Monocytes and monocyte-derived dendritic cells (DCs) from symptomatic (n = 12) and asymptomatic atopic donors (n = 11), healthy nonatopics (n = 14) and from patients with psoriasis (n = 13) were analyzed for their expression of TLR2, TLR4 and TLR9 by real-time PCR.
Overall, the data suggest that the release of CpG-rich DNA from mammalian DNA may contribute to the pathogenesis of autoimmune diseases such as systemic lupus erythematosus and psoriasis in which activation of TLR9 in DCs by self DNA has been implicated in disease pathogenesis.
For example, TLR7 and TLR9 activation by endogenous RNA and DNA, transported to the endosomes in the form of immune complexes or non-covalently associated with cationic peptides, could be an important mechanism involved in promoting diseases such as systemic lupus erythematosus and psoriasis.