MRI Alone Cannot Yet Support Diagnosis
“Dr. Wijburg and colleagues raise an important point in our understanding of the development of PML by showing that small brain lesions may be present at what may be the start of JCV infection when the virus is still undetectable in CSF,” said Eugene O. Major, PhD, a consultant in the Division of Neuroimmunology and Neurovirology at NINDS in Bethesda, Maryland, in an accompanying editorial. “However, it is not yet clear how well the relationship between viral load in CSF and MRI brain lesions approximates the stages of the disease and the processes with which it affects its target brain cells.”
Repeat testing may be worthwhile when CSF testing is negative, because some patients test positive weeks after testing negative, he added. “Suspicion for PML may be increased when MRI shows signs of PML despite negative CSF testing, but it is too early to rely on MRI alone for diagnosis.”
Dr. Major has received consulting fees while serving on independent adjudication committees for Takeda/Millennium, Roche/Genentech, and GlaxoSmithKline.He has patent rights at the NIH as coinventor of the Ultrasensitive Quantitative PCR Multiplex assay for the detection of JCV DNA–distinguishing viral variants.
—Nicola Garrett
Suggested Reading
Major EO. Progressive multifocal leukoencephalopathy lesions and JC virus: the limits and value of imaging. JAMA Neurol. 2018 Mar 12 [Epub ahead of print].
Wijburg MT, Kleerekooper I, Lissenberg-Witte BI, et al. Association of progressive multifocal leukoencephalopathy lesion volume with JC virus polymerase chain reaction results in cerebrospinal fluid of natalizumab-treated patients with multiple sclerosis. JAMA Neurol. 2018 Mar 12 [Epub ahead of print].