In: Biology
Linda is a 22-year-old white female presenting signs of sever poison ivy dermatitis (red rash, itching, swelling, and blisters). She stated that she was exposed to poison ivy last year but barely noticed any signs of it. Explain why her first exposure was very mild, but her second exposure was severe in terms of her immune system. If you performed an immune cell blood profile, which leukocyte would you expect to be elevated?
Answer :
Most people do not have an Immune
response to poison ivy, the first time they are exposed to it. This
is an example of delayed hypersensitivity. Upon first exposure, the
T-cells recognize the antigen and there are memory cells created
for it. Upon the second exposure, there is an immune response known
as dermatitis.
The poison ivy plant releases a chemical substance known as
Urishiol which enters the skin where it is metabolized. This is
recognized by the T-lymphocyte which in turn activates the
macrophages through cytokines. The antigen is then phagocytosed by
the macrophage but during this process they also damage the skin
cells resulting in the inflammation seen on the skin.
In the case of Linda, there is this type of delayed hypersensitivity seen which lead to red rashes, itching, swelling and blisters. In her immune cell blood profile, T4 lymphocytes will be elevated. There will also be increase in the number of eosinophils and IgE antibodies.