Diagnosis of nail psoriasis: evaluation of nail-derived microRNAs as potential novel biomarkers

Background MicroRNA levels in sera or hair may potentially be useful biomarkers for various diseases. The diagnosis of nail diseases is sometimes difficult, and nail psoriasis without skin lesions is indistinguishable from nail changes caused by other diseases. Objectives We evaluated nail microRNA levels as biomarkers for the diagnosis of psoriasis patients. Materials & methods MicroRNA levels were examined in psoriasis patients with (11 patients) and without (six patients) nail changes. Normal control nails were collected from 17 healthy subjects. Eight patients with other diseases who also had nail changes were also included as disease controls. Results Microarray, real-time PCR, and in situ hybridisation indicated that the expression levels of nail miR- 4454 were decreased in psoriasis patients with nail changes, compared to those patients with other diseases involving nail change, or healthy subjects. The miR-4454 levels in nails showed a significant inverse correlation with the Nail Psoriasis Severity Index (NAPSI) score, suggesting that nail miR-4454 levels reflect nail condition. Conclusion The levels of microRNAs in nails may be suitable biomarkers for diagnosis or evaluation of disease activity of psoriasis.