Autoimmune Flashcards
Autoimmune diseases
- breakdown of tolerance
- genetic factors are important
- original insult
- some autoimmune diseases are organ-specific (type II) and others systemic in distribution (type III)
Breakdown of tolerance
“tolerance” is developed as part of becoming immunocompetent
genetic factors important in autoimmune disease
affected members may not develop the same autoimmune disease; some people may have more than one autoimmune disease (tendencies are what’s inherited)
Original insult in autoimmune
- may be identifiable - often drug, virus, or bacteria
- often preexisting infections that leave no trace
Theories of autoimmune disease development
- Normal self-antigens are altered by a drug, pathogen, or other mutation and are no longer seen as “self” (no longer look like your own)
- antibodies against foreign antigens cross-react with a similar self-antigen
- Clonal deletion theory
Clonal deletion theory
suggests that self-reactive lymphoid cells are eliminated during immunological development
SLE stands for?
Systemic Lupus Erythematousus
Epidemiology for SLE
- 1 in 2,500 people
- 10x more women than men
- familial (ID twins have 30% concordance rate)
- 5 year survival rate = 93-95%
- mortality is low, but impose on quality of life is high
Type III SLE
Has a wide range of symptoms including:
- arthritis (90%) - complexes stuck in synovial membranes
- vasculitis and rash (75%) - stuck in blood vessels of skin
- kidney disease (40-50%) - stuck in glomerulus
- blood abnormalities (50%)
- cardiovascular disease (30-50%) - unknown mechanism but there’s correlation
SLE info
large variety of autoantibodies are produced including ones against DNA and RNA ( = ANA’s: anti-nuclear antibodies)
Treatment of SLE
- glucocorticoids/ corticosteroids - strong anti-inflammatory
- antimalarials - no known reason
- monoclonal antibody (anti-body against autoantibodies)
Downside of long-term corticosteroid treatment of SLE
- increased susceptibility to infections
- atherosclerosis -> stroke, Coronary Artery Disease (heart attack)
- obesity -> hypertension, diabetes type 2
- Cushing’s disease (hypercorticoidism: over tim. adrenal gland)
- others
Immunodeficiency diseases
- primary (congenital)
- secondary (acquired): as a result of infections, metabolic diseases, cancer or treatment
- may involve primarily B cells or different types of T cells or it may be generalized
All immunodeficiencies are characterized by ___________
lymphopenia (lymphocytes not making antibodies)
Primary Immunodeficiency
- SCID (severe combined immunodeficiency)
- lack both T and B cells
- thymus is hypoplastic (never gets big) and lymph nodes are small
- used to die early in infancy
- new treatments are bone marrow transplant and gene therapy trial (14/16 worked)
AIDS stands for?
Acquired immunodeficiency syndrome
syndrome
a group of symptoms that occur together
about AIDS
- HIV (human immunodeficiency virus)
- HIV as an affinity for T cells and monocytes
- macrophages can therefore also be infected, as well as fixed tissue phagocytes)
- HIV is cytotoxic - a depletion of these cells is typical of AIDS
- initial infection simulates B cells to produce antibodies, allowing most infected people to enter a latent stage
- latent = hidden (Aka asymptomatic)
AIDS process
- eventually both cell-mediated T cell and humoral B cell immunity both become depressed
- individuals can not defend themselves from infection and may die from a minor disease that overwhelms their immune system (chicken pox most common killer in children)
- some patients also develop tumors of different kinds (lymphomas, Kaposi’s sarcoma)
- HIV virus may act as an oncogene
Four groups of HIV-infected persons
- Acute illness
- Asymptomatic infection
- Generalized lymphadenopathy
- other diseases superimposed
Acute illness
- occurs in 50%, 3-6 weeks post-exposure
- nonspecific symptoms which last 2 to 3 weeks, then spontaneously disappear
- during this period, some patients develop antibodies
Asymptomatic infection
- variable duration (few months - few years)
- no symptoms, but carries the virus and is infectious
Generalized Lymphadenopahty
- in patients who were initially asymptomatic, or develop early on and persist
- lymphadenopathy - abnormal, usually enlarged LN
Other diseases superimposed
- opportunistic infections = organisms that only cause infections when the immune system is suppressed
- gastrointestinal disorders
- central nervous system involvement
- neoplasia (lack of immunosurveillance)
