Characteristics of progressive multifocal leukoencephalopathy clarified through internet-assisted laboratory surveillance in Japan.
BACKGROUND
Progressive multifocal leukoencephalopathy (PML), a rare but fatal demyelinating disease caused by JC virus (JCV), occurs mainly in immunocompromised patients. As PML develops in individuals with various underlying disorders sporadically and infrequently, a nationwide survey of PML is difficult. This study was conducted to elucidate the characteristics of PML in Japan through an internet-assisted laboratory surveillance program.


METHODS
A diagnostic support system for PML was established using a real-time PCR assay of JCV DNA in cerebrospinal fluid (CSF), and requests for testing were received from clinicians via specialized websites. Medical histories of patients were collected through standardized questionnaires, and a database of CSF JCV loads and clinical information was created and analyzed.


RESULTS
For 4 years from April 2007 to March 2011, CSF specimens from 419 patients were tested. Forty-eight individuals were found positive for JCV DNA in their CSF and were diagnosed with PML. PML primarily occurred not only in HIV-positive patients (33.3%) but also in patients with hematologic disorders after receiving stem cell transplantation, chemotherapy, and/or immunosuppressive treatment (39.6%). The frequencies of PML cases among the subjects in these two categories were 20.3% and 23.5%, respectively. Although no significant features were observed with respect to CSF JCV loads in PML patients with an HIV infection or hematologic disorder, males were predominant in both groups (100% and 89.5%, respectively). The proportion of PML cases with autoimmune disorders (6.3%) or solid-organ transplants (2.1%) was smaller than those with HIV infection or hematologic disorders, probably due to the limited availability of therapeutic monoclonal antibodies and transplantation from brain dead donors.


CONCLUSIONS
The results suggest that the internet-assisted laboratory surveillance program might be a useful strategy for collecting precise real-time information on PML on a national level. The current database provides important background information for the diagnosis and treatment of patients with risk factors for PML.
Department of Virology 1, National Institute of Infectious Diseases, Toyama, Shinjuku-ku, Tokyo, 162-8640, Japan.
Kazuo
K
Nakamichi
Hidehiro
H
Mizusawa
Masahito
M
Yamada
Shuji
S
Kishida
Yoshiharu
Y
Miura
Toshio
T
Shimokawa
Tomohiko
T
Takasaki
Chang-Kweng
CK
Lim
Ichiro
I
Kurane
Masayuki
M
Saijo
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D019411:Clinical Laboratory Techniques / Q000706:statistics & numerical data*; D015897:Comorbidity; D057286:Electronic Health Records / Q000706:statistics & numerical data; D005260:Female; D055991:Health Records, Personal; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D020407:Internet; D007577:JC Virus / Q000302:isolation & purification*; D007564:Japan / Q000453:epidemiology; D007968:Leukoencephalopathy, Progressive Multifocal / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D027601:Polyomavirus Infections / Q000134:cerebrospinal fluid* / Q000453:epidemiology*; D011159:Population Surveillance / Q000379:methods*; D015995:Prevalence