Viral Infections in Transplants Flashcards
How are viral infections acquired by transplant recipients?
What viral infections are most prevalent post-transplant?
Either due to presence of the virus in the donated tissue or acquired from the environment post-transplant as a consequence of immunosuppression.
Herpesviruses, respiratory viruses (Parvo/adeno), and BK virus.
Polyomaviruses
Describe their structure, shape, and genome.
Summarize its gene products.
Name two examples.
Polyomaviruses
They are naked, icosahedral viruses with a circular dsDNA genome.
Early & late regions encoding “large/small” and structural antigens, as well as agnoprotein (unknown) and miRNAs (inhibit early expression).
Merkel cell polyomavirus, and BK polyomavirus (11 known).
Polyomaviruses
What is the significance of the large T antigen?
How is its tropism specified?
Polyomaviruses
It is involved in DNA replication, but it is also a major oncoprotein as it disrupts tumor suppressor proteins to facilitate replication.
VP1 (a late region product) recognizes specific surface gangliosides. Pretty typical.
BK Polyomavirus
How many serotypes are there?
Describe its infection.
Describe its pathology.
BK Polyomavirus
Four.
Infection occurs early on (mechanism unknown). Persists in renal tubular cells.
Asymptomatic in healthy individuals, the immunosuppressed experience nephropathy and hemorrhagic cystitis (post-transplant).
JC Polyomavirus
How many serotypes are there?
Describe its infection.
Describe its pathology.
JC Polyomavirus
Only 1 serotype.
Infection occurs early on (mechanism of transmission unknown), grows in glial cells (5-HT2A receptor tropic).
The immunosuppressed experience progressive multifocal leukoencephalopathy, as well as tumors (especially merkel cell carcinoma following integration).
What measures are taken prior to transplant to prevent viral infection?
What infections may result from pre-engraftment immunosuppressive regimens?
Screening for common viruses implicated in post-transplant infection: Hep C, Hep B, HIV, CMV, EBV (and syphilis).
Respiratory viruses, enteric viruses, HHV1/2/6.
What viral infections tend to occur 30-100 days following engraftment?
What condition facilitates viral infection past 100 days?
What virual infection tends to reactivate several months following transplant?
CMV, Adenovirus, HHV6, RSV and other respiratory viruses.
Chronic graft-versus-host disease requires continued (major) immunosuppression and may be associated with barrier disruption.
Herpes Zoster Virus (85%; 15% develop chickenpox).
Which viruses can cause hemorrhagic cystitis (post-transplant)?
How is adenovirus monitored and treated (post-transplant)?
BKPyV, JCV, and adenoviruses.
Monitored via qPCR. Treated with sidofovir, IVIG.
