However, Mp was not detectable via PCR (targeting the Mp P1 adhesion gene) in lesional biopsies of patients with Mp-associated EM in a more recent study [7] and indirect pathomechanisms such as polyclonal B-cell activation, cross-reacting autoantibodies resulting from molecular mimicry, akin to Mp-associated Guillain-Barré syndrome, immune complex deposition and complement activation, have all been discussed and seem to be favored in the current literature [15–17, 43, 47, 48]. Here, PPP1CB is linked to erythema multiforme.