10x single cell gene expression and V(D)J immune profiling of T cells from the blood, synovial fluid and synovial tissue in psoriatic arthritis patients

This study shows the pronounced expansion of CD8 T cell clones at sites of active inflammation within the joints of psoriatic arthritis (PsA) patients compared to blood, and characterises the gene expression of expanded clones using droplet based single cell RNA sequencing. Mononuclear cells were separated from freshly acquired paired peripheral blood and synovial fluid samples from 3 PsA patients using density gradient separation, then enriched for CD4 and CD8 T cells using FACS. Additionally, CD45+ leukocytes were enriched by FACS from the cryopreserved synovial tissue of 2 further PsA patients. All cells were then processed using a 10x Chromium Controller and sequenced by Illumina HiSeq 4000 (peripheral blood / synovial fluid) or NovaSeq with S2 flowcell (synovial tissue).