Immunopathology Flashcards
What are cytokines
messenger molecules of the immune system
Who makes INF-Gamma
NK cells and TH1
What are the effects of mast cell activation ?
Histamine- causes increased vascular permeability, smooth muscle contraction, Mucous production, adenosine (Bronchoconstriction and inhibits platelet aggregation) Proteases which generate kinins and cleave complement
What lipid mediators are contained in mast cells ?
Prostaglandin and Leukotrienes
What does prostaglandin do ?
Generated by the cyclooxygenase pathway in the mast cell. It causes intense bronchospasm as well as increases mucous secretion
What do Leukotrienes do ?
They are the most potent vasoactive and spasmogenic agents known. Much more powerful than histamine.
What do eosinophils produce ?
Mahor basic protein and eosinophil cationic protein which are toxic to epithelial cells, LTC4 and PAF which promote inflammation
What is malaise
is a feeling of general discomfort or uneasiness, of being “out of sorts”, often the first indication of an infection or other disease. Malaise is often defined in medical literature as a “general feeling of being unwell”
What is the main immuno mechanism of lupus ?
Failure of self tolerance which results in the formation of a large array of auto-antibodies that can damage tissue directly or in the form of immune complex deposits.
What will a serum test in a patient with Lupus show ?
Anti- dsDNA Anti-Sm and Anti-Histone
What is the main pathologic problem associated with Lupus ?
The Classic presentation is a facial rash which is photo reactive and renal failure which is indicated by proteinuria hematuria ( immune complex deposition in the glomeruli ) Defective clearnace and increased burden of nuclear apoptotic bodies is the main mechanism
What is molecular mimicry
When a microbial antigen cross reacts with a normal tissue
If a patient presents with symptoms of Lupus what will be the difference between in vivo coagulation and in vitro coagulation and what is the reason for this difference ?
Antiphospholipid antibodies will interfere with the in vitro coagulation tests but in vivo
What is arthralgia ?
Joint pain
What is the most common mechanism of tissue injury in Lupus ?
Immune complex deposition. Kidney and skin biopsies will indicate heavy glandular deposits which will activate the classical complement pathway and which is a type 3 hypersensitivity.
What are the autoantibodies that are developed in SLE ?
Antinuclear antibodies against DNA, Histones, Nonhistone proteins, phospholipids
What will increase the incidence of thrombosis in SLE ?
Antiphospholipid antibodies- These will target Platelets WBC’s and RBC’s leading to cytopenias
What are the morphological patterns that will bo observed in SLE ?
Glomeruleronephritis which is due to immune deposits in the within the glomeruli which will induce inflammatory responses.
What causes Lupus Nephritis with Wire Loops ?
Deposition of antigen complexes in the sub-endothelial space of the glomerulus.
What causes the facial rash in Lupus ?
Erytheromatous or maculopapular eruption over the malar eminances
What will SLE do to the joints ?
It will cause swelling and mononuclear cell infiltration into the synovial membranes inducing pain.
What will SLE do to the heart and spleen and serosal membranes ?
It will cause enlargement of the spleen and capsular fibrosis. Inflammation of the pericardia and pleura. In the heart you will see pericarditis and myocarditis
What is pancytopenia, will you see this in SLE
A reduction in red and white bood cells. This is due to anti-phospholipid antibodies
Will you see a reduction of Complement proteins in SLE ?
Yes
What will a mutation in the common gamma chain lead to ?
Nonfunctional cytokine receptors in helper T cells. Leads to SCID
What causes wire loops in glomerulonephritis ?
Thickening of capillary walls
How do you treat SLE ?
Corticosteroids and immunosuppressants.
What is CD-40
Key mediator of T helper cell function. It binds to CD40 on B cells and macrophages, TH1 cells will be activated and produces INF-Gamma which will activate macrophages
What are TH1 cells most effective against and why ?
Intracellular pathogens because they activate macrophages but they are also involved in IgG production so play a bog role in Opsonization and initiation of the classical complement pathway
What in SLE can cause inflammation ?
Necrosis and fibrinoid deposits in the vessel walls containing, Antibody, DNA, complement fragments, Fibrinogen and leukocyte fragments. This will increase hydrostatic pressure
What is a receptor that is a target of mutation that will render a cell immune to the effects of the HIV virus ?
For the HIV virus to infect the T cells it must be taken in by a macrophage or lymphocyte. This is mediated by binding to CD-4 receptor which is a chemokine receptor on the surface of T cells and macrophages.
What will a deficiency in CD40 cause
Hyper IgM syndrome
What is the defect that leads to hyper IgM syndrome
CD-40 deficiency.
What allows T cells to class switch and produce antibodies of another type ?
The interaction of cytokines as well as contact mediated signals from CD4 T cells via the CD-40 cell surface ligand
Other than Ab deficiencies, what other problems will patients with CD-40 deficiencies have ?
They will have difficulty mounting a cell mediated immune response. CD-40 is critical in activation of macrophages.
What do Hyper IgM patients present with ?
Recurrent Pyrogenic infections because they fail to produce IgG and thus cannot opsonize bacteria. They are normally male and will present with tons of infections. Remember they cannot opsonize anything.
What will happen in adenosine deaminase deficiency ?
SCID- ADA is involved with purine biosynthesis and if defective it will halt DNA synthesis and kill the Leukocyte
What are the two most common causes of SCID ?
Gamma chain deficiency and Adenosine Deaminase