CCR5 and tick-borne encephalitis: That suggests that either (1) CCR5 does not play a role in driving lymphocyte migration into cns in TBE, (2) CCR5 drives lymphocyte migration in TBE but its impaired expression may be compensated by alternative pathways, or (3) CCR5 drives lymphocyte migration in TBE, but its expression in CCR5Δ32/wt is induced to a level sufficient to fulfill that role.