Immunopathology Flashcards
Explain the ABCD mnemonic for hypersensitivity reaction classification.
Type I: Anaphylaxis, IgE-mediated
Type II: Blood reactions, IgG- or IgM- produced against tissues (Grave’s dz, myasthenia gravis, pernicious anemia)
Type III: (Ag-Ab) Complex diseases (SLE)
Type IV: Delayed, T-cell mediated (contact dermatitis, graft rejection)
What are the features of SLE? What is needed for diagnosis?
Autoantigens: nuclear protein, dsDNA, Sm
Symptoms: low blood cell counts, butterly rash, kidney disease, endocarditis, serositis, focal neuro symptoms.
Dx: 4 criteria or biopsy-proven lupus nephritis
Which hypersensitivity reactions are involved in the pathogenesis of SLE?
Type II and III (antibody mediated)
What are ANAs and why do they form?
Antinuclear antibodies
Membrane blebs of apoptotic cells contain nuclear material. In cases when apoptosis proceeds abnormally, nuclear proteins may be exposed to the immune system and trigger a response, which can develop into an autoimmune reaction with an environmental trigger like viral infection.
What are the symptoms of Sjogren’s syndrome? What diseases are associated with it?
Dryness due to destruction of lacrimal and salivary glands.
Often appears with RA and other autoimmune dz and comes with an increased risk of non-Hodgkin lymphoma.
What is the pathogenesis of scleroderma? Which visceral organs can be involved?
Cytokine stimulation of fibroblasts leading to deposition of collagen in the skin and internal organs, especially esophagus, GI tract, lungs, heart, and kidney.
What is CREST syndrome?
Localized (as opposed to diffuse) scleroderma:
Calcinosis (Ca deposit in skin)
Raynaud’s phenomenon
Esophageal dysfunction
Sclerodactyly (tight thick skin on fingers)
Telangiectasias (red marks on skin due to capillary dilation)
How can polymyositis be differentiated from fibromyalgia on physical exam?
Polymyositis is painful inflammation of muscles with muscle weakness.
Fibromyalgia is also muscle pain, but there is no inflammation and less weakness.
What is Bruton’s agammaglobulinemia? What does the mutation result in?
Inherited immunodeficiency, inability to produce mature B cells/plasma cells, resulting in agammaglobulinemia.
In male infants, recurrent infections beginning around 6mo.
Is common variable immunodeficiency a single disease?
No. It is a group of disorders characterized by B cell maturation defect and hypogammaglobulinemia.
What fails to develop in DiGeorge syndrome, and what does it result in?
Failure of 3rd and 4th pharyngeal pouches, which results in the absence of parathyroid glands and thymus (lack of T cell maturation)
Why is SCID more common in males? How has tx changed over time?
Severe combined immunodeficiency: combined deficiency of cell-mediated (T cells) and humoral (antibodies) immunity due to stem cell defect.
Found in males more often because one form is X-linked.
Former treatment was gene therapy, but it’s impractical because very expensive and the vector used generates an immune response, so it’s not permanent. Replaced by stem cell transplant and possibly interference RNAs.
What are the common systemic diseases that cause a functional immunosuppression?
DM, collagen vascular diseases (SLE), chronic alcoholism. Also burns.
What 3 types of rejection occur in renal transplantation?
Hyperacute:
occurs immediately after transplant
ab mediated
kidney turns dusty blue color due to neutrophilic vasculitis with thrombosis (neutrophils attack blood vessels and generate blood clots)
Acute:
~6mo later
abrupt onset of oliguria (reduced urine flow) and azotemia (excess N compounds in blood)
Tx with increased immunosuppresives
Chronic: >6mo, may be years gradual onset of oligura, HTN, azotemia interstitial lymphocytes, fibrosis of blood vessels only Tx is a fresh transplant
