<prompt> Which type of cells are prominently infiltrated in Rheumatoid arthritis?B cellsT-cellsNK-cellsBoth B T Cells  <response>: B T-cells?Role of T cells in RAoProminent T-cell infiltrate in RA synoviumoGenetic similarities between RA patients-Specific human leukocyte antigen HLA-DR genes - HLA DR4, DR14 and DR1oShared Epitope: The third hypervariable region of DR b chains, especially amino acids 70 through 74.oCD4 T helper Th cells may initiate the autoimmune response in RA by reacting with an arthritogenic agent, perhaps microbial or a self-antigenoSynovial lining or intimal layer: Normally, this layer is only 1-3 cells thick. In RA, this lining is greatly hypertrophied 8-10 cells thick.oPrimary cell populations in this layer are fibroblasts and macrophages. 