PROINFLAMMATORY CYTOKINE PRODUCTION BY HUMAN PERIPHERAL-BLOOD MONONUCLEAR-CELLS STIMULATED WITH CELL-FREE SUPERNATANTS OF VIRIDANS STREPTOCOCCI

Viridans streptococci (VS) have become recognized as an increasingly i mportant cause of bacteraemia in neutropenic patients undergoing chemo therapy, Surprisingly, VS bacteraemia is associated with toxic shock-l ike syndrome (TSLS) and adult respiratory distress syndrome (ARDS), fe atures not seen in non-neutropenic patients with viridans streptococca l bacteraemia, The mechanism by which these Gram-positive bacteria cau se hypotension in the absence of endotoxin is not known. In this study we have analysed the ability of cell-free bacterial supernatants deri ved from VS to induce the production of a number of cytokines from hum an peripheral blood mononuclear cells (PBMC). These cytokines were tum our necrosis factor alpha (TNF-alpha), tumour necrosis factor beta (TN F-beta) and interleukin 8 (IL-8), All 59 strains were able to induce t hese proinflammatory cytokines. We conclude that VS do produce secrete d products which are able to stimulate the production of cytokines whi ch may be important in the pathogenesis of shock caused by these bacte ria. (C) 1996 Academic Press Limited