Today I just read a published paper " Progressive multifocal leukoencephalopathy genetic risk variants for pharmacovigilance of immunosuppressant therapies", the PDF file can be downloaded here:
Incidentally, Mayo Clinic also has similar warning in this page:
“Carriers of any one of these variants are shown to be at high risk of PML when drug-exposed PML cases are compared to drug-exposed matched controls”
I checked my nebula database, it seems I do not have any of these variants.