Hypersensitivity IV Reactions: Cell mediated by https://padlet.com/eelde6881_/26yzyhec98e6tlxj Elisabeth Elder, Hadeel Kasji, Josilin Johnson en-us 2023-10-11 18:06:28 UTC 2023-10-16 00:04:14 UTC hello@padlet.com eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742334295 2023-10-11 18:45:32 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742334295 https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742334498 T cells that trigger an inflammatory response in response to endogenous or external antigens are the mediators of a Type IV hypersensitivity reaction. Other cells, including neutrophils, eosinophils, and monocytes, may also be implicated in certain circumstances. Leukocytes are drawn in by the early inflammatory and immunological response that follows antigen exposure. T cells are exposed to the antigen after being taken up by macrophages and monocytes, which causes them to become activated and sensitized. Afterwards, these cells release chemokines and cytokines, which have the potential to harm tissue and induce diseases. Type IV hypersensitivity responses may cause a variety of disorders, such as medication hypersensitivity and contact dermatitis.
Marwa, K., & Kondamudi, N. P. (2023). Type IV Hypersensitivity Reaction. In StatPearls. StatPearls Publishing.]]> 2023-10-11 18:45:41 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742334498 eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742336442 2023-10-11 18:47:06 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742336442 This image displays what someone's reaction could manifest as, this person has been itching the inflamed area and has broken skin. eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742338009 2023-10-11 18:48:15 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742338009 eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742339424 I chose this picture because the visual graphic helps me understand the cellular process of the hypersensitive reaction. I can see the dendritic cell consuming the skin proteins that bind to the urushiol oil. The visual of T helper cells activating different T cells to do more jobs is helpful. I like to imagine all these cells and chemicals doing their different jobs under my skin! The picture is easy to understand and coordinated with the text below from McCance &Huether's Pathophysiology textbook. ]]> 2023-10-11 18:49:25 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742339424 eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742340529 2023-10-11 18:50:15 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742340529 Anyone spending time in the woods could be exposed to Poison Ivy and have a reaction to the oil, urushiol. People most at risk are hikers, hunters, and outdoor workers. eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742347630 2023-10-11 18:55:46 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742347630 eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742348484 Urushiol oil is a chemical that comes from the sap of poison oak, poison sumac, and poison Ivy plants. The oils are only released from the leaves of the plants when they are damaged. This can happen while working around the plants, stepping on them or walking through them. Urushiol oil is highly potent and it only requires a minuscule amount to evoke a skin reaction. 

Arney, Kat. (2017, June 13) Magnificent Molecules: Urushiol.       Royal Society of Chemistry. https://edu.rsc.org/magnificent-molecules/urushiol/3007556.article]]> 2023-10-11 18:56:27 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2742348484 Antigens from target cells stimulate T cells into cytotoxic T cells which then release granzymes and cause apoptosis. Other T cells are activated into T helper cells and they attract Macrophages to the site of contact with the allergen e.g. poison Ivy. The macrophages cause most of the cell damage by releasing enzymes and reactive oxygen species. eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2746104890 Rogers, J. L. (2023). McCance & Huether’s Pathophysiology: The Biology Bass for Disease in Adult and Children, (9th ed). Elsevier.

]]> 2023-10-14 13:55:22 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2746104890 Type IV hypersensitive reactions are delayed. They are delayed because it takes time for the T cell system to activate and travel to the site of contact and to release the associating cytokines, macrophages and enzymes. eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2746109456 Rogers, J. L. (2023). McCance & Huether’s Pathophysiology: The Biology Bass for Disease in Adult and Children, (9th ed). Elsevier.]]> 2023-10-14 14:01:41 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2746109456 eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2746120114 This short video highlights in the beginning that it's not really the oil that causes the damage, but it's the way that our skin proteins react and bind forming a complex that sets off the skin reaction.  When these complexes are in the body they are identified by T helper cells as an invader and the immune system cascade responds accordingly. By attempting to rid the body of the invader (the protein and oil-bound compound) the chemicals called to the site are what cause harm to the tissues. The cytokines, enzymes, and reactive oxygen species cause the skin to blister, itch, and weep. 

Institute for National Safety and Health. (2022, May 24) Poisonous Plants. The Center for Disease Control. https://www.cdc.gov/niosh/topics/plants/exposure.html

]]> 2023-10-14 14:16:28 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2746120114 Poison Ivy rashes can be treated by initially cleansing and rinsing the known exposed area in an attempt to rid the body of the urushiol oil. Over the counter medications such as anti-itch cream, calamine lotions, and antihistamines can help manage the itching the reaction causes. It is also important to not scratch to not create open sores on your body to prevent infection. eelde6881_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2746138380 Cleveland Clinic. (2023, May) Poison Ivy, Poisin Oak, Poisin Sumac. ClevelandClinic.org]]> 2023-10-14 14:39:59 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2746138380 Clinical manifestations of contact dermatitis include erythema and edema with pruritic (itching) vesicular lesions, seen in the areas of allergen contact. The antigen must be removed for the inflammatory response to resolve and for tissue repair to begin. jjohn5113_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2747021753 Rogers, J. L. (2023). McCance & Huether’s pathophysiology: The biologic basis for disease in adults and children. Elsevier.  ]]> 2023-10-15 19:38:21 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2747021753 jjohn5113_ https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2747026009 Begin by washing the affected area. Avoid itching to prevent infection. Begin OTC treatment with topical calamine lotion, oatmeal baths, baking soda & water, cool, wet compress, and wash all exposure clothing. ]]> 2023-10-15 19:44:39 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2747026009 Age, occupational exposure, and a family history of atopic dermatitis are all factors that can increase the likelihood of developing allergic contact dermatitis. https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2747048037
The following are some of the most prevalent triggers of allergic contact dermatitis:

Plants or parts of a plant (botanicals), like poison ivy.
Skin care products with fragrances.
Metals, such as nickel.
Medications, including antibiotics.
Preservatives or chemicals.

Litchman G, Nair PA, Atwater AR, et al. Contact Dermatitis. [Updated 2023 Feb 9]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459230/ ]]> 2023-10-15 20:19:19 UTC https://padlet.com/eelde6881_/26yzyhec98e6tlxj/wish/2747048037