doktorska disertacija
Miša Marušić (Author), Tatjana Avšič-Županc (Mentor)

Abstract

Klopni meningoencefalitis (KME) je virusna bolezen centralnega živčnega sistema (CŽS), ki jo povzroča virus klopnega encefalitisa (KMEV). Najbolj učinkovita zaščita pred KME je cepivo, vendar nekateri posamezniki zbolijo kljub cepljenju. Cepljeni bolniki s KME so v primerjavi z necepljenimi starejši, imajo enofazni potek bolezni in razvijejo hujše bolezenske znake. Zaradi vse več dokazov o vpletenosti imunskega sistema v patološke manifestacije KME, smo z doktorsko nalogo želeli raziskati, ali se funkcionalnost Toll-u podobnih receptorjev (TLR) 3, 7 in 8 ter aktivacija imunskega sistema pri bolnikih s KME, ki zbolijo kljub cepljenju proti bolezni, razlikuje od necepljenih bolnikov s KME. Z genotipizacijo enonukleotidnih polimorfizmov (SNP), povezanih s funkcionalnostjo TLR, smo ugotovili, da je frekvenca divjega alela za TLR8 pri cepljenih bolnicah s KME višja kot pri necepljenih bolnicah, zato bi lahko funkcionalni TLR8 predstavljal dejavnik tveganja za pojav KME kljub cepljenju. S stimulacijo mononuklearnih celic iz periferne krvi (PBMC) cepljenih in necepljenih bolnikov s KMEV in vitro smo poskusili poustvariti dogajanje v začetni fazi patogeneze KME. Ugotovili smo, da se cepljeni in necepljeni bolniki s KME ne razlikujejo po izražanju površinskih aktivacijskih molekul na dendritičnih celicah, smo pa pri cepljenih bolnikih s KME v zgodnjih časovnih točkah in vitro simulacije izmerili statistično značilno nižje koncentracije citokinov IFN-α, IL-12p70 in IL-15, kar bi lahko omogočilo obsežnejše virusno razmnoževanje in vodilo v šibkejšo aktivacijo drugih imunskih celic ter nižji protitelesni odziv. Po drugi strani pa smo v pozni točki in vitro stimulacije izmerili višjo koncentracijo IL-6, ki bi lahko ojačala vnetni odziv in prispevala k porušenju krvno-možganske pregrade. V kliničnih vzorcih cepljenih bolnikov s KME, odvzetih v nevrološki fazi bolezni, smo izmerili sistemsko povišane koncentracije vnetnih citokinov. Večina vnetnih citokinov, povezanih s prirojenim in Th1 celičnim odzivom, je bila koncentrirana v likvorju in je pozitivno korelirala z imunskimi celicami, kar kaže na lokalizacijo Th1 in vnetnih odzivov v CŽS. Cepljeni bolniki s KME so imeli še posebej izrazito povišan VEGF-A, ki bi lahko povzročil obsežnejše porušenje krvno-možganske pregrade in omogočil vstop imunskih celic v CŽS ter tako prispeval k oblikovanju intratekalnega vnetnega žarišča in k težjemu poteku bolezni. Obenem so imeli cepljeni bolniki s KME še dva meseca po pojavu nevroloških simptomov sistemsko povišane vrednosti IL-8/CXCL8 in GROα/CXCL1, kar kaže na dolgotrajno aktivacijo imunskega sistema. Obsežnejši in dlje časa trajajoč vnetni odziv pri cepljenih bolnikih s KME nakazuje na vpletenost imunskega odziva v pojav in potek bolezni pri tej skupini bolnikov s KME, vendar so za podrobnejše razumevanje mehanizma, ki leži za pojavom bolezni kljub cepljenju, potrebne še dodatne raziskave.

Keywords

klopni meningoencefalitis;KME;virus;Toll-u podobni receptorji;imunski odziv;dendritične celice;citokini;kemokini;cepivo;doktorske disertacije;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UL MF - Faculty of Medicine
Publisher: [M. Marušić]
UDC: 616.831.9-002(043.3)
COBISS: 100410115 Link will open in a new window
Views: 205
Downloads: 41
Average score: 0 (0 votes)
Metadata: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Other data

Secondary language: English
Secondary title: Immune response and functionality of Toll-like receptors in vaccine breakthrough patients with tick-borne encephalitis
Secondary abstract: Tick-borne meningoencephalitis (TBE) is a viral disease of the central nervous system (CNS) caused by tick-borne encephalitis virus (TBEV). The most effective protection against TBE is vaccination, however, despite highly immunogenic vaccine, vaccine breakthrough (VBT) infections still occur. VBT TBE patients are usually older, develop a monophasic disease and more severe symptoms compared to unvaccinated TBE patients. In contrast to unvaccinated TBE patients, VBT TBE patients are older and more often develop monophasic disease with more severe clinical symptoms. With growing evidence on pathological involvement of immune system in TBE, we aimed to investigate the functionality of Toll-like receptors (TLRs) 3, 7 and 8 and the activation of the immune system in VBT TBE patients. Genotyping of single nucleotide polymorphisms (SNPs) associated with TLR functionality showed that the frequency of the wild allele for TLR8 was higher in vaccinated females with TBE than in unvaccinated females with TBE, therefore functional TLR8 receptor could represent a risk factor for VBT TBE in women. To recreate the events in the initial phase of TBE pathogenesis, we stimulated peripheral blood mononuclear cells (PBMC) from VBT TBE and unvaccinated TBE patients with TBEV in vitro. Vaccinated and unvaccinated TBE patients did not differ in the expression of activation molecules dendritic cells after stimulation with TBEV in vitro, however, significantly lower concentrations of IFN-α, IL-12p70 and IL-15 were measured in supernatants of stimulated PBMCs from VBT patients in early time points. This could lead to more extensive viral replication and impair the activation of other immune cells. On the other hand, an observed increased IL-6 expression in VBT patients in late stages of in vitro stimulation, could support the extensive inflammatory responses and contribute to the blood-brain barrier disruption. Additionally, in acute phase of the disease, VBT TBE patients had systemically elevated inflammatory cytokines, with majority of them concentrated in cerebrospinal fluid and positively correlating with immune cell counts, indicating a localized Th1 and inflammatory responses in the central nervous system. Markedly elevated VEGF-A could lead to an extensive disruption of the blood-brain barrier, supporting immune cells entry and the formation of an intrathecal inflammatory focus, therefore contributing to a more severe disease. Also, VBT TBE patients had systemically upregulated levels of IL-8/CXCL8 and GROα/CXCL1 up to two months after the onset of neurological symptoms, indicating long-term systemic immune activation, which could explain the need for longer hospitalization of VBT TBE patients. An observed more extensive and prolonged inflammatory response in VBT TBE patients suggests an involvement of the immune response in the onset and development of the disease. However, additional studies are needed to better understand the mechanism behind vaccination breakthrough infections.
Secondary keywords: tick-borne encephalitis;virus;Toll-like receptor;immune response;dendritic cell;cytokine;chemokine;vaccine;
Type (COBISS): Doctoral dissertation
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak.
Pages: XV f., 151, [2] str.
ID: 14665238