Soluble T lymphocyte markers in the diagnosis of cellular rejection and cytomegalovirus hepatitis in liver transplant recipients

Hepatic dysfunction following liver transplantation is often caused by cellular rejection or infection with cytomegalovirus. These etiologies can at times be difficult to differentiate. We measured the levels of soluble T lymphocyte markers sIL2R, sCD4, and sCD8 in serum as possible diagnostic indicators of cellular rejection and cytomegalovirus hepatitis. Pretransplant levels, and serial post-transplant levels of soluble T lymphocyte markers were measured in five control patients without cellular rejection or cytomegalovirus infection, ten patients with cellular rejection, and six patients with cytomegalovirus hepatitis. In all cases, cellular rejection and cytomegalovirus hepatitis were documented with liver histology. For each group of patients, we calculated the mean ratio of the post-transplant marker level divided by the pre-transplant level. We found an elevation in the mean ratio of sIL2R in patients with cellular rejection shortly before or at the time of diagnosis of rejection as compared to the transplant control group. Levels of sCD8 were not significantly increased in patients with cellular rejection. We found a more pronounced elevation in the mean marker ratios of both sIL2R and sCD8 in patients with cytomegalovirus hepatitis which were higher compared not only to the transplant control group but also compared to the cellular rejection group. The rise of serum levels preceded the histologic diagnosis of cytomegalovirus hepatitis and detection of cytomegalovirus in blood cultures. Increased serum levels of sIL2R with concomitant elevation of sCD8 suggest the diagnosis of cytomegalovirus hepatitis over cellular rejection. We conclude that serial measurements of sIL2R and sCD8 may be useful to differentiate cytomegalovirus hepatitis from episodes of acute cellular allograft rejection, particularly those rejection episodes occurring late (>20 days posttransplantation).