text: <unk>  causes acquired immunodeficiency syndrome by depleting CD4+ T helper lymphocytes. The virus is acquired by either sexual contact, exposure to contaminated blood, or mother-to-child transmission. Once the virus is acquired, it disseminates to the majority of lymphoid organs, where it enters a period of rapid viral replication. This leads to the acute phase of the infection, which is characterized by a very elevated viral titer and an acute drop in CD4 T-lymphocyte count. As the immune response mounts, viral replication and the CD4-cell depletion rate drops. The immune system continues to deteriorate, but at a slower pace. This is known as the chronic phase of<unk>  infection. The<unk>  virus causes CD4-cell death by a variety of mechanisms including cytopathic single-cell destruction, syncytia formation, autoimmunity, and superantigen formation.
option_0: HIV AIDS pathophysiology
option_1: HIV AIDS drug resistance
option_2: HIV AIDS Coinfections
option_3: HIV AIDS differential diagnosis
option_4: Cardiac diseases in AIDS pathophysiology
option_5: Cardiac diseases in AIDS laboratory findings
option_6: Neurosyphilis risk factors
option_7: Virus cancer link