Clinicopathologic features of post-transplant lymphoproliferative disorders arising after pediatric small bowel transplant

Few studies examined the clinicopathologic features of PTLD arising in pediatric SBT patients. Particularly, the association between ATG and PTLD in this population has not been described. Retrospective review of 81 pediatric patient charts with SBT--isolated or in combination with other organs--showed a PTLD incidence of 11%, occurring more frequently in females (median age of four yr) and with clinically advanced disease. Monomorphic PTLD was the most common histological subtype. There was a significant difference in the use of ATG between patients who developed PTLD and those who did not (p < 0.01); a similar difference was seen with the use of sirolimus (p < 0.001). These results suggested a link between the combination of ATG and sirolimus and development of more clinically and histologically advanced PTLD; however, the risk of ATG by itself was not clear. EBV viral loads were higher in patients with PTLD, and median time between detection of EBV to PTLD diagnosis was three months. However, viral loads at the time of PTLD diagnosis were most often lower than at EBV detection, thereby raising questions on the correlation between decreasing viral genomes and risk of PTLD.

Successful isolated intestinal transplantation in sensitized recipients with the use of virtual crossmatching

We evaluated virtual crossmatching (VXM) for organ allocation and immunologic risk reduction in sensitized isolated intestinal transplantation recipients. All isolated intestine transplants performed at our institution from 2008 to 2011 were included in this study. Allograft allocation in sensitized recipients was based on the results of a VXM, in which the donor-specific antibody (DSA) was prospectively evaluated with the use of single-antigen assays. A total of 42 isolated intestine transplants (13 pediatric and 29 adult) were performed during this time period, with a median follow-up of 20 months (6-40 months). A sensitized (PRA ≥ 20%) group (n = 15) was compared to a control (PRA < 20%) group (n = 27) to evaluate the efficacy of VXM. With the use of VXM, 80% (12/15) of the sensitized patients were transplanted with a negative or weakly positive flow-cytometry crossmatch and 86.7% (13/15) with zero or only low-titer (≤ 1:16) DSA. Outcomes were comparable between sensitized and control recipients, including 1-year freedom from rejection (53.3% and 66.7% respectively, p = 0.367), 1-year patient survival (73.3% and 88.9% respectively, p = 0.197) and 1-year graft survival (66.7% and 85.2% respectively, p = 0.167). In conclusion, a VXM strategy to optimize organ allocation enables sensitized patients to successfully undergo isolated intestinal transplantation with acceptable short-term outcomes.

Split liver transplantation

We analyzed the results of 55 patients who underwent split liver transplantation at our center between September 1996 and December 2008, 30 adults (54.5%) and 25 children (45.5%). Median follow-up was 12 years. Overall patient survival was 71%, adult 70% and pediatric 72%. Mean patient survival was 61.58 months, and mean graft survival was 44.35 months. Pediatric survival and pediatric graft survival after 1 and 5 years were 84% and 72% and 72% and 52.4%, respectively. Adult survival and adult graft survival after 1 and 5 years were 75% and 66.2% and 60.7% and 51.5%, respectively. Twelve patients required retransplantation, 6 for primary nonfunction, 3 for chronic rejection, and 3 for vascular complications. Blood groups of the recipient patients were: 34 O, 14 A, 7 B, and 0 AB. The use of split liver for adult and pediatric populations allows us to expand the cadaveric donor pool and has the potential to significantly reduce waiting list mortality, especially for certain blood groups.

Citrulline evaluation in bowel transplantation

INTRODUCTION

The purpose of this study was to evaluate the correlation of plasma citrulline and rejection episodes in intestinal transplantation.

METHODS

From January 2007 until present, we performed citrulline assays on our small bowel patients. We investigated the correlation of these assays with the rejection status of the patients. The rejection status of the graft was defined based on graft biopsies.

RESULTS

Of 5195 citrulline samples, average serum citrulline levels decreased significantly when the patients presented a rejection episode. We found the following: no rejection, 17.38 microm/L; mild rejection, 13.05 microm/L; moderate rejection, 7.98 microm/L; and severe rejection, 6.05 microm/L. Our current emphasis is to determine the predictive power of citrulline with other biomarkers versus as a separate and isolated measurement.

CONCLUSIONS

In our study, citrulline levels correlated significantly with the rejection status of the graft. Serial follow-up of the patients using this assay may alert us to the possibility of increased alloreactivity and rejection episodes.

Sorafenib in hepatocellular carcinoma (HCC) patients after liver transplantation

e15579

Background: Sorafenib has been approved for the treatment of advanced HCC. However, there is no data on its use for HCC patients (pts) after liver transplantation (OLT). Pts at high risk for tumor recurrence (native liver showing vascular invasion, multiple tumors >3 in number, size >6 cm, or lymph node involved) after OLT or who develop recurrence after OLT have worse prognosis. These pts may potentially benefit from sorafenib. Methods: We reviewed our experience with HCC pts after OLT treated with sorafenib. 15 pts had a starting dose of 400 mg po bid and 3 had a starting dose of 200 po bid. Sorafenib was started 3 months (mo) after OLT as adjuvant therapy (7 pts) or at the time of tumor recurrence after OLT (11 pts). CT or MRI scans of the chest/abdomen and physical exams were performed every 2–3 mo. Lab tests including serum AFP were performed monthly. Results: Median age was 60 (range 53–75). Median performance status was 90%(range 80–100). In terms of toxicity, 4 of the 15(27%) pts on the initial dose of 400 mg bid stopped sorafenib due to unacceptable toxicity and 5 (33%) had dose reduction due to toxicity. Grade 3/4 toxicity included skin rash, fatigue and anorexia, hyperbilirubinemia, chest/abdominal pain. Only 40% could continue at the full recommended starting dose of sorafenib.For the 11 pts with recurrent disease after OLT treated with sorafenib, the sites of evaluable disease include liver (5 pts), lung (3), others (3). One pt (9%) had a partial response in lung metastases for 10 mo. and the median time to tumor progression (TTP) was 4 mo. (range 2–10 mo). For pts on adjuvant sorafenib after OLT, no pt has relapsed so far with a median followup of 6+ mo. (range 2+ to 15+ mo). Conclusions: The response rate and TTP for pts treated with sorafenib for recurrent HCC after OLT is similar to HCC pts without OLT (Llovet, NEJM 2008). Since the majority of HCC pts after OLT treated with sorafenib required either dose reduction or stoppage due to toxicity which is higher than previously reported, a lower starting dose with dose escalation may be preferred. Contributing factors for toxicity may include the anti-rejection drugs (tacrolimus, mycophenolate, steroids) used for OLT which might affect pharmacokinetics(PK) of sorafenib. Further PK studies with sorafenib in HCC pts after OLT for future clinical trials are indicated.

No significant financial relationships to disclose.

Liver transplantation at the Miami Transplant Institute: a 14-year single-center experience

The clinical outcome of LT has improved significantly with refinements in surgical skill and immunosuppressive agents. Over the past decade, nationally most LT centers have improved their standard care in LT. As a result, short-term survival after LT has increased remarkably. However, recurrence of original liver disease, chronic rejection, and the adverse effect of immunosuppressive agents still impose significant limitations on long-term survival. Here at the MTI, it is our mission to continue technical innovation, improve the management of hepatitis C patients, search for better immunosuppressive protocols, and work towards achieving tolerance after LT to improve the long-term outcome.

Complications of liver donation for living related liver transplantation

Living related liver transplantation (LRLT) has gained popularity, especially in Asian countries as the primary mode of liver transplantation. LRLT, however, carries the inherent problem of potential donor harm. In view of reports of donor deaths and significant donor morbidity (as high as 67%), we examined donor complication rates in our LRLT program. All sixteen LRLT donors between February 2000 and January 2003 were retrospectively analyzed. The 16 donors (13 men, 3 women) of mean age 30 years (range, 18-49 years) included 5 donations from siblings, 2 from parents, and 9 from offsprings. The portion of liver donated was L hepatectomy (n = 4) R hepatectomy (n = 7), and Modified Extended R hepatectomy (n = 5) with the weight of resected liver being 618.9 g (range, 380-1000). The mean blood loss was 936 mL (range, 400-1900 mL), but only 2 donors required transfusion of banked blood. The mean intensive care unitstay was 1.06 days (range, 1-2 days) and the mean hospital stay was 9.12 days (range, 7-14 days). There was no case of reoperation and no mortality. There was no biliary or vascular complication. Four of 16 (25%) donors had a minor morbidity; 2 of 16 (12.5%) had a morbidity requiring intervention. In conclusion, with meticulous preoperative, intraoperative, and postoperative management, successful LRLT can be performed with minimal donor morbidities.

Developmental differences in the expression and modulation of extracellular matrix proteases and inhibitors in mouse skin fibroblasts

To investigate developmental differences in the wound repair process between fetal and adult skin fibroblasts, we studied the expression of plasminogen activator, plasminogen activator inhibitor, matrix metalloproteinase, and tissue inhibitor of metalloproteinase in E-15, E-17, newborn and adult mouse skin fibroblasts cultured within three dimensional matrices of either collagen or fibrin. Fibrin overlay and reverse overlay analyses revealed that mouse skin fibroblasts secreted tissue plasminogen activator and type1 plasminogen activator inhibitor. However, only E-15 and E-17 fibroblasts secreted the active form of tissue plasminogen activator, while in newborn and adult fibroblasts tissue plasminogen activator was conjugated to type1 plasminogen activator inhibitor. Only adult fibroblasts expressed a high level of active type1 plasminogen activator inhibitor. Gelatin zymography revealed that the predominant matrix metalloproteinase secreted by all the mouse fibroblasts was gelatinase A (matrix metalloproteinase -2). Matrix metalloproteinase -2 was partially activated in the adult fibroblasts cultured within a collagen matrix. The tissue inhibitor of metalloproteinase-2 was expressed by all fibroblasts, but levels were highest in the newborn and adult fibroblasts. When E-15 fibroblasts were cultured within a fibrin matrix, tissue plasminogen activator was downregulated. Transforming growth factor-betadownregulated tissue plasminogen activator while upregulating type1 plasminogen activator inhibitor, and platelet-derived growth factor enhanced tissue plasminogen activator expression in E-15 fibroblasts. Therefore, plasminogen activator and its inhibitor, and matrix metalloproteinase and its associated tissue inhibitor are differentially expressed in fetal and adult fibroblasts, and their expression is controlled by extracellular matrix components and growth factors present in wounds.