Expression of the C5a receptor (CD88) on granulocytes and monocytes in patients with severe sepsis

Treatment of patients with severe sepsis with agents antagonising the effects of C5a has been proposed based on beneficial effects in animal experiments and in vitro studies demonstrating upregulation of the C5a receptor (CD88) on granulocytes by endotoxin.

CD88 expression on leukocytes from 12 patients with severe sepsis or septic shock was analysed by flow cytometer, and serum complement factors C3a and C5b-9 were measured by enzyme immunoassay techniques.

The granulocyte CD88 expression on day 1 was lowered (36; range, 2-59) in comparison with controls (63; range, 25-88) (P < 0.001), despite complement activation, while the monocyte CD88 expression was unchanged. The receptor reduction correlated significantly to the APACHE II score (r2 = 0.35, P < 0.05). The recovery of CD88 expression was slow.

In contrast to the findings in animals, it is concluded that granulocyte CD88 expression is reduced at the time when the diagnosis of severe sepsis or septic shock can clinically be made. The reason for this needs further investigation but it may be due to a previous complement activation or to cytokine effects.