Role of Topical Treatments in the Modulation of Skin Microbiome in Psoriatic Skin

Changes in microbiome have been reported recently in psoriasis lesions compared to healthy surround skin. Preliminary data showed that systemic treatments of psoriasis induce modification of the skin microbiome that becomes similar to healthy individuals after successful treatment. The causative role of microbiome in psoriasis remains in debate. The modification of skin microbiome is suspected to be able to activate the innate immune response, namely natural killers (NKs) and immune lymphoid cells (ILCs). Three types of ILCs have been reported. ILC1 (immune lymphoid cells1) that trigger a Th1 response, ILC2 (immune lymphoid cells 2) that stimulate Th2 response and ILC3 (immune lymphoid cells 3) that induce Th17 response. Interestingly, ILC2 have been reported to be increased in atopic dermatitis while ILC3 are increased in psoriasis.