HHV-6 integrates into the chromosome during latency and reactivates in response to chemical stimulation.
Peter Medveczky and colleagues determined that HHV-6 uses a novel form of latency. The virus finds safe harbor inside the human chromosomes to evade the immune system. Medveczky made this surprising finding by studying patients who have a rare form of HHV-6. These patients are actually born with HHV-6 integrated into every cell of their body, and the virus is passed from parent to child. Many scientists believed that this integrated virus could not be reactivated, but Medveczky’s group determined that chemical stimulation can cause the integrated virus to reactivate and start producing active virus. See Abstract from PNAS.