SOLUBLE FRACTION OF CLASS-I HUMAN HISTOCOMPATIBILITY LEUKOCYTE ANTIGENS IN THE SERUM OF LIVER-TRANSPLANT RECIPIENTS

In previous studies we reported a solid-phase, enzyme-linked immunoass ay (ELISA) that can be used to quantitate the soluble fraction of huma n histocompatibility leukocyte class I antigens (S-HLA-I) and study th eir relevance in transplantation. In this study we determined the conc entration and distribution of S-HLA-I in patients with end-stage liver disease (ESLD), as well as in liver transplant recipients. Sera were obtained from 51 patients with ESLD and 40 donor-recipient pairs. We a nalyzed the S-HLA-I in sera obtained from liver donors, as well as fro m liver transplant recipients (patients with ESLD), with sera from the latter obtained before and at various intervals up to 3 yr after tran splantation. The results of the analyses justify the following conclus ions: 1) Patients with ESLD had mean values of S-HLA-I (909 +/- 596 ng /ml) greater than those for the normal population (643 ng/ml) (P < 0.0 5); the S-HLA-I secretion decreased with increasing severity of liver disease. 2) Patients with tumors had mean S-HLA-I levels (399 ng/ml) s ignificantly lower than those in patients with ESLD related to other c auses. 3) In liver transplant recipients the S-HLA-I levels stabilized at approximately 1 month after transplant and remained relatively sta ble thereafter (mean level 950 +/- 536 ng/ml). The observed levels wer e also greater than those for the normal population (P < 0.05). 4) Pre operative and postoperative S-HLA-I values in liver transplant recipie nts demonstrated a biphasic distribution, dividing patients into high- and low-secretor groups. 5) During the post-transplant observation pe riod, of these selected liver transplant recipients there was no diffe rence between high- and low-secretor groups in the incidence of reject ion (high, 70%; low, 67%), graft survival (high, 95%; low, 94%), or pa tient survival (high, 95%; low, 94%). 6) Measurement of the total amou nt of S-HLA-I, containing yet undefined ratios of both donor and recip ient S-HLA-I, cannot be used to predict a state of tolerance in liver transplant recipients.