In terms of human pathology, polyomaviruses are since its discovery (1953) studied as oncogenic viruses. There were decsribed two types of human polyomaviruses - BK virus and JC virus. For a large part of the population (up to 60 %) primary infection occurs in childhood often with the symptoms of a upper respiratory tract infection. In 70 % of adults antibodies against one of them or both are detected. It is assumed that both viruses after the primary infection may persist inapparent in kidneys and possibly also in B-lymphocytes. The reactivation of the viruses occures mainly in patients with disorders of cell-mediated immunity (HIV, transplant patients etc..) but also during the pregnancy period.

BK polyomavirus

The primary infection is asymptomatic, frequently in the respiratory tract. Then the virus migrates to the primary site of latency, e.g. kidneys and the urothelium.

Generally it moves by seroprevalence BK virus in the urinary tract between 0.3% and 6%, but the infection rate increases with the level of immunosuppression. The reactivation of symptoms is associated with urinary tract infections and manifests as haemorrhagic cystitis, urethral stenosis, tubulointestinal nephropathy and interstitial nephritis. Especially in renal transplant patients, BK virus nephropathy is one of the serious complications which manifests similarly as a rejection episode or drug toxicity. The diagnosis of BK viral nephropathy (BKN) can only be by histological, immunohistochemical, ultrastructural or molecular genetic evidence of the virus. Monitoring the viral load of the BK virus in transplant patients using Real-Time PCR will allow for early reduction of immunosuppression, which is in most cases sufficient to prevent damage to the kidney graft.

Examination

  • Method:
    Quantitative detection by real-time PCR. The detection sensitivity of 100 copies / ml of sample.
  • Material:
    • whole blood (EDTA tube transport to the laboratory within 24 hours from taking it at room temperature)
    • plasma (after centrifugation of whole blood in EDTA tube at 1200xg for 10 min. To 7 days may be stored at 2/8 °C, longer at -18 / -22 °C)
    • cerebrospinal fluid, urine, biopsy * (-18 / -22 °C) (* of labeled material is recommended to perform only a qualitative detection)

JC POLYOMAVIRUS

The JC virus in immunosuppressed patients such as etiological agents is primarily associated with progressive multifocal leukoencephalopathy (PML). It rarely may also cause polyomavirus nephritis.

Examination

  • Method:
    One round of PCR and sequencing confirmation. The detection sensitivity of 200 copies / ml of sample.
  • Material:
    • whole blood (EDTA tube transport to the laboratory within 24 hours from taking it at room temperature)
    • plasma (after centrifugation of whole blood in EDTA tube at 1200xg for 10 min. To 7 days may be stored at 2/8 °C, longer at -18 / -22 °C)
    • cerebrospinal fluid, urine, biopsy (-18 / -22 °C)

Analytical sensitivity and specificity of the sequencing of 99%.

Limitations:

In the case of analysis of somatic mutations by sequencing, mutations will not be detected, as long as the altered cell line is not represented at least 20%.