What is the primary immunologic mechanism by which HIV infection increases susceptibility to opportunistic infections?

HIV causes irreversible neutrophil dysfunction that primarily predisposes to fungal and intracellular infections.

HIV triggers massive complement depletion leading to inability to opsonize pathogens and causing OIs. 

HIV destroys plasma cells causing immediate loss of all specific antibodies and resulting in OIs before CD4 decline.

HIV progressively depletes CD4⁺ T cells and impairs cell-mediated (Th1) immunity and macrophage activation, allowing reactivation of latent and opportunistic pathogens.