CD135 expression in healthy individuals and rheumatoid arthritis and gout patients. (A), (B) No differences were observed in CD135 expression in rheumatoid arthritis (RA) patient (n = 12), gout patient (n = 11) and healthy individual (HI; n = 7) synovial tissues (STs) by immunohistochemical analysis. (B) Right: CD135 gene expression in STs of RA (n = 22) and gout (n = 12) patients by quantitative polymerase chain reaction. Results presented as mean ± standard error of the mean (SEM) mRNA expression of CD135 relative to GAPDH. No differences were observed. (C) CD135 expression on CD14+ monocytes, CD56+ natural killer (NK) cells, CD304+ plasmacytoid dendritic cells (DC), CD19+ B cells and CD1c+ myeloid DC by flow cytometry. The percentage and mean fluorescence intensity (MFI) of CD135+CD14+ monocytes was higher in RA peripheral blood (PB) compared with HI PB (P = 0.0115 and P = 0.0260 respectively). In RA PB, CD135+CD56+ NK cell MFI was higher compared with HI PB (P = 0.0115). There were no differences for percentage or MFI of CD135+CD1c+ myeloid DC in RA compared with HI, or RA PB compared with paired synovial fluid (SF). The CD135+CD304+ plasmacytoid DC percentage was higher in RA SF compared with paired PB (P = 0.0029). Both the percentage and MFI of CD135+CD19+ B cells were higher in RA SF compared with paired PB (P = 0.0068 and P = 0.0491 respectively). Graphs represent mean ± SEM of five to 10 RA patients and HI. *P <0.05, **P <0.01.
Ramos et al. Arthritis Research & Therapy 2013 15:R209 doi:10.1186/ar4403