CD38 and E2F transcription factor 2 have uniquely increased expression in rheumatoid arthritis synovial tissues.

The purpose of the current study was to find novel rheumatoid arthritis ( RA)-specific gene expression by simultaneously comparing the expression profiles of the synovial tissues from patients with RA, osteoarthritis ( OA) and ankylosing spondylitis ( AS). The Illumina Human HT-12 v4 Expression Bead Chip was used to investigate the global gene expression profiles in synovial tissues from RA ( n = 12), OA ( n = 14) and AS ( n = 7) patients. By comparing the profiles in synovial tissues from RA, OA and AS, we identified the CD38, ankyrin repeat domain 38 ( ANKRD38), E2F transcription factor 2 ( E2 F2), craniofacial development protein 1 ( CFDP1), cluster of differentiation ( CD)7, interferon-stimulated exonuclease gene 20 kDa ( ISG20) and interleukin-2 receptor gamma ( IL)-2 RG genes as differentially expressed gene expression in RA synovial tissues. The increased expression of CD38, E2 F2 and IL-2 RG, as revealed using real-time polymerase chain reaction ( PCR) with synovial tissues from RA ( n = 30), OA ( n = 26) and AS patients ( n = 20), was in agreement with the microarray data. Immunohistochemistry revealed significant CD38 expression and E2 F2 in synovial membranes from RA patients ( n = 5). The CD38+ cells had high a percentage in the RA patients' blood ( n = 103) and in the CD3+ and CD56+ subsets. The CD38+ cell percentage was correlated significantly with RF level ( P = 0·026) in RA patients. The IL-1α and IL-β levels were depressed significantly in the culture medium of RA synovial fibroblast cells ( n = 5) following treatment with siRNAs targeting the E2 F2 or CD38 genes. This study suggests that the uniquely increased expression of CD38 and E2 F2 in RA synovial tissues contribute to the immunoactivation of the disease. [ABSTRACT FROM AUTHOR]