Anti-JC virus antibody levels in serum or plasma further define risk of natalizumab-associated progressive multifocal leukoencephalopathy.
Bottom Line: Anti-JCV antibody index data were available for serum/plasma samples collected >6 months prior to PML diagnosis from 71 natalizumab-treated PML patients and 2,522 non-PML anti-JCV antibody-positive patients.In patients with no prior immunosuppressant use, anti-JCV antibody index distribution was significantly higher in PML patients than in non-PML patients (p < 0.0001).Continued evaluation of anti-JCV antibody index and PML risk is warranted.
Affiliation: Biogen Idec, Cambridge, MA.Show MeSH
Related in: MedlinePlus
Mentions: The initial exploratory analysis of the association between index and PML risk using the test data set showed that the distribution of anti-JCV antibody index was significantly higher in pre-PML samples from natalizumab-treated patients who developed PML than in samples from non-PML anti-JCV antibody–positive patients (median = 2.4 vs 1.4; p < 0.0001; Fig 1A). Subsequent analysis using the verification data set confirmed the association between index and PML, with a significantly higher index distribution for pre-PML samples from PML patients than for samples from non-PML patients (median = 2.3 vs 1.9; p = 0.0199; see Fig 1B). In cross-sectional analysis of the combined PML and non-PML population for both data sets, there was no association detected between index and natalizumab treatment duration or prior immunosuppressant use (Fig 2).