Serum interleukin-6 levels as an indicator of acute rejection after liver transplantation in cynomologous monkeys.

This study was designed to evaluate whether the sequential monitoring of serum interleukin-6 levels (SIL-6) could be helpful for diagnosing the occurrence of hepatic allograft rejection. An SIL-6 post-transplant study was conducted on nine cynomolgus monkeys which had undergone orthotopic hepatic allotransplantation, six of which were treated with FK-506 (a new immunosuppressant agent isolated from Streptomyces tsukubaensis) and three of which were not. All the nontreated animals showed biochemical abnormalities from days 5-6, characterized by a marked elevation of serum alkaline phosphatase levels, and they eventually died on days 8, 12, and 63 (group I). Acute cellular rejection was confirmed by histological study of the hepatic grafts taken at autopsy or biopsy. On the other hand, four of the treated animals (group IIa) survived more than 30 days. Biochemical examination of this group showed no abnormal signs apart from a slight elevation of alkaline phosphatase (< 2000 IU/l). Histological examination carried out around 30 days after transplantation revealed a transient infiltration of polynuclear cells into Glisson's area, with the portal vein and bile duct remaining intact. The remaining two animals (group IIb) died of dehydration and arterial thrombosis on days 5 and 7, respectively. A kinetic study of SIL-6 conducted during the first 2 weeks showed quite different patterns among the three groups. All recipients in group I demonstrated two peaks following grafting on days 1 and 3 or 4, the second peak of above 2.0 U/ml preceding biochemical abnormalities by 2 to 3 days.(ABSTRACT TRUNCATED AT 250 WORDS)