Research PML: 60% Prevalence of JC Virus in MSers


Bozic C, Richman S, Plavina T, Natarajan A, Scanlon JV, Subramanyam M, Sandrock A, Bloomgren G Anti-John Cunnigham virus antibody prevalence in multiple sclerosis patients: Baseline results of STRATIFY-1. Ann Neurol. 2011 Nov;70:713-21. doi: 10.1002/ana.22606

OBJECTIVE: A study was undertaken to define the prevalence of anti-JC virus (JCV) antibodies in multiple sclerosis (MS) patients and to evaluate the analytical false-negative rate of a 2-step anti-JC virus antibody assay.

METHODS:STRATIFY-1 is an ongoing, longitudinal, observational study of relapsing MS patients in the United States who are being treated or considering treatment with natalizumab (Tysabri). Baseline serum and plasma samples were collected for anti-JC virus antibody detection using an analytically validated, 2-step, virus-like particle-based enzyme-linked immunosorbent assay. Urine was collected for JC virus DNA detection.

RESULTS: At baseline (n = 1,096), overall anti-JC virus antibody prevalence was 56.0% (95% confidence interval [CI], 53.0-59.0) in STRATIFY-1 patients, with an assay false-negative rate of 2.7% (95% CI, 0.9-6.2). Prevalence was significantly lower in females (53.4%; 95% CI, 49.9-56.8) than males (64.3%; 95% CI, 58.2-70.0) and increased with age, p = 0.0019 and p = 0.0001, respectively. Prevalence was similar in patients regardless of natalizumab exposure or prior immunosuppressant use, p = 0.9709 and p = 0.6632, respectively. STRATIFY-1 results were generally consistent with those observed in another large North American cohort, TYGRIS-US (n = 1,480).

INTERPRETATION:Baseline results from STRATIFY-1 are consistent with other studies utilizing this assay that demonstrate a 50 to 60% prevalence of anti-JC virus antibodies, a low false-negative rate, and an association of increasing age and male gender with increasing anti-JC virus antibody prevalence. Neither natalizumab exposure nor prior immunosuppressant use appear to affect prevalence. Longitudinal data from STRATIFY-1 will confirm the stability of anti-JC virus antibody prevalence over time.

JC virus is one of the main virus that cause PML that occurs notably with treatment with Tysabri. As you can see it is a common virus and so needs to be considered when selecting treatment options

I’m sure Prof G may have something to say on this.

About the author



  • I afraid I don't know,

    If we have Biogen Readers out there, which I'm sure there are then maybe they can chip-in.

  • STRATIFY-1 is a study to determine the prevalence of JCV in MSers, the validity of their antibody test, and changes in antibody status over time. I'm a participant in STRATIFY-2 Both are sponsored by Biogen. In the US, Biogen is the only company offering a JCV antibody test. I believe the UK uses an antibody test provided by the HPA, but correct me if I'm wrong.

  • Re: I believe the UK uses an antibody test provided by the HPA, but correct me if I'm wrong. "I believe the UK uses an antibody test provided by the HPA, but correct me if I'm wrong."

    Yes, we use both the Biogen-Idec assay and one provided by the Health Protection Agency.

By MouseDoctor



Recent Posts

Recent Comments