Long-term duration of reduced serum complement level following burn injury

We report the case of a boy whose serum CH50 was below the detection limit following burn injury and skin transplantation. The APCH50 level was slightly decreased, although C3, C4, and the other complements were within the normal range. Cold activation was not detected in his plasma. His peripheral blood monocyte ratio slightly elevated to 19% and then decreased to 5.9%. In this case, burn injury caused the depletion of the complement, particularly in the alternative pathway, and resulted in the reduced CH50 level, although C3 did not show the typical pattern of alternative pathway depletion. In previously reported cases of burn injury, the CH50 level returned to the normal range within 2 weeks. In this patient the reduced level of CH50 continued for 4 months. We should consider burn injury one of the causes of complement deficiency even in cases with a duration of more than 1 month.