Sebaceous gland atrophy in psoriasis: An explanation for psoriatic alopecia?. Homo sapiens

In a transcriptome study of psoriatic (PP) vs. normal (NN) skin, we found a co-expressed gene module (N5) enriched 11.5-fold for lipid biosynthetic genes. We also observed fewer visible hairs in PP skin, compared to uninvolved (PN) or NN skin (p 4, 54.1-fold). The intersection of PP-downregulated and SH-upregulated gene lists generated a gene expression signature consisting solely of module N5 genes, whose expression in PP vs. NN skin was inversely correlated with the signature of IL17-stimuated keratinocytes. Despite loss of visible hairs, morphometry identified elongated follicles in PP vs. PN skin (average 1.7 vs. 1.2 Jm, p=0.020). These results document SG atrophy in non-scalp psoriasis, identify a cytokine-regulated set of SG signature genes, and suggest that loss of visible hair in PP skin may result from abnormal SG function. Overall design: Gene expression was compared between sebaceous hyperplasia lesions (n = 5) and normal skin (n = 3) from control subjects.