Detection of JC virus DNA from whole blood and urine samples

摘要

JC polyomavirus (JCPyV) is ubiquitous in humans and an etiological agent of progressive multifocal leukoencephalopathy (PML). The primary infection with this virus occurs in childhood and persists in the kidneys throughout life. Recently, detection of JC virus DNA from blood samples has been needed for forensic purposes. However, the reported detection rate of this virus from whole blood is unclear. Here, we detected JCPyV DNA from the whole blood and urine of 50 forensic cases who died from external injuries with no apparent illness. JCPyV DNA was detected in eight urine samples (16%) and one blood sample (2%). However, the case we detected from blood died in poor physical condition. Therefore, JCPyV may not present in the blood of healthy individuals and only re-spread into blood vessels in cases with immunosupressed status. Introduction JC polyomavirus (JCPyV) is known to be an etiological agent of progressive multifocal leukoencephalopathy (PML), a central nervous system demyelinating disease found in immunosuppressed patients such as those with AIDS and leukemia. Especially, in AIDS patients, around 10% of them suffer from PML (1). In those patients, JCPyV DNA is detected from urine and peripheral blood mononuclear cells (PBMC). According to serological studies, this virus is found to be a ubiquitous virus among humans worldwide. More than 75% of adults tested positive for antibodies (2). Primary infection of this virus occurs in childhood asymptomatically from their parents (3). The site of persistence in healthy humans is the kidney (4,5,6). Thus, JCPyV DNA is excreted into the urine of about 20-80% of adults (7,8,9).Recently, the JCPyV genotype was found to be a good marker for revealing human birth origins in criminal investigation (10,11,12). For example, when we have a cadaver or a urine spot on the bed sheets at a crime scene, we cannot establish the crime victim's origins if there are no belongings, no eyewitnesses or no fingerprints on record. In such cases, we try to detect JCPyV DNA from the kidneys or the urine spot. From the worldwide genotype distribution, we can estimate the host's geographic origin. Therefore, detection of JCPyV DNA from whole blood samples is extremely important, as well as that from urine. Although there have been several reports on detecting JCPyV DNA from blood leukocytes, the detection rate is not clear. It ranged from 0% to 83% (13,14,15). However, most reports detected JCPyV DNA from hospitalized, immunocompetent individuals. Therefore, it is doubtful they can assume those patients to be “healthy” individuals, even if they do not suffer from immunocompromised-type diseases.Here, we tried to detect JCPyV DNA from the whole blood and urine of 50 forensic cases who died from external injuries, not diseases. We compared the JCPyV sequences and genotypes detected from urine and whole blood DNA. Material and Methods Whole blood and urine samplesTotally, 50 whole blood and urine samples were collected during forensic autopsies in Chiba University. The postmortem time was within 24 hours to guarantee fresh samples for this study. None of the present cases had any illnesses, including immunosuppressive diseases, such as AIDS and leukemia, and died from external injuries a judged from autopsy findings and police department reports. Table 1 shows the cause of death of positive subjects. All samples were stored at –20oC until use. DNA was extracted from 200μL of whole blood and urine using a QiaAmp DNA mini Kit (Qiagen GmbH, Hilden, Germany).