Day 8 CD4+CD45RO+ Tck cells phenotypically resemble rheumatoid synovial T cells. Freshly elutriated peripheral blood lymphocytes (PBLs) from healthy donors were stained with antibodies against CD4 and CD45RO in combination with antibodies against CD25, CD69, HLA-DR, CD62L, CD18, CD29, CD49d, CCR7, CXCR4, CXCR3, or CCR5 at time 0 (left panels) and day 8 (middle panels) after culture with IL-2, IL-6 and tumour necrosis factor (TNF)-α (as detailed in Materials and methods). Rheumatoid synovial cells were also stained with the same panel of antibodies as PBLs. In all, 1 × 104 PBLs and 5 × 103 synovial T cells were collected and the expression of different cell markers on the CD4+ gated lymphocyte population versus CD45RO+ expression was analyzed on the CellQuest Pro software. CCR, CC chemokine receptor; CXCR, CXC chemokine receptor; HLA, human leucocyte antigen.