Immunology of the skin
MUDr. Langerová Eliška
Immune reactions
 Specific vs. Non- specific
 Cellular immunity ( against viruses, mycotic
elem., IC bacteria, cancer, GvH reaction, Cellmediated
reaction )
 vs. Humoral (EC bacteria, some viruses,
toxins)
Cellular immunity
 Non-specific:
 fagocyting cells, NK cells, keratinocytes, mast cells,
fibroblasts…
 Specific:
 T- lymphocytes, APC
Humoral immunity
• Non- specific:
• complement system, proteins of acute reaction
• Specific:
• antibodies produced by B- lymphocytes
SIS (skin immune system)
 Functional unit - epidermis, dermis, blood
vessels, lymphatics, lymph nodes
SIS
 Cells - Keratinocytes
- Langerhans cells
- dermal denritic cells
- fibroblasts
- Lymphocytes
- Macrophages
- Granulocytes
- Mast cells
 All units of SIS cooperate x redundant
 Communication : selectins, integrins, cytokines
Cytokines
 Polypeptides
 Changes in cellular proliferation,
differentiation, migration
 Stimulate imunoglobulins and cellular
immunity
 Specific receptors
 Pleotropic effect
Cytokines- 5 groups
 1. interleukins:
 Leukocytes ( lymfokiny, monokiny)
 2. interferons (α,β,γ):
 Antivirotic
 Synthesis of Ig by B-lymphocytes, activate
macrophages, NK cells, lymphocytes-T
 Antiproliferative → cytostatic/cid against
tumours
Cytokines – 5 groups
 3. chemokins:
 Induce inflammation ( eg. IL 8)
 Chemotaxes
 Physiological migration of leukocytes
 4. Colony stimulating factors (CSF):
 Prolifer. of specific pluripotent cells of bone
marrow in adults
 Granulocytic vs. Macrofages
Cytokines – 5 groups:
 5. tumor necrosis factor (TNF):
 TNFα (kachektin)
 Growth f., interleukins
 TNF β (lymfoxin)
 Cytotoxic
 effects: support cellular, humoral imm.,
proinflammatory, regulation of
hematopoesis, cell proliferation,
differentiation, healing wounds
Other mediators:
 Neuropeptides (substance P)
 Eikosanoidy – allergic reactions,
inflammation
Physiological reactions:
 Elimination of extracorporal and bodie´s
„damaged“ structures
 Phases: aferent, amplification, effector
 Damage of skin → non- spec. immume
reaction = acute inflammation
 keratinocytes, complement sys., fagocyt. cells (
polymorfonuclears, macrophages), NK , mast
cells, cytokins, activation of lysosomal
enzymes,…..
→fagocytosis / cytolysis of most of patogens
 Rest activate SPECIFIC immune system
 Specific :
 T+B – lymphocytes
 APC ( Langerhans cells,dermal denritic cells,
macrophages, keratinocytes), fagocytes,
cytokines, complement
 HLA compatibility between APC and
lymphocytes
Immunological reaction
 In the skin- swallow of antigen by APC → to the
sentinel lymph node → remodelation of „naive“ Tlymphocyte
to „memory“ T-cell →
 → differentiation to cytotoxic ( CD 8+) and helper
(CD4+) → subpop. Th1 (supress Ig) and Th2 (
support Ig)
 Activation of B-lymfocyte → differentiate to
plasmocytes → produce Ig ( IgM)
Immunological memory
 Memmory T and B lymphocytes
 Secondary immune reaction
 Effector cells and Ig (mainly IgG)- more,
quicker reaction, longer
Homing
• Sensitized T cells return to the skin
Pathological immune reactions
 Immunodeficiency - insufficiency
 Autoimmune deseases – bad tolerance
 Allergies
 Intensified defensive reaction
 Alergens, haptens
 Harmful
 80% of allergies- on skin and mucosae
Allergies :
division Coombse-Gell- IV types:
 Type I: immediate hypersensitivity reaction
(mediated by IgE and mast cells)
 Type II: Humoral cytotoxic reaction
(mediated by IgG, IgM, C)
 Type III: Immune complex reaction
(mediated by IgG, IgM, IgA and C)
 Type IV: Cell-mediated reaction
(lymphocytes, lymphokines)
Type I: immediate hypersensitivity r.
(mediated by IgE and mast cells)
 Seconds to minutes (x latent -hours- mites)
 Anaphylaxis , Angioedema
 Urticaria
 Atopy
 Sting
 allergy to food
Type II: Humoral cytotoxic reaction
(mediated by IgG, IgM, C)
 Complement/ antibody mediated cytolysis
 6 hours
 Hemolysis in newborns, hemolytical anemia, purpura,
pemphigus vulgaris,pemfigoid bullosus, DHD, …..
Type III: Immune complex reaction
(mediated by IgG, IgM, IgA and C)
 6-12 hours
 Vasculitis – subpapilar, periadnexal vessels
 SLE, erythema nodosum,EEM, DHD- cytotox type
 Arthus reaction – localised variant ( eg. Insulin)
T. IV: Cell-mediated r.(lymphocytes,
lymphokines)
 sensitised T cells → antigen specific receptors
 Effector- macrophages
 delayed hypersensitivity – 7 days –refractory phase – after
1st contact, 24-72 hours after 2nd…n contact
 intracellular microorganisms – eg. TBC- tuberkulin r.,
viruses, mykotic, parazites, cancer
 allergic contact dermatitis
Langerhans cell