Dengue haemorrhagic fever (DHF) is more commonly seen on secondary infection with a different dengue serotype. The immunological mechanism responsible is:

• A Molecular mimicry between dengue antigens and platelet surface proteins
• B Direct viral cytopathic effect on endothelial cells
• C Deposition of immune complexes in small vessels causing vasculitis
• D Antibody-Dependent Enhancement (ADE) leading to increased viral replication in monocytes ✓

Explanation

Antibody-Dependent Enhancement (ADE) explains the severe manifestations of secondary dengue infection. Pre-existing non-neutralizing antibodies from prior infection with a different serotype bind the new serotype dengue virus and facilitate its uptake into Fc receptor-bearing monocytes/macrophages. This enhances intracellular viral replication, triggering massive cytokine release and capillary leakage, leading to DHF/DSS.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.