MIR155 and inflammation of heart layer: To assess the impact of elevated Mir155 expression levels in infected B6 heart tissue on carditis (Table 1), we infected B6, Mir155-/-, Il10-/-, and DKO mice with B. burgdorferi and measured Lyme carditis severity by blinded histopathology scoring at 2 and 3 weeks post-infection, periods reported to display peak disease (Table 2).