L2 - Immunodeficiency and Autoimmunity Flashcards
Features of the innate immune system
Rapid
Non-specific
Works immediately
No memory
What makes up the innate immune system?
Physical barriers
Chemical barriers
Resistance to pathogens (dendritic cells, macrophages, neutrophils)
What makes up the adaptive immune system?
Humoral - antibodies
Specialised cells
- B cells (produce antibodies)
- T cells (helper and killer)
Features of adaptive immunity?
Delayed response Specific Self/non self recognition Diversity in types of response Memory
- protects against reinfection of specific antigens
Where are B cells made/matured?
Made and matured in the bone marrow
Where are T cells made and matured?
Made in the bone marrow but mature in the thymus
Which cell type can be described as a gatekeeper of the immune system?
T helper cells CD4
What activates t helper cells CD4?
Activated by binding of MHCII
What to t helper cells CD4 do?
Presents antigen to cytoxic T cells CD8+ and naive B cells and undergo clonal expansion
What do cytoxic T cells CD8+ do?
Bind MHCI
defects damaged MHC from infected/diseased cell, or non-self MHC directly
When is IgM antibody used?
Primary response
When is IgG antibody used?
Secondary response
When is IgA antibody used?
Protects mucosal surfaces
When is IgD antibody used?
B cell receptor
When is IgE antibody used?
Antibody of allergy found on mast cells
What is immunosuppression and what is it’s uses?
Natural or artificial process which can turn off the immune response either partially or fully
Uses: transplant rejection, autoimmune diseases, lymphoproliferative diseases
What is immune deficiency?
Lack of an efficient immune system - susceptible to infection
NB: X-linked/autosomal recessive traits
What is primary/secondary immunodeficiency?
Primary: very rare, often diagnosed in early childhood (recurrent infection often suggests immunological problems)
Secondary: acquired immunodeficiency, causes; stress, cancer, surgery, malnutrition, irradiation, AIDS, infection
NB can also be acquired due to immunosuppressive effects of drugs eg chemotherapy
What is organ specific autoimmunity?
- affects single organ
- autoimmunity restricted to auto antigens of that organ
- overlap with other organ specific diseases
- autoimmune thyroid disease is typical (hasimotos and grave’s)
What is hashimotos thyroiditis?
Destruction of thyroid follicles
- associated with autoantibodies to thyroglobulin and thyroid peroxidase
- leads to hyperthyroidism
What is Graves’ disease?
Inappropriate stimulation of thyroid gland by anti-TSH-autoantibodies
- leads to hyperthyroidism
Why does autoimmunity occur?
Autoreactive B cells
Autoreactive T cells
Defects in T cells
which type of precursor cell will give rise to dendritic, macrophage and neutrophils?
myeloid precursor cells
which type of precursor cell will give rise to B and T cells?
Lymphoid precursor cells
what type of cell is CD4?
T helper cell
what type of cell is CD8?
T cytotoxic cell
Cells from innate immune system (macrophage, dendritic, NK cells and mast cells) are
armed with Pattern Recognition Receptors (PRRs) - what do PRRs do?
recognise foreign material but they are not specific
activate cytokines and surface molecules which will instruct the T cells to
recognise the microorganism for the right immune response
what is autoimmunity?
- theoretical concept
- genetically determined
what is an autoimmune disease?
- breakdown of self-tolerance
- environmental factors acting on a favourable genetic background
are autoimmune disease more common in women or men?
women (hormonal influence)
what are some environmental triggers of autoimmunity?
infection
trauma tissue damage
smoking
what is the most common autoimmune disease?
Rheumatoid Arthritis
which autoimmune disease ischaracterised by inflammatory joint pathology
associated with synovial joint inflammation and tissue destruction?
Rheumatoid Arthritis
Susceptibility of what autoimmune disease is associated with defined HLA-DRB1 alleles?
Rheumatoid Arthritis
What is systemic specific autoimmunity?
- affect several organs simultaneously
- autoimmunity associated with auto antigens found in most cells of body
- overlap with other non-organ specific diseases
- connective tissue diseases are typical (SLE, scleroderma, polymyositis, sjogrens syndrome)
is using inflammatory markers as a diagnostic test disease specific or non specific?
non specific
is using autoantibody testing as a diagnostic test disease specific or non specific?
disease specific
is using HLA typing as a diagnostic test disease specific or non specific?
disease specific
why do we measure antibodies?
- diagnostic/early diagnosis/exclusion of diagnosis
- sub typing of patients
- monitoring of exacerbation or remission
- cost effective
what is HLA?
human leukocyte antigens
HLA are antigens on most cells in your body. Your immune system uses HLA to recognize which cells belong in your body and which do not.
which cells are used in antinuclear antibody testing? (ANA)
HEP 2000 cells
large nuclei and most autoimmune conditions target DNA
when would we carry out ANA tests?
when we suspect an autoimmune disorder
which test would you carry out if you suspect an autoimmune disorder?
Antinuclear antibody (ANA) testing
in a positive ANA test, what will you see under a microscope?
patterns of florescent markers
- Immunofluorescence matters are disease specific
what is immunosuppression?
a natural or artificial process which turns off the immune
response, partially or fully, accidentally or on purpose.
when would we use immunosuppressive treatments?
- transplant rejection
- autoimmune diseases
- lymphoproliferative diseases
what are causes of secondary/acquired immunodeficiencies?
- stress
- surgery/burns
- malnutrition
- cancer
- immunosuppressive drugs
- irradiation
- AIDS
- infection
