EFFECT OF SOLUBLE COMPLEMENT RECEPTOR-TYPE-1 ON REPERFUSION EDEMA ANDNEUTROPHIL MIGRATION AFTER LUNG ALLOTRANSPLANTATION IN SWINE

Objective: Soluble complement receptor type 1 inhibits complement acti vation by blocking C3 and C5 convertases of the classical and alternat ive pathways, We evaluated the effect of soluble complement receptor t ype 1 on lung allograft reperfusion injury, Methods: Left lung transpl antation was performed in 13 weight-matched pigs (25 to 31 kg) after p rolonged preservation (20 hours at 1 degrees C), One hour after reperf usion the: recipient contralateral right lung was excluded to assess g raft function only. Complement activity and C3a levels were measured a fter reperfusion and at the end of the assessment. Extravascular lung water index, intrathoracic blood volume, and cardiac output were asses sed during a 5-hour observation period, Gas exchange and hemodynamics were monitored, at the end of the 5-hour assessment period, myeloperox idase assay and bronchoalveolar lavage were performed to assess neutro phil migration, and C5b-9 (membrane attack complex) deposits in the al lograft were detected by immunohistochemistry. Two groups were studied , In group II (n = 6) recipient animals were treated with soluble comp lement receptor type 1 (15 mg/kg) 15 minutes before reperfusion. Group I (n = 7) served as the control group. Results: Serum complement acti vity was completely inhibited in group II, In contrast to group I, C5b -9 complexes were not detected in group II allograft tissue samples. C 3a was reduced to normal levels in group II (p = 0.00005). Extravascul ar lung water index was higher in group I animals throughout the asses sment period (p = 0.035). No significant difference in allograft myelo peroxidase activity (p = 0.10) and polymorphonuclear leukocyte count o f the bronchoalveolar lavage fluid (p = 0.057) was detected. Conclusio n: Inhibition of the complement system by soluble complement receptor type 1 blocks local complement activation in the allograft and reduces posttransplantation reperfusion edema but does nod. improve hemodynam ic parameters.