr\u00edmsd\u00f3ttir"},"content":{"rendered":"
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F\u00f6studaginn 14. mars 2025 ver Hildur Sigurgr\u00edmsd\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: \u00d3n\u00e6mism\u00f3tandi \u00e1hrif LL-37 \u00ed meinger\u00f0 s\u00f3ra. The immunomodulatory role of LL-37 in the pathogenesis of psoriasis. <\/strong><\/p>\n

Andm\u00e6lendur eru dr. Christopher Griffiths, pr\u00f3fessor emeritus vi\u00f0 H\u00e1sk\u00f3lann \u00ed Manchester, og dr. Silke Appel, pr\u00f3fessor vi\u00f0 H\u00e1sk\u00f3lann \u00ed Bergen.<\/p>\n

Umsj\u00f3narkennari var Bj\u00f6rn R\u00fanar L\u00fa\u00f0v\u00edksson, pr\u00f3fessor, og lei\u00f0beinandi J\u00f3na Freysd\u00f3ttir, pr\u00f3fessor. Auk \u00feeirra s\u00e1tu \u00ed doktorsnefnd Gu\u00f0mundur Hrafn Gu\u00f0mundsson, pr\u00f3fessor, Ingibj\u00f6rg Har\u00f0ard\u00f3ttir, pr\u00f3fessor og Una Bjarnad\u00f3ttir, n\u00e1tt\u00farufr\u00e6\u00f0ingur.<\/p>\n

S\u00e6d\u00eds S\u00e6varsd\u00f3ttir, pr\u00f3fessor og varadeildarforseti L\u00e6knadeildar, stj\u00f3rnar ath\u00f6fninni sem fer fram \u00ed H\u00e1t\u00ed\u00f0asal H\u00e1sk\u00f3la \u00cdslands og hefst kl. 9.00.<\/p>\n

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

S\u00f3ri er sj\u00e1lfsofn\u00e6missj\u00fakd\u00f3mur sem herjar \u00e1 h\u00fa\u00f0 og algengasta formi\u00f0, skellus\u00f3ri, l\u00fdsir s\u00e9r sem upphleyptum, afm\u00f6rku\u00f0um, rau\u00f0leitum skellum me\u00f0 hv\u00edtleitu hr\u00fa\u00f0ri. Meinger\u00f0in er blanda af Th1 og Th17 b\u00f3lgusvari \u00fear sem hyrnisfrumur \u00ed ne\u00f0sta lagi h\u00fa\u00f0arinnar fj\u00f6lga s\u00e9r of hratt og \u00feroskast ekki r\u00e9tt. LL-37 er varnarpept\u00ed\u00f0 sem tilheyrir \u00f3s\u00e9rh\u00e6f\u00f0a \u00f3n\u00e6miskerfinu og getur m\u00f3ta\u00f0 \u00f3n\u00e6missvari\u00f0. \u00cd \u00feessu verkefni var markmi\u00f0i\u00f0 a\u00f0 skilgreina betur hvernig LL-37 m\u00f3tar \u00f3n\u00e6missvar og hefur \u00e1hrif \u00e1 seytingu hyrnisfrumna og \u00f3n\u00e6misfrumna \u00e1 l\u00edfmerkjum. Doktorsritger\u00f0in byggir \u00e1 \u00feremur ranns\u00f3knum: \u00cd \u00feeirri fyrstu var tenging T17 frumna sta\u00f0fest vi\u00f0 alvarleika s\u00f3ra, \u00fear sem T17 frumum f\u00e6kka\u00f0i vi\u00f0 me\u00f0fer\u00f0. Auk \u00feess var j\u00e1kv\u00e6\u00f0 fylgni milli f\u00e6kkunar \u00e1 Th17 frumum \u00ed bl\u00f3\u00f0i og alvarleika sj\u00fakd\u00f3ms. T frumum f\u00e6kka\u00f0i \u00ed h\u00fa\u00f0inni og tj\u00e1ning IL-17 \u00ed le\u00f0urh\u00fa\u00f0inni haf\u00f0i j\u00e1kv\u00e6\u00f0a fylgni vi\u00f0 alvarleika sj\u00fakd\u00f3ms. \u00cd annarri greininni voru T frumur sem voru \u00e1 lei\u00f0 \u00ed s\u00f3rah\u00fa\u00f0 sko\u00f0a\u00f0ar n\u00e1nar me\u00f0 \u00fev\u00ed a\u00f0 m\u00e6la flakkbo\u00f0avi\u00f0takana CXCR3, CCR4 og CCR6. Tj\u00e1ningarmynstur T frumna \u00e1 flakkbo\u00f0avi\u00f0t\u00f6kum var mismunandi eftir tj\u00e1ningu \u00feeirra \u00e1 CLA og CD103. Hnattkjarna frumur \u00far bl\u00f3\u00f0i voru einangra\u00f0ar og \u00f6rva\u00f0ar me\u00f0 b\u00f3lgubo\u00f0efnum sem l\u00edktu eftir Th1 og Th17 \u00f3n\u00e6missvari. Seyting \u00feeirra eftir \u00f6rvun mynda\u00f0i \u00f3l\u00edk tj\u00e1ningarmynstur sem LL-37 haf\u00f0i \u00e1hrif \u00e1. \u00cd \u00feri\u00f0ju greininni var seyting hyrnisfrumna sko\u00f0u\u00f0 vi\u00f0 s\u00f6mu \u00f6rvunara\u00f0st\u00e6\u00f0ur og \u00e1\u00f0ur var l\u00fdst fyrir hnattkjarna frumur \u00far bl\u00f3\u00f0i. Ni\u00f0urst\u00f6\u00f0urnar gefa til kynna a\u00f0 hyrnisfrumur seyta fj\u00f6ldanum \u00f6llum af flakkbo\u00f0um, vaxtar\u00fe\u00e1ttum og b\u00f3lgubo\u00f0efnum sem Th1 og Th17 \u00f6rvun hafa mikil \u00e1hrif \u00e1. A\u00f0 auki hefur LL-37 \u00e1hrif \u00e1 seytinguna.<\/p>\n

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

Psoriasis is an autoimmune disease of the skin, and the most common form, plaque psoriasis, is characterized by raised, well-demarcated, erythematous plaques with adherent silvery scales. The immunopathogenesis has a mixed Th1 and Th17 inflammatory profile, and keratinocytes in the basal layer of the skin hyper proliferate and do not mature properly. LL-37 is an anti-microbial peptide of the innate immune system that has extensive immunomodulatory functions. In this project, we wanted to further define the immunomodulatory effect of LL-37 upon various immune biomarker secretion by keratinocytes and white blood cells. The dissertation is based on three studies: In the first study, the role of T17 cells in the pathogenesis of psoriasis was corroborated, as the percentage of Th17 and Tc17 cells was reduced following phototherapy. Within the skin, the number of T cells reduced with psoriasis treatment, and the intensity of immunofluorescent staining of IL-17 in the dermis correlated to severity of disease. In the second study, further phenotypic analysis of these skin-homing T cells in psoriasis patients was performed by measuring the expression of the chemokine receptors CXCR3, CCR4, and CCR6. Different chemokine receptor expression patterns emerged when T cells were subtyped based on the expression of CLA and CD103. When peripheral blood mononuclear cells (PBMCs) were stimulated in vitro with two distinct stimulations mimicking the Th1 and Th17 microenvironment, various biomarker secretory patterns emerged, particularly in association with the presence of LL-37. In the third study, keratinocytes were cultured in the same immunomodulatory microenvironment, as previously described for the PBMCs, and their secretory profile analysed. The results demonstrate that primary keratinocytes secrete a wide array of immune biomarkers that can be significantly affected by Th1 and Th17-driven stimulation. Furthermore, their immune biomarker fingerprinting was frequently altered in the presence of LL-37.<\/p>\n

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

Hildur Sigurgr\u00edmsd\u00f3ttir er f\u00e6dd \u00e1ri\u00f0 1986 \u00e1 Selfossi. H\u00fan \u00fatskrifa\u00f0ist af n\u00e1tt\u00farufr\u00e6\u00f0ibraut Fj\u00f6lbrautask\u00f3la Su\u00f0urlands \u00e1ri\u00f0 2004 og lauk b\u00fafr\u00e6\u00f0ingspr\u00f3fi fr\u00e1 Landb\u00fana\u00f0arh\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2007. Hildur h\u00f3f n\u00e1m \u00ed l\u00edfeindafr\u00e6\u00f0i \u00e1ri\u00f0 2008 og lauk M.Sc. n\u00e1mi \u00e1ri\u00f0 2013. \u00cd framhaldinu h\u00f3f h\u00fan doktorsn\u00e1m \u00ed l\u00edf- og l\u00e6knav\u00edsindum vi\u00f0 H\u00e1sk\u00f3la \u00cdslands \u00e1ri\u00f0 2015. Ranns\u00f3knarverkefni\u00f0 hefur hloti\u00f0 styrk fr\u00e1 Ranns\u00f3knarsj\u00f3\u00f0i Rann\u00eds og V\u00edsindasj\u00f3\u00f0i Landsp\u00edtalans. Samhli\u00f0a doktorsn\u00e1minu hefur Hildur starfa\u00f0 \u00e1 \u00d3n\u00e6misfr\u00e6\u00f0ideild Landsp\u00edtalans. Foreldrar Hildar eru Herborg P\u00e1lsd\u00f3ttir og Sigurgr\u00edmur Vernhar\u00f0sson, stj\u00fapfa\u00f0ir er \u00dalfar Gu\u00f0mundsson. Unnusti Hildar er Svanur Halld\u00f3rsson.<\/p>\n<\/div><\/div>","protected":false},"featured_media":5746,"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":"2025-03-14T09:00:00+00:00","_phd_date_end":"2025-03-14T12:00:00+00:00","_phd_location":"A\u00f0albygging A\u00f0albygging","_phd_admission":"A\u00f0gangur \u00f3keypis","_phd_thesis_title":"\u00d3n\u00e6mism\u00f3tandi \u00e1hrif LL-37 \u00ed meinger\u00f0 s\u00f3ra. 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