Infectious Diseases and Microbiology - Progressive Multifocal Leukoencephalopathy (PML) (JC Virus)

Infectious Diseases and Microbiology - Progressive Multifocal Leukoencephalopathy (PML) (JC Virus)
Progressive Multifocal Leukoencephalopathy (PML)
PML is a consequence of the JC virus (JCV), a polyomavirus that affects humans. JCV is transferred through respiratory droplets, primarily during early childhood, and eventually affects 70%–80% of adults. Severely immunosuppressed patients experience the reactivation of latent infections.

PML is a neurological disorder characterized by the loss of myelin in the brain, typically affecting individuals with weakened immune systems, especially those with AIDS. The beginning of the disease is gradual and difficult to detect. Initial indications manifest as atypical speech and visual impairments, along with changes in cognitive abilities. PML follows a gradual clinical trajectory, ultimately leading to a state of coma and death, typically occurring within a span of 6 months after the initial onset.
 JCV is most frequently contracted through inhalation and spreads through the bloodstream to create a dormant infection in the kidneys, lungs, and lymphoid organs. Immunocompromised patients have activation of JCV, which then extends to the brain and leads to the development of PML. Within the central nervous system (CNS), the JC virus (JCV) binds to the serotonin receptor located on oligodendrocytes, resulting in a lytic infection. Oligodendrocytes are the primary cells responsible for creating myelin in the central nervous system (CNS). JCV utilizes opportunistic immune evasion mechanisms in immunosuppressed individuals.

 The presence of JCV infection can be identified through the use of PCR on cerebrospinal fluid (CSF) or brain biopsy samples obtained from individuals with progressive multifocal leukoencephalopathy (PML).
 There is currently no targeted therapy or immunization available for the treatment or prevention of PML.
 PML is a medical condition that is used to define the presence of AIDS.