Anaphylatoxin formation in plasma and burn bullae fluid in the thermally injured patient

Plasma anaphylatoxins (C3a and C5a) were measured in 19 thermally injured patients with a mean total burned surface area of 39 per cent (range 10-90 per cent) of partial and full skin thickness loss. Extensive burns were associated with increased anaphylatoxin activity. Patients with greater than 50 per cent burned surface area had higher plasma C3a and C5a concentrations than patients with 10-25 per cent burns (P less than 0.001) 1 week after injury. Six out of seven patients with greater than 50 per cent burned surface area developed adult respiratory distress syndrome (ARDS) and four out of seven bacteraemia. Twelve patients had 10-25 per cent burns and none of them developed ARDS or bacteraemia. The mean C3a concentration per millilitre of fluid from the burn bullae from nine different individuals was 2570 +/- 260 ng/ml. The C5a content in fluid from the bullae did not differ from the corresponding plasma range. Increased anaphylatoxin activity might explain extensive extravasation of fluid in burned patients. This increase might also be one reason for leukocyte accumulation in burned areas.