Imaging Mass Cytometry in Psoriatic Disease Reveals Immune Profile Heterogeneity in Skin and Synovial Tissue

Imaging mass cytometry is a technology that enables comprehensive analysis of cellular phenotypes at the tissue level. We performed a multiparameter characterization of structural and immune cell populations in psoriatic skin and synovial tissue samples aimed at characterizing immune cell differences in patients with psoriasis and psoriatic arthritis. A panel of 33 antibodies was used to stain selected immune and structural cell populations. Imaging mass cytometry data were segmented into single cells on the basis of combinations of antibody stains. Single cells were then clustered into cell categories on the basis of prespecified markers. The spatial relationships of different cell populations were assessed using neighborhood analysis. Among all cell types in the skin and synovium, lymphoid cells accounted for the most prevalent cell type. T cells and macrophages were the most prevalent immune cell type in the synovium, and B cells and NK cells were also identified. Neighborhood analysis showed high correlation between synovial T cells, B cells, macrophages, dendritic cells, and neutrophils, suggesting spatial organization. Innate and adaptive immune cells can be reliably identified using imaging mass cytometry in the skin and synovium. Interpatient heterogeneity exists in tissue cell populations. Imaging mass cytometry provides opportunities for exploring in depth the underlying immunological mechanisms driving psoriasis and psoriatic arthritis.