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Compliment activity patterns in patients with sepsis after human purified C1-esterase inhibitor infusion


Our purpose was to assess the effects of super physiologic dosages of human purified C1-esterase inhibitor infusion (C1INH) on complement-dependent pathways of systemic inflammatory response in patients with sepsis.


In the terms of an open-label prospective control study, human purified C1INH (Bicizar; BioGenius LLC, Russia) was administered at total dosage of 12,000 U to 20 sepsis patients. Patients (n = 22) who did not receive C1INH infusion were enrolled as controls. C3 and C4 complement subunits, IL-6, C-reactive protein and procalcitonin results were analyzed in quartiles according to C1INH baseline activity.


C1INH activity was different in quartiles at entry in both groups (P < 0.03). C1INH infusion resulted in elevation of C1INH activity in the treatment arm (Figure 1). The most significant difference was observed between the upper quartiles of the groups (P < 0.01). The degree of C1INH activity shift had a negative association with the baseline results (r = -0.635, P < 0.01). C3 (P < 0.01) and C4 (P < 0.05) levels displayed a more rapid and pronounced rise after C1INH infusion in patients with higher baseline C1INH activity. The C-reactive protein concentration dropped significantly in patients who received C1INH (130 mg/l (28 to 293)) already on the third day of the study in comparison with the control (185 mg/l (72 to 343); P = 0.022). The same trend characterized the IL-6 level. Patients with elevated procalcitonin values at the onset of sepsis had a more significant C1INH increase (r = 0.635, P < 0.05).

Figure 1
figure 1

C1INH activity in the Bicizar (q) and control groups (c): analysis in quartiles.


Downregulation of complement activity with C1INH might help to contain severe systemic inflammation. Presumably, the response to C1INH infusion was related to its baseline activity.

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Igonin, A., Lazareva, N. & Dolzhenkova, L. Compliment activity patterns in patients with sepsis after human purified C1-esterase inhibitor infusion. Crit Care 13 (Suppl 1), P363 (2009).

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  • Complement Activity
  • Procalcitonin
  • Sepsis Patient
  • Baseline Result
  • Baseline Activity