Type O blood group associates with higher anti-JC polyomavirus antibody levels

Background: Patients with multiple sclerosis (MS) and high anti-JC polyomavirus (JCPyV) antibodies in blood have an increased risk for the development of progressive multifocal leukoencephalopathy (PML) when treated for MS. To test the hypothesis that type O blood group associates with anti-JCPyV antibody levels and the risk of developing PML, we characterized ABO blood group antigen on blood samples of 62 patients with PML, and 64 MS controls without PML.

Methods: Monocentric retrospective cohort study. Anti-JCPyV antibody levels in arbitrary units (AU) were determined in sera using an ELISA-based method, and blood group specific antibodies using standardised test erythrocytes.

Results: Anti-JCPyV antibody levels were higher in individuals with blood group O compared with all other blood groups (O: median AU: 129; not O: median AU: 53; p = .005). This association was not observed for the closely related BK virus. Of the 62 patients with PML, 29 (47%, 95% confidence interval (CI) 35%-59%) were of blood group O, which showed a nonsignificant trend to differ from the expected distribution in the German population (41%), and the MS controls studied (36%, 95% CI 25%-48%).

Conclusion: The ABO blood group O antigen associates with higher anti-JCPyV antibody levels and may impact the risk of the later development of PML. The overrepresentation of blood group O in cases with PML was in line with a previous publication. Larger studies are warranted to assess a potential value of host genetic markers, such as the ABO status, for PML risk prediction during immunotherapy.