Syllabus cAD Flashcards
increased incidence in CAD:
beagle, bichon frise, boxer, bulldog, bull mastiff, great Dane, Labrador retriever, pug, shar-pei, Staffordshire terrier and West Highland white terrier (WHWT)]
new def
hereditary, gener- ally pruritic and predominantly T-cell-driven inflamma- tory skin disease,
involving an interplay between skin
barrier abnormalities, allergen sensitisation and mi- crobial dysbiosis
5 breeds predisposed world- wide
boxer, bulldog, Labrador retriever, pug and WHWT
AD sensu stricto
- positive intradermal test and/or serological confirmation of allergen-specific immunoglobulin (Ig)E
atopic-like dermatitis
clinical diagnosis of AD, negative intradermal test and negative serological results
Genes associated with AD
- fillagrin- LR
- PROM 1 (prominin 1) -GR
- RAB3C (ras-related protein Rab-3c)-GR
- high IgE -chromsome 5 (LR),35 (WHWT)
+GSD-PKP2 (but it was latter disputed) - chromosome 3 (CFA), F2R (thrombin receptor/member of PAR familiy)- WHWT
- WHWT-CFA17 with a candidate gene PTPN22
- SNPs in IL-4R and IL-13-
IL-4R Cys 688 variant reduces the risk of AD in dachshund
PTPN22- for what is it used
protein tyrosine phosphatase nonreceptor type 22
-involved in the negative regulation of both the innate and adaptive (via downregulation both B- and T-cell receptor signalling) immune response
how are miRNA inflencing allergies
-influence the cells of the innate and adaptive immune system including the keratinocytes, thereby potentially affecting the course of the disease.
-biomarker
studies on miRNA genes
- incerased PDE4D in PBMC
- decrease of PIAS1, RORA and SH2B1
protective factors in human AD
-growing up in a rural environment
-contact with farm animals (“farming effect”)
- a diet rich in dietary fibre
-high food diversity
-early contact with siblings or peers
Protective factors for AD in dogs
-living with another dog
-been born in the current owner’s household
-living in a detached house (compared to an apartmen
-nonprocessed meat-based diet early in life
-living with another dog
-walking in wood, fields, beaches
Risk facors in dogs
-dogs living in extremely clean households
-urban environment
-receiving flea control
-being allowed on furniture
Does the exposure to endotoxins and microbial proteases has a protective effect for AD
-no stat significance
synthetic triacylated lipopeptide (TLR1/2 ligand) cell-wall component of Staphylococcus spp. induces what
TSLP via Toll-like receptor 2 (TLR2) activation in a canine keratinocyte cell line
-contriubutes to Th2 response ?
do dogs with non food-induced AD have a risk for sensitization to M. pachydermatis
-yes
-11/15 dogs
Does the T. canis has a protecive role in AD
YES
-infected dogs higher levels of T. canis spec IgG, IgE, D.faine IgE and total IgE and LOWER LESIONAL SCORES and SHORTER DURATION of pruritus
Which protease groups of HDM promote allergic sensitisation
- cysteine (group 1 mite allergens)
- serine ( group3, 6,9 allergens)
What is thought the moa for serine proteases in AD
-D.farinae-derived serine can upregulate IL-33 mRNA expression via protease-activated receptor-2 (PAR-2) activation
Group 2 and 7 mite allergens are speculated to play a role in what
TLR interactions
Dermatophagoides genus is the most common allergen in dogs (h). what is positivity rate
-60-90%
≤63% of clinically healthy dogs can show positive IDT reactions to HDM, while ASIS can be positive in ≤97% of cases.
How common are other dust and storage mite allergies
Tyrophagus putrescentiae (36%–80%)
Acarus siro (18%–80%)
(≥45%) co-sensitised to house dust and storage mites
-parallel exposure and sensitization, in vitro cross reactivity
Most common plant based allergens
Japan-Japanese cedar
+Bermuda rye, fescue
-South Korea-ash, sage, Johnson grass, plantain, oak, white ash, seeps sorrrel, mugwort, Bermuda grass
-pollen reacivity is increased during summer and autumn!
What are miRNAs?
short, single-stranded RNA molecules, of about 22 nu- cleotides in length, that play a role in the regulation of gene expression at the post-transcriptional level
Do molds play a role in sensitization of AD dog
-Rhizopus and mold mix- 2nd most common after HDM
+ in one study it was + 67% patients
-ASIS-44.8 % for Pullalaria and 39.6% Alternaria
-Aspergillus in 39.6%
-variable results depending on geographical and climatic factors
What is the rate of positivity to Malassezia
ASIS- 21.9-60%
IDT-24-73%
What is major allergen
if ≥50% of patients allergic to the “parent” allergen source have detectable positive IgE serological results or immediate skin test reactivity
Major allergens in dogs
Major allergens in humans
D.pteronyssinus (Der p 1 and Der p 2)
D. farinae (Der f 1 and Der f 2)
What are the potential genetic biomarkes of cAD
miR- 141, miR-187, miR-200a, miR-203, miR-215 and miR-429
General info about IL-33
-member of the IL-1 cytokine family
- binds to IL-1 receptor family member suppression of tumorigenicity 2 (ST2)
Where is IL-33 expressed
constitutively expressed as a nuclear protein in epithelial tissues of various organs, such as the lung, stomach and skin
How is IL-33 released
It is released extracellularly upon tissue damage and cell death or cell stress, and functions as an endogenous danger signal (alarmin)
-released full-length IL-33 is already active,
+ it can be processed by inflammatory proteases into a shorter ‘hyperactive’ mature form to further enhance allergic inflammation
How is IL-33 up or down regulated in skin/blood
-higher transcription levels in ch lesions of AD (when compared to helathy)
-expressed in KC, endothelial cells and dermal infiltrating cells in AD skin (IHC)
(no staining in helathy skin)
+ higher transcription levels in skin lesions with EXCORIATIONS (slef trauma may be associated with up regulation?)
-mRNA was upregulated in skin and PBMC in expterimnetal AD dogs
What is TSLP
epithelial cell-derived cytokine
-has a critical role in linking events between the body and environment to Th2 responses and the development of allergic inflammation
-might be involved in induction of flares in AD
How can be TSLP upregulated
-trypsin (a protease activated receptor-2 , PAR-2)- receptor for HDM derived proteases
-synthetic triacylated lipopeptide (TLR1/2 ligand)- receptors for membrane proteins of Staphylococcus
What staining pattern is seen with TSLP and cAD
-condensed staining pattern in SB
What is CCL17
-C-C motif chemokine ligand 17
-thymus and activation regulated chemokine (TARC),
- potent Th2 chemoattractant via its receptor CCR4 that is selectively expressed on Th2 cells
-PAR -2 agonist causes production of TARC
IS CCL17 up or down regulated in cAD
-upregulated
-significant differnece between helathy and lesional skin (but not with non-lesional)
Does CCL17 correlates with diseae severity- dog, people?
-hAD- correlates with disease severity
-serum CCL17/TARC concentration showed moderate correlation with CADESI-04
+ after tretamnet with GC, oclacitinib- significant reduction of CCL17
-biomarker
Has CCR4 inhibitor (AZ445) been tesed in dogs?
-no significant overall reduction of CADESI-03 scores
BUT, five treated dogs (35%) showed a moderate clinical improvement (40% reduction of CADESI-03 scores) with a reduction of acanthosis and dermal inflammation
What is CCL22?
C-C motif chemokine ligand 22, also known as macrophage-derived chemokine (MDC),
-another ligand for CCR4;
What is the function of CCL22
-CCL22/MDC also can recruit Th2 cells to the inflammatory loci of AD skin.
Any stuides about CCL22 in dogs
-upregulation of CCL22/MDC mRNA expression in both lesional and nonlesional skin
-positive correlation with pVAS and CADESI-04 scores
-might play an essential role in the pathogenesis of Th2-dominated cAD skin lesion
Role of IL-4
-potent regulator of immunity
-primarily secreted by Th2 cells, mast cells, eosinophils and basophils
-important role in leucocyte survival in Th2 cell-mediated immune responses and in IgE class switching of B cells;
How is IL-4 expressed in cAD
-variable
-HDM-induced cAD-elevated mRNA & protein expression in skin
4 studies using serum-no difference betwen healthy and AD dogs
-Incerased expression of IL-4RA (alpha subunit) in skin, but IL-4 levels remain uncahnged (incerased susceptibility in the skin? )
-maybe plays a role during acute flares / induction , diffrenet phenotypes of AD
-during 1 year oclacitinib- no change in % of IL-4 producing T regs
Importance of IL-5
produced primarily by Th2 cells and mast cells
-induces survival, activation and migration of eosinophils;
Do we see some imporvement with mepolizumab (anti IL-5) and is it elevated
- upregulated mRNA in skin of diffrenet AD models
-limited success in humans
What are the functions of IL-13
-contributes to IgE production
- differentiation of T cells towards the Th2 subtype.
Name mAb for IL-13
-dupilumab (the monoclonal an- tibody targeting the common receptor of IL-4 and IL-13; IL-4RA)
-lebrikizumab and tralokinumab
Is IL- 13 up or down regulated in cAD?
increased mRNA or protein levels of IL-13 in either skin or blood (sera or PBMCs)
How many mRNA splice variants of IL-31 receptor alpha subunit (IL-31RA) are in dogs and how many protein forms do they encode
- 5 varinats
-encode 2 protein isoforms:
1. the full-length isoform X1
2. truncated isoform X2 (lacks the N-terminal signal peptide and parts of the cytokine-binding domain; therefore, it may not bind to IL-31)
Is there a diffrence between transcription of isoform X1 and X2
-transcription of IL-31RA X2 was significantly higher than that of IL-31RA X1 in both HDM-induced atopic and healthy dogs
- the difference in the function remains to be confirmed
Has IL-31RA been demonstraed on dorsal root ganglia neurons and in nerve fibers in the skin
yes
Is there a connection between anti-IL 31 and TEWL
-decreased trans epidermal water loss (TEWL) during 12weeks of treatment
-suggesting a direct or indirect contribution of excessive IL-31 to skin barrier dysfunction
When used proactively, lokivetmab prevents flares in what %
-for more than one year in 28% of client-owned dogs, when it was used as proactive monotherapy
Is there any evidence for anti-IL31 vaccine in cAD
-IL-31 coupled to virus-like particles
- induced the production of anti-IL-31 antibodies
- resulted in an apparent reduction of itching (HDM)
Function of IFN-gamma
-produced by Th1 cells, Tc cells and natural killer cells
-promoting Th1 responses by enhanc- ing antigen presentation and inhibiting viral replication
-inhibits Th2 immune responses.
Are Th1 cytokines incerased or decerased in cAD
-inconsistent
-1 study incerased mRNA in PBMC
-reduced in serum, plasma and PBMC
-after oclacitinib: reduced on day 240,300
WHich cytokines are considered as IFN-gamma inducing factors
-Interleukin-12, IL-15 and IL-18
-part of the Th1 cy- tokine group.88
Are T regs elevated or decerased in cAD
-controversial results
-probable functional insufficeny of T regs
-AIT - presumed action inceraseing i
IL-10, and TGF-beta but study from 2021 could not find any difference after 1 year of ASIT
Function of IL-17
-IL-17A-F
- potent inducers of local tissue inflammation through the upregulation of proinflammatory and neutrophil-mobilising cytokines- IL-6, GM-CSF, TNF-alpha, IL-1 beta..
IL-17A showed upregulation of what cytokines in canine
-IL19, GM-CSF, S100 A8, IL-8,
+ plays a role in Th2 associated inflammation
-no upregulation of CCL17, CCL22, IFN-gama
Is IL-17 up or down regulated
-up in PBMC
-down in skin (mRNA)
IL-22 ?
-activator of keratinocyte proliferation
- induce the expression of epidermal host defence peptides (HDPs), such as S100A7, S100A8, S100A9, β-defensins and cathelicidin, and neutrophil chemoattractants, such as CXCL1, CXCL5 and CXCL
IL-7 roles
-haematopoietic growth factor
-secreted by stromal cells in the bone marrow and thymus, although it is also produced by keratinocytes
-development and homeostasis of immune cells, including CD4+ memory T cell
DOwn or upregulated IL-7
-up in cAD
IL-34 ?
-expressed by keratinocytes and by neurons in the brain
Il-34 in cAD
-higher serum IL-34 concentrations compared to healthy dogs with a significant positive correlation with CADESI-04 and pVAS scores
+ remained increased after GC and olcacitinib
IL-36
-expressed mainly on the barrier sites of the body- bronchial, intestinal and dermal epithelium
-secreted in an inactive form and activated by different proteases
-associated with host defence against pathogenic microbes- Staphyloccoucus + for amplification of inflammation
-upregulated
MIF - macrophage migration inhibitor factor
-expressed on both immune and nonimmune cells
-involved in T-cell activation and delayed-type hypersensitivity by recruiting and activating macrophages at inflammatory loci
MIF -up or down regulated
-upregulated in cAD in serum but no correlation between CADESI-04 or pVAS
Which factors are associated with neurogenic inflammation and how do they promote ch AD
-NGF, Substance P, periostin
-promoting vasodilation and leucocyte-mediated inflammation
NGF?
- keratinocytes and promotes the growth
fibroblasts, epithelial and endothelial cells
-NGF- elevated or down
-up 6 h after allergen challenge
-decrease after 48 h
-NGF+ KC increased in lesional skin after 72h of epicutaneous exposure
-involved in flares ?
Substance P - up or downregulated
-up by RNA-seq analysis in lesional skin , but mRNA did not change in ac canine model of HDM-induced skin lesions
Substance P -role
secreted from free nerve endings in the skin, keratinocytes and various inflammatory cells
- may induce cutaneous inflammation
Periostin- role
-extracellular matrix protein secreted by produced by keratinocytes and promotes the growth fibroblasts, epithelial and endothelial cell
-promotes differentiation and migration of fibroblasts and proliferation of keratinocytes
-a critical role in the remodelling and repair of damaged tissues
-directly activates itch sensory neurons - robust itch
Periostin- down or up regulated
-up
Which cermides are most commonly altered in cAD
-ceramide 1/CER[EOS],
-ceramide 9/CER[EOP]
-ceramide CER[NP]
HOw are corneocytes changed in AD
-SC of atopic dogs is characterised by a hexagonal lipid packing
-instead of the classic orthorhombic packing characteriing the lamellar organisation of lipids in healthy skin
+ decrase in relative abundance of free fatty acids
-decreased ratio of CER[NS] C44/C34 was seen in atopic skin
cutaneous dysbiosis definition
an imbalance in the composition of microbial population associated with reduction in microbial diversity and in the number of beneficial bacteria
Which Malassezia predominates in helathy dogs
M. globosa
What bacteria were found in AD ears compared to helathy
Staphylococcus spp. (Firmicutes) Ralstonia spp. (Proteobacteria) organisms
+ higher abundance of E. coli in healthy
Is there a differnce in bacteria diversity in helthy dogs in different areas
-no difference in bacterial diversity among the different body sites of healthy dogs
-most abundant bacterial phyla, in descending order, included Actinobacteria, Proteobacteria, Firmicutes and Bacteroidetes
What phya was found in dogs with AD regarding bacetrial diversity
-no difference in bacterial diversity among body sites
- most abundant organisms belonging to the phyla Proteobacteria and Actinobacteria,
followed by Firmicutes and Bacteroides
What was the conclusion in GSD with and without AD about bacterial diversity
atopic German shepherd dogs have a different bacterial community composition and a lower diversity when compared to healthy dogs of the same breed.
What are the bactera and fungi present in healthy dogs
-Cutibacterium acnes, S.pseudinter- medius, Porphyromonas cangingivalis, Capnodiales,
-unclassified fungal species and Alternaria
In clinically affeted dogs with AD , what bacteria were found
-S.pseudintermedius and S.schleiferi.
-Bacteroides pyogenes and Peptoniphilus grossensis
From clinically affeted ears , what bactera and fungi were isolated
M.pachydermatis, S.pseudintermedius, S.schleiferi and a few anaerobic bacteria such as Finegoldia magna, Peptostreptococcus canis and P. cangingivalis.
Bacteria and fungi found in helthy ears
C. acnes, S. pseudintermedius, Streptococcus sp. and the top three most dominant fungi included M. pachydermatis, Capnodiales and Pleosporales
What effect did malasseb had on microbial diversity when bathed 2 x weekly for 3 weeks
- no difference in bacterial micorbiome
-decerase in diversity of Epicoccum and Blumeria in heathy and atopic skin!
What was the effect of phototherapy on microbiome in healthy and atopic dogs
-phototherapy was associated with a significantly increased relative abundance of Actinobacteria and Cyanobacteria in atopic dogs
-phototherapy resulted in an overall decrease in S.pseudintermedius in atopic dogs.
Did the skin was fluid from AD dogs had lower or increasd inhibitory activiti againts Spathylocci and why
-lower inhibitory activity
-it suggest poorer antimicrobial activity
What did the immuno-scanningelectron microscopy showed in atopic skin and healthy regarding AMP
Atopic skin - higher levels of HDP/AMPs retained inside the keratinocytes and a lower level secreted in the supernatant compared to healthy skin
-canine β-defensin 103 was retained on the outermost layer of the SC and the number of bacteria-adhered peptides was higher in atopic when compared to healthy skin
What is the conclusion regading AMP in AD
-atopic skin shows higher HDP/AMP gene expression nonassociated with an increase in protein expression
-dysregulation in the :
secretion (tendency to be retained in the keratinocytes),
dispersion (tendency to remain attached on the skin surface),
antimicrobial efficacy (lower antibacterial inhibitory effect)
of atopic compared to healthy HDPs.
What was concluded in AMP in ears between healthy and atopic dogs
- decreased amount of cBD3-like and cCath in noninfected ears of atopic dogs when compared with healthy ears
