Differential modulation by glucocorticoids of alternative complement protein secretion in cells of the...

The effect of the synthetic glucocorticoid dexamethasone (DXM) on the secretion by human monocytes of alternative complement proteins C3, factor B and factor H was investigated. Results indicated that DXM modulates this secretion in a direction which would be consistent with its anti-inflammatory properties. DXM, at therapeutic concentrations, had a suppressive effect on C3 and factor B secretion and a stimulatory effect on factor H secretion by monocytes. This differential modulation on C3, factor B and factor H secretion was similar in mature macrophages. Together with previous studies showing that DXM had a suppressive effect on C3 and factor B secretion and a stimulatory effect on factor H secretion by human endothelial cells, our results indicate that DXM appears to have the general property of regulating local production of complement components so as to control complement activation.