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46 Cards in this Set
- Front
- Back
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what three types of cells/ coenzymes are a part of innate immune system?
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complements (coenzymes that induce C1-C9 cascade of events to induce MAC), NK cells and phagocytic cells.
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what two types of capsules are T-cell independent?
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polysaccharide and lipopolysaccharide
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what interleukins are necessary for class-switching? what do they class switch IgM into? what other non-interleukin can cause class-switching to IgE?
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IL4- Class-switch into IgE
IL5- Class-switching into IgA IgE- TGF beta |
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what is IL-6 necessary for?
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B-cell differentiating factor (critical for B cell into plasma cell)
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what necrosis factors are used therapeutically for tx of Hep B and C? who produces these factors?
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TNF alpha and beta produced by the cells that are infected w/ the virus.
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what type of infection triggers a humoral response?
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extracellular infections
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Th1 activates what 3 cell types?
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macrophages, CTLs and NK cells.
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what happens when the CD4:CD8 ratio is inversed? what should it be?
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AIDS
should be 2:1 |
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what is primary immunodeficiency? what is secondary immunodeficiency?
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primary: deficiency in T cell, B cell or any other components of immune system
secondary: immunodeficiencies secondary to chemo, infection, nutritional deficiency, AIDs |
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what are the four categories of primary immunodeficiency?
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- defective antibody response (B cell defect)
- Defective cell-mediated immunity (T cell or T cell-related defects) - Hereditary complement deficiencies or complement component defect - defect in phagocytes |
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what are the 5 Primary B cell defects?
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x-linked agammaglobulinaemia
IgA and IgG subclass deficiencies Hyper IgM syndrome Common variable immunodeficiency Transient hypoglobulinemia of infancy |
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what do primary B cell defects result in? what are the consequences?
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results in inability to clear extracellular pathogens.
The consequence is recurrent pyogenic infection esp d/t capsulated pathogens (strep, klebsiella and haemophilus) which causes pneumonia, otitis media and sinusitis. |
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what will recurrent pneumonia in untreated individuals lead to?
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severe obstructive lung dz- bronchiectasis.
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what is defective in X-linked agammaglobulinaemia? What is this defect in charge of? what will you see on serology?
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defective: Bruton's tyrosine kinase (required for growth and differentiation of pre-B cells. On serology you will see an absence of mature B-cells and most of the cells will be in the pre-B cell stage.
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what two immunoglobulins are markers for naive mature B cells? what immunoglobulin is on a pre-B cell?
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Naive mature B cells- IgM and IgD
Pre-B cell--> cytoplasmic IgM |
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A 2 year old boy presents to your office with recurrent respiratory infections over the pat year. A sweat test is done and came up negative. Dx and explain what you will see on physical exam.
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Dx: X-linked agammaglobulinemia
No B cells in LN --> very small LN and absence of tonsils w/ rudimentary germinal centers, but B cell precursors are found in normal numbers in bone marrow. |
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What is the B-lineager CD marker?
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CD19
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why do pt w/ X-linked agammaglobulinemia have recurrent RT infections? what pathogens are these pts most susceptible to?
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D/T normal flora already present and heir lack of antibodies
pathgens: Haemophilus influenzae, S. pneumoniae, S. pyogenes, S.aureus, enterovirus and parasites. |
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what is the #1 waterborne parasite infection? what does it look like?
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Giardia Lamblia; pear-shaped organism w/ ventral suckers.
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what type of x-chromosome inactivation does X-linked agammaglobulinemia?
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nonrandom X-chromosome
a mixture of defective and non- defective cells would be an example of random X-chromosome inactivation. |
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CD19 is a marker for what type of cell? what about CD3? what is the marker for NK cells? what CD on B cells is associated with EBV?
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CD19- B cell
CD3- T cells CD56- NK cells EBV CD21 |
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what CD is on Fc Gamma receptors and is expressed by NK cells? what is another name for the LPS receptor and who expresses it?
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CD16
LPS receptor: CD14- expressed by macrophages |
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how do you tx XLA?
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periodical (usually monthly) infusion of large doses of gammaglobulin
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what is the most common form of B cell deficiency?
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IgA deficiency. - more common in europeans.
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23 year old male had a motor vehicle accident and was rushed to the ER and admitted to the hospital. He was suffering from a rupture appendix and was rushed into the OR and given a blood transfusion. Pt had an allergic reaction to the blood despite proper blood cross reaction and test prior to administration. DX and how do you tx it?
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IgA deficiency
periodical (usually monthly) infusion of large doses of gammaglobulin |
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what does Hyper IgM syndrome result from?
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failure of immunoglobulin isotype switching
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what is the first antibody produced in body in response to an antigen? where are the other immunoglobulins located? how is IgD formed?
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IgM- 1st
IgG- serum and extravascular space IgA- mainly in the gut and also in other mucosal regions IgE- other epithelial surfaces. IgD is formed via alternate splicing |
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what is deficient in Hyper IgM syndrome pts that is crucial for antibody isotype swicthing??
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CD40L is deficient--> resulting in a lot of IgM and low IgG, IgA, IgE
CD40 (b cells)/ CD40L (t cells) is crucial for antibody isotype switching. |
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what is the fxn of IgM?
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complement activation and can serve as a scavenger
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how does Hyper IgM syndrome result in a low GM-CSF?
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d/t the CD40L being deficient, CD40 can't bind to CD40L and activate macrophages. The lack of macrophage activation results in low GM-CSF. The most important one being neutrophils.
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Hyper IgM pts suffer from what types of infections? how do you tx it?
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pyogenic infections
fungal infections tx: w/ antibiotic and periodic infusion w/ gammaglobulin neutropenia tx w/ IV GM-CSF |
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in the absence of IL-4 or IL-5 what does IgM become? A heavy chain contains what to distinguish it from a light chain?
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IgG (either 2 or 3)
heavy: VDJ Light: VJ |
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which immunoglobulin does not have C region gene?
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IgD
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IN Hyper IgM syndrome, is there something wrong w/ the T cell or B cell?
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T cell. B cell is perfectly fine.
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what is required for isotype switching to IgE?
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B cell + IL-4 + activated T cells
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4 year old boy presents to your office w/ acute infection w/ sinusitis. history reveals that he chronically suffers from sinusitis since his early childhood. 1 year ago, brian suffered from Pneumocystis pneumonia and recovered following tx w/ TMP-SX. Culture of material obtained from nose and throat revealed GAS. dx and tx
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dx: Hyper IgM syndrome (they suffer from both pyogenic and opportunistic infections)
tx: IV gamma globulin every month |
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how does hyper IgM syndrome manifest differently than XLA?
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Hyper IgM pts suffer from both pyogenic and opportunistic infections as opposed to XLA pts who suffer from only pyogenic infections.
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Expression of what CD indicates T cell activation?
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CD25 (IL-2 receptor alpha)
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Hyper IgM syndrome can also be caused by a deficiency in 2 enzymes, what are those enzymes and what do they cause?
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1) Activation-induced cytadin deaminase (AID) which converts cytidine to uridine and edits DNA or mRNA that helps w/ isotype swicthing.
2) Uracil-DNA glycosylase (UNG): removes the uracil base from the rest of the nucleotide causing the cellular DNA repair mechanisms to remove the damage region and repair the two broken ends resulting in class switching. |
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how is Hyper IgM syndrome transmitted? AID gene?
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Hyper IgM syndrome- X-linked
AID gene: Autosomal |
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how do the LN of an AID deficient pt differ from XLA and (non aid deficient) hyper IgM syndrome?
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AID deficiency: enlarged follicles in the LN.
XLA and hyper IgM syndrome: No germinal centers at all. |
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WHat types of infections will AID deficiency pts have?
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pyogenic infections NOT opportunistic infections because the defect is solely in the B cell
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How does AID affect B cells? how does this result in enlarged follicles?
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it is involved in somatic hypermutation in B cells which results in selection of B cells. B cells w/ higher affinity for the antigen is selected over the cells w/ lower affinity--> affinity maturation. B cells w/o AID fail to undergo affinity maturation and the only response they make is to proliferate resulting in enlarged follicles.
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how long does it take for Abs against bacterial capsular polysaccharides to start in a newborn? what happens in Transient hypogammaglobulinaemia of infancy?
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They start producing those Abs by the 2nd year of life.
Transient: IgG synthesis can be delayed for as long as 36 months (d/t impaired proper T cell help) resulting in infection. |
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when is common variable immunodeficiency acquired? WHat is the problem? what do many pts who have CVID also suffer from?
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-acquired in the 3rd or 4th decade of life
- B cells don't receive proper T cell help - many pts suffer from autoimmune dzs mostly pernicious anemia. |
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33 female presents w/ recurrent sinopulmonary pyogenic infections. Blood is drawn and normal B cells are present in the peripheral blood, but there are very few plasma cells. On LN biopsy, the follicles are seen to be hyperplastic. DX
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CVID
diff btwn XLA and CVID: CVID has normal B cells in the peripheral blood but those B cells cannot differentiate into ab secreting plasma cells. on histo: the hyperplastic LN follicles indicates defective immunoregulation (lack the feedback inhibition of IgG producing a lot of B cells that can't differentiate). |
