Long-term survival of heart and liver xenografts with splenectomy and FK 506

We have reported that while hamster-to-rat liver xenograft survival is prolonged by FK 506, hamster hearts undergo humoral rejection under this immunosuppressant.1 Because the spleen has been shown to be one of the main sources of xenoantibodies,2 ,3 and in vivo experiments have demonstrated that splenectomy (Spx) is able to increase the efficacy of various immunosuppressive agents after xenotransplantation,4 –6 we combined Spx with FK 506 to test whether survival of the intractable cardiac xenografts is prolonged, and of liver xenografts improved.

The 11-year Pittsburgh experience with liver transplantation for hepatocellular carcinoma: 1981-1991

Experience with liver transplantation over a period of 11 years at the University of Pittsburgh is presented. The application of liver transplantation to cases of hepatocellular carcinoma has changed considerably over this 11-year period with the sequential introduction of adjuvant and, more recently, neoadjuvant chemotherapy. Results with the combination of chemotherapy plus surgery appear to be better than results with either agent alone. Moreover, the early results with neoadjuvant therapy appear to be better than those achieved with adjuvant therapy. As a result of this experience, conceptual changes in the approach to the problem of hepatic cancer and the role of both chemotherapy and liver transplantation in its management have changed at the University of Pittsburgh. These changes are identified and discussed.

Induction of donor-specific transplantation tolerance to skin and cardiac allografts using mixed chimerism in (A + B-->A) in rats

Mixed allogeneic chimerism (A + B-->A) was induced in rats by reconstitution of lethally irradiated LEW recipients with a mixture of T-cell depleted (TCD) syngeneic and TCD allogeneic ACI bone marrow. Thirty-seven percent of animals repopulated as stable mixed lymphopoietic chimeras, while the remainder had no detectable allogeneic chimerism. When evaluated for evidence of donor-specific transplantation tolerance, only those recipients with detectable allogeneic lymphoid chimerism exhibited acceptance of donor-specific skin and cardiac allografts. Despite transplantation over a major histocompatibility complex (MHC)- and minor-disparate barrier, animals accepted donor-specific ACI skin and primarily vascularized cardiac allografts permanently, while rejecting third party Brown Norway (BN) grafts. The tolerance induced was also donor-specific in vitro as evidenced by specific hyporeactivity to the allogeneic donor lymphoid elements, yet normal reactivity to MHC-disparate third party rat lymphoid cells. This model for mixed chimerism in the rat will be advantageous to investigate specific transplantation tolerance to primarily vascularized solid organ grafts that can be performed with relative ease in the rat, but not in the mouse, and may provide a method to study the potential existence of organ- or tissue-specific alloantigens in primarily vascularized solid organ allografts.

A clinicopathological study of human liver allograft recipients harboring preformed IgG lymphocytotoxic antibodies

Twenty-six adult patients with preformed IgG donor lymphocytotoxic antibodies received primary liver allografts under FK 506 immunosuppression. The effect of the crossmatch-positive state on early graft function and on the immunopathological and histopathological findings was compared with that of 52 crossmatch-negative control recipients. The presensitized (crossmatch-positive) patients had prolongation of early graft dysfunction, underwent more clinically indicated biopsies and had a higher incidence of cellular rejection, both overall (p less than 0.05) and within 10 days of transplantation (p less than 0.01). They also had a higher incidence of graft failure in the first 180 days (p less than 0.01). Hyperacute rejection with necrotizing or neutrophilic arteritis was not seen in the crossmatch-positive grafts. However, histological findings associated with presensitization included platelet margination in central veins and sinusoids in biopsy specimens 60 to 90 min after graft revascularization. Later biopsy specimens had neutrophilic portal venulitis followed by cholangiolar proliferation, acute cholangiolitis and centrilobular hepatocyte swelling that mimicked preservation injury, endothelial activation of arteries with medial changes and relapsing episodes of acute cellular rejection. These clinicopathological observations suggest that lymphocytotoxic antibodies can have a deleterious effect on liver allograft function and survival, even if they do not precipitate immediate or hyperacute rejection.

Intestinal transplantation in composite visceral grafts or alone

Under FK 506-based immunosuppression, the entire cadaver small bowel except for a few proximal and distal centimeters was translated to 17 randomly matched patients, of whom two had antigraft cytotoxic antibodies (positive cross-match). Eight patients received the intestine only, eight had intestine in continuity with the liver, and one received a full multivisceral graft that included the liver, stomach, and pancreas. One liver-intestine recipient died after an intestinal anastomotic leak, sepsis, and graft-versus-host disease. The other 16 patients are alive after 1 to 23 months, in one case after chronic rejection, graft removal, and retransplantation. Twelve of the patients have been liberated from total parenteral nutrition, including all whose transplantation was 2 months or longer ago. The grafts have supported good nutrition, and in children, have allowed growth and weight gain. Management of these patients has been difficult and often complicated, but the end result has been satisfactory in most cases, justifying further clinical trials. The convalescence of the eight patients receiving intestine only has been faster and more trouble free than after liver-intestine or multivisceral transplantation, with no greater difficulty in the control of rejection.

Tacrolimus (FK 506)--a new therapeutic agent for severe recalcitrant psoriasis

BACKGROUND

Psoriasis, a disease of unknown etiology, is in some patients severe, extremely debilitating, and unresponsive to conventional therapies, including UV-B, oral psoralen with long-wave UV radiation in the A range (PUVA), oral retinoids, and methotrexate. We report the results from our study of seven patients with refractory psoriasis who were treated with the new immunosuppressive drug, tacrolimus (FK 506).

OBSERVATIONS

All seven patients showed a dramatic resolution of psoriasis that remained in remission as long as they received full-dose therapy. Serial skin biopsy specimens demonstrated a rapid disappearance of the inflammatory infiltrate and a slower resolution of the epidermal changes. Tacrolimus was well tolerated during the 5.5 to 14 months of observation. Side effects, including nephrotoxicity and hypertension, were controlled by appropriate modification of drug dosage.

CONCLUSIONS

Tacrolimus, a new immunosuppressive agent, is effective in treating patients with severe recalcitrant psoriasis. The mechanism of its action in psoriasis is unknown, but it may be related to its ability to modulate immune function. Further studies will establish criteria for patient selection and drug dosage, to maximize efficacy of this agent in psoriasis, while minimizing its toxicity.

Management of intestinal transplantation in humans

We report here the clinical experience and management guidelines for the nine consecutive cases who received either an isolated small intestinal graft (n = 1) or an intestine liver combination at the University of Pittsburgh, with FK 506 being the basic immunosuppressive drug therapy.