Determination of interleukin-6 in lung transplantation: association with primary graft dysfunction

Primary graft dysfunction (PGD) secondary to damage caused by ischemia/reperfusion is responsible for significant morbidity. It constitutes the main cause of early death following implantation. Our objective was to verify the association between PGD and activation of the inflammatory cascade by measuring interleukin-6 (IL-6) in the blood and the bronchoalveolar lavage (BAL) of the recipient.

The 31 patients, including 22 bipulmonary and 9 unipulmonary cases, had severe PGD (ISHLT grade II) defined by: (1) radiographic infiltrates during the first 72 hours after transplantation, (2) PO2/FiO2 ratio <200 in the first 72 hours after the operation, and (3) no other cause of dysfunction. BAL and peripheral arterial blood samples were extracted prior to implantation (baseline level) and at 12, 24, and 48 hours after reperfusion. Samples were frozen to -80 degrees C until determination of IL-6 using an immunoassay technique (ELISA).

In the 31 transplants (100%), there were elevated IL-6 contents in the BAL and blood compared with the baseline level (P < .0001). Among 11 patients with severe PGD (38.70%) In the BAL samples the concentration of IL-6 was significantly elevated (P < .05) compared with patients without PGD (P < .031). These finding were also observed in blood (P < .016) obtained at 12 hours. The analyses at 24 and 48 hours showed higher levels of IL-6 in the PGD group, although they were not significant.

There was a significant elevation of IL-6 in blood and BAL during the first few hours after reperfusion of the graft, which was directly related to the development of PGD.