Ahmed has worked as a phlebotomist in the local hospital for the last 7 years. Last year, he began to complain of watery, nasal congestion and wheezing whenever he went to work. He suspected he was allergic to something at the hospital because his symptoms abated when he was at home over the weekends. One day, he arrived at work for the morning shift and put on his gloves. Within minutes, he went into severe respiratory distress requiring treatment in the emergency ward. It was determined at that time that his allergic response was due to latex exposure. 1. Ahmed experienced a type I, IgE-mediated hypersensitivity response. How can this be determined by his signs and symptoms? How might another type of latex hypersensitivity reaction present?2. How do T2H cells, mast cells, and eosinophils function to produce the signs and symptoms typical of a type I hypersensitivity disorder?3. How is it that someone who does not come into direct contact with latex can still have a hypersensitivity response to the material? What do food allergies have to do with latex allergies?

Answers and Explanations:

1. Symptoms of type I IgE-mediated allergic reactions may include hives, itching, stuffy, runny nose and asthma symptoms such as nasal congestion, wheezing or shortness of breath. Allergic reactions may occur within minutes after exposure to latex items. The Type IV hypersensitivity (i.e., delayed hypersensitivity reactions associated with cell-mediated immunity) represents a type of T cell-mediated response dependent on the presence of antigen-specific T cells.

2. During type I hypersensitivity reactions the TH2 cells secrete interleukin 4 (IL-4) that stimulates B-cells in order to produce Immunoglobulin E (IgE) antibodies. Moreover, TH2 cells also secrete distinct types of IL-3, and IL-5 that recruit and activate eosinophils. Finally, when IgE antibodies bind to the allergen substance, it causes the degranulation of the mast cell.  

3. Direct interaction with latex items is not needed to produce allergic reactions, and serious allergic reactions may occur only by inhaling latex proteins suspended in the air resulting from the powder in the latex glove. The allergenic latex proteins show a similar structure to allergenic protein foods from kiwis, bananas, avocado, tomatoes, etc, and thereby people with latex allergy may also exhibit cross-sensitivity to these foods.