doc179
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An appropriate, useful type I hypersensitivity response of the immune system, accompanied by eosinophilia, would most likely be directed against which of the following?
A Amyloid protein
B Spirochetes
C Neoplasms
D Inhaled dusts
E Liver flukes
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| cyra
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E
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| robin082006
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E
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| drk1980
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can someone plz mention wht wud be the appropriate immune system response for the remaining choices?? 
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| drk1980
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Also cud you name some of those parasites that are killed by Antibody Dependant Cell-Cytotoxicity?
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| 26malik
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D
in case of liver fluke, wont the response be too much and can progress to anaphylactic shock? so it cant be E. plz explain
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| ramo7
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i agree with 26malik..is it not D?
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| doc179
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the ans is E
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| enthu
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its E.
Inhaled dust will not necessrily give that response unless u are sensitive....correct me plz
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| pearljam59
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Type I is IgE ABs and effector cells (mast cells, basophils, esoinophils).
The IgE response is the main defense against parasites because they are too big to be phagocytized.
Eosinophils release granules that kill parasite.
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| gyh1126
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good explasion,pearljam
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| gyh1126
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gyh1126 wrote:
good explanasion,pearljam
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| paganini
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I cant believe that this question was posted in Feb 23, 06 and nobody have tried to correct the Big mistake. Sorry people but the correct answer is D. I read this same question in Webpath and they said that the correct answer is E but is a Big mistake. I have found many in that page and a few in the Robbins Review of Pathology from the same author. Well this is why the answer is D and Not E: First the question is asking about a type I hypersensitivity, and you should know that Antibody (IgG, IgE) - dependent cell-mediated cytotoxicity (ADCC) is a type II hypersensitivity. An example of ADCC is host defense against helminths (in this case flukes). IgE is the antibody involved and eosinophils are the effector cells. IgE binds to surface proteins on the worm, and the surface of eosinophils display receptors for the epsilon heavy chain. Then, major basic protein is released and damages the surface of the worm. Again, this is a type II hypersensitvity. Tumor cells (neoplasia, answer C) develop new antigens, this bind MHC I proteins that are recognized by CD8 cells, which are stimulated by IL-2 and kill the tumor cells; a type IV hypersensitvity. Spirochetes (B). Well the antigens of T. Pallidum induce nonspecific antibodies (reagin). Syphilitic reagin (IgM, IgG) should not be confused with the reagin (IgE) antibody involved in allergy. Amyloid proteins (A) are not related neither with Type I hypersensitvity nor to eosinophilia. Now, pay attention to what i'am going to say. The eosinophil count is elevated in two medically important types of diseases: parasitic diseases (helminths [remember that protozoa are Not characterized by eosinophilia]), the other important disease is hypersensitvity diseases such as asthma (A TYPE I HYPERSENSITVITY). Eosinophils are involved in asthma, and you are asking where asthma fix in this question? Well, house dust which has feces of dust mite (answer D----> Inhaled dusts), pollens, animal danders, occupational airborne alergens induce asthma after exposure to the specific allergen. So you get a Type I hypersensitvity with an increased IgE as a result of increased class switching in Th-2 cells stimulated by IL-4. Il-13 also increases IgE. Again, eosinophilia is present in asthma. So answer is D. Uff i'm tired....
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| doc179
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Thank you for the good explanation paganini
I had posted this Q long ago when I was doing Qs from webpath. I had opted for D and it said I was wrong. So had posted this Q to see what others say. Did not know that webpath could be wrong though I was not able to explain to myself why it has E as the answer.
Thank you very much.
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| 26malik
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thanks for explaination paganini
i cant believe there could be wrong answers in webpath 
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| meroon
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I am going with E(sorry to disagree).the q-stem asks about a useful Ig-E response.and the appropriate useful respone is the antiparasitic action.Ig-E mediated hypersentivity against inhaled dust is not useful and it is inappropriate.
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| paganini
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 TYPE I HYPERSENSITIVITY
Host defense against helminths like flukes is a Type II hypersensitivity [Antibody (IgE) - dependent cell-mediated cytotoxicity (ADCC), and the question is asking about a TYPE I !!!!!!!!! Appropriate or not, useful or not, it doesnt matter, here the most important concept to know is which is a TYPE I HYPERSENSITIVITY.
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| meroon
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This is just my thought(I may be wrong)
The only hypersensitivity reaction that uses IgE is type 1.the type II and type III uses mainly Ig G(may also IgM).
As you said ADCC using IgE and EOsinophil(effector cell) is the protective response mounted against parasites.I dont think This ADCC comes under hypersenitivity reactions.
the stem may have a twist in the wordings or i am wrong.but i would like to choose E as they have used the term type 1 hypersensitivity and usefulness togother.
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| tolito
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the question asks about type 1 and throws a spanner in by asking for 'USEFUL'. hypersensitivity reactiosn are not known to be useful but eosinophilia in type 1 is said to be useful to reduce the severity of reaction cos eosinophils produce histaminase and aryl sulphatase that degrade histamine and SRSA.
now, reaction to worms is cytotoxic ADCC mediated by IgE and not IgG. this is the anomaly with respect to worms ie E and not G. cos this is a cytotoxic reaction, it falls under type 2 and not type 1. second, the question does not ask about the type of Ig so do not be distracted by that. third, if we say the reaction to worms is NOT hypersensitivity reaction then we rule it out as an answer option cos the question is about hypersensitivity reaction.
so i think D is the most appropriate answer. the eosinophilia that accompanies allergies is meant to reduce the severity of the reaction. hypersensitivity to dust is not a normal condition but is called an atopy.
reference
kaplan ln
mmi
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| tolito
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more information, kaplan qbank says that cytotoxic reaction to filarial worms which are coated with IgE is type 2. however, there is ALSO a local anaphylactic reaction is triggered by the ige coated worms from the release of vasoactive subst from mast cells and basophils in a type 1 reaction.
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