Allograft inflammatory factor-
1 (AIF-
1) is a cytoplasmic protein expressed in various human cells such as monocyte/macrophages and activated T lymphocytes. A recent study showed that AIF-
1 is strongly expressed in infiltrating mononuclear cells and synovial fibroblasts in rheumatoid arthritis and that AIF-
1 induces the proliferation of cultured synovial cells. In this study we analysed the expression of AIF-
1 in peripheral blood monocytes and synovial membranes from patients with rheumatoid arthritis (RA).
Methods
10">We examined 71 patients with rheumatoid arthritis and 25 control subjects.
Results
15">Using flow cytometry we found significantly increased numbers of circulating AIF-1+ monocytes in peripheral blood from RA patients compared with controls. Moreover, there were statistically significant positive correlations between AIF-1+ monocytes, DAS28 and the Sharp erosion score.
Immunofluorescence staining showed strong expression of AIF-1 by infiltrating mononuclear cells – predominantly macrophages in RA synovial tissues – compared with tissues derived from joints affected by osteoarthritis.
Conclusion
The results of this study suggest that AIF-1 may be associated with the pathogenesis of RA and may be a novel cytokine involved in the immunological process underlying RA.
