Question: Which cell types are known to be driving Rheumatoid Arthritis?

Context:
Integration of GWAS results with cell-type specific gene expression or epigenetic marks have highlighted regulatory T cells and CD4 memory T cells as critical cell types in RA
A subset of synovial DCs is important in the response to cigarette smoke
 we demonstrate that autoimmune patient (systemic lupus erythematosus and rheumatoid arthritis) serum activates both pDC and B cells, but IRAK1/4 kinase inhibition affects only the pDC response, underscoring the differential IRAK1/4 functional requirements in human immune cell
In rheumatoid arthritis (RA), activated synovial fibroblasts (SFs) have the ability to invade joint cartilage, actively contributing to joint destruction in RA
Recently, RASFs have been shown to be able to migrate to non-affected areas and joints through the blood stream and to invade distant cartilage
MSC interaction with B cells provides stimuli for B-cell survival and therefore may contribute to the pathogenesis of rheumatoid arthritis
Fibroblast-like synoviocytes (FLS) are resident mesenchymal cells of synovial joints that have been recognized to play an increasingly important role in the pathogenesis of rheumatoid arthritis (RA)
This study investigates the production of CCL18 in polymorphonuclear neutrophils (PMN), the predominant cell type recruited into synovial fluid (SF)
In this regard, macrophages, T cells and their respective cytokines play a pivotal role in RA
it has been understood that resident, fibroblast-like cells contribute significantly to the perpetuation of disease, and that they may even play a role in its initiation
RASFs are no longer considered passive bystanders but active players in the complex intercellular network of RA
These rheumatoid arthritis synovial fibroblasts (RASFs) constitute a quite unique cell type that distinguishes RA from other inflammatory conditions of the joints
The molecular feature that defines the myofibroblast-like phenotype was reflected as an increased proportion of myofibroblast-like cells in the heterogeneous FLS population
ur findings support the notion that heterogeneity between synovial tissues is reflected in FLS as a stable trait, and provide evidence of a possible link between the behavior of FLS and the inflammation status of RA synovium
This change was accompanied by a significant decrease in the synovial monocyte/macrophage population
In RA patients, both etanercept and infliximab are able to induce cell type-specific apoptosis in the monocyte/macrophage population
Furthermore, fluorescent double-staining showed that the HOXD9 protein was expressed in fibroblast-like synoviocytes (FLS)
AHR gene expression was demonstrated in rheumatoid synovial tissues and nodules with significantly greater expression in synovia.
Twenty synovial and eighteen subcutaneous nodule tissue samples from 31 patients with RA were studied. Patient smoking status at the time of tissue collection was established
Release of the chemokine CCL18 has been widely attributed to antigen-presenting cells, including macrophages and dendritic cells

Answer: Macrophages, T cells and their respective cytokines play a pivotal role in RA. Rheumatoid arthritis synovial fibroblasts (RASFs) constitute a quite unique cell type that distinguishes RA from other inflammatory conditions of the joints. Activated synovial fibroblasts (SFs) have the ability to invade joint cartilage, actively contributing to joint destruction in RA.
Exact answer: Macrophages
T-cells
Fibroblast-like synoviocytes (FLS)
Dendritic cells
synovial fibroblasts