BK virus capsid antibodies are associated with protection against subsequent development of PML in HIV-infected patients

Abstract

Progressive multifocal leukoencephalopathy (PML) is caused by JC polyomavirus (JCPyV). Because a reciprocal relationship has been described between antibody levels to JCPyV and BK polyomavirus (BKPyV), we performed a nested case control study with pre-diagnostic serum samples from HIV infected subjects to examine the relationship between BKPyV capsid antibodies and the risk of PML. Serum samples collected 0.5–2 years before PML diagnosis from 25 cases (66 samples) and 80 matched controls (204 samples) were tested in ELISA for JCPyV, BKPyV type 1 and type 4 capsid antibodies. High levels of BKPyV 1 and 4 antibodies were associated with a lower risk of PML (BKPyV 1 OR, 0.56, 95% CI, 0.35–0.89; BKPyV 4 OR, 0.40, 95% CI, 0.24–0.0.67). Our study demonstrates that antibodies to BKPyV capsids are an immunological marker of protection against development of PML. Further studies are needed to define the mechanism.