This study was aimed to investigate whether there is any change in palsma nitric oxide during acute rejection of infection after lung allotransplantation.

After lung allotransplantation, dogs were immunosuppressed with standardized triple therapy and divided into 3 groups : in group 1(control: n=4), immunosuppression was maintained; in group 2(n=7), triple therapy discontinued to induce acute rejection at the postoperative day 5; in group 3(n=6), infection was inudced by bronchoscopic inoculation of E. coli at the postoperative day 5. Plasma nitric oxide was measured by chemiluminescene method prior to surgery(day 0), and at postoperative day 5 and 9. In each group, plasma nitric oxide level at day 9 was compared to that at day 0. Plasma nitric oxide levels at day 9 were compared in three groups.

During acute rejection period, plasma nitric oxide concentration was found to be elevated significantly at postoperative day 9, compared to day 0(11.52±2.58 vs 6.01±0.88uM/L ; p<0.05). However, plasma nitric oxide concentration wasn't altered by the E. coli-induced infection(14.53±5.19 vs 6.12±0.98uM/L ; p>0.05). Plasma nitric oxide of day 9 weren't different in three groups(p>0.05).

Plasma nitric oxide may be a good marker for acute rejection after allotrans-plantation, but not for infection.