Editors' note: Prospective validation of the PML risk biomarker l-selectin and influence of natalizumab extended intervals
Citation Manager Formats
Make Comment
See Comments

This article requires a subscription to view the full text. If you have a subscription you may use the login form below to view the article. Access to this article can also be purchased.
In “Prospective validation of the PML risk biomarker l-selectin and influence of natalizumab extended intervals,” Schwab et al. reported that natalizumab is associated with reduction in l-selectin (CD62L) values and an increase in risk of PML but that cessation of natalizumab or extension of treatment intervals leads to recovery of CD62L values, which could potentially decrease risk of PML. Tugemann commented that the sensitivity of this biomarker was affected by inclusion of samples from patients who developed PML—which could falsely increase results about the sensitivity of the marker—and patients who were JC virus (JCV)-negative, which could falsely decrease results about the sensitivity of the marker. Therefore, Tugemann believes that the analysis should have been restricted to patients who were JCV-positive without PML. Schwab et al. responded that (1) because this study was conducted prospectively, they were not aware of PML diagnosis when they processed the samples but that this mirrored a real-world scenario in which a clinician would send the biomarker without knowing a patient had PML, only to subsequently make the diagnosis and (2) they did not have JCV data for all patients. Despite these limitations, they emphasized the utility of CD62L values to stratify risk for PML and to assist with decision-making about the timing of natalizumab dosing, recognizing that the challenging methodology precludes widespread use. Thus, most clinicians will still have to resort to risk stratification for natalizumab use based on duration of treatment, exposure to other immunosuppression regimens, and JCV positivity.
In “Prospective validation of the PML risk biomarker l-selectin and influence of natalizumab extended intervals,” Schwab et al. reported that natalizumab is associated with reduction in l-selectin (CD62L) values and an increase in risk of PML but that cessation of natalizumab or extension of treatment intervals leads to recovery of CD62L values, which could potentially decrease risk of PML. Tugemann commented that the sensitivity of this biomarker was affected by inclusion of samples from patients who developed PML—which could falsely increase results about the sensitivity of the marker—and patients who were JC virus (JCV)-negative, which could falsely decrease results about the sensitivity of the marker. Therefore, Tugemann believes that the analysis should have been restricted to patients who were JCV-positive without PML. Schwab et al. responded that (1) because this study was conducted prospectively, they were not aware of PML diagnosis when they processed the samples but that this mirrored a real-world scenario in which a clinician would send the biomarker without knowing a patient had PML, only to subsequently make the diagnosis and (2) they did not have JCV data for all patients. Despite these limitations, they emphasized the utility of CD62L values to stratify risk for PML and to assist with decision-making about the timing of natalizumab dosing, recognizing that the challenging methodology precludes widespread use. Thus, most clinicians will still have to resort to risk stratification for natalizumab use based on duration of treatment, exposure to other immunosuppression regimens, and JCV positivity.
Footnotes
Author disclosures are available upon request (journal{at}neurology.org).
- © 2020 American Academy of Neurology
AAN Members
We have changed the login procedure to improve access between AAN.com and the Neurology journals. If you are experiencing issues, please log out of AAN.com and clear history and cookies. (For instructions by browser, please click the instruction pages below). After clearing, choose preferred Journal and select login for AAN Members. You will be redirected to a login page where you can log in with your AAN ID number and password. When you are returned to the Journal, your name should appear at the top right of the page.
AAN Non-Member Subscribers
Purchase access
For assistance, please contact:
AAN Members (800) 879-1960 or (612) 928-6000 (International)
Non-AAN Member subscribers (800) 638-3030 or (301) 223-2300 option 3, select 1 (international)
Sign Up
Information on how to subscribe to Neurology and Neurology: Clinical Practice can be found here
Purchase
Individual access to articles is available through the Add to Cart option on the article page. Access for 1 day (from the computer you are currently using) is US$ 39.00. Pay-per-view content is for the use of the payee only, and content may not be further distributed by print or electronic means. The payee may view, download, and/or print the article for his/her personal, scholarly, research, and educational use. Distributing copies (electronic or otherwise) of the article is not allowed.
Disputes & Debates: Rapid online correspondence
REQUIREMENTS
If you are uploading a letter concerning an article:
You must have updated your disclosures within six months: http://submit.neurology.org
Your co-authors must send a completed Publishing Agreement Form to Neurology Staff (not necessary for the lead/corresponding author as the form below will suffice) before you upload your comment.
If you are responding to a comment that was written about an article you originally authored:
You (and co-authors) do not need to fill out forms or check disclosures as author forms are still valid
and apply to letter.
Submission specifications:
- Submissions must be < 200 words with < 5 references. Reference 1 must be the article on which you are commenting.
- Submissions should not have more than 5 authors. (Exception: original author replies can include all original authors of the article)
- Submit only on articles published within 6 months of issue date.
- Do not be redundant. Read any comments already posted on the article prior to submission.
- Submitted comments are subject to editing and editor review prior to posting.