PDCD1 and infection: Given a prior study showing an association between early development of high anti-E2 IgG titers and spontaneous clearance of infection [9], it was somewhat surprising that we did not see a difference in plasma anti-E2 IgG levels, FCRL5, or PD-1 expression between the Clearance and Persistence groups, despite testing acute infection samples and matching the two groups for duration of infection.