"Occult" hepatitis B virus as source of infection in liver transplant recipients

Hepatitis B virus (HBV) infection almost always recurs after liver transplantation in patients who were surface antigen (HBsAg) positive before surgery but apparent de novo acquisition of infection in a transplant setting has not previously been reported. We have used sensitive techniques to elucidate the origin of such infections in patients in a California transplantation programme. We tested post-transplant serum from 207 patients who had been HBsAg negative and found 20 to be HBsAg positive. The origin of infection was identified in 7 patients, being occult pre-transplant infection in 5 and occult infection in the donor in 2. No pre-transplant patient nor donor with demonstrable HBV DNA had serological markers of hepatitis B. Post-transplant HBV DNA was present in serum from 19 patients. Analysis of the variable pre-S region of HBV demonstrated 100% sequence homology between recipient liver and post-transplant serum (2 patients) and between donor serum and recipient post-transplant serum (2). There was only 84% homology between the 2 different patients infected with subtype adw. 19 patients are alive, 9 without histological evidence of hepatitis (mean follow-up 33 months), and survival was significantly greater than that of a group with recurrent HBV infection. Apparent acquisition of HBV infection with liver transplantation is not rare, and may be due to occult pre-transplant infection or occult infection in the donor. The post-transplant outcome of this infection tends to be benign but our findings do underscore the clinical relevance of HBV infection in the absence of serological markers.

Major histocompatibility complex class I deficiency prolongs islet allograft survival

Because of islet allograft rejection, nonimmunosuppressed pancreatic islet allotransplantation has been unsuccessful for the treatment of type I diabetes. The role of major histocompatibility complex class I antigen expression on islet allograft survival was evaluated with the use of mice homozygous for a beta 2-microglobulin gene disruption. These mice express little if any functional major histocompatibility complex class I antigen. When these major histocompatibility complex class I-deficient islets were used as donors in an allogenic murine transplantation model, islet allograft survival was markedly prolonged. These results demonstrate a major importance for the alloresponse directed against major histocompatibility complex class I antigen.

Immunosuppressive therapy as a determinant of transplantation outcomes

Although surgical proficiency is essential to the immediate outcome of transplantation, long-term success depends upon how adequately the transplantation recipient is managed. Immunosuppression, the most critical aspect of after care, is subject to wide variation. In January 1990, a survey was sent to the directors of all transplant programs in the United States performing one or more kidney, heart, liver, heart-lung, or pancreas transplant in 1988. Detailed data were obtained on both the drugs and methods used for induction and maintenance immunosuppression, as well as the treatment of rejection. Each program director was asked to rank each immunosuppressive approach according to its perceived impact on patient outcomes. Over 85% of all eligible program directors completed the survey. There is no evidence of survey respondent bias. The use of polyclonal and monoclonal agents for induction immunosuppression was favored most by pancreas program directors (72-76%). These agents were least preferred by liver transplant programs (35-37%). About half of kidney, heart, and heart-lung program directors preferred these agents. Triple-drug therapy consisting of CsA, PRED, and AZA was considered the most preferable maintenance protocol for all transplants (i.e., kidney, 89%; heart, 94%; liver, 88%; heart-lung, 86%; pancreas, 96%). Either i.v. steroids or OKT3 were regarded as the preferred approaches for the treatment of acute or resistant rejection. Finally, the acceptability of outpatient treatment of rejection varied by transplant type (i.e., kidney, 9%; heart, 58%; liver, 5%; heart-lung, 29%; pancreas, 8%). Although there are similarities in the ratings of various aspects of immunosuppressive therapy, there are important differences. This information is critical to anticipate the implications of new immunosuppressive agents and to evaluate changes in the use of existing drugs and therapeutic approaches.

Liver transplantation for fulminant hepatic failure

OBJECTIVE

The purpose of this study was to assess outcome after liver transplantation for fulminant (FHF) and subfulminant (SHF) hepatic failure and to determine the factors responsible for outcome.

PATIENTS AND SETTING

Thirty-five patients who underwent 42 liver transplantations for FHF and eight patients who underwent eight liver transplantations for SHF at a large university medical center were followed up for 1 month to 5 years.

OUTCOME MEASURES

Actuarial patient and graft survival for FHF and SHF were assessed and compared with the outcome for all patients who underwent liver transplantation at the same center over the same period (445 transplants in 420 patients). Patients were treated with intracranial pressure monitoring, aggressive measures to decrease intracranial pressure, and rapid transplantation. Functional status and recurrent disease were additional end points.

RESULTS

One-year actuarial patient survival rates for FHF and SHF were 92% and 100%, respectively. Minor neurological sequelae were noted in two patients. Functional status was excellent. Posttransplant hepatitis was present in two patients with an original diagnosis of FHF and acute hepatitis B and in three patients with an original diagnosis of FHF and non-A, non-B, non-C hepatitis.

CONCLUSION

Patients with FHF and SHF can achieve excellent results after liver transplantation. Rapid assessment of candidacy with monitoring of intracranial pressure and aggressive treatment for intracranial hypertension are thought to be essential in the outcome of these patients.

New immunologic insights into mechanisms of allograft rejection

Our current understanding of liver allograft rejection indicates that multiple cellular interactions, involving a variety of cell-associated and soluble mediators, are critical to the response. The extravasation and localization of recipient immune cells to the allograft is dependent on recognition and interaction of complementary adhesion molecules expressed on circulating leukocytes and endothelium. Similar receptor-ligand pairs can also augment the binding of effector cells to target tissue within the allograft. Inflammatory mediators such as IL-1, IL-6, TNF-alpha, and IFN-gamma produced within the allograft can increase the local expression of adhesion molecules and thereby promote the entry of specific and nonspecific cells. The TCR expressed on T lymphocytes has the potential to recognize MHC antigens expressed on the allograft in many different forms. Thus, the T cell response to graft-associated alloantigens appears to be complex and dynamic. The production of T cell-derived cytokines is central to the activation and maturation of effector cells within the allograft. The identification of cytotoxic mediators such as serine protease and MBP within rejecting human allografts supports the role of cytotoxic T cells and eosinophils as effector cells. Undoubtedly, the development of genetically manipulated animal models will serve to further elucidate our understanding of the cellular mechanisms of graft rejection.

Nonoperative management of biliary leaks after orthotopic liver transplantation

Specific therapy should be instituted expeditiously once the diagnosis of a biliary leak has been made in patients who have undergone orthotopic liver transplantation. Controversy exists over whether to use nonoperative or operative management. The results of 325 consecutive orthotopic liver transplants in 297 adult and pediatric recipients were reviewed. The biliary tract was reconstructed using a choledochocholedochostomy anastomosis (254/325 or 78%) or a Roux-en-Y choledochojejunostomy anastomosis (71/325 or 22%). The incidence of biliary leaks was 23% (74/325). Overall, only 3% (10/325) of the orthotopic liver transplant recipients required operative repair of a biliary leak. Biliary leaks occurring in patients with Roux-en-Y choledochojejunostomy anastomoses (9/71 or 13%) commonly required operative repair (6/9 or 67%), whereas leaks that occurred in patients with choledochocholedochostomy anastomoses (65/254 or 26%) seldom required operative repair (4/65 or 6%). All choledochojejunostomy leaks occurred at the anastomosis, whereas choledochocholedochostomy leaks occurred either at the anastomosis (17/254 or 7%) or the T-tube insertion site (45/254 or 18%). Our study confirms that in centers with proficient endoscopic and interventional radiologic support, resolution of biliary leaks in orthotopic liver transplant patients can be achieved with nonoperative management.

Creation of transjugular intrahepatic portosystemic shunts with the wallstent endoprosthesis: results in 100 patients

One hundred patients underwent transjugular intrahepatic portosystemic shunt (TIPS) creation for variceal bleeding (n = 94), intractable ascites (n = 3), hepatorenal syndrome (n = 2), and preoperative portal decompression (n = 1). Shunts were completed in 96 patients. Portal vein pressure was reduced from 34.5 mm Hg +/- 7.6 (standard deviation) to 24.5 mm Hg +/- 6.2; the residual portal vein-hepatic vein gradient was 10.4 mm Hg +/- 0.9. Acute variceal bleeding was controlled in 29 of 30 patients. Of the 96 patients who underwent successful TIPS creation, 26 have died and 22 have undergone liver transplantation; the remaining 48 patients have survived an average of 7.6 months. Variceal bleeding recurred in 10 patients. Fifteen patients developed shunt stenosis (n = 6) or occlusion (n = 9). Patency was reestablished in eight of the nine occluded shunts. Seventeen patients developed new or worsened encephalopathy. The authors conclude that TIPS creation is an effective and reliable means of lowering portal pressure and controlling variceal bleeding, particularly in patients with acute variceal bleeding unresponsive to sclerotherapy and patients with chronic variceal bleeding before liver transplantation.

IL-2 and IL-5 gene expression in response to alloantigen in liver allograft recipients and in vitro

IL-2 and IL-5 gene expression in response to alloantigen was studied in liver allograft recipients and in an in vitro system. Seventy-seven sequential liver allograft biopsies from 22 patients were analyzed for IL-2 and IL-5 mRNA by polymerase chain reaction and Southern blot hybridization. Message for IL-5 was present in 74% of allografts with rejection, 46% of allografts with resolving rejection, and 33% of allografts with no evidence of rejection. The frequency of IL-5 transcripts in rejecting allografts was significantly different than the frequency of IL-5 transcripts in grafts without evidence of rejection (P = 0.003). Message for IL-2 was detected in 29% of rejecting allografts, 18% of allografts without evidence of rejection, and 43% of allografts with resolving rejection. There was no significant association between IL-2 gene expression and the histopathological status of the allograft. Interestingly, 9 of 15 biopsies that contained IL-2 message in the no rejection and resolving rejection categories went on to display rejection shortly thereafter. IL-2 and IL-5 gene expression rarely occurred simultaneously within allografts. An in vitro system consisting of irradiated, allogeneic stimulator cells and normal peripheral blood mononuclear cells as responders was established to further investigate alloantigen-driven IL-2 and IL-5 production. Both IL-2 and IL-5 were produced in response to alloantigen as determined by specific bioassays. Maximal levels of IL-5 activity in culture supernatants generally followed maximal IL-2 levels by 24 hr, but both IL-2 and IL-5 production were dramatically inhibited by CsA. Analysis of cytokine gene expression revealed that IL-2 transcription peaked within the initial 24 hr of culture, whereas IL-5 transcription was maximal at 120 hr of culture. The expression of a CTL-specific serine esterase gene was similar to IL-5 in that it was maximal during the latter phases of the culture period. Thus, both human IL-2 and IL-5 are produced in response to alloantigen and are inhibitable by CsA. These data suggest that IL-2 and IL-5 may participate in cellular pathways of tissue damage within the rejecting allograft.

Evidence for a nonclassical pathway of graft rejection involving interleukin 5 and eosinophils

The role of IL-5 and eosinophils in allograft rejection was studied in human liver allograft recipients. Liver allograft biopsies were analyzed for intragraft IL-5 gene expression, and the percentages of eosinophils and plasma cells within the portal infiltrate as well as peripheral eosinophil levels were determined. The majority of allografts with evidence of rejection had concomitant IL-5 mRNA and eosinophilia, while no resolving or nonrejecting allografts had simultaneous IL-5 mRNA and eosinophilia. In fact, rejecting liver allografts that contain IL-5 mRNA and eosinophils also contain infiltrating cells that produce the cytotoxic mediator major basic protein. In contrast, intragraft plasma cell and peripheral eosinophil levels did not correlate with the histopathologic status of the allograft. Cyclosporine and FK506 had similar effects on the frequency of IL-5 gene expression in rejecting and nonrejecting allografts. However, OKT3 appeared to profoundly modulate IL-5 gene expression, since 0 of 11 biopsies obtained during OKT3 treatment for rejection contained IL-5 transcripts. These observations raise the possibility of a cellular pathway of liver allograft rejection mediated by IL-5-activated eosinophils.

Use of Prograf (FK 506) as rescue therapy for refractory rejection after liver transplantation. US Multicenter FK 506 Liver Study Group

This report describes the clinical characteristics and demographics of patients enrolled into this rescue trial for patients experiencing refractory rejection after liver transplantation. Actuarial graft and patient survival at 12 months postconversion was 50% and 72%, respectively. Actual treatment success at 3 months postconversion was 70%. Karnofsky scores and liver function tests were significantly improved for patients continuing on therapy indicating clinical benefit in these patients. The safety profile of FK 506 is acceptable for such a high-risk group of patients. These preliminary clinical results support the conclusion that FK 506 can effectively control and reverse refractory rejection in a majority of liver transplantation patients.

Transjugular intrahepatic portosystemic shunts: preliminary results in 25 patients

A retrospective study of transjugular intrahepatic shunts performed between June 1990 and June 1991 is reported. Twelve patients were actively bleeding at the time of the procedure; 12 other patients had had one to five bleeding episodes within the previous 2 weeks, and one patient had massive ascites from Budd-Chiari syndrome. Most patients had severe liver disease: 21 Child's class C, three Child's class B, and one Child's class A. Transjugular intrahepatic shunting was technically successful in all cases. Portal vein pressures were reduced on average from 36 +/- 7 cm H2O to 22 +/- 6 cm H2O. Variceal bleeding ceased after transjugular intrahepatic shunting in all patients who were actively bleeding. Five patients died (30-day mortality, 20%), and eight patients subsequently underwent elective liver transplantation. The transjugular intrahepatic shunts in the 12 other patients have remained patent an average of 5.5 months. Shunt occlusion occurred in three patients at 21, 24, and 102 days, respectively. All three occlusions were successfully reopened with percutaneous techniques, yielding a primary shunt patency of 88% and secondary shunt patency of 100%. Complications included new onset encephalopathy in one patient, which cleared with medical therapy and transient renal failure in one patient. These preliminary data suggest that transjugular intrahepatic shunting is a safe and effective therapy for the short-term treatment of patients with variceal hemorrhage, particularly in patients with severe liver disease awaiting transplantation. The long-term benefit of transjugular intrahepatic shunting awaits further follow-up.

Intracranial pressure monitoring and liver transplantation for fulminant hepatic failure

Cerebral edema and intracranial hypertension, commonly present in fulminant hepatic failure, may lead to brainstem herniation and limit the survival of comatose patients awaiting liver transplantation before a donor organ becomes available. Also, they are likely responsible for postoperative neurological morbidity and mortality. Although intracranial pressure monitoring has been proposed to aid clinical decision making in this setting, its use in the prevention of brainstem herniation preoperatively, in the selection of patients for liver transplantation who have the potential for neurological recovery and in the maintenance of cerebral perfusion during liver transplantation has not been examined in detail. To address these issues, we established a protocol for intracranial pressure monitoring in comatose patients with fulminant hepatic failure as part of their preoperative and intraoperative management. Twenty adults and three children underwent intracranial pressure monitoring. Ten patients required preoperative medical therapy with mannitol, barbiturates or both for a rise in intracranial pressure above 25 mm Hg. Four patients had a sustained lowering of intracranial pressure, three of whom survived hospitalization. Six patients had intracranial hypertension refractory to medical management, were removed from a waiting list for a donor organ and died with brainstem herniation. Of the remaining 17 patients, 3 died of other causes while awaiting a donor organ, 2 recovered spontaneously without neurological sequelae and 12 underwent liver transplantation. All but one patient undergoing liver transplantation had transient intraoperative intracranial hypertension develop, requiring medical treatment. The 12 patients who had transplants recovered neurologically and were discharged from the hospital.(ABSTRACT TRUNCATED AT 250 WORDS)

Recurrent and acquired hepatitis C viral infection in liver transplant recipients

To examine the postliver transplant recurrence of hepatitis C virus (HCV) infection in patients with pretransplant infection, as well as its acquisition in patients without prior infection, we used the polymerase chain reaction to amplify HCV RNA in serum and/or liver samples of 89 patients with alcoholic and cryptogenic cirrhosis undergoing liver transplantation. Results were correlated with histologic findings from posttransplant liver biopsies. Ninety-five percent of patients with pretransplant infection had posttransplant viremia. In contrast, 35% of patients without pretransplant infection acquired the virus (P less than 0.0001). Pretransplant HCV infection predisposed patients to hepatitis in the new graft. HCV RNA was present in serum of 96% of patients with posttransplant hepatitis. Fifty-six percent of patients with posttransplant HCV infection had no evidence of liver damage at least 1 year posttransplant. However, of those patients with histologic hepatitis, chronic active hepatitis was common. It is concluded that although HCV infection recurs posttransplant in almost all infected patients, acquisition of the HCV infection with transplant is common. Pretransplant HCV infection is an independent risk factor for the development of posttransplant hepatitis. HCV infection accounts for the majority of posttransplant hepatitis not due to cytomegalovirus, and although many patients with posttransplant viremia have little evidence of histologic hepatitis, significant hepatic damage may occur.

Hepatitis B virus and apparent fulminant non-A, non-B hepatitis

While there is evidence that hepatitis C virus (HCV) does not cause fulminant non-A, non-B hepatitis, the causal agent remains unknown. To evaluate the role of hepatitis B virus (HBV) in this disease, we used a two-step polymerase chain reaction (PCR) to amplify the surface and core regions of HBV DNA in serum and liver samples taken prospectively from twenty-six patients (mean age 36 years, range 1 to 64) with acute hepatic failure undergoing liver transplantation. HBV DNA was absent from the serum of all patients before transplantation. Seventeen patients were diagnosed as having non-A, non-B hepatitis because they lacked serological evidence of hepatitis A virus or HBV infection. Liver samples were taken from twelve of these patients, and six samples were positive for HBV DNA. By contrast HBV DNA was not detected in liver from three patients with acute liver failure caused by hepatitis A or toxins. HCV RNA was not found in pretransplant samples by PCR. Four of the six patients with detectable HBV DNA in liver and presumptive non-A, non-B hepatitis had detectable HBV DNA in serum after transplantation. One additional patient who did not donate pretransplant liver had HBV DNA in a post-transplant serum sample. Thus, HBV DNA was present before or after transplantation in seven of seventeen patients with apparent non-A, non-B hepatitis. Three of five patients with detectable post-transplant serum HBV DNA were serologically positive for HBV surface antigen. These findings indicate that HBV may be a common cause of fulminant hepatic failure in patients lacking serological evidence of HBV infection.

Cell subsets responding to purified hepatocytes and evidence of indirect recognition of hepatocyte major histocompatibility complex class I antigen. II. In vitro-generated "memory" cells to class I+ class II- hepatocytes

Purified hepatocytes stimulate the development of L3T4-, Ly2+ allospecific cytolytic T cells from naive splenocytes after 5 days in primary mixed lymphocyte-hepatocyte culture (MLHC). Previous studies indicate that the immunogenicity of purified hepatocytes relates to the expression of MHC class I antigen. The purpose of the following experiments was to identify the cell subsets that specifically recognize hepatocyte MHC class I antigen. We employed primed lymphocyte testing (PLT) in order to test for a "second set" response. Cells from primary MLHC reverted to a functionally quiescent state when they were grown in culture for an additional 7-9 days. The cells were then tested for cytotoxicity or rechallenged with allogeneic, syngeneic, or "third party" hepatocytes and tested for proliferation. Allocytotoxicity was low on day 12 in MLHC, but the sensitized cell population demonstrated peak proliferation in response to allogeneic hepatocytes 48 hr after restimulation. When bulk PLT cells were immunodepleted, both L3T4+, Ly2- and L3T4-, Ly2+ T cell subsets demonstrated a "second set" response to allogeneic hepatocytes consistent with specific recognition of and retention of "memory" for hepatocyte MHC class I alloantigen.

Cell subsets responding to purified hepatocytes and evidence of indirect recognition of hepatocyte major histocompatibility complex class I antigen. I. The role of L3T4+ T cells in the development of allospecific cytotoxicity in hepatocyte-sponge matrix allografts

The purpose of this study was to determine the role of L3T4+, Ly2- T cells in the development of allospecific cytolytic T cells in response to purified allogeneic MHC class I+, class II- hepatocytes in vivo in hepatocyte-sponge matrix allografts (HC-SMA). In previous studies we have shown that 99% pure murine hepatocytes stimulate the development of allospecific cytolytic T cells in vitro in mixed lymphocyte-hepatocyte culture (MLHC) and in vivo in HC-SMA. Furthermore, depletion of L3T4+, Ly2- T cells from responder splenocytes inhibits the development of allo-CTLs in response to purified hepatocytes in mixed lymphocyte-hepatocyte culture. Here, using an anti-L3T4 monoclonal antibody, we tested the effect of in vivo immunodepletion of L3T4+, Ly2- T cells on the subsequent development of allo-CTLs in HC-SMA. Sponge cells were harvested on day 4 and day 12 after grafting from control and treated groups and phenotypically analyzed by FACS and immunofluorescent labelling. Splenocytes from the same animals were similarly analyzed to assess for completeness of immunodepletion. Allospecific cytotoxicity was assessed on day 12 after grafting. We found that immunotherapy with anti-L3T4 mAb was effective in depleting L3T4+, Ly2- T cells from the spleen; however, a similar number of L3T4+ cells was isolated from the sponge between control and treated groups. Furthermore, the development of allo-CTLs in response to hepatocytes in HC-SMA was completely abrogated by both local and systemic immunotherapy with anti-L3T4 mAb. We conclude from these and previous data that host or responder L3T4+, Ly2- T cells and responder accessory cells in MLHC or host macrophages in HC-SMA may participate in "indirect" recognition of hepatocyte class I antigen both in vitro and in vivo.

Using transjugular intrahepatic portosystemic shunts to control variceal bleeding before liver transplantation

OBJECTIVE

To determine the safety and efficacy of transjugular intrahepatic portosystemic shunts (TIPS) in controlling bleeding from esophageal varices in patients awaiting liver transplantation.

DESIGN

Prospective, uncontrolled trial.

SETTING

University medical center with an active liver transplant program.

PATIENTS

Thirteen patients referred for liver transplantation with either active variceal hemorrhage or recurrent variceal hemorrhage despite sclerotherapy; four patients had been previously treated with surgical portosystemic shunts.

INTERVENTION

An intrahepatic portosystemic shunt created via a transjugular approach to the hepatic veins using expandable, flexible metallic stents.

MEASUREMENTS

Portal pressures before and after the creation of the shunt, the direction of portal blood flow at differing diameters of the shunts, procedure-related complications, and outcome in terms of survival, liver transplantation, and recurrent variceal bleeding.

MAIN RESULTS

The transjugular intrahepatic portosystemic shunt was placed successfully in 13 patients, and bleeding was controlled acutely in all 13. After the procedure, the mean portal pressure decreased from 34 +/- 8.9 cm H2O to 22.4 +/- 5.4 cm H2O (P less than 0.001). No complications were associated with the procedure; however, two patients died of causes unrelated to the procedure. Seven patients subsequently underwent liver transplantation and are doing well, and three patients are being managed conservatively. Bleeding recurred in one patient 102 days after the procedure secondary to shunt occlusion caused by neointimal proliferation.

CONCLUSION

Placement of a transjugular intrahepatic portosystemic shunt is apparently safe and effective therapy for variceal hemorrhage in patients referred for liver transplantation.

Intragraft cytokine profile during human liver allograft rejection

Forty-three human liver allograft biopsies and normal liver were directly analyzed for inflammatory and immunoregulatory cytokine gene expression by polymerase chain reaction (PCR). IL-5 gene expression was predominantly present in biopsies from liver allografts with histopathological evidence of acute rejection. IL-2 gene expression was rarely observed in rejecting allografts or allografts without evidence of rejection. In contrast, IL-4 message was readily detectable in the majority of liver allografts regardless of clinical status. The inflammatory mediators IL-1 beta, TNF-alpha, and IL-6 were detected with similar frequency in rejecting allografts and allografts without evidence of rejection. These findings suggest that inflammatory and immunoregulatory cytokines are produced within the allograft. Moreover, IL-5 may play a role in the local mechanisms of liver allograft rejection.

The potential supply of organ donors. An assessment of the efficacy of organ procurement efforts in the United States

OBJECTIVES

To estimate the potential supply of organ donors and to measure the efficiency of organ procurement efforts in the United States.

METHODS

A geographic database has been developed consisting of multiple cause of death and sociodemographic data compiled by the National Center for Health Statistics. All deaths are evaluated as to their potential for organ donation. Two classes of potential donors are identified: class 1 estimates are restricted to causes of death involving significant head trauma only, and class 2 estimates include class 1 estimates as well as deaths in which brain death was less probable.

RESULTS

Over 23,000 people are currently awaiting a kidney, heart, liver, heart-lung, pancreas, or lung transplantation. Donor supply is inadequate, and the number of donors remained unchanged at approximately 4000 annually for 1986 through 1989, with a modest 9.1% increase in 1990. Between 6900 and 10,700 potential donors are available annually (eg, 28.5 to 43.7 per million population). Depending on the class of donor considered, organ procurement efforts are between 37% and 59% efficient. Efficiency greatly varies by state and organ procurement organization.

CONCLUSIONS

Many more organ donors are available than are being accessed through existing organ procurement efforts. Realistically, it may be possible to increase by 80% the number of donors available in the United States (up to 7300 annually). It is conceivable, although unlikely, that the supply of donor organs could achieve a level to meet demand.

Histopathologic study of transjugular intrahepatic portosystemic shunts

A detailed histopathologic analysis of intrahepatic portosystemic shunts was performed following liver transplantation in five patients. Gross examination revealed that all stents were patent and unchanged in size, shape, and position from initial placement. Histologic examination at 4 days revealed an irregular luminal surface with liver parenchyma protruding between the stent wires and a single, patchy layer of endothelial cells lining the shunt surface. By 3 weeks, the stent wires were covered by a pseudointima of granulation tissue, and the luminal surface was lined with a contiguous layer of endothelial cells. Excessive pseudointimal proliferation resulted in shunt occlusion at 3 months in one patient whose shunt was subsequently reopened percutaneously.

Evidence for direct and indirect pathways in the generation of the alloimmune response against pancreatic islets

The role of the direct and indirect pathways of alloantigen presentation in the generation of the alloimmune response was dissected using the murine mixed lymphocyte-islet coculture system (MLIC). Stimulator DBA/2J (H-2d) pancreatic islet populations consisted of whole islets (MHC class I+, II+) or FACS-purified beta cells (MHC class I+, II-). Responding C57Bl/6 (H-2b) splenocyte populations were either: (1) untreated; (2) depleted of helper T cells with anti-L3T4 monoclonal antibody plus complement; (3) depleted of cytotoxic T lymphocytes with anti-Lyt2 mAb plus complement; or (4) depleted of antigen-presenting cells by passage through a Sephadex G-10 column. Whole islets were capable of stimulating a significant C57Bl/6 anti-DBA cytotoxic T cell response if the responding population was untreated or treated with complement alone. Depletion of responding splenocytes with either anti-Lyt2 or anti-L3T4 mAb plus complement abrogated the generation of allospecific CTL. If the responding splenocyte population was depleted of APCs, the allo-CTL response against whole islets was decreased, but still significant. If, however, the stimulator population consisted of FACS-purified DBA 2J beta cells, APC-depleted C57Bl 6 splenocytes were incapable of generating any CTL response. Adding responder type (C57Bl/6) APCs back to the microwells restored the capacity for both whole islets and purified beta cells to stimulate a strong allo-CTL response. These data demonstrate that both indirect and direct pathways of alloantigen presentation function in the MLIC.

Demonstration of local immunosuppression with methylprednisolone in the sponge matrix allograft model

This study evaluated the effect of locally delivered methylprednisolone on the systemic and local immune response in the sponge matrix allograft model. Polyurethane sponges were coated with peritoneal exudate cells from DBA/2 (H-2d) or C57Bl/6 mice (H-2b) and placed subcutaneously in C57BL/6 recipients 24 hr later. Each mouse received both a syngeneic and an allogeneic sponge graft. Local immunosuppression was effected by placement on day 0 of cellulose/matrix pellets containing a preparation of increasing quantity of controlled release MP or by daily intrasponge injection of MP. Local immunosuppression was demonstrated by decreased cytotoxicity on day 12 in the allogeneic sponge receiving MP directly, as compared with the groups that received MP in the opposite syngeneic sponge or no MP. This effect was noted at a specific MP dose (0.5 mg/kg/day). Absolute numbers of precursor cytolytic cells and mature cytolytic cells (determined by limiting dilution analyses) infiltrating the allografts were also decreased in the sponges receiving MP directly, relative to the groups receiving MP in the opposite syngeneic sponge. Maintenance of systemic (in contrast to local) immunity was also demonstrated. Animals treated with local MP into a simultaneously placed syngeneic sponge or in whom no MP was delivered became sensitized to a synchronous DBA/2 sponge and rejected a subsequent DBA/2 skin graft in second-set fashion. Conversely, animals that received local MP into their synchronous DBA/2 sponge rejected a subsequent DBA/2 skin graft or a third-party graft with first-set kinetics. The presence of local MP at the initial graft site prevented the animals from becoming sensitized to the presented alloantigen but did not keep the animal from developing a rejection response to a third-party skin graft with first-set kinetics. It appears that delivery of MP locally to the site of antigen is an effective method to modulate alloreactivity. In addition, the sponge matrix allograft appears to be a useful model for studying local immunosuppression.

Graft vs. host disease after liver transplantation in humans: a report of four cases

Four cases of patients in whom graft vs. host disease developed after liver transplantation are described. The clinical course of each patient was similar with fever, pancytopenia, diarrhea and a skin rash developing 1 or 2 mo after liver transplantation. The clinical diagnosis was made from skin or colon biopsy specimens. Liver dysfunction did not occur in the patients at the time of diagnosis. Extrahepatic donor DNA was identified in the three patients it was tested for. Three patients died from the complications of the disease primarily related to sepsis. The other patient recovered from the graft vs. host disease but died from lymphoproliferative disease.

Early liver transplantation is indicated for tyrosinemia type I

Liver transplantation is now accepted as the treatment of choice for tyrosinemia type I (hereditary tyrosinemia). In an effort to determine whether any factors in these patients would aid in predicting optimal timing of the transplant procedure, we evaluated several clinical, biochemical, and radiographic parameters in five successive patients undergoing liver transplant for tyrosinemia type I at the University of Minnesota. All five patients evidenced prolonged periods of clinical and metabolic stability with dietary therapy and four of five remained stable at the time of evaluation for transplantation. Nevertheless, all five suffered significant and unexpected complications of tyrosinemia prior to the time of liver transplant. Four developed renal stones, two were in liver failure, and one developed a neurologic crisis that left him completely paralyzed. Hepatocellular carcinoma was found in one of the five at transplant. We could identify no clinical, biochemical, or radiographic study that was predictive of the likelihood of significant complications of the disorder. Survival from the transplant procedure itself was 100%. The inability to predict or prevent significant complications of tyrosinemia and the favorable outcome from transplantation lead us to recommend liver transplant for all patients with tyrosinemia type I by 12 months of age.

Cladosporium trichoides cerebral phaeohyphomycosis in a liver transplant recipient. Report of a case

Cerebral phaeohyphomycosis (also referred to as cerebral chromomycosis), one of the diseases caused by the dematiaceous (black) fungi, is most commonly caused by Cladosporium trichoides (referred to by some as Xylohypha bantiana) and is a rare disease, with 31 culture-proven cases reported to date. Although most cases have occurred in immunocompetent hosts, recent experimental evidence suggests that host immunosuppression may predispose patients to the disease. The authors report a case of fatal cerebral phaeohyphomycosis in a liver transplant patient, the first to occur in a transplant patient of any type, to the best of the authors' knowledge. This case provides support for the hypothesis that immunosuppressed patients may be at increased risk for development of this disease.

Hepatitis C in patients undergoing liver transplantation

OBJECTIVE

To determine the prevalence of antibodies to hepatitis C virus (anti-HCV) among patients undergoing liver transplantation and the relation between anti-HCV and post-transplant hepatitis.

DESIGN

Retrospective cohort.

PATIENTS

Serum samples from 128 patients who underwent liver transplantation. Sixty-six patients who had 6 months of follow-up and for whom both pretransplant and post-transplant serum samples were available were included in a study to asses the relation between anti-HCV and post-transplant hepatitis.

MEASUREMENTS

Sera were tested for anti-HCV using an enzyme-linked immunosorbent assay (ELISA) and, if positive, two confirmatory tests were done. Patients had a biopsy every week until two specimens showed no abnormal findings.

MAIN RESULTS

Only patients with chronic non-A, non-B hepatitis (15 of 30; 50%), alcoholic cirrhosis (7 of 19; 37%), and chronic hepatitis B infection (3 of 11; 27%) were anti-HCV positive. No patient with another form of chronic liver disease or with acute liver failure due to non-A, non-B hepatitis was anti-HCV positive. After transplantation, loss of anti-HCV was frequent and acquisition rare. Hepatitis developed in the graft in 17% of patients, but the incidence was similar among anti-HCV negative and anti-HCV-positive patients.

CONCLUSIONS

Hepatitis C virus is a common cause of chronic liver disease in patients requiring liver transplantation, but anti-HCV is rarely found in patients with acute liver failure. Previous HCV infection, based on detection of anti-HCV, is not an independent risk factor for post-transplant hepatitis.

Hepatitis C in liver transplant recipients

HCV infection is commonly found in patients with chronic liver disease undergoing liver transplantation. However, the presence of antibody to HCV does not appear to be associated with the development of hepatitis posttransplant. No other risk factors were identified that appear to predispose patients to development of hepatitis in the posttransplant period, including amount of blood product exposure. The role of immunosuppression in the acquisition and expression of liver disease caused by HCV remains to be determined.