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The following is a summary of “CERS1 is a Biomarker of Staphylococcus aureus Abundance and Atopic Dermatitis Severity,” published in the September 26 issue of Allergy & Immunology by Kenney et al. 

Atopic dermatitis (AD) involves variable Staphylococcus aureus levels, affecting disease severity. Molecular mechanisms driving these differences remain unclear. 

Researchers conducted a retrospective study to investigate host genes predictive of Staphylococcus aureus abundance and their relation to AD severity. 

They analyzed data from the NIH/NIAID-funded (NCT03389893 [ADRN-09]) randomized, placebo-controlled dupilumab trial in adults with moderate-severe AD (n=71). Bulk RNA-sequencing of skin biopsies (n=57 lesional, 55 non-lesional) was compared to S. aureus levels, lipidomics, and clinical measures. 

The results showed S. aureus abundance and CERS1 expression were positively correlated at baseline in non-lesional (r=0.29, P=0.030) and lesional (r=0.41, P=0.0015) skin. Lesional CERS1 expression also correlated with AD severity (SCORing AD [SCORAD] r=0.44, P=0.0006) and skin barrier dysfunction (transepidermal water loss [TEWL AUC] r=0.31, P=0.025). CERS1 expression, linked to C18:0-sphingolipids, was negatively associated with ELOVL6 expression (C16:0→C18:0) and shorter chain sphingolipid composition. Dupilumab reduced CERS1 expression by day 7, eliminating its association with S. aureus abundance and ELOVL6 by day 21. 

Investigators concluded that CERS1 served as a unique biomarker for S. aureus abundance and AD severity, contributing to skin barrier dysfunction and shorter chain sphingolipid composition due to fatty acid sequestration in response to reduced ELOVL6. 

Source: jacionline.org/article/S0091-6749(24)00991-6/abstract