Christopher McCullough

Improved outcome of orthotopic liver transplantation for chronic hepatitis B cirrhosis with aggressive passive immunization

Passive immunization with hepatitis B surface antibody (anti-HBs) is important to prevent hepatitis B virus (HBV) recurrence after orthotopic liver transplantation for chronic HBV cirrhosis. Hepatitis B immune globulin (HBIG) dosing regimens have been poorly defined, utilize numerous routes of administration, and result in a high rate of HBV relapse and mortality. Twenty-five of 27 (93%) patients transplanted (four retransplants) for chronic HBV cirrhosis show no evidence of recurrent HBV (range, 2-55 months). Anti-HBs titers necessary to minimize the risk of hepatitis B surface antigen detectability were >500 IU/L for days 0 to 7, >250 IU/L for days 8 to 90, and >100 IU/L thereafter. Pretransplant HBV E antigen (HBeAG)-positive patients required more HBIG to achieve these goals than HBeAG-negative individuals. The elimination of anti-HBs changed continually for the initial 3 posttransplant months. The anti-HBs half-life increased from 0.7 days to 14.1 days. Anti-HBs elimination was significantly different in HBeAG+ and HBeAG- patients for the first week, but was subsequently indistinguishable after week 1. After 3 months, the half-life was statistically less for HBeAG+ patients, but the difference did not influence the clinical treatment regimens. Quantitative hepatitis B DNA levels did not predict the amount of HBIG required. HBV recurrence after orthotopic liver transplantation can be reduced by aggressive passive immunization. Pharmacokinetic analysis of anti-Hbs elimination can improve immunoglobulin therapy and prevent recurrence of clinical hepatitis.

UNI- AND MULTI-VARIATE ANALYSIS OF RISK FACTORS FOR EARLY AND LATE HEPATIC ARTERY THROMBOSIS AFTER LIVER TRANSPLANTATION

Background. Hepatic artery thrombosis (HAT) is a significant cause of morbidity after liver transplantation. The aims of this study are to identify and compare risk factors that might contribute to HAT. Methods. A total of 424 liver transplants performed at the University of Virginia were reviewed. HAT was defined as complete disruption of arterial blood flow to the allograft and was identified in 29 cases (6.8%). HAT was classified as early (less than 1 month posttransplant, 9 cases: 2.1%) or late (more than 1 month posttransplant, 20 cases: 5.4%). Possible risk factors for HAT were analyzed using Pearson &khgr;2 test for univariate analysis and logistic regression for multivariate analysis. Results. Multiple transplants, recipient/donor weight ratio >1.25, biopsy-proven rejection within 1 week of transplant, recipient negative cytomegalovirus (CMV) status, arterial anastomosis to an old conduit (defined as a previously constructed aorto-hepatic artery remnant using donor iliac artery), and CMV negative patients receiving allograft from CMV positive donors were found to be significant risk factors for developing early HAT. After logistic regression, factors independently predicting early HAT included arterial anastomosis to an old conduit [odds ratio (OR)=7.33], recipient/donor weight ratio >1.25 (OR=5.65), biopsy-proven rejection within 1 week posttransplant (OR=2.81), and donor positive and recipient negative CMV status (OR=2.66). Female donor, the combination of female donor and male recipient, recipient hepatitis C-related liver disease, donor negative CMV status, and the combination of recipient CMV negative and donor CMV negative were found to be significant risk factors for late HAT. Factors independently predicting late HAT by logistic regression included negative recipient and donor CMV status (OR=2.26) and the combination of a female donor and male recipient (OR=1.97). Conclusion. Therefore, in nonemergency situations attention to these factors in donor allocation may minimize the possibility of HAT.

Clinical and histologic patterns of early graft failure due to recurrent hepatitis C in four patients after liver transplantation

Hepatitis C viral recurrence after orthotopic liver transplantation is almost universal. Hepatitis C-induced graft failure may occur, but the clinical and histologic profiles are not well defined. The aim of this study was to describe the pattern of early graft failure in patients with recurrent hepatitis C after liver transplantation. Thirty patients with hepatitis C underwent liver transplantation from October 1989 through September 1994. Four patients were excluded because of death (2 patients), graft failure unrelated to hepatitis C (1 patient), and lost to follow-up (1 patient). Hepatitis C recurred in 24 of the 26 remaining patients. In 4 patients with hepatitis C virus recurrence and cholestasis, graft failure developed at 5.25, 11.0, 11.0, and 18.5 months. The medical records and liver biopsies were reviewed. In all 4 patients, a histologic pattern characterized by centrilobular ballooning degeneration developed and progressed to involve more than two-thirds of the lobules. Moderate to severe cholestasis and bridging fibrosis were present in all grafts at explant. Two patients had portal inflammation on 3-month biopsies consistent with viral hepatitis. All patients had mild macrovesicular steatosis, but only 1 patient had significant lymphoid aggregates. No patient had evidence of hepatic artery thrombosis. One patient had potential drug-induced cholestasis. One patient had 3 episodes of rejection that were not believed to contribute to graft loss. All 4 patients developed clinical features of hepatic failure and were retransplanted. Two patients had early recurrence of graft failure. We conclude that a pattern of progressive centrilobular ballooning degeneration, bridging fibrosis, and cholestasis occurs in some patients with hepatitis C with early graft failure, similar to fibrosing cholestatic hepatitis seen in some transplant patients with recurrent hepatitis B.

Implication of advanced donor age on the outcome of liver transplantation.

Historically, age has been considered to be a relative contraindication for organ donors. The use of elderly donors for liver transplantation remains controversial due to the fear of inferior outcome. According to United Network for Organ Sharing (UNOS) data, the proportion of older donors has been increasing annually. This study describes the short‐ and long‐term outcomes for transplantation of elderly donor livers. Three hundred and seventy‐four primary liver transplantations, which had been performed at the University of Virginia Health System from 7 February 1988 to 31 December 1998, were included. Graft survival, incidence of primary non‐function, and hepatic artery thrombosis (HAT) after transplantation according to the different age groups of liver donors were analyzed. Cases were analyzed by donor age (group I, n=106: aged <20 yr; group II, n=217: aged between 20 and 49 yr; group III, n=51: aged ≥50 yr), and by donor age in comparison with recipient age (group IV, n=65: recipients transplanted with organs from donors within 5 yr of their age; group V, n=266: recipients from donors> 5 yr younger than their age; group VI, n=43: recipients from donors> 5 yr older than their age). Group III or VI (group of advanced donor age) and group II or V (control group) were compared by age, gender, race, body weight, height, pre‐transplantation cytomegalovirus (CMV) status of the recipients donors, cause of brain death of donors, total or warm ischemic time, ABO matching, and degree of human leucocyte antigen (HLA) mismatching. No significant difference in 5 yr graft survival was found between the groups by donor age (p=0.604) and by donor age compared with recipient age (p=0.567). Moreover, no significant differences in the incidence of primary non‐function and HAT after transplantation were found between the groups by donor age and by donor age compared with recipient age. Older donors were more likely to be women and to have antibodies to CMV, as well as to have died by cerebrovascular causes. Race, body weight, height of both recipients and donors, total or warm ischemic time of grafts, ABO matching, and degree of HLA mismatching were not significantly different between the groups. We conclude from this study that advanced donor age is not a contraindication to liver transplantation if careful assessment of donors is made on a case‐by‐case basis. There is a need to maintain an open mind with regard to the use of livers from older donors due to the current situation of serious organ shortages.

Retransplantation of patients with severe posttransplant hepatitis B in the first allograft

BACKGROUND The outcome of orthotopic liver transplantation (OLTX) in patients retransplanted for severe hepatitis B virus (HBV) in the first allograft has been poor due to high rates of HBV reinfection and even more aggressive disease in the second graft. Recent data suggest that hepatitis B immunoglobulin (HBIg) given after transplantation can be successful in delaying or preventing HBV reinfection in patients transplanted for chronic hepatitis B cirrhosis. We report the successful retransplantation of patients who developed recurrent or de novo hepatitis B after OLTXY. METHODS Using similar HBIg regimens, two centers retransplanted seven patients after they developed recurrent or de novo hepatitis B in the first allograft. At retransplantation all seven patients were HBs antigen (Ag) positive; four patients were positive for HBeAg and HBV DNA by immunoblot assay, two patients were negative for HBeAg and HBV DNA, and one patient was positive for HBV DNA and negative for HBeAg. All patients were either HDV Ag or anti-HDV negative. One patient was anti-HCV positive. All patients received HBIg infusions after retransplantation to maintain serum anti-HBs levels >500 IU/L indefinitely. RESULTS After retransplantation, six of seven patients are alive (86%): all are without evidence of HBV recurrence with serum negative for HBsAg, HBeAg, and HBV DNA by immunoblot assay. Liver biopsies are normal on routine studies with immunohistochemical stains for HBcAg and HBsAg also being negative. Mean follow-up of these six patients is 40.1 months (range 21-63 months). One patient (14%) developed HBV reinfection 7 months after his second transplant, in spite of maintaining target anti-HBs levels. He maintained stable liver function with minimal evidence of clinical hepatitis B, but died 8 months later from an unrelated stroke. CONCLUSIONS We conclude that patients with recurrent or de novo hepatitis B after OLTX can be successfully retransplanted using aggressive immunoprophylaxis to prevent HBV reinfection. The failure of HBIg therapy in one patient underscores the need for other effective adjunctive anti-HBV modalities.

Gadolinium-based Contrast and Carbon Dioxide Angiography to Evaluate Renal Transplants for Vascular Causes of Renal Insufficiency and Accelerated Hypertension

PURPOSE To evaluate the utility and potential nephrotoxicity of gadolinium-based contrast angiography when used with carbon dioxide angiography in renal transplant patients with suspected vascular causes of renal insufficiency and/or accelerated hypertension. MATERIALS AND METHODS Thirteen consecutive renal transplant patients with suspected vascular causes of renal insufficiency and/or accelerated hypertension were evaluated with gadolinium-based contrast and CO2 angiography with use of digital subtraction techniques. Stenotic lesions were treated with angioplasty with/or without stent placement. No iodinated contrast agents were used. Serum creatinine levels were obtained before and at 24 and 48 hours after the procedure. An increase in creatinine levels greater than 0.5 mg/dL (44 micromol/L) was considered significant. RESULTS Nine patients were studied for renal insufficiency, two for accelerated hypertension, and two for both. All 13 studies were considered diagnostic. Significant stenoses were treated in four patients with angioplasty with or without stent placement. Two patients had progression of their renal insufficiency. One of these patients underwent biopsy and was found to have both acute and chronic rejection. The other patient underwent cardiac catheterization 2 days after a transplant renal artery angioplasty. In the remaining nine patients with renal insufficiency (creatinine range, 1.8-3.9 mg/dL [159-345 micromol/L]; mean, 2.7 mg/dL [239 micromol/L]), renal function improved or did not worsen. CONCLUSION Based on this limited study, gadolinium-based contrast angiography appears to be a promising supplement to CO2 angiography for the diagnosis and treatment of vascular lesions in patients with renal transplant insufficiency and/or accelerated hypertension. Further study is necessary to determine safety, optimal gadolinium dosage, and imaging parameters.

The use of pronase-digested human leukocytes to improve specificity of the flow cytometric crossmatch

Two-color fluorescence cytometry (FCXM) has recently been introduced to improve the detection of anti-HLA antibodies that react to donor cells, especially in recipients receiving kidney allografts. Although this assay system is highly sensitive, it lacks specificity. Between 70% and 90% of potential kidney recipients with a positive FCXM would have been denied transplant if such an assay had been used alone to detect antidonor antibodies. Lack of specificity is principally due to normal or irrelevant IgG in aggregates or immune complexes binding to Fcλ R receptors on lymphocytes including B cells and a significant subset of T cells. To circumvent this problem, we digested Fcλ R receptors on lymphocytes with pronase. We present data demonstrating that pronase digestion of lymphocytes does not alter HLA antigenicity. In addition, pronased lymphocytes allow one to use either single- or two-color FCXM. With single-color FCXM, one can quantitate antibody reactivity to lymphocytes via a cursor (on the fluorescence histogram) that separates lymphocytes that do not bind to antibodies. We present data demonstrating that this modification renders FCXM highly sensitive and specific. In addition, one can discriminate between IgG and IgM antibodies that react to lymphocytes.

Percutaneous embolization of a high-flow pancreatic transplant arteriovenous fistula

Percutaneous endovascular techniques were used to treat an arteriovenous fistula (AVF) associated with pancreatic transplantation. A pancreatic transplant superior mesenteric artery-to-superior mesenteric-vein AVF was successfully embolized while flow to the pancreas transplant was preserved. The embolization was aided by the use of Guglielmi detachable coils and a detachable balloon. No complications were encountered. At 23 months follow-up, the patient is doing well with no recurrence.

Improved specificity and sensitivity when using pronase-digested lymphocytes to perform flow-cytometric crossmatch prior to renal transplantation

Abstract Several laboratories have resorted to flow‐cytometric crossmatch (FCXM) in an effort to prevent hyperacute and accelerated renal allograft rejections. The currently employed FCXM has problems with both false‐positive and ‐negative reactions, largely as a result of irrelevant IgG binding to Fc IgG receptors. In 1980, we circumvented this problem by digesting Fc IgG receptors with pronase, and demonstrated that, with immunofluorescnce microscopy (IF), detection of IgG anti‐HLA antibodies was highly sensitive and specific. In 1995, we introduced the pronase technique to FCXM and showed that this enzyme did not decrease HLA expression. We present herein a prospective study at our institution to determine whether FCXM using pronase‐digested (PD) lymphocytes is as sensitive and more specific than FCXM with undigested (UD) lymphocytes when compared with the highly sensitive and specific IF assay. In analyzing the 186 donor‐specific prerenal‐transplant crossmatches, we found that PD FCXM was as sensitive and specific as IF and was able to detect weak IgG anti‐HLA antibodies that bound to B cells. Fourteen of these patients would have been denied transplants if one were to have relied on UD FCXM. The data clearly indicate that PD FCXM can reliably be used to detect weak IgG anti‐HLA antibodies before renal transplantation.

Hyperacute renal allograft rejection from anti‐HLA class 1 antibody to B cells ‐antibody detection by two color FCXM was possible only after using pronase‐digested donor lymphocytes

Abstract We present a report of a transplant recipient who lost her renal allograft from hyperacute rejection. This was secondary to a weak IgG anti‐HLA class I antibody that was only reactive to donor B lymphocytes. This antibody was not detected in her pretransplant serum by the conventional complement‐dependent cytotoxicity assays using donor blood lymphocytes. Pretransplant sera were analyzed retrospectively by two‐color flow cytometric crossmatching (FCXM). It was difficult to determine if the recipients serum contained an IgG antibody specific for HLA on donor B cells since IgG from control AB sera and pretransplant sera bound equally well to CD19 B cells. However, when donor lymphocytes were pretreated with pronase to digest the membrane receptor for Fc domain of IgG (FcyR) on non‐T‐cells, control IgG in AB serum did not bind to B cells and, hence, it was easy to detect binding of IgG (in pretransplant sera) to HLA on B cells. This case underscores the importance of identifying weak anti‐HLA class I antibodies reactive only to B cells. Moreover, it shows that the currently used two‐color FCXM lacks the specificity to detect such antibodies.