Use of intralesional blood to determine diffusible biomarkers from skin lesions.

Background: Biomarkers provide beneficial information to make diagnoses and monitor the progression of many skin diseases. However, biomarkers produced by skin lesion may be too low at concentration to be detected in the systemic circulation.

Objective: To address whether intralesional blood (ILB) is advantageous to detect skin-derived biomarkers over circulation blood (CB) of patients with skin diseases.

Methods: ILB was collected as overflowing blood when a small incision was made in lesions of patients with mastocytoma and psoriasis. Concentrations of histamine and Human β-Defensin 2 were determined by ELISA. IL-8 was measured using a cytometric beads array (CBA) kit. IL-8 levels in psoriatic lesions were assessed by immunohistochemical staining and quantitative (q) RT-PCR. MicroRNA levels were measured using qRT-PCR.

Results: Plasma histamine levels were increased in ILB of mastocytoma compared with those in CB. Patients with psoriasis showed increased levels of IL-8, β-Defensin 2 in ILB as compared to those in CB. IL-8 levels in ILB correlated with local PASI scores and therefore reversed to those in CB after attenuation of psoriasis with treatment. Furthermore, ILB in psoriasis patients showed increased miR-203, which was highly expressed in psoriatic epidermis.

Conclusion: ILB contains disease-specific biomarkers at higher concentrations than those in CB, and may be useful for diagnosis and monitoring the progression of skin diseases. Thus, this study illustrates the versatility of ILB with an easy accessibility of biomarkers of chemicals, proteins as well as nucleic acids for a myriad of diseases including inflammatory dermatoses and cancers.