Upregulation of plasma CCL8 in mouse model of graft-vs-host disease

Objective Using a proteomic approach, we recently identified plasma CCL8 as a potential biomarker for diagnosis of graft-vs-host-disease (GVHD) in mice as well as humans. Because mass spectrometric analysis is only semi-quantitative, a quantitative method of measuring plasma CCL8 levels in mice is needed. Materials and Methods We established an enzyme-linked immunosorbent assay for the quantitative measurement of CCL8 concentrations in mouse plasma. Results Our newly established enzyme-linked immunosorbent assay revealed that the plasma CCL8 concentrations (mean ± standard error; n=12) were 1287 ± 55.7 ng/mL and 1604 ± 110.8 ng/mL on days 7 and 14 after allogeneic bone marrow transplantation (BMT), respectively, while the plasma concentrations was 316.6 ± 16.3 ng/mL on day 7 after syngeneic BMT. A Western blotting analysis also showed a difference in the plasma CCL8 levels between the allogeneic and syngeneic BMT groups, as did clinical GVHD scores. Neither lipopolysaccharide nor poly(I:C) elevated the plasma CCL8 concentrations, although a dramatic increase in interleukin-6 was detected after both treatments. Conclusion An elevated plasma CCL8 concentration may be a promising plasma marker for GVHD in mouse models.