The role of bacterial DNA in septic arthritis (review)

Unmethylated CpG motifs are frequently found in bacterial DNA and have rece ntly been shown to exert immunostimulatory effects on leukocytes. Bacteria produce severe septic arthritis; bacterial DNA may be involved in this proc ess. We injected intraarticularly bacterial DNA and oligonucleotides contai ning unmethylated CpG motifs into knee joints of mice. Arthritis was seen b y histopathology within 2 h and lasted for at least 14 days, and was charac terized by an influx of monocytic, Mac-1(+) cells and by a lack of T lympho cytes. Macrophages and their products such as tumor necrosis factor (TNF) a are essential for development of arthritis triggered by bacterial DNA cont aining CpG motifs. In contrast, neurophils, NE; cells, and T/B cells were n ot instrumental in this condition. This review demonstrates that bacterial DNA containing unmethylated CpG motifs induces arthritis and indicates an i mportant pathogenic role for bacterial DNA in septic arthritis.