cytotoxic T cell mediated vs delayed type hypersensitivity

[MudPhud20XX]

Here is a Kaplan question:

A nurse develops pruitic papules and vesicles on an erythematous base after wearing latex-containing gloves for several hours. The rash develops as a result of which of the following immune processes?

A. Anaphylactic-type hypersensitivity
B. Complement-dependent cytotxocity
C. Cytotoxic T cell mediated hypersensitivity
D. Delayed-type hypersensitivity
E. Immune complex dz

Answer: C

I chose D. I am now kind of consfused. When we say type 4 hypersensitivity, it refers to both cytotoxic T cell mediated and delayed-type hypersensitivity, right?

I considered latex allergy as contact dermatitis, which is categorized as delayed (type 4) type hypersensitivity.

Can anyone help me out? Many thanks in advance.

---

Members don't see this ad.

 

[001100010010011]

I think the question is asking what the rash develops from, which is cytotoxic T cells.

I agree, it sounds like it could be a Type I (wheal/flare) or contact dermatitis (Type IV), which I think latex can cause. I remember doing this question and realizing why Kaplan is a bank worth doing, but not always worth annotating.

 

[dyspareunia]

I thought latex allergy was type 1 HS?

 

[notbobtrustme]

errr, wtf, this question is wrong on so many levels. DTH and CD8+ mediated cytotoxicity are the same thing, there's no distinction between the two. It's simply mediated by T-cells instead of innate immunity or antibodies as in types 1-3. No USMLE question will ever ask you to differentiate between DTH and cytotoxic (mostly because it's the same goddamn thing).

secondly, the time course is way too short. DTH is called DTH because it occurs 2-4 days after exposure. When you rub your dick on poison ivy, you don't get a rash until 2-3 days later, not after a couple hours. It takes time for the T cells to get activated and do their mojo.

 

[dyspareunia]

errr, wtf, this question is wrong on so many levels. DTH and CD8+ mediated cytotoxicity are the same thing, there's no distinction between the two. It's simply mediated by T-cells instead of innate immunity or antibodies as in types 1-3. No USMLE question will ever ask you to differentiate between DTH and cytotoxic (mostly because it's the same goddamn thing).

secondly, the time course is way too short. DTH is called DTH because it occurs 2-4 days after exposure. When you rub your dick on poison ivy, you don't get a rash until 2-3 days later, not after a couple hours. It takes time for the T cells to get activated and do their mojo.

So would you agree that this is an atopic dermatitis (IgE)?

 

[notbobtrustme]

So would you agree that this is an atopic dermatitis (IgE)?

yea, as written, I'd say it was IgE, but even then, the timeline doesn't work, since she would have had a reaction within 20 minutes or so. Overall, this question is just garbage and teaches you nothing while confusing the crap out of less versed individuals.

 

[mcloaf]

errr, wtf, this question is wrong on so many levels. DTH and CD8+ mediated cytotoxicity are the same thing, there's no distinction between the two. It's simply mediated by T-cells instead of innate immunity or antibodies as in types 1-3. No USMLE question will ever ask you to differentiate between DTH and cytotoxic (mostly because it's the same goddamn thing).

secondly, the time course is way too short. DTH is called DTH because it occurs 2-4 days after exposure. When you rub your dick on poison ivy, you don't get a rash until 2-3 days later, not after a couple hours. It takes time for the T cells to get activated and do their mojo.

The time course could be legit since the question doesn't actually say how much later the rash developed, but yeah C and D are the same ****ing answer.

 

[CherryRedDracul]

DTH isn't quite the same thing as cytotoxic T cell mediated hypersensitivity. Cytoxic hypersensitivity is a TYPE of DTH; just like oranges are a type of fruit, it wouldn't be correct to say an orange is the exact same thing as a fruit.

One form of DTH that doesn't involve a cytotoxic T cell response is the IL-12/IFN-gamma axis in response to M. tuberculosis. The cells doing the killing here are macrophages. This is called granulomatous hypersensitivity. The other two types of DTH are contact hypersensitivity (the cytotoxic hypersensitivity we're talking about) and tuberculin-type hypersensitivity.

C and D are both correct, but C is more correct. Nonetheless, it's a bit of a nasty question and I don't expect trick questions like that on the real thing.

 

[notbobtrustme]

DTH isn't quite the same thing as cytotoxic T cell mediated hypersensitivity. Cytoxic hypersensitivity is a TYPE of DTH; just like oranges are a type of fruit, it wouldn't be correct to say an orange is the exact same thing as a fruit.

One form of DTH that doesn't involve a cytotoxic T cell response is the IL-12/IFN-gamma axis in response to M. tuberculosis. The cells doing the killing here are macrophages. This is called granulomatous hypersensitivity. The other two types of DTH are contact hypersensitivity (the cytotoxic hypersensitivity we're talking about) and tuberculin-type hypersensitivity.

C and D are both correct, but C is more correct. Nonetheless, it's a bit of a nasty question and I don't expect trick questions like that on the real thing.

true, but Type 4 hypersensitivity isn't necessarily cytotoxic T cell mediated, but rather T cell mediated. Whether it's helpers or cytotoxics, I don't think that matters. In a way, it's all CD4+ mediated, since CD4+s will activate CD8+s.

Regardless, I don't think Step 1 will make a distinction between the different subtypes, at least not in this context.