General Pathology, Exam II, Section 4

What is an antigen?

foreign substance that stimulates an immune response

What is an antibody?

Blood protein produced in response to an antigen

What is IgE responsible for?

Allergic response, release of histamine

What is the most common antibody in blood? Where else is it found?

IgG; lymph and saliva

What is the 1st antibody formed after antigen exposure? Where is it found?

IgM; blood, lymph, spleen

Which antibody is found in mucous membranes?

IgA

What is the immune-mediated injury to healthy tissues that is inappropriately targeted or controlled?

Hypersensitivity

What can cause hypersensitivity reactions?

Autoimmunity, excessive/persistent microbial infections, reaction to harmless environmental stimuli

What type of reaction is type I hypersensitivity? Which antibody responds and what does it do? When does the reaction occur?

Allergic; IgE releases histamine; immediately

In type I hypersensitivity, ________________ cells stimulate ______ cells to increase production of ________

Helper T; B; IgE

In type I hypersensitivity, what does re-exposure cause?

Mast cell degranulation

What does histamine release cause in a type I hypersensitivity reaction?

Vasodilation, bronchoconstriction, increased mucus secretion

What are the characteristics of a late phase type I hypersensitivity reaction?

4-8 hours after exposure; epithelial damage

What type of reaction is type II hypersensitivity? Mediated by?

Cytotoxic opsonization; antibodies IgG and IgM

What does opsonization in type II hypersensitivity lead to?

Inflammation and phagocytosis

What does IgG do in type II hypersensitivity?

Neutrophils and NK cells

What does IgM do in type II hypersensitivity?

Membrane attack complex

Which test is used to determine a type II hypersensitivity?

Coombs

What are some examples of type II hypersensitivity?

ABO incompatibility, rheumatic fever, myasthenia gravis, Graves' disease

What type of -thyroidism is Graves' disease? What type of hypersensitivity?

Hyperthyroidism; type II

What type of hypersensitivity would be characterized by ACh inhibition?

Type II

What type of hypersensitivity is antibody mediated and characterized by soluble immune complexes?

Type III

Which antibodies respond to antigen exposure in type III hypersensitivity?

IgG and IgM

Where do immune complexes form and where do they go in type III hypersensitivity?

Form in vasculature, go to tissues

What type of inflammation does type III hypersensitivity stimulate and when?

Complement-mediated inflammation; 1-2 weeks

What types of tissues can be damaged in type III hypersensitivity?

Vessel walls (vasculitis), kidneys (hlomerulonephritis), joints (arthritis)

What are some examples of type III hypersensitivity?

Lupus, polyarteritis nodosa, serum sickness

What type of necrosis is a result of type III hypersensitivity?

Fibrinoid necrosis

What type of cells mediate type IV hypersensitivity?

T cells

What are the characteristics of cytokine-mediated type IV hypersensitivity?

CD4 T cells, 24-48 hours, neutrophils and macrophages, progresses into chronicity

What are the characteristics of direct cytotoxicity?

CD8 T cells, apoptosis

What are some examples of type IV hypersensitivity?

Poison ivy, TB, MS, RA, type I diabetes, Crohn's

What is the result of central tolerance and where does it most commonly occur?

Apoptosis; thymus or marrow

What is the result of peripheral tolerance?

Inactivation or apoptosis

What type of alleles can lead to autoimmunity?

HLA alleles

What are human leukocyte antigens/MH1/2?

Surface proteins located on ALL nucleated cells and leukocytes

Which chromosome is associated with MH complexes? What is unique about it?

Chromosome 6; never develop autoimmunity

How do HLA/MH promote antibody formation?

Presents viral fragments to cell's surface

What is one of the most high risk HLAs? Which HLA allele?

Ankylosing spondylitis; B27

What is cross reactivity?

one antibody interacting with multiple antigens

T/F: Males are at higher risk of developing autoimmune disorders?

FALSE, females are at higher risk

Which antibodies form with systemic lupus erythematosus (SLE)?

Antinuclear antibodies and IgG

What are the 4 most important diagnostic criteria for SLE?

Malar rash, photosensitivity, renal disorders, antinuclear antibodies

Which type of hypersensitivities are most likely to cause injury in someone with Lupus?

II and III

A red blood cell cast in urine is indicative of?

Lupus and renal failure

What happens with vasculitis in Lupus?

Thickened tunica intima, thrombi, fibrinoid necrosis

What does UV exposure cause in Lupus?

Malar rash

What is it called when lupus impacts pleural and pericardial tissues?

Serositis

How can lupus impact CNS?

Seizures, psychosis

Which type of twin is at higher risk for lupus, monozygotic or dizygotic?

Monozygotic

An increase in what hormone can lead to lupus?

Estrogen

What do most people with lupus pass away from?

Renal failure

What is the autoimmune attack on exocrine glands?

Sjogren syndrome

Which ducts does sjogren syndrome impact?

Lacrimal and salivary

What is it called when sjogren syndrome impacts the tongue?

Xerostomia

What is it called when sjogren syndrome impacts the eyes?

Keratoconjunctivitis

Which gland is enlarged with sjogren syndrome?

Parotid

What is isolated sjogren syndrome called?

Sicca sydrome

What causes secondary sjogren syndrome?

Other autoimmunity; MC RA

What does sjogren syndrome increase the risk of?

B cell lymphoma

What is the widespread fibrosis/hardening of connective tissues? What does it lead to?

Systemic sclerosis or scleroderma; destruction of small arteries

Where is systemic sclerosis most common?

Skin (95%) and GI (90%)

What are some results of systemic sclerosis?

Raynaud phenomenon, arthritis, HTN

Where does limited systemic sclerosis occur?

Fingers and face

What does CREST stand for regarding systemic sclerosis?

Calcinosis, raynaud, esophageal dysmotility, sclerodactyly, telangiectasia

What type of systemic sclerosis is aggressive?

Diffuse

How are primary immune deficiencies acquired? Onset timeline?

Genetically inherited; 6 months (no more antibodies from mom)

What are two examples of primary immune deficiency disorders?

Bruton and Severe combined immunodeficiency (SCID)

What is the issue with Bruton's disease? What does it lead to? Who is it most common in?

B cells can't mature to make antibodies; leads to many bacterial and viral infections; 6 month old males

What is the issue with severe combined immunodeficiency (SCID)? What does it lead to?

B and T cell lymphopenia and lymphoid atrophy; infection from ALL microbes (bacterial, viral, fungal)

T/F: primary immune deficiencies are more common than secondary

FALSE, secondary are more common

What is the most common cause of secondary immune deficiency disorders?

Therapy induced (chemo, radiation therapy)

By what mechanisms does secondary immune deficiency occur?

Marrow suppression, lymphocyte dysfunction (AIDS)

What types of cells does AIDS destroy?

CD4 T cells, macrophages

What is the most common method of AIDS transmission in the US? Globally?

Homosexual sex; heterosexual sex

What do you look for when screening for AIDS?

Gp120

Which laboratory tests are used to detect gp120 in AIDS cases?

ELISA and western blot

What role does CCR5 play in HIV infection?

Allows HIV to gain access to T cells

What happens during clinical latency of HIV?

Patient has mild symptoms that come and go, don't know they have HIV

What will decrease if someone has HIV/AIDS? What will increase?

CD4 T cells; viremia

What are the symptoms of acute phase HIV/AIDS? Timeline? What decreases?

Flu-like (fever, pharyngitis, myalgia); 3-6 weeks post infection; viremia (12 weeks)

What are the symptoms of chronic (latent) phase HIV/AIDS? Timeline? What decreases and what increases?

Generalized lymphadenopathy, fatigue, fever; 2-10 years; CD4 T cells decrease; Viremia increases

What are the symptoms of the crisis phase of HIV/AIDS?

T cell count less than 200, spiked viremia, cachexia (extreme weight loss), fatigue, fever lasting more than a month, diarrhea, CNS defects

What type of cancer is indicative of HIV/AIDS?

Kaposi sarcoma

What are the consequences of AIDS?

Opportunistic infections and CNS damage

What accounts for 80% of AIDS deaths?

Opportunistic infection

What type of tumors are a result of AIDS?

CNS lymphoma

What type of cells spread HIV to CNS?

Monocytes

What are non-branching proteins with fibrillation proteins?

Amyloid

Which stains are used to identify amyloid?

Congo red and apple green birefringence

Why do amyloid proteins accumulate?

Failed phagocytosis

What type of amyloid protein is a plasma cell proliferation from antibody light chains?

Amyloid light (AL)

Which type of cancer is caused by amyloid light proteins? What special name is given to them?

Multiple myeloma; bence-jones

Which type of amyloid proteins are produced by the liver? Which diseases are they associated with?

Amyloid associated; TB, RA, ankylosing spondylitis, IBD

What type of amyloid protein makes cerebral plaques responsible for Alzheimer's?

Beta amyloid

What type of amyloid protein is an amyloid precursor protein?

Beta amyloid

Why are those with Down syndrome at higher risk for Alzheimer's?

Chromosome 21 carries protein that causes beta amyloid to form

What type of amyloid protein is the normal serum protein that accumulates when mutated or misfolded?

Transthyretin (TTR)

What does an accumulation of transthyretin (TTR) lead to?

Senile systemic amyloidosis

Which pattern of amyloidosis impacts multiple organ systems?

Systemic