[1] Univ Alabama Birmingham, Dept Biostat, Birmingham, AL 35294 USA
[2] Biogen, Cambridge, MA USA
[3] Icahn Sch Med Mt Sinai, Dept Neurol, Corinne Goldsmith Dickinson Ctr Multiple Scleros, New York, NY 10029 USA
[4] Icahn Sch Med Mt Sinai, Friedman Brain Inst, New York, NY 10029 USA
[5] Univ Texas Hlth Sci Ctr Houston, McGovern Med Sch, Houston, TX 77030 USA
[6] Natl Inst Neurol Disorders & Stroke, NIH, Bethesda, MD USA
[7] Natl Inst Neurol Disorders & Stroke, Viral Immunol Sect, NIH, Bethesda, MD USA