NOD1 and disease arising from reactivation of latent virus: Although intracellular persistence of P. acnes in macrophages could not be demonstrated in the present study, possible impairment of autophagy induction in many sarcoidosis patients and some non-sarcoidosis subjects with the NOD1 796A-allele may permit latent infection even in macrophages by increasing the cytosolic P. acnes, which seems to proliferate intracellularly more readily than P. acnes in autophagic vacuoles.