HIV-associated neuropathies: role of HIV-1, CMV, and other viruses

The role of the human immunodeficiency virus (HIV) and other viruses in the development of neuropathies associated with HIV infection is controversial . Distal symmetric polyneuropathy (DSP), the most common subtype of HIV-ass ociated neuropathy, is characterized by an abundance of reactive macrophage s within the peripheral nerve, but HIV replication is limited to a small pe rcentage of the macrophages. Thus, the pathological destruction may be medi ated by pro-inflammatory signals amplified by activated glial elements with in the nerve, similar to the proposed mechanism of damage caused by HIV wit hin the central nervous system. In contrast, in mononeuropathy multiplex (M M) and progressive polyneuropathy (PP), cytomegalovirus (CMV) replication i n the peripheral nerve is consistently demonstrable, and this replication l ikely results in direct damage to the infected cells (neurons and glia). Th e rarest form of HIV-associated neuropathy, the diffuse infiltrative lympho cytosis syndrome (DILS), is characterized by an intense CD8(+) T lymphocyte infiltration into the nerve and abundant HIV infection of macrophages. Fin ally, while other viruses (varicella tester, herpes simplex) are associated with myelitis in HIV-infected individuals, there is little support for a r ole for these viruses in HIV-associated neuropathy.