Microglia

Microglia are a type of glial cell located in the brain and spinal cord. They are the resident macrophages of the central nervous system scavenging dead or damaged cells or encircling them when the brain is injured or infected. They are more abundant in grey matter than white.

Chronic fatigue syndrome
Chronic inflammation of microglia has been found in ME/CFS patients.

Valcyte (valganciclovir), a drug commonly used as an off-label treatment for ME/CFS and Cytovene (ganciclovir) inhibit microglial activation. Low-dose naltrexone (LDN, another off-label treatment,) inhibits microglial activation via the TLR4 receptor.