Bone marrow and blood plasma levels of IL-8 in aplastic anemia and their relationship with disease severity.

Interleukin-8 (IL-8), a CXC chemokine, is also a potent inhibitor of myelopoiesis, the hematopoietic process that is severely impaired in aplastic anemia (AA). To elucidate its role in the disease, we have investigated levels of IL-8 by quantitative enzyme-linked immunosorbent assay in bone marrow and peripheral blood plasma of 27 AA patients and in the marrow of 16 controls and blood of 20 controls. Significantly increased levels of IL-8 were observed in the marrow and blood of patients as compared to controls (470.4 +/- 549.6 vs. 37.5 +/- 30.3; P < 0.0001) and (247.3 +/- 286.3 vs. 7.9 +/- 5.5; P < 0.0001), respectively. Among the patients, the IL-8 levels were higher in patients with severe AA than those with nonsevere AA in the marrow (568.8 +/- 586.9 vs. 126.3 +/- 102.5; P < 0.005) as well as in the blood (296.6 +/- 305.5 vs. 75.0 +/- 84.4; P < 0.008) plasma. The marrow and blood of 74% (20/27) of the patients had increased levels of IL-8 compared to 12% (2/16; P < 0.001) and 10% (2/20, P < 0.001) of the controls, respectively. These results suggest that IL-8 may have an important role in the pathogenesis of AA.