Activation of the alternative pathway of complement may be initiated by a variety of factors, including components of the bacterial cell wall (1, 2). It has been demonstrated in Gram-negative bacteremia leading to septic shock that C3 levels in serum are decreased (3). However, in bacteremia without shock, normal or increased C3 levels (3) and hemolytic complement activity (4) have been demonstrated.

It has been reported recently that properdin, C3, C5, C6, and C9 levels are lower in patients with bacteremia who develop shock than in normal individuals and normotensive bacteremic patients (5). Factor B3 levels in the above study were in general lower for patients in shock. However, factor B levels in all patients with bacteremia did not differ significantly from controls.

Circulating conversion products of factor B have been found in serum from two patients with arthritis after intestinal bypass surgery (6). Activation in these patients was postulated to be caused by an immunoglobulin cryoprecipitate.

1

This research was supported entirely by the Pediatric Blood Research Fund and the “Jimmy Memorial Fund” of the University of Rochester.

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Copyright © 1976 by The American Association of Immunologists, Inc.
1976
The Williams & Wilkins Company