*4.1. Study Subjects*

This study was conducted in accordance with the Declaration of Helsinki and was approved by the institutional review board of Chang-Gung Memorial Hospital, Taiwan (104-9618A3, 01/08/2016). Signed informed consent was obtained from all patients. 40 PsA patients and 40 PsO patients were diagnosed by both dermatologists and rheumatologists. All patients of the PsA group fulfilled the CASPAR criteria. 40 healthy adults were included as a control group (HC). The absence of psoriatic lesions and inflammatory joint were examined thoroughly in HC group. The Psoriasis Area and Severity Index (PASI) score, comorbidities of arthritis, presence of uveitis and treatment regimens were recorded. Peripheral blood from all participants was acquired at baseline and from patients after 28 weeks of standard biologics treatment (etanercept, adalimumab, secukinumab, or ustekinumab).

#### *4.2. Isolation and Culture of Peripheral Monocytes*

Monocytes were isolated directly from PBMCs using CD14+ MicroBeads (Miltenyi Biotec, Auburn, CA, USA) according to the manufacturer's instructions. The purity of the CD14+ cells after the selection is above 95% using flow cytometry showed according to our previous study [28].
