Diseases of the Immune System Flashcards
What are the characteristics of an inflammatory response?
- nonspecific/generalized process ot neutralize & eliminate foreign entity
- acute/local inflammation
- neutrophils, macrophages, T-lymphocytes
What are the characteristics of an immune response?
- response to neutralize & eliminate specific foreign entity
- identify & isolate antigens unique to a single pathogen
- T-lymphocytes, B-lymphocytes, NK cells, APC
What are the cells of the immune system?
- intravascular leukocytes: monocyte, eosinophil, basophil, neutrophil, lymphocyte
- extravascular: histiocyte, plasma cell, mast cell
What are the myeloid cells?
- nuetrophils: acute response
- eosinophils: respond to parasitic infection
- cytoplasmic granules
- basophils: histamine, heparin, serotonin -> anaphylactic shock
- monocytes: APC, chronic inflammation-> phagocytosis
What are the lymphoid cells?
- T, B, NK
- CD4+/CD8+ influences function
What is innate immunity?
- major role by epithelial barriers, neutrophils, macrophages, NK cells
- acute inflammation
- stimulates adaptive immunity
What are natural killer cells in innate immunity?
- CD8- or CD4-
- important for immunoserveillance
What is the humoral response in adaptive immunity?
- requires antigen-specific molecules
- more effective than innate immunity
- B lymphocyte
What are T lymphocytes?
- thymus derived
- 70% of lymphocytes in blood
- recognize MHC-bound peptides on APC via TCR
What are the classes of T lymophocytes?
- MHC class 2 -> CD4+ T cells
- MHC class 1 -> CD8+ T cells
What is the role of CD4+ and CD8+ T cells?
- CD4+: interact with B cells, macrophages,produce cytokines, eliminate extracellular pathogens
- CD8+: cytotoxic T cells, destroy intracellular pathogens
What are B lymphoytes?
- 20% of lymphocytes
- undergo antigen stimulation in lymph nodes/organs
- interact with CD4+ T cells
What are the characteristics of the Ig families?
- 95% of circulating antibodies (IgG, IgM, IgA)
- IgG: coats microbes, targets for phagocytosis, promotes passive immunity
- IgG & IgM: activate complement system
- IgA: mucosal secretions
- IgE: tissue mast cells
- IgD: surface on B cells; not secreted
What are aberrant inflammatory responses?
type 1, 2, 3, and 4 hypersensitivity
What are the immune disorders?
- autoimmune disease
- transplant rejection
- immunodeficiency
What is type 1 hypersensitivity (IgE)?
- allergy reaction; treated with anti-histamine
- immediate hypersensitivity
- Ab response to external antigen
- IgE binds & activates mast cells (histamine) -> affinity for Fc of IgE heavy chain
When linked, what does IgE promote the release of?
- histamine, prostaglandins,cytokines
- results in vasodilation, mucus secretion, SM spasm, leukocyte activation
What are the 3 subtypes of type 2 hypersensitivity?
- opsinization & phagocytosis
- inflammation & complement mediated
- antibody mediated
What is opsonization & phagocytosis in type 2 hypersensitivity?
- C3b-dependent
- host cell opsonized with autoantibodies
- typified by thrombocytopenia purpura
- no association with inflammation
What is iodiopathic thrombocytopenia purpura in type 2 hypersensitivity?
- low number of platelets in blood
- < 5000 platelets per cubic mL
- treated with platelet transfusion
- bone biopsy shows megakaryocytic hyperplasia
- pupura: 3-10mm hemorrhages
- petachae: < 3mmhemorrhages
What is inflammation & complement mediation in type 2 hypersensitivity?
- autoantibodies on host cells activate C3a/C5a
- typified by Rh factor incompatibility, Goodpasture syndrome
What is Goodpasture syndrome?
autoantibodies to domain of alpha 3 chain of collagen 4 (basement membrane)
What is antibody mediated cellular dysfunction in type 2 hypersensitivity?
- autoantibodies impair host cell receptors without phagocytosis or inflammation
- typified by Graves disease or myasthenia gravis
What is myasthenia gravis in type 2 hypersensitivity?
- caused by defect in transmission of nerve impulses to muscles (usually in the face)
- treated with pyridostigmine -> increase half-life of Ach
- presents as ptosis (drooping eyelids), diplopia (double vision), dyasarthria (difficulty speaking)
What is Graves disease in type 2 hypersensitivity?
- antibodies bind receptors on thyroid follicular cells
- scalloping of colloid (thyroid gland)
- hyperfunctional thyroid, exopathalmos
- treated with immunosuppressants & radioactive iodine
What is type 3 hypersensitivity?
- host antigen-autoantibody immune complex
- circulation of immuno-complexes in blood vessels
- depends on deposition of performed immuno-complexes
- typified by systemic lupus & scleroderma
What is systemic lupus in type 3 hypersensitivity?
- women > men
- form antigen-antibody complexes
- antinuclear antibodies: dsDNA
- glomerulonephritis leads to renal failure & death
- deposition of complexes causes malar (rash on skin)
- cryoglobulins produce Raynaud’s phenomenon
What is systemic sclerosis in type 3 hypersensitivity?
- common among older women
- skin derived; progressive fibrosis
- can lead to dysphagia
- anitgen complexes
What are the 2 subtypes of systemic sclerosis?
- diffuse pattern: widespread skin, rapid progression, visceral involvement; Abs to DNA topoisomerase 1
- limited pattern: lmited ksin & visceral involvement, slow progression; Abs to centromere
What is CREST syndrome in systemic sclerosis?
associated with
* calcinosis
* Raynauds syndrome
* esophageal dysmotility
* scelrodactyly
* telangiectasia
What is type 4 hypersensitivity?
- delayed-type
- T-cell mediated to external or self Ag
- NO Abs
- 12-48 hours after exposure
- CD4+ T cells promotes cytokine secretion & tissue destruction
- CD8+ T cells directly cytotoxic to Ag
- TB and poison ivy reactions
What are the characteristics of a poison ivy recation in type 4 hypersensitivity?
- triggered by urushiol (external Ag)
- treated with methotrexate
What are the characteristics of a transplant rejection?
- incompatibility b/w donor & host
- autograft (donor=self)
- allograft (donor=identical twin)
- xenograft (donor=another species)
- split ( dead organ divided b/w 2 patients)
- domino ( mulitple transplants)
What is a hyperacute transplant rejection?
- occurs within minutes to hours
- interaction of preformed host Abs
- vascular disorders
- acute fibrinoid necrosis in blood vessel walls precipitates occlusion
What is an acute transplant rejection?
- occurs within days-months in immunosuppressed patient
- cellular/humoral based
- require immunosuppressive therapy
- acute cellular response: CD4+ and CD8+ T cells
What 3 types of hypersensitivity are autoimmune?
types 2, 3, & 4
What is a chronic transplant rejection?
- over years
- intimal hyperplasia develops in graft blood vessels
- not retarded by immunosuppression
What is a graft vs host transplant rejection?
- occurs when donor lymphocytes respond to host MHC
- common in bone marrow trans.
- time onset varies
- acute: days to week after trans.; destruction of liver
- chronic: follows acute GvH or independ.
What is congenital immunodeficiency?
- severe immunodeficiency
- 6 months-2 years as repeated infections
What 3 types of hypersensitivity are autoimmune?
types 2, 3, & 4
What is Brutons disease in the B cell lineage of congenital immunodeficiency?
- X-linked recessive agammaglob.
- absence of immature (IgD/IgM) B cells
- depressed serum levels of all classes of IgGs
- normal T cell repsonses
- males > females
What 3 types of hypersensitivity are autoimmune?
types 2, 3, & 4
What is the B cell lineage of congenital immunodeficiency?
- X-linked recessive agammaglob. (Bruton’s Disease)
- absence of immature
What is common variable immunodeficiency (CVID) in the B cell lineage of congenital immunodeficiency?
- prone to autoimmune disorders
- normal T cell responses
- immature B-cells present
- males=females
What is hyper IgM syndrome in the B cell lineage of congenital immunodeficiency?
- normal immature B cells
- normal/overproduction of IgM; fail to Ig isotype-switch
- X-linked recessive
- increased infections
What 3 types of hypersensitivity are autoimmune?
types 2, 3, & 4
What is IgA deficiency in the B cell lineage of congenital immunodeficiency?
- normal immature B cells
- normal production of IgM; normal isotype switch to IgG & IgE NOT IgA
- sinopulmonary infections and diarrhea
What is DiGeorge syndrome in the T cell lineage of congenital immunodeficiency?
- deficient T cell maturation
- T cell receptor capable of Ag recognition
- reduced T cell cytokine production
- thymic hypoplasia
- repeated infections
What is MHC class 2 deficiency in the T cell lineage of congenital immunodeficiency?
- inability to develop CD4+ T cells
- B cell and serum Igs are indirectly affected
- reduced T cell cytokine production
What are the characteristics of HIV?
- acquired immunodeficiency
- targets CD4+ T cells; eventually depletes
- surface protein gp 120 binds to Cd4+
- changes in gp 41 promote gp 120 cellular entry
- 7-12 years
What is leukopenia in non-proliferative WBC disorders?
- reduced lymphocytes
- secondary to disease or therapy/drugs
What is lymphopenia in non-proliferative WBC disorders?
- reduced granulocytes
- neutropenia as reduced neutrophils
What is neutrophilic leukocytosis?
- reactive proliferative disorder
- result of bacterial infection or sterile inflammation
What is eosinophilic leukocytosis?
- reactive proliferative disorder
- result of allergic recations & parasitic infections
What is basophilic leukocytosis?
- reactive proliferative disorder
- associated with conditions like neoplastic disease
What is lymphocytosis?
- reactive proliferative disorder
- associated with infections
- increased lymphocytes
- caused by EBV -> B ell proliferation
What is lymphadenitis?
- reactive proliferative disorder
- associated with lymphadenopathy
- acute: enlarged B cell germinal centers
What are the types of chronic lymphadenitis?
- follicular: activated B cells migrate into follicular zone
- paracortical hyperplasia: activation of T cells thta proliferate and displace B cell germinal centers
- sinus histiocytosis: distention of lymphatic sinusoids due to endothelial hypertrophy
What are the 3 sets of words of neoplastic WBC disease?
- acute (fast/blastic) or chronic (slow)
- myeloid (RBC/granulocyte) or lymphoid (T/B cells)
- leukemia (bone marrow/thymus) or lymphoma (lymphoid tissues)
What is contained in the bone marrow?
- all hematopoietic stem cells
- progenitor lymphoid cells
- myeloid progenitor & differentiated cells
What is contained in the thymus & lymph nodes?
- thymus -> differentiated T cells
- lymph nodes -> differentiated B cells, some T cells
Any myleoid cancer has to be ….
a leukemia
What are the 4 types of leukemia?
- ALL: acute lymphoblastic leukemia
- AML: acute myeloblastic leukemia
- CLL: chronic lymphocytic leukemia
- CML: chronic myeloid leukemia
What is acute lymphoblastic leukemia (ALL)?
- 80% of child leukemias
- pre B/T cell origin
- bone marrow involvement
- cytopenia of normal mature hematopoietic cells
- 80% cure rate in all
What is acute myeloblastic leukemia (AML)?
- proliferation of precursor myeloid cells
- affects more adults (>50 years old)
- contains auer rods
- bone marrow involvement
- 50-80% remission with treatment
What is chronic myeloid leukemia (CML)?
- mature but abnormal myeloid
- associated with philadelphia chromosome
- bcr-abl fusion protein
- affects 25-60 year old
- slow disease progression
What is chronic lymphocytic leukemia (CLL)?
- B cell lineage
- asymptomatic
What is Hodgkin’s lymphoma?
- has Reed-Sternberg cells
- bilobed (mirror image)
- large cells meausre 15-45 um
- express CD30 & CD15
- B cell derived
- contiguous spread
- cured with chemo
