hottie99
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which hypersensitivity is it? i figured its type 2 since it's autoimmune disease but my one friend says its type 4 since cytotoxic T cells involved.. i said Type 4 is delayed, but can anyone explain??? thanks!!
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| hottie99
Forum Guru
Topics: 31
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i see no one has any ideas on this either??? any thoughts at all??? or are we just not thinking anymore 
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| sigh
Forum Senior
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I just look in Kaplan...Hashimoto... immune reaction against thyroglobulin...humoral and T-cell Mediated...can be both correct? No idea
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| hottie99
Forum Guru
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yeah that's hat my friend said, she also looked up in her kaplan, i always thought type 2 b/c it's autoimmune and there are antibodies, but then she said in her FA 2007 version (mine is 2006 and not that FA is end all be all of things, iknow there's errors galore in it) but she said it mentioned under hypersensitivity types that this was listed under type 4, along with DM type 1 (another one i thought had type 2 since they have antibodies as well).. so which would u select if given both? i too agree with both, but this is where im getting stuck 
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| sigh
Forum Senior
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I hope we are not going to get this question because it is seems to be confusing...
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| Tiff
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Hashimotos thyroiditis is Type IV - delayed cell mediated. On the other hand, Graves disease is a Type II hypersensitivity.
Autoimmune disorders can fall into different categories of hypersensitivity. For example SLE is a Type III - immune complex.
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| Tiff
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hottie99 wrote:which hypersensitivity is it? i figured its type 2 since it's autoimmune disease but my one friend says its type 4 since cytotoxic T cells involved.. i said Type 4 is delayed, but can anyone explain??? thanks!!
Hi. Just to add, Type IV hypersensitivity reactions are antibody-independent T cell mediated reactions. This includes both delayed type and cel-mediated cytotoxicity. Hope this helps.
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| hottie99
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yes i know sle and psgn, and rheumatoid arthritis are type 3 due to immune complex deposition. but i wasnt saying that all autoimmune should be type 2, i guess i just thought that if they had antibodies to the antigen, that would be type 2, bc type 2 is also cytotoxic rite?? why is hashimoto's type 4, b/c they have antibodies right? that was why i keep on asking the mechanism behind hashimoto's and DM type 1 having type 4 hypersensitivity since both have antibodies, so confused 
oh wait so since type 4 is independent, then it act like both typ 2 & 4?? then i'm not confused anymore, that was my confusion, i wanted to say it was both types, but please confirm
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| Tiff
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Type II hypersensitivity - Humoral antibodies participate directly in injuring cells by predisposing them to phagocytosis or lysis. Antibodies are directed toward antigents on cell surfaces. This can be complement-dependent, antibody-dependent cell mediated, or antibody-mediated cell dysfunction. Graves disease for example is antibody-mediated. Antibodes are directed toward TSH receptor.
Type IV hypersensitivity - Tissue injury in which cell-mediated immune responses with senstized T lymphocytes are the cause of cellular and tissue injury. Delayed type is initiated by CD4 t cells. Cytotoxic is mediated by CD8 t cells. Hashimotos is a disease mainly reflective of T cell dysfunction. T cells are directed to the thyroid antigens with MHC. Activated T cells will either interact with B cells to secrete antibodies (antithyroid Ab) or the T helpers will promote CD8 formation. (This part is what confuses many, becuase T helpers are always percieved to be associated wih CD4, but it's important not to forget the intricate mechanism. CD4 can use IL-2 to activate CD8). Autoantibodies in Hashimotos doesn't arise until B lymphocytes are activated. Antibodies may play a role here but it's important to know that T cells are what's really emphasized. the role of T cells in this case supercedes the role of the antibodies.
I hope this clears up any confusion. 
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| hottie99
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YESS!!! thx so much, that helps a lot!! now i get the clarification, so much appreciated!!
so does u FA also say DM type 1 is also type 4?? just curious! 
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| Tiff
Forum Guru
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No it doesn't. But that sounds correct. Type 1 DM is cell mediated hypersensitivity - type IV
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