CD14(++) monocytes, CD14(+)/CD16(+) subset and soluble CD14 as biological markers of inflammatory systemic diseases and monitoring immunosuppressive therapy

The majority of peripheral blood monocytes strongly positive for the lipopo lysaccharides (LPS)-receptor CD14 are negative for Fc gamma receptor type I II (CD16). However, a subset of monocytes coexpressing GD14 and CD16 accoun ts for about 8% of all monocytes. This population exhibits features of tiss ue macrophages, and is largely expanded (> 20 %) during acute and chronic i nflammatory diseases including cases with pararheumatic systemic vasculitis . In addition, compared to normal controls, soluble CD14 (sCD14) is elevate d (> 3 mu g/ml) in serum specimens of these patients. CD14(+)/CD16(+) monoc ytes show a higher phagocytosis rate than CD14(+)/CD16 negative cells, and express higher levels of interleukin-l and major histocompatibility complex , such as histocompatibility antigens HLA-DR, -DP and -DQ antigens. Glucoco rticoids downregulate expression of CD14 and rapidly deplete CD14(+)/CD16() monocytes from peripheral blood. Patients under chronic immunosuppressive therapy exhibit low CD14/+/CD16+ rates, which may rise during infectious a nd non-infectious inflammatory complications, however. Thus, serial analyse s for sCD14 and the proinflammatory CD14(+)/CD16(+) subset of monocytes sug gest a valuable tool monitoring patients under immunosuppressive and/or ant iinflammatory therapy.