Overview of FK506 in transplantation

FK506 is a potent immunosuppressive agent which is undergoing clinical testing in liver, kidney, heart, and bone marrow transplantation. It has been shown to effectively prevent and reverse ongoing rejection in these models. From the outset, FK506 was used with low-dose steroids to treat 110 primary liver, 30 heart, and 66 kidney graft recipients. FK506 was also used in the setting of complications related to CsA or to ongoing chronic or acute rejection. One hundred seventy-three liver, 21 kidney, 10 heart, and 11 bone marrow recipients were converted to FK506 and low-dose steroids, from a combination of CsA, steroids, and/or Aza. A randomized, prospective trial comparing FK506 with CsA in primary liver transplantation has verified the lower incidence of rejection and greater ease in treating rejection episodes, with fewer adverse effects. In summary, FK506 has proven to be an effective baseline immunosuppressive agent, as well as a dose-adjustable agent for the treatment of rejection.

The University of Pittsburgh: a three and three-quarter-year experience with cadaveric renal transplantation under the point system

Eight hundred and sixty kidney transplants were performed at the University of Pittsburgh over a 3.75-year period between January 1, 1986 and October 19, 1989. Recipient selection was by means of a computerized point system designed to allocate organs equitably. Ninety-three percent 1-year patient survival and 74% 1-year graft survival were obtained in the overall group; 80% 1-year graft survival was obtained in patients receiving immunosuppression with CsA, azathioprine, and prednisone. These data serve as a measure of what can be achieved with an equitably based allocation system and can serve as a basis of comparison with other allocation protocols or new immunosuppressive regimens.

HLA antigen expression on cultured human arterial endothelial cells

Flow cytometric analysis and cellular assays were used to determine constitutive and induced expression of class I HLA antigens and class II antigens encoded by the HLA-DR, -DQ and -DP subregions on cultured human arterial endothelial cells (HAEC) derived from transplant donors. Class I but no or minimal quantities of class II HLA antigens were found on HAEC. Prior incubation of HAEC with gamma-IFN increased class I HLA antigen expression and induced class II HLA antigen expression on HAEC. The induced expression of HLA-DQ was lower than that of HLA-DR, but both were significantly reduced in comparison to the frequency of these antigens on EBV transformed lymphoblastoid cell lines derived from the same donor. In addition, supernatants from class I and class II alloreactive clones were shown to induce class II antigen expression on HAEC. By PLT analysis, it was shown that these antigens are functionally capable of generating a lymphocyte response. In this regard, HAEC have proved to be a helpful tool in designing in vitro lymphocyte-endothelial cell studies.

Histocompatibility and liver transplant outcome. Does HLA exert a dualistic effect?

An analysis of more than 500 liver transplants has demonstrated that HLA compatibility is associated with diminished allograft survival. Liver transplants with zero mismatches for class I and/or class II HLA antigens have shown significantly lower actuarial survival rates than transplants with one or more mismatches for these loci. In a group of 119 failed liver allografts from patients undergoing retransplantation, a higher incidence of failure due to rejection correlated with a lower degree of HLA compatibility especially for HLA-DR. In contrast, the incidence of liver transplant failures due to primary nonfunction was relatively higher with HLA-DR compatible transplants. Considering the role of HLA as a restriction element in cellular interactions during the immune response, these findings suggest that HLA compatibility may have a dualistic effect on liver transplant outcome. On one hand, HLA compatibility reduced transplant rejection--and on the other hand, it may enhance other immunological mechanisms leading to allograft dysfunction, particularly in patients at risk of developing recurrent autoimmune diseases or infection.

Relationship between the diagnosis, preoperative evaluation, and prognosis after orthotopic liver transplantation

The purpose of this study was to identify which of the biochemical, immunological, or functional parameters derived before surgery as part of a systemic evaluation were helpful in predicting the frequency of rejection episodes, the chance of survival, and the cause risk of death (should death occur) of patients after orthotopic liver transplantation (OLTx). Ninety-eight adult patients who had an extensive preoperative protocol evaluation were studied before OLTx. The biochemical parameters assessed were albumin, prothrombin time, bilirubin, and ICG clearance. The immunologic parameters assessed included total lymphocytes, T3 cells, T4 cells, T8 cells, and the T4/T8 ratio. The degree of histocompatibility antigen (HLA) matching between the donor and the recipient was also evaluated in 80 of the 98 patients studied. Most postoperative deaths occurred within 12 weeks of the procedure (24%; 24 of 98 patients); 13 patients (13%) died within the first 6 postoperative weeks, of either bacterial or fungal sepsis. An additional 14 patients (14%) died after the initial 6 postoperative weeks due, primarily of an acquired viral and/or protozoan infection (p less than 0.01). During the first 6 weeks, survival was better for patients with cholestatic liver disease (ChLD, 93%, n = 45) and miscellaneous liver diseases (MISC, 100%, n = 10) than it was for those with parenchymal liver diseases (PLD, 77%, n = 43). Although albumin, prothrombin time, T4/T8 ratios, and per cent T8 cells were statistically different in patients with PLD as compared with those with ChLD, these parameters, as well as the per cent T4 cells, serum bilirubin level, per cent retention of ICG at 15 minutes, and the plasma ICG disappearance rate were not found to be of substantial help in predicting patient survival or non-survival. Moreover, neither the degree of HLA matching nor the number of rejection episodes differed between surviving and nonsurviving patients. The results of this study suggest that patients with PLD are at increased risk of early postoperative death after OLTx because of bacterial and/or fungal sepsis, as compared with patients operated upon for ChLD. Better pre-, intra-, and postoperative predictors of risk of death and complications are needed to reduce the early mortality observed after orthotopic liver transplantation.

Isolation and primary cultures of human intrahepatic bile ductular epithelium

A technique for the isolation of human intrahepatic bile ductular epithelium, and the establishment of primary cultures using a serum- and growth-factor-supplemented medium combined with a connective tissue substrata is described. Initial cell isolates and monolayer cultures display phenotypic characteristics of biliary epithelial cells (low molecular weight prekeratin positive; albumin, alphafetoprotein, and Factor VIII-related antigen negative). Ultrastructural features of the cultured cells show cell polarization with surface microvilli, numerous interepithelial junctional complexes and cytoplasmic intermediate prekeratin filaments.

Immunological factors influencing liver graft survival

Donor-recipient ABO blood group mismatching is associated with a decreased graft survival rate in liver transplantation. We have been unable to demonstrate an effect of high levels of panel reactive antibody or a positive donor-specific cytotoxic antibody cross-match on graft survival. A limited analysis of HLA-matching for the A, B, and DR loci suggests a paradoxical effect, but much more experience is needed before the true effect of HLA matching on graft outcome can be reliably evaluated.

OKT3 in the reversal of acute hepatic allograft rejection

OKT3 was an effective immunosuppressant agent in patients with acute cell-mediated allograft rejection that had not responded to initial steroid therapy. OKT3 was also valuable for treating patients with early hepatic graft dysfunction caused by other factors than rejection. In such recipients, the doses of CyA can be greatly reduced, allowing recovery of frequently damaged kidneys while maintaining effective immunosuppression.