Ahmed has worked as a phlebotomist in the local hospital for the ...

[Haya94]

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 his allergic response was due to latex exposure.
 
  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?
 
  How do T2H cells, mast cells, and eosinophils function to produce the signs and symptoms typical of a type I hypersensitivity disorder?
 
  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?

Question 2

Patience is 29 years old and has been HIV positive for 9 years. She has remained asymptomatic and is not taking antiretroviral medication.
 
  Recently she was at the drop-in clinic to talk to a public health nurse about having a baby through artificial insemination. She said she had met a man who wanted to marry her and have children with her, but she was concerned about the baby contracting HIV. Her latest blood tests indicated her CD4+ count was 380/ L. The PCR test indicated her viral load was 850. The nurse referred her to the physician to discuss antiretroviral therapy during her pregnancy.
 
  What are the factors that increase the chance of HIV transmission from mother to infant, and how the transmission occurs?
 
  Patience was told that after she became pregnant, she would begin HAART therapy. Describe what this therapy is and what particular antiretroviral medication would be particularly useful to her during her pregnancy. What concern is there about administering certain antiretrovirals early in the pregnancy?
 
  Individuals with HIV are prone to contracting opportunistic infections. What are opportunistic infections and the risk factors that leave an individual with HIV particularly prone to contracting this type of illness?

[jlaineee]

Answer to Question 1

Ahmed demonstrated a type I, IgE-mediated hypersensitivity reaction as indicated by his rhinoconjunctivitis and asthmatic symptoms. The rapid onset of his respiratory symptoms shortly after putting on the gloves is also typical of the type I response. Latex allergy can also be attributed to a type IV, T-cell-mediated response that presents with dermatological signs and symptoms that are more delayed in their onset.

In a type I hypersensitivity disorder, T2H cells differentiate in response to an allergen and in turn release IL-3, IL-4, and IL-5. Interleukins-3 and 5 recruit and activate eosinophils, while interleukin-4 stimulates the differentiation of B cells into IgE-producing plasma cells. The IgE antibodies in turn sensitize mast cells, which subsequently undergo degranulation when exposed to the allergen. Mast cells produce vasodilation and smooth muscle spasm. Both mast cells and eosinophils contribute to the mucosal edema, secretion, and bronchospasm seen in type I hypersensitivity responses.

The latex proteins responsible for allergic reactions bind readily with the cornstarch used to coat gloves. In any environment where gloves are frequently changed, the cornstarch becomes airborne and liberates aerosolized latex. A susceptible individual can react to the airborne proteins without having had contact with the latex material itself.
The proteins responsible for latex allergy reactions have a similar structure to the proteins found in bananas, avocado, kiwis, tomatoes, and chestnuts. Those with latex allergy often show cross-sensitivity to these foods.

Answer to Question 2

A number of factors increase the risk of HIV transmission from mother to infant. A mother who exhibits a low CD4+ count or high viral load during pregnancy increases the risk of transmitting the disease to the unborn child. Delayed delivery after rupture of the amniotic sac is another factor that puts the fetus at risk. Transmission can occur in utero, during delivery, or with breast-feeding.

HAART therapy refers to highly active antiretroviral therapy. The treatment protocol involves the administration of two or three antiretroviral medications that collectively destroy the HIV at various stages of replication. The aim of the therapy is to reduce the presence of HIV RNA to an undetectable level while increasing CD4+ cell counts. Zidovudine is a particularly effective antiretroviral medication to be administered to the pregnant woman as it greatly reduces the risk of perinatal transmission to the fetus. Some antiretrovirals, however, are teratogenic and should not be administered to the mother during the first trimester.

An opportunistic infection occurs when otherwise benign or common microorganisms cause disease in a compromised host. Individuals with HIV are prone to opportunistic infection because of CD4+ deficiency. The level of CD4+ cells directly correlates with the risk of developing an opportunistic infection. Viral load is another risk factor, and higher HIV RNA levels predispose the individual to opportunistic illness.