Skin Immunology Flashcards
What are keratinocytes and what are their function
they are structural and functional cells of the epidermis
sense pathogens via cell surface receptors and help mediate an immune response
produce antimicrobial peptides
produce cytokines and chemokines
what are lagerhans and what are their function
dendritic cells found in the epidermis
antigen presenting cells, process microbial fragments and present them to T cells
help activate T cells
what types of T cells are found in the epidermis
Mainly CD8+
what types of T cells are found in the dermis
CD4+ and CD8-
what do dermal dendritic cells do
antigen presenting and secreting
what do plasmacytoid dendritic cells do
produce IFN alpha, found in diseased skin
what are the two types of dendritic cell found in the dermis
dermal dc
plasmacytoid dc
where are T cells produced and sensitised
produced in bone marrow
sensitised in thymus
What do CD4+ T cells do
Helper T cells
TH1- activate macrophages
TH2 -help B cells make Ab
What do CD8+ cells do
Cytotoxic T cells
kill infected cells directly
what do dendritic cells do
antigen presenting cells: present antigens to T and B cells
secrete cytokines/chemokines during inflammatory response
what do neutrophils do
circulating leukocytes attracted to tissues by chemokines to kill cells
What do mast cells do and where are they found
Tend to be found in ‘barriers’ eg. skin
they are the effectors of IgE mediated response (allergy), IgE binds which activate the mast cells causing them to release inflammatory mediators
What are the preformed inflammatory mediators released from mast cells
Tryptase
Chymase
TNF
Histamine
what activates mast cells
physical trauma, certain drugs, micro-organisms
what do MHC I molecules do and where are they found
found on almost all cells
present antigen to cytotoxic T cells
present endogenous antigens (antigens that come from inside the cell itself)
What do MHC II molecules do and where are they found
Found on antigen presenting cells, present exogenous antigens (antigens from outside the cell) to Th cells
what immune cells are involved in the immunopathogenesis of psoriasis
Keratinocytes are under stress
they activate dendritic cells which migrate to lymph nodes to present to T cells
T cells are attracted to the dermis and secrete interlukins
this stimulates keratinocyte proliferation
antimicrobial peptides are increased in atopic eczema true/false
false
decreased
mutations in which gene is associated with severe/early onset of atopic eczema
fillagrin
what are 3 autoimmune skin diseases
psoriasis
vitiligo
systemic lupus erythematous
what is primary immunodeficiency
inherited defect, can be specific or non specific
what is secondary immunodeficiency
acquired
AIDS malignancy Ageing Diabetes Renal malfunction Burns Alcoholic cirrhosis Malnutrition
What is type 1 hypersensitivity
IgE mediated rapid/early response
degranulation of mast cells
what is type 2 hypersensitivity
important in autoimmunity and transplantation
blood transfusion recipients
IgG
what is type 4 sensitivity
mediated by TH1 cells
DELAYED response, T cell mediated which then recruits other cells to site
peaks at 24-48 hours after contact with antigen
metals (nickel, chromate), drugs
what factors can affect skin immune responses
Organ transplant (immunosuppression)
sunlight/UV
Aging
what immune cells are in the epidermis
T cells (CD8+) and langerhans cells
what non-immune cells are in the epidermis
keratinocytes
melanocytes
what immune cells are in the dermis
dendritic cells
macrophages
T cells (CD8+, CD4+)
natural killer cells
