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*Patient developed systemic anaphylaxis after bee sting, he was treated with Epi pen, he felt better but after few hours he again develops systemic manifestations of anaphylaxis(Bronchonstriction,Hypotension,Tachycardia with weak pulse)what was responsible for immediate reaction to bee sting and what was responsible for delayed response?
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*PREFORMED ANTIBODY(IGE) is the cause of Rapid reaction after exposure.*IgE cross linking on mast cells after re-exposure to presensitized antigen >Degranulation of mast cells>Histamine release(PRE-formed, just like ArylsuflatASE(Neutralizes leukotrienes) and HistaminASE(neutralizes histamine) from eosinophils along with serotonin).*But Delayed response is due to Leukotrienes(Arachidonic acid metabolite) released from mast cells(DE NOVO synthesized not preformed- other late phase recatants are also de novo synthesized like PAF and PG) and BOY THEY WILL ASK about delayed response(6-24 hours after repeat exposure).**Note Trypatase is a marker of Mast cell degranulation.
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*They will confuse you with different manifestations of Autoimmune diseases and will ask you what lab will you order first?
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*ANA+ is highly sensitive marker that can help you to know that patient really does have autoimmune problem, afterwards you go to more specific tests to diagnose particular condition(anti Ds DNA, SnRP antibodies in SLE for example)
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*Baby with recurrent bacterial pneumonia's at the age of 9 months has defect in ?*Note on physical exam you note:Scanty lymph nodes/tonsils, NO CIRCULATING mature B cells in plasma, BUT NORMAL CD19+Bcell count.
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*Maturation of Pre B cells into Mature B cells can not take place, Due to defective BTK(Tyrosine Kinase), if they want to fck you up:Maturation stops After HEAVY chain recombination so you do HHave HHeavy chains but you LLack LLight chains.*This B cell maturation defect predisposes to Bacterial infections after 6 month of age(IgG of mother goes away- Remember igG is an Opsonin that tags bacteria and facilitates phagocytosis and begins to be synthesized in baby after 3 months<doesn't happen here)*Patient will most likely be boy as this disorder is X-linked recessive and he will have decrease in ALL TYPES OF IMMUNOGLOBULINS(Due to B cell maturation defect), So lack of IgA would also predispose to Salmonella,influenza,Giardia Lamblia and Enteroviral infections.*Avoid LIVE vaccines like Salmonella-Oral(can still give polysaccharide vaccine-IM), BCG, POLIO(Sabin)
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*Patients who are matched for MHC(DP,DQ,DR) have lower complications of renal transplants, why?
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*If we match correctly donor and recipient for MHC(DP,DQ,DR) that means we match them for MHC2 molecules thus we would prevent CD4+ mediated damage of transplant( Don't write GVHD as this is NOT found in Renal transplants but can be found in Bone marrow and maybe in some liver transplants, as these organs can have Competent T lymphocytes of DONOR organ can kill off immunocompromised host's tissues)*MHC2 mismatch is not a problem in Bare Lymphocyte syndrome(cells Lack MHC2),Donor potent lymphocytes can't mount response against MHC2 antigens when they are simply not expressed, but this lack leads to SCID(B lymphocytes are affected too because T lymphocytes don't activate them)
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*So male infant had multiple viral and bacterial infections(even PCP,CMV,Cryptosporidum), while levels of T and B cells are Normal and then they MIGHT not tell you which Ig's are high or low but give you labs and ask what is the mechanism of disease
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*Look i would remember that normal igM levels are 60-320 because they might give you just labs of different Ig's and if patient has CD40-CD40 Ligand defect(CD40 L is on T cell which activates CD40 receptor on B cell and >Isotype switching from non-specific igM to other immunoglobulins) his IgM levels will be high while all other immunoglobulin levels will be low(So instead of memorizing normal values of all ig's i would know normal values of igM and if it is way higher than normal, this is a good clue of Daa, HYPER IGM SYNDROME, for which mechanism once again is defective CD40-CD40L interaction(Defect is on LIGAND loacted on Tcell).*Hyper IgM is X-linked recessive disorder so patient most likely will be boy.
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*Female with Symmetric proximal muscle weakness, violaceous erruption on upper eyelids with periordbital edema, with fever, Morning stifness,Dysphagia of Solid and Liquids in UPPER esophagus(Skeletal Muscle is there),you see endomysial inflammation with CD8+ Tcells(Cytotoxic) she most likely has ?Note:she could have penumonitis,vasculitis,myocarditis too.(Patients with Polymyositis can also have these conditions)
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*Polymyositis characterized by endomysial inflammation and muscle damage by CD8+ Tcells.*Note Patients with DM have Perimysial inflammation with CD4+ cell involvement.just remember 1 so you don't mess them up: PM me at 8 oClock Dis night and we END this relationship lol, that's how i remember hope that helps :PP)*Remember patients might have Anti-Jo1 (HistidyltRNA syntethase) antibodies.*Anti SNRP antibody is more common in PM and indicates poor prognosis.*Both can be ANA+(Don't confuse with SLE) and can show increased CK/Aldolase on labs.*Note Atropy is a Prominent feature of DM while it is not prminent in PM+those with DM will often have Skin manifestations like Gottron patches over knuckles(Purple-red papules)+Heliotrope eyelids(Purple/red discoloration of eyelids),CD4 +tcells, ANTIBODIES and Complement are involved in capillary damage in DM.
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*Female with raynaud's phenomon, developed extremely high BP(Malignant hypertension), her creatinine and BUN begin to rise, ANA antibody test will show?
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*Nucleolar pattern.*Patient most likely has Scleroderma, characterized by AntiDNA toposiomerase I antibodies.*Note:they might describe to you patient with scleroderma who presented with MALIGNANT HYPERTENSION and can ask you what would you see on kidney biopsy>Answer:NODULAR GLOMERULOSCLEROSIS(this process can be seen with scleroderma and can cause M.hypertension)
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*Tender irregular raddish, itchy rash develops in a guy who traveled to North America, this rash got worse in next few days but disappeared after few weeks, what type of hypersenstivity?
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*Type IV-Delayed hypersensitivity that involves Tcells which activate macrophages also, NO ANTIBODIES are involved.(Other examples include PPD,Nickel allergy, GVHD in liver or bone marrow transplant,Multiple sclerosis)*He most likely has Contact Dermatitis due to exposure to poison ivy.*Macrophages and CD8+ tclells produce most of the damage associated with Type 4 hypersensitivity reactions however, CD4+Tcells is what activate and recruit them, trough cytokine release.*Note GVHD which is type of hypersensitivity 4 can produce fine scaling skin rash trough Apoptosis of Keratinocytes(Remember CD8+Tcells can provoke apoptosis by perforating membrane and dropping ganzymeB)
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*What test you order in a patient who developed Edema, induration,pain at the site of injection of vaccine?
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*Immunofluorescent staining.*Patient has Arthus reaction(Type III-Atigen antibody complex mediated hypersenstivity) due to intradermal injection of antigen in presensitized individual(Has igG antibodies against it)*Note arthus reaction is characterized by Activation of Complement(IgG can activate Classic pathway) and Necrosis
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*Protein from which gene serves as TRANSCRIPTION factor that is involved trasncription and regulation of TREGS(CD4+ cells that block other Tcell activation by expressing CTL4 which will compete for B7 on APC and thus prevent B7 binding to CD28 on Tcell , lack of this Co-stimulatory molecule>Anergy,+ They secrete IL10 and TFGB(aTENuate response)-IL10 inhibits Macrophage/dendritic cell by Prventing expression of MHC2 which now can't activate Tcells ,+It prevents Expression of B7 , TGFB has same inhibitory effect on Macrophages/Dendritic cells +It promotes Tcell apoptosis, cell cycle arrest.
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*Remember TREGS are part of Self-tolerance, so dysfunction of these cells>Autoimmune disease.*Gene is FOXP3 which is located on X chromosome.*Mutation in FOXP3>IPEX syndrome(Immune dysfunction,Polyendocrinopathy,Enteropathy,X-linked)-Patient can have Thyroditis,Type1 diabetes(Endocrine pancreas damage-islets),Autoimmune enteropathy, Can have Eczema of the skin and can present in child.*CD25 polymorphism- are associated with MS and Type 1 diabetes(CD25 is needed for TREGS as it is part of IL2 receptor-So TREGS can't proliferate>Can't prevent activation of self-reactive lymphocytes>Autoimmunity.)*Remember TREGS are CD25+,FOXP3+,CD4+.HY to know gene that codes for FOXP3 is on SHORT(P) arm of X chromsome(Xp11.23).
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*In which part of LN are T,B lymphocytes,macrophages,Plasma cells?
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*T cells are in Paracortex*Bcells are in Cortex.*Plasma cells-Medullary CORDS*Macrophages-Medullary Sinus.
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*Why the fact that Type 2 hypersensitivity involves antibodies directed against Antigen that is Fixed To cell surface and the fact that type 3 hypersensitivity involves CIRCULATING Antigen-Antibody complexes is Not BS?
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*Because that will help you to think of Manifestations of these diseases and which diseases would be example of each.*Type 2 hypersensitivity involves Antibodies that are directed against antigen that is FIXED to cell SURFACE thus type 2 hypersensitivity would cause diseases that are SPecific to site where antigen is found,like Grave's disease(TSH receptor stimulating antibodies>Hyperthyroidism),Myasthenia Gravis(Antibodies against AchReceptor on Post synaptic membrane)*While in The case of TypeIII hypersensitivity ,Circulating Antigen-Antibody complexes will deposit when they get stuck in small vessels in multiple parts of body>Activation of Complement,recruitment Of neutrophils>Multi organ manifestations like in SLE(Anti DNA anti SnRP antibodies) and Serum sickness(Antibodies are formed against Foreign protein, now mostly caused by Haptens-Drugs)*Artthus reaction is Exception to systemic manifestations of Type 3 hypersensitivities, as antigen-antibody complexes are only deposited in TISSUE (In this case Site of injection-for toxoid vaccine)and don't enter blood>Local Tissue damage.
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*Mechanism of specific tissue damage in Type 2 Hypersensitivity?
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*IgM and IgG activating CLASSICAL complement pathway>Opsonization(C3b and IgG are PRIMARY Opsoning)+Phagocytosis +Formation of MEMBRANE ATTACK COMPLEX(MAC-C5B-9,C5a is not included)>Pores in membrane>Osmotic lysis of cell.*Note NK cells with ADCC are also involved in Type 2 hypersensitivity reaction.
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*Why relationship between NF-kB and ikB relationship is not BS?
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*Because IkB is what inhibits NF-kB(which in case you didn't know is master switch on of Inflammatory response by promoting cytokine release like TNFA)Now when you Phosphorylate IkB(By increased IkB KINASE activity),will lead to deactivation of IkB and thus will remove inhibition onf NFKB>NF-kB is Turned ON<CORTICOSTEROIDS BLock This NF-kB activation>Decrease Transcription of Cytokines >Supresson of T and B lymphocytes, T lymphocytes are also removed trough APOPTOSIS, so that's why We use corticosteroids for treatment of Transplant rejection and for lot's of inflammatory conditions(Rheumatic disorder,COPD,IBD.), corticosteroids are also used in cachexia treatment as it is strong sitmulator of apetite/decreases TNFa(remember TNFA is responsible for cachexia) but still this treatment is palliative So for now at least know mechanism of Corticosteroid action and NF-kB/iKB relationship, also you should probably know that this drug can inhibit Phospholipase A2(Note Phospholipace C) thus inhibiting Arachidonic acid metabolism.
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*Female who is Rh- who had a child with Rh+ male hasn't received RHOGAM at 28th week of pregnancy, which type of hypersensitivity is the mechanism for the condition fetus is at high risk of?
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*Type 2 hypersensitivty in fetus due to Rh incompatibility(Rh- mom sensitized to Rh+ from previous prengnancy/amniocentesis/abortion forms Antibodies which destroy Baby's Rh+ RBC>Erythroblastosis fetalis>Severe anemia and baby can even DIE)*Now better question would be how you know that mom can have antibodies against baby's Rh+RBC's, and that is done by INdirect coomb's test(You check for Anti Rh+ Antibodies present in Maternal circulation)*Direct coomb's test will test for Antibodies DIRECTLY attached to RBC's(So good to test infant for presence of maternal antibodies covering his RBC's)
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