Hepatitis G virus infection in acute fulminant hepatitis: prevalence of HGV infection and sequence analysis of a specific viral strain

Hepatitis G virus (HGV) is a recently discovered RNA virus, which belongs to the Flaviviridae family. Although HGV infection is usually not associated with elevated serum transaminases, some recent studies have reported that HGV infection is found in a significant number of patients with fulminant hepatitis and may play a role in its etiopathogenesis. In this study the prevalence of HGV infection was determined in 500 healthy blood donors and in 24 patients admitted to hospital because of acute liver failure caused by fulminant hepatitis. The presence of HGV RNA was tested in sera, obtained at admission and before any transfusion was given, by a sensitive seminested reverse transcriptase-polymerase chain reaction (RT-PCR) assay specific for detection of the non-structural (NS)5 region. Nine of the 500 blood donors (1.8%) and two of the 24 patients (8.3%) were found to be HGV RNA positive. One patient was co-infected with HCV and was known to be an intravenous (i.v.) drug user. After intensive supporting treatment, this patient recovered completely. The second patient had no serological markers of known viral hepatitis infection, including hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), cytomegalovirus (CMV), Epstein-Barr virus (EBV) and herpes simplex virus (HSV). This patient was successfully transplanted. From both patients, from HGV RNA-positive healthy blood donors and from other patients coinfected with HCV, a part of the HGV NS3 region (nucleotides 4191-4345, EMBL entry U45966) was cloned and sequenced. Sequence comparison revealed that the NS3 region of HGV in patients with fulminant hepatitis contained three nucleotide substitutions as part of the six substitutions described in previous work. These nucleotide substitutions were not found in the tested blood donors or in patients with HCV co-infection. Our findings therefore support the concept of the association of fulminant hepatitis with infection of a specific HGV strain.

Effect of peritransplant FTY720 alone or in combination with post-transplant tacrolimus in a rat model of cardiac allotransplantation

FTY720 is a recently discovered compound that is derived from the fungus Isaria sinclairii. Using a DA donor-to-LEW recipient rat combination, we assessed the efficacy of peritransplant FTY720 alone or in combination with post-transplant tacrolimus on the survival of cardiac allografts. Peritransplant FTY720 given orally at a dose of 5 mg/kg on days-1 and 0 prolonged graft survival from 5 to 13 days (P < 0.05). Combining peritransplant FTY720 with post-transplant tacrolimus resulted in a further prolongation of allograft survival. The lymphocyte count in transplanted rats decreased within 24 h to 46.6%. Analysis of lymphocyte subsets by FACS revealed that FTY720 affected the total population of CD3-bearing T cells while the ratio of CD4 to CD8 cells remained unchanged. Kidney and liver biochemistry remained elevated for 2 weeks. In conclusion, FTY720 is a powerful immunosuppressive agent when used as induction therapy and may have an additive effect--perhaps a synergistic one--with post-transplant tacrolimus.

Encouraging results of split-liver transplantation

BACKGROUND

Liver donor shortage presently accounts for a 10 per cent waiting list mortality rate. Split-liver transplantation (SLT) can improve utilization of this scarce resource.

METHODS

Twenty-four SLTs (11 left, 13 right grafts) from 13 livers were performed in 23 patients (nine adults, 14 children), comprising 4.5 per cent of all orthotopic liver transplants (14 urgent or emergency, ten elective). The left graft comprised segments II and III, whereas the right graft comprised segments V-VIII in eight cases, IV-VIII in three, and segments I, IV-VIII, and I, V-VIII in one case each. Additional arterial extension grafts were required in six of 24 cases, and portal venous interposition graft in one.

RESULTS

Twenty-one grafts showed good initial function, with one primary non-function and two initial poor function. The median peak aspartate aminotransferase level was 782 (range 94-2301) and 982 (range 382-2520) units/l for left and right grafts respectively. Five patients died (all urgent recipients), all within the first 30 days after surgery. Two SLT recipients underwent subsequent retransplantation. All ten elective recipients are alive. The 1-year actuarial patient and graft survival rates at a median follow-up of 20 months were 78 and 68 per cent respectively.

CONCLUSION

These encouraging results compare favourably with those of reduced-size and whole-liver transplantation and justify wider application of this technique, thereby optimizing donor resource use.

[Intestinal transplantation: a clinical reality in 1998]

Each year, thousands of peoples die, suffering from an anatomical or functional loss of their intestine; these patients would benefit from bowel transplantation; the difficulties of bowel transplantation are as follows: 1. the physiological characteristics of the small bowel, and the fact that denervation, lymphatics interruption and ischemia, independently from rejection, may disturb its function; 2. secondly, the organ is septic; thus, its transplantation causes major infectious problems; 3. at last, the immunological characteristics of the intestinal allograft. Bowel transplantation causes a two-way immunological conflict, not only a standard rejection response, but also a graft-versus-host disease, similar to that observed after bone marrow transplantation; this reaction is caused by the lymphoid tissue conveyed within the bowel graft. The introduction of a new immunosuppressive molecule, FK 506, in combination with profound antibiotic prophylactic regimens, decontamination protocols and vigorous anti-viral protection (against cytomegalovirus and Epstein-Barr), have significantly improved the results. Bowel transplantation has recently reached clinical application. The one-year survival rate of intestinal grafts reaches now 70%. Still, there is no doubt that, due to its microbiological and immunological characteristics, the small bowel will remain the most challenging abdominal organ to transplant.

Combined liver-total bowel transplantation has no immunologic advantage over total bowel transplantation alone. A prospective study in a porcine model

BACKGROUND

Rejection remains a major obstacle to successful bowel transplantation in humans. It has been suggested that a simultaneous liver transplant would shield the bowel graft from immunologic attack, but the liver shortage would be aggravated. In a preclinical model, we studied the influence of simultaneous liver grafting by comparing the incidence of early bowel rejection after combined liver-total (small- and large-) bowel transplants vs total bowel transplants alone.

METHODS

We assessed the incidence of early post-transplant rejection, graft-vs-host disease, and infection after combined liver-total bowel transplants (group 1, n = 10) and total bowel transplants alone (group 2, n = 9) in outbred Yorkshire Landrace pigs. Liver and bowel grafts were transplanted orthotopically with portal vein drainage after recipient hepatectomy (group 1) and total enterectomy (groups 1 and 2). Posttransplant immunosuppression was performed with intravenous tacrolimus (whole blood levels, 15 to 30 ng/mL) and prednisolone. In groups 1 and 2, bowel biopsy specimens from the ileostomy were obtained daily. In group 1, liver biopsy specimens were obtained weekly. Rejection was graded according to a 4-point scoring system (none, mild, moderate, and severe).

RESULTS

Overall graft survival at days 7, 14, and 21 was 89%, 44%, and 11%, respectively, in group 1 vs 100%, 100%, and 86%, respectively, in group 2 (P < .001). Death rates owing to (irreversible) rejection at days 7, 14, and 21 were 0% in groups 1 and 2 (P = .48). Grading of bowel rejection episodes, based on the results of daily biopsy specimens, was not significantly different between the groups whether on individual days or overall. In group 1, the incidence of liver rejection episodes was as high as 66% (day 14 and at autopsy). At autopsy, generalized graft-vs-host disease (skin, native intestine, and native liver) was noted in 55% of group 1 and 43% of group 2 pigs (P = .55). Graft-vs-host disease was noted concurrently with rejection episodes of the liver or bowel grafts.

CONCLUSIONS

Simultaneous liver grafting did not further reduce the incidence of early bowel rejection or graft-vs-host disease when compared with total bowel transplants alone. Based on the results of this preclinical study, simultaneous liver grafting is not indicated for patients with short-bowel syndrome and normal liver function.

Current status of pancreas transplantation for treatment of type I diabetes mellitus

Pancreas transplantation is the only treatment of Type I diabetes that consistently establishes an insulin-independent, normoglycemic state. Currently long-term (> 1 year) insulin-independence is achieved in > 80% of recipients of pancreas grafts placed simultaneous with the kidney and > 70% in recipients of a pancreas after a kidney, and > 60% of non-uremic recipients of a pancreas alone. The penalty is immunosuppression, already obligatory for a kidney recipient, but the benefits are improvement in quality of life and the effect that perfect control of glycemia can have on secondary complications.

Colon perforation after renal transplantation: a single-institution review

Colon perforation (CP) is an uncommon but dramatic complication after renal transplantation. Of 1530 consecutive kidney transplants performed at our center, 8 recipients had an CP (incidence of 0.5%), either early (n = 5, 2-14 days) or late (n = 3, 8-48 months) post transplant. Clinical symptoms were generally vague. Biological findings were inconstant. Risk factors for CP included a cadaver graft (versus a living donor), high body weight, history of diverticulitis, and Kayexalate use. Crucial to outcome were: 1) immediate diagnosis and 2) aggressive surgical care consisting of resectional therapy, broad-spectrum antibiotics, and reduced immunosuppression. Applying these principles, mortality in our patients (25%) was lower than in previously reported series (33-64%). All grafts were functioning at the time of diagnosis; graft function was preserved in recipients who recovered from CP. Patients with a documented history of diverticulitis should undergo prophylactic colonic resection. Constipation and colonic dilatation should be treated aggressively in the early post-operative period.

Combined liver and kidney transplantation

Patients with end-stage renal and hepatic failure may be treated with combined liver and kidney transplantation (CLKTx). We reviewed the indications and outcomes of 16 CLKTx performed at the University of Minnesota between 1980 and 1994. The majority of the recipients (87.5%) were young patients affected by congenital hepatic anomalies and concomitant end-stage renal failure. Fourteen were treated with cyclosporin-based immunosuppression and had an excellent outcome: with an average of 6 years of follow-up, patient survival was 85.7%, liver graft survival 85.7%, and kidney graft survival 72%. The incidence of rejection episodes was similar to the rate of rejection in our solitary kidney and liver transplants. In conclusion, our experience supports the value of CLKTx in treating patients with simultaneous failure of both organs or with congenital enzymatic hepatic deficits leading to renal failure.

Recipient preconditioning and donor-specific bone marrow infusion in a pig model of total bowel transplantation

BACKGROUND

In an outbred pig model of total bowel transplantation, we previously showed that simultaneous donor-specific bone marrow infusion (DSBMI), rather than promoting engraftment, sensitizes recipients and causes rejection; it also aggravates the risk of generalized graft-versus-host disease (GVHD) and infection, and tends to reduce recipient and graft survival. Small and large animal models of bone marrow-induced transplant tolerance suggest that some form of recipient preconditioning (RPC) may facilitate engraftment of co-transplanted bone marrow cells and fully expose their tolerogenic potential.

METHODS

In a preclinical model, we prospectively studied the effect of RPC on simultaneous DSBMI and total (i.e., small and large) bowel transplantation. RPC consisted of whole body irradiation with 400 R (day 0); some recipients additionally received horse anti-pig antithymocyte globulin (days -2, -1, and 0). We studied six groups of outbred pigs, all of which underwent at least a total bowel transplant: group 1, nonimmunosuppressed control pigs (n=5); group 2, nonimmunosuppressed DSBMI pigs (n=13); group 3, tacrolimus pigs (n=7); group 4, DSBMI+tacrolimus pigs (n=15); group 5, RPC+nonimmunosuppressed DSBMI pigs (n=11); and group 6, RPC+DSBMI+tacrolimus pigs (n=14).

RESULTS

RPC did not prolong overall survival at 7, 14, 21, and 28 days after transplant. Survival rates were 100%, 100%, 86%, and 71% in group 3; 71%, 43%, 29%, and 29% in group 6; 55%, 9%, 0%, and 0% in group 5; and 60%, 0%, 0%, and 0% in Group 1. Moreover, RPC (groups 5 and 6) increased the incidence of death from rejection, GVHD, and infection when compared with group 3. Survival was significantly higher for RPC+DSBMI+tacrolimus pigs (group 6), compared with RPC+nonimmunosuppressed DSBMI pigs (group 5). Survival greater than 28 days was noted only in pigs that received tacrolimus after transplant: 71% in group 3 versus 29% in group 6. With both RPC and DSBMI (groups 5 and 6), rejection, GVHD, and infection were not mutually exclusive events. In groups 5 and 6, at autopsy, the incidence of rejection and GVHD was 17%; rejection and infection, 17%; and GVHD and infection, 45%. A combination of all three immunologic events was noted in 14%.

CONCLUSIONS

RPC, combined with DSBMI, and with or without posttransplant immunosuppression, does not prolong survival after total bowel transplantation. Rather, it increases the incidence of death from rejection, GVHD, infection, or a combination of these three immunologic events. According to this preclinical study, RPC and unmodified DSBMI do not improve patient and graft outcome after total bowel transplantation and need to be refined before being applied clinically.

Donor-specific unmodified bone marrow transfusion does not facilitate intestinal engraftment after bowel transplantation in a porcine model

BACKGROUND

The immunosuppression required to prevent rejection of intestinal transplants causes a high rate of infection and lymphoma. It is crucial that immunomodulatory strategies be developed to facilitate intestinal engraftment.

METHODS

We prospectively examined the effect of unpurified donor-specific bone marrow transfusions (DSBMTs) on rejection, infection, graft-versus-host disease (GVHD), and survival after intestinal transplantations in 44 Yorkshire Landrace pigs. Four groups that differed according to presence or abscence of treatment with FK506 and DSBMT were analyzed.

RESULTS

In nonimmunosuppressed pigs, DSBMTs had no effect on survival (8 days versus 9 days in controls; p = 0.9). In FK506 pigs, DSBMTs tended to reduce survival (21 days versus 37 days in FK506 controls; p = 0.1); no difference was seen between two bone marrow dosages 5 x 10(7) or 5 x 10(8) bone marrow cells/kg. No difference in the incidence of death caused by rejection was seen between DSBMTs and controls, but there was a marked tendency toward more deaths caused by rejection in DSBMTs + FK506 versus FK506-only pigs (p = 0.09). Daily stomal assessment showed a higher rate of moderate and severe interstitial rejection in DSBMT + FK506 versus FK506-only pigs; DSBMT was also associated with increased vascular rejection. Finally, groupwise comparison showed an order of susceptibility to lethal GVHD and infection as follows: DSBMT + FK506 > FK506 > DSBMT > controls.

CONCLUSIONS

Rather than promoting engraftment, DSBMT can sensitize recipients and cause rejection after intestinal transplantation. It aggravates the risks of generalized GVHD and infection and tends to reduce graft and recipient survival. Before being applied clinically, DSBMT needs to be refined to increase its tolerogenic potential without causing GVHD.

Combined liver and kidney transplantation

Patients with end-stage renal and hepatic failure may be treated with combined liver and kidney transplantation (CLKTx). We reviewed the indications and outcomes of 16 CLKTx performed at the University of Minnesota between 1980 and 1994. The majority of the recipients (87.5%) were young patients affected by congenital hepatic anomalies and concomitant end-stage renal failure. Fourteen were treated with cyclosporin-based immunosuppression and had an excellent outcome: with an average of 6 years of follow-up, patient survival was 85.7%, liver graft survival 85.7%, and kidney graft survival 72%. The incidence of rejection episodes was similar to the rate of rejection in our solitary kidney and liver transplants. In conclusion, our experience supports the value of CLKTx in treating patients with simultaneous failure of both organs or with congenital enzymatic hepatic deficits leading to renal failure.

Short-bowel syndrome. Medical aspects and prospects of intestinal transplantation

Major intestinal resection may result in diarrhea and malabsorption, a clinical entity known as the short-bowel syndrome. Nutritional prognosis after a wide intestinal resection depends on the extent of resection, the nature of the intestinal segment removed (ileum or jejunum), the function and the adaptative capacity of the remaining intestine, and the preservation of the colon and the ileocecal valve. Adequate management of this dreadful syndrome requires a multidisciplinary effort between various medical specialties: general and pediatric surgery, intensive care unit, nutrition, psychology, pediatric and adult gastroenterology. Intestinal transplantation is the only chance for a real cure in patients who depend on total parenteral nutrition. Although results of small bowel transplantation have dramatically improved over the last few years, it remains a challenging surgical and immunologic enterprise. Severe rejection and infection are the major obstacles.