Polyomaviridae Flashcards
Human polyoma viruses? DNA/RNA, enveloped, type of genome?
BK, JC, Merkell cell
Non enveloped DNA virus with circular genome
Presentations of BK virus in immunocompromised?
Haemmorhagic cystitis
Ureteric strictures
BKVAN - BK virus associated nephropathy
Possibly bladder/urothelial cancers
Very rare - pneumonitis, pulmonary fibrosis
Investigation of possible BKVAN?
First sign is decoy cells and viruria.
Followed by viraemia which usually precedes graft dysfunction
Log 4 viraemia is predictive of BKVAN (93% sens/specificity)
Renal biopsy - demonstrates positive SV40 staining
Treatment of BKVAN
Reduction of immunosuppression
Monitoring for BK nephropathy
3 monthly for first 2 years, annually from yeasr 2 -5
Path stain indicationg BK VAN?
SV40
JC virus pathogensis leading to PML?
It establishes life long infection and is found latent in the kidney. Mostly doesn’t cause any symptoms but can mutate to become more neurotropic resulting in PML. Patients who lack cellular immunity (HIV, natalizumab, ritux, etc) are especially prone to this. JC extracts from people with neurological disease have shown a high level of rearrangement in the non coding control region of the genome. Mode of CNS infection isn’t established.
JC epidemiology
50-90% adults infected
Treatment of PML
HAART - immune reconstitution
??plasma exchange in natalizumab (no real evidence for this)
Checkpoint inhibitors - no real evidence again and used in heterogenous patient groups
