CD62L is not a reliable biomarker for predicting PML risk in natalizumab-treated R-MS patients. Author Response.

Abstract

Editors' Note: Commenting on “Natalizumab-related PML 2 weeks after negative anti-JCV antibody assay” Ontaneda and Fox suggest, backed by analysis of progressive multifocal leukoencephalopathy (PML) cases with fingolimod and dimethyl fumarate, that age is a potential risk for PML in patients with multiple sclerosis (MS) and that age should be assessed as a risk stratifier for PML with MS therapies. Gagne Brosseau et al., authors of the initial report, agree and give additional clarification regarding the relation between age and JC virus. Schwab et al. disagree with “CD62L is not a reliable biomarker for predicting PML risk in natalizumab-treated R-MS patients,” pointing to how tested samples appear to be compromised and how the assay was changed from published protocols. Cahir-McFarland et al., authors of the study, explain why CD62L is not a reliable biomarker for PML risk, why the assay was changed, and that the samples were not compromised but reflect the differences between CD62L count in healthy volunteers vs patients with MS or natalizumab-treated patients. —Chafic Karam, MD, and Robert C. Griggs, MD Cells for the study …