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Toll-like Receptors in Allergic Rhinitis

Fransson, Mattias LU (2006)
Abstract (Swedish)
Popular Abstract in Swedish

Allergisk rinit är en immunförmedlad sjukdom som huvudsakligen drabbar nässlemhinnan. Vid kontakt med allergen, t.ex. pollen, uppkommer typiska symptom såsom klåda, nysningar, rinnsnuva och nästäppa. Immunförsvaret brukar traditionellt indelas i två samverkande delar, den medfödda och den förvärvade delen. Den medfödda delen aktiveras snabbt vid en första kontakt med mikroorganismer för att förhindra infektion. Den förvärvade delen utvecklar, under loppet av några dagar, specifika cellbaserade verktyg för att effektivt bekämpa angripande mikroorganismer.



En viktig och relativt nyupptäckt komponent av det medfödda immunförsvaret är Toll-lika receptorer (TLR) som är en familj... (More)
Popular Abstract in Swedish

Allergisk rinit är en immunförmedlad sjukdom som huvudsakligen drabbar nässlemhinnan. Vid kontakt med allergen, t.ex. pollen, uppkommer typiska symptom såsom klåda, nysningar, rinnsnuva och nästäppa. Immunförsvaret brukar traditionellt indelas i två samverkande delar, den medfödda och den förvärvade delen. Den medfödda delen aktiveras snabbt vid en första kontakt med mikroorganismer för att förhindra infektion. Den förvärvade delen utvecklar, under loppet av några dagar, specifika cellbaserade verktyg för att effektivt bekämpa angripande mikroorganismer.



En viktig och relativt nyupptäckt komponent av det medfödda immunförsvaret är Toll-lika receptorer (TLR) som är en familj bestående av 10 olika proteiner (TLR1-10). Deras uppgift är att identifiera bakterier, virus och andra mikroorganismer och därmed aktivera kroppens immunförsvar. TLR utför denna funktion genom att känna igen vissa strukturer på förekommande mikroorganismer. Ett exempel på en sådan struktur är lipopolysackarid (LPS), som förekommer på ytan av en viss typ av bakterier och identifieras av TLR4.



Allergi är ett uttryck för en obalans i immunförsvaret vilken leder till att kroppen reagerar mot i normalt sätt ofarliga ämnen som pollen. När en allergisk individ kommer i kontakt med pollen aktiveras mastceller till att frisätta inflammatoriska substanser. Dessa substanser medför ett ökat inflöde av vita blodkroppar vilka ytterligare förvärrar det inflammatoriska tillståndet. Den inflammatoriska processen kan via blodet påverka andra organ såsom benmärg och lunga. Många forskare tror att även det medfödda immunförsvaret kan ha betydelse för uppkomst och utveckling av allergiska sjukdomar.



Syftet med föreliggande avhandling är att kartlägga hur förekomsten av TLR i olika celltyper i näsa, blod och benmärg påverkas vid pollenorsakad inflammation i näsan.



Arbetet har varit centrerat till följande tre frågeställningar.



- Förekommer TLR2, TLR3, TLR4 och TLR9 i nässlemhinna och i olika vita blodkroppar i nässköljvätska, blod och benmärg?



- Påverkas förekomsten av vita blodkroppar och inflammatoriska mediatorer i näsan av lokal TLR4-stimulering med LPS?



- Ändras förekomsten av TLR2, TLR3, TLR4 och TLR9 i nässlemhinna och i olika vita blodkroppar i nässköljvätska, blod och benmärg vid allergisk rinit?



För att belysa dessa frågeställningar genomfördes sex studier med totalt 111 patienter som led av allergisk rinit, dessutom medverkade 55 friska försökspersoner som kontrollgrupp. Prov från näsmussla, nässköljvätska, blod och benmärg analyserades för att kunna bestämma mängd och lokalisation av genuttryck och proteinförekomst. Följande resultat framkom.



- TLR2, TLR3, TLR4 och TLR9 påvisades i nässlemhinna och i olika typer av vita blodkroppar i nässköljvätska, blod och benmärg.



- Den inflammatoriska aktiviteten, återspeglat som ett ökat antal vita blodkroppar och en ökad förekomst av inflammatoriska mediatorer i nässköljvätska, ökade efter en sprayning med LPS i näsan. Samtidigt minskade förekomsten av ett anti-inflammatoriskt ämne såväl i nässlemhinna som i nässköljvätska.



- Förekomsten av TLR2, TLR3 och TLR4 ökade i nässlemhinnan efter sprayning med pollen i näsan. Under pollensäsong ökade förekomsten av TLR4 i olika vita blodkroppar i nässköljvätska, blod och benmärg, medan förekomsten av TLR3 i eosinofila granulocyter minskade i blod och benmärg. TLR9 påverkades inte vid pollenallergi.



Resultaten visar att förekomsten av olika TLR påverkas då patienter med allergisk rinit kommer i kontakt med pollen, vilket stödjer teorin att det medfödda immunförsvaret kan vara av betydelse för allergisk luftvägssjukdom. (Less)
Abstract
Allergic rhinitis is an inflammatory disorder with the characteristic symptoms itching, sneezing, secretion and blockage upon allergen contact. In addition to the local inflammation in the nose, there is a systemic component that influences peripheral blood, bone marrow and lungs.



The immune system is conventionally divided into innate and acquired (adaptive) immunity. The former is important in the early phase of the defense against previously unknown intruders, since there is a delay of 4-7 days for a full function of the adaptive immunity. Repeated encounters with the same antigen will result in a faster and more effective response of the adaptive immunity. Development of allergic airway inflammation is traditionally... (More)
Allergic rhinitis is an inflammatory disorder with the characteristic symptoms itching, sneezing, secretion and blockage upon allergen contact. In addition to the local inflammation in the nose, there is a systemic component that influences peripheral blood, bone marrow and lungs.



The immune system is conventionally divided into innate and acquired (adaptive) immunity. The former is important in the early phase of the defense against previously unknown intruders, since there is a delay of 4-7 days for a full function of the adaptive immunity. Repeated encounters with the same antigen will result in a faster and more effective response of the adaptive immunity. Development of allergic airway inflammation is traditionally related to T helper type 2 (Th2) lymphocytes and their production of inflammatory cytokines as a part of the adaptive immunity, but recent data suggest that the innate immunity might also have a role in this process. Toll-like receptors (TLRs) have emerged as key receptors of the innate immune system but information about their role in allergy and airway inflammation is so far limited.



The aims of the present study were to investigate the expression of TLR2, TLR3, TLR4 and TLR9 in the nose, peripheral blood and bone marrow, and to find out if pollen encounter affects the local and systemic expression of these proteins. The effects of nasal provocation with lipopolysaccharide (LPS), a ligand to TLR4, were investigated and the functional activity of TLR3 in eosinophils was explored in a series of in vitro experiments.



In the six studies included in this thesis, a total of 111 patients with allergic rhinitis and 55 healthy volunteers were investigated. Samples of nasal mucosa, nasal lavage fluid, peripheral blood and bone marrow were examined using enzyme-linked immunosorbent assay (ELISA), real-time polymerase chain reaction (RT-PCR), immunohistochemistry and flow cytometry.



TLR2, TLR3, TLR4 and TLR9 were found in the nasal epithelium and in inflammatory cells in the submucosa, and TLR2, TLR4 and TLR9 were expressed in neutrophils in nasal lavage fluid. In bone marrow, TLR2, TLR3, TLR4 and TLR9 were found in neutrophils, eosinophils, monocytes and immature granulocytes. These TLRs also appeared in peripheral blood, except for the absence of TLR3 in neutrophils. In addition, TLR9 was seen in basophils and lymphocytes. Generally, the leukocyte expression of TLRs was higher in nasal lavage fluid compared to bone marrow, where it in turn was higher than in peripheral blood. Stimulation of isolated eosinophils with the TLR3 agonist polyinosinic-polycytidylic acid (poly(I:C)), resulted in an enhanced expression of CD11b and release of interleukin (IL)-8, involving the intracellular pathways of p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-?B).



Nasal provocation with the TLR4 ligand LPS resulted in leukocyte recruitment and increase in IL-6 and albumin in nasal lavage fluid after 6 hours. In addition, it caused a reduction in the tissue expression and the nasal lavage fluid levels of the anti-inflammatory mediator uteroglobin.



Nasal pollen challenge in allergic patients resulted in an increased amount of neutrophils in nasal lavage fluid after one hour and an increased expression of TLR2, TLR3 and TLR4 in the nasal epithelium after 24 hours. Patients with seasonal allergic rhinitis had an activated expression of TLR4 in neutrophils, eosinophils and monocytes in peripheral blood during pollen season. Similarly, an activated expression of TLR4 was found in immature granulocytes and neutrophils in bone marrow and in neutrophils in nasal lavage fluid. The expression of TLR3 in eosinophils decreased in peripheral blood and bone marrow during pollen season, whereas the expression of TLR9 was not affected by allergen exposure.



The present findings that pollen-induced upper airway inflammation affects the expression of TLRs locally and systemically, support the idea of a role for the innate immune system during symptomatic allergic rhinitis. (Less)
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author
supervisor
opponent
  • Professor Stierna, Pontus, Department of Otorhinolaryngology, Karolinska Institutet
organization
publishing date
type
Thesis
publication status
published
subject
keywords
neutrophils, poly(I:C), uteroglobin, Toll-like receptors, Medicine (human and vertebrates), Medicin (människa och djur), Otorhinolaryngology, audiology, auditive system and speech, Otorinolaryngologi, audiologi, hörsel- och talorganen, innate immunity, LPS, allergic rhinitis, bone marrow
pages
149 pages
publisher
Department of Otorhinolaryngology, Lund University
defense location
Lilla aulan, Ingång 59, Medicinskt Forskningscentrum, UMAS, Malmö
defense date
2006-09-15 13:00
ISSN
1652-8220
ISBN
91-85559-16-4
language
English
LU publication?
yes
id
8bc66c26-4643-42d6-b237-54cc2d503124 (old id 547073)
date added to LUP
2007-09-12 07:04:30
date last changed
2018-11-21 20:47:40
@phdthesis{8bc66c26-4643-42d6-b237-54cc2d503124,
  abstract     = {Allergic rhinitis is an inflammatory disorder with the characteristic symptoms itching, sneezing, secretion and blockage upon allergen contact. In addition to the local inflammation in the nose, there is a systemic component that influences peripheral blood, bone marrow and lungs.<br/><br>
<br/><br>
The immune system is conventionally divided into innate and acquired (adaptive) immunity. The former is important in the early phase of the defense against previously unknown intruders, since there is a delay of 4-7 days for a full function of the adaptive immunity. Repeated encounters with the same antigen will result in a faster and more effective response of the adaptive immunity. Development of allergic airway inflammation is traditionally related to T helper type 2 (Th2) lymphocytes and their production of inflammatory cytokines as a part of the adaptive immunity, but recent data suggest that the innate immunity might also have a role in this process. Toll-like receptors (TLRs) have emerged as key receptors of the innate immune system but information about their role in allergy and airway inflammation is so far limited.<br/><br>
<br/><br>
The aims of the present study were to investigate the expression of TLR2, TLR3, TLR4 and TLR9 in the nose, peripheral blood and bone marrow, and to find out if pollen encounter affects the local and systemic expression of these proteins. The effects of nasal provocation with lipopolysaccharide (LPS), a ligand to TLR4, were investigated and the functional activity of TLR3 in eosinophils was explored in a series of in vitro experiments.<br/><br>
<br/><br>
In the six studies included in this thesis, a total of 111 patients with allergic rhinitis and 55 healthy volunteers were investigated. Samples of nasal mucosa, nasal lavage fluid, peripheral blood and bone marrow were examined using enzyme-linked immunosorbent assay (ELISA), real-time polymerase chain reaction (RT-PCR), immunohistochemistry and flow cytometry.<br/><br>
<br/><br>
TLR2, TLR3, TLR4 and TLR9 were found in the nasal epithelium and in inflammatory cells in the submucosa, and TLR2, TLR4 and TLR9 were expressed in neutrophils in nasal lavage fluid. In bone marrow, TLR2, TLR3, TLR4 and TLR9 were found in neutrophils, eosinophils, monocytes and immature granulocytes. These TLRs also appeared in peripheral blood, except for the absence of TLR3 in neutrophils. In addition, TLR9 was seen in basophils and lymphocytes. Generally, the leukocyte expression of TLRs was higher in nasal lavage fluid compared to bone marrow, where it in turn was higher than in peripheral blood. Stimulation of isolated eosinophils with the TLR3 agonist polyinosinic-polycytidylic acid (poly(I:C)), resulted in an enhanced expression of CD11b and release of interleukin (IL)-8, involving the intracellular pathways of p38 mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-?B).<br/><br>
<br/><br>
Nasal provocation with the TLR4 ligand LPS resulted in leukocyte recruitment and increase in IL-6 and albumin in nasal lavage fluid after 6 hours. In addition, it caused a reduction in the tissue expression and the nasal lavage fluid levels of the anti-inflammatory mediator uteroglobin.<br/><br>
<br/><br>
Nasal pollen challenge in allergic patients resulted in an increased amount of neutrophils in nasal lavage fluid after one hour and an increased expression of TLR2, TLR3 and TLR4 in the nasal epithelium after 24 hours. Patients with seasonal allergic rhinitis had an activated expression of TLR4 in neutrophils, eosinophils and monocytes in peripheral blood during pollen season. Similarly, an activated expression of TLR4 was found in immature granulocytes and neutrophils in bone marrow and in neutrophils in nasal lavage fluid. The expression of TLR3 in eosinophils decreased in peripheral blood and bone marrow during pollen season, whereas the expression of TLR9 was not affected by allergen exposure.<br/><br>
<br/><br>
The present findings that pollen-induced upper airway inflammation affects the expression of TLRs locally and systemically, support the idea of a role for the innate immune system during symptomatic allergic rhinitis.},
  author       = {Fransson, Mattias},
  isbn         = {91-85559-16-4},
  issn         = {1652-8220},
  keyword      = {neutrophils,poly(I:C),uteroglobin,Toll-like receptors,Medicine (human and vertebrates),Medicin (människa och djur),Otorhinolaryngology,audiology,auditive system and speech,Otorinolaryngologi,audiologi,hörsel- och talorganen,innate immunity,LPS,allergic rhinitis,bone marrow},
  language     = {eng},
  pages        = {149},
  publisher    = {Department of Otorhinolaryngology, Lund University},
  school       = {Lund University},
  title        = {Toll-like Receptors in Allergic Rhinitis},
  year         = {2006},
}