HYPERSENSITIVITY
CLASSICAL ALTERNATE AND LECTIN PATHWAYS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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early
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late
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Either A or B
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None of the above
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Detailed explanation-1: -There are three variants of delayed hypersensitivity as listed below and their maximal reaction time appears in brackets: Contact (48 to 72 hours) Tuberculin (48 to 72 hours) Granulomatous (21 to 28 days)
Detailed explanation-2: -Delayed-type hypersensitivity (DTH) is defined as the recruitment of T cells into tissues to be activated by antigen-presenting cells to produce cytokines that mediate local inflammation. CD8+ T cells are now known to mediate DTH responses in allergic contact dermatitis, drug eruptions, asthma, and autoimmune diseases.
Detailed explanation-3: -Late-phase reaction A reaction that typically develops after 2–6 h and peaks 6–9 h after allergen exposure. It is usually preceded by a clinically evident early-phase reaction and fully resolves in 1–2 days. Skin late-phase reactions involve oedema, pain, warmth and erythema (redness).