Role of Cathelicidin (Ll-37) and Human Β-Defensin In Atopic Dermatitis And Psoriasis

Abstract

The Human epithelium, including the epidermis produces antimicrobial peptide (AMP)
as part of innate immunity. Cathelicidin and human β-defensins are the most AMP
found on the skin. This antimicrobial peptide has a role in the response of the natural
immune system by becoming the front line of the defense system against infection. The
discussion of this literature review will focus on cathelicidin and human β-defensin-1
which are the main AMPs that affect atopic dermatitis and psoriasis. Antimicrobial
peptides are excessively produced in lesional psoriatic scales or rosacea in contrast to
the atopic skin that shows lower AMP levels when compared with psoriasis. Despite
the impaired skin barrier which facilitates potentially pathogenic microbes to colonize
the epidermis, patients with psoriasis surprisingly present a low frequency of skin
infections, whereas patients with atopic dermatitis are predominantly susceptible to
particular cutaneous bacterial, fungal and viral infections. One possible explanation of
the fact is the difference in the expression of AMPs. DA patients have fewer AMP
expression characteristics, especially cathelicidins LL-37 and HBD-2. Research on
antimicrobial use can help reduce pathogen colonization so that clinical improvement
of AD occurs. In the case of psoriasis, AMP expression increases, especially LL-37 and
HBD-2, showing synergistic antimicrobial activity that is effective in eradicating
microbial colonization, so there is no strong evidence to support antibiotic use in
treating psoriasis or in preventing disease.