Why are type IV hypersensitivities called delayed hypersensitivity reactions?
A) Type IV reactions manifest slowly over 12-72 hours after the stimulating antigen is encountered.
B) Although type IV reactions can cause skin lesions, watery eyes, and a runny nose, treatment for those symptoms needs to be delayed due to the rapid drop in blood pressure which soon follows and needs to be dealt with first.
C) Drugs to counteract type IV reactions are large and slow to be absorbed by the affected cells causing the patient to tolerate a lengthy symptomatic phase before recovery is complete.
D) Type IV reactions only occur in underdeveloped countries and medical attention often needs to be delayed until the patient can be brought to a hospital.
E) Type IV reactions affect nerve cells and cause nerve impulses to slow resulting in visibly slower movements from the patient.
Answer: A
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