Seeking beyond rejection: an update on the differential diagnosis and a practical approach to liver allograft biopsy interpretation

MicroRNAs 155-5p, 122-5p, and 181a-5p Identify Patients With Graft Dysfunction Due to T Cell-Mediated Rejection After Liver Transplantation

MicroRNAs (miRNAs) are small noncoding RNAs that can be detected in plasma and whose expression is associated with pathological processes. The role of miRNAs in the noninvasive diagnosis of T cell-mediated rejection (TCMR) after liver transplantation (LT) is unclear. Thus, we aimed to assess the effectiveness of a panel of 4 miRNAs (155-5p, 122-5p, 181a-5p, and 148-3p) in diagnosing TCMR in LT recipients with graft dysfunction (GD), and we compared its accuracy with previously published tests for diagnosing TCMR based on routine laboratory parameters. From a prospective cohort of 145 patients followed during the first year after transplant, 49 developed GD and underwent a liver biopsy and plasma collection for miRNA analysis using quantitative real-time polymerase chain reaction. Patients with GD due to TCMR (n = 21) exhibited significantly higher (P < 0.001) expression of miRNA 155-5p (2.05 versus 0.07), 122-5p (19.36 versus 1.66), and 181a-5p (1.33 versus 0.37) compared with those with GD from other causes (n = 28). The area under the receiver operating characteristic curve of miRNAs 155-5p, 122-5p, and 181a-5p for the diagnosis of TCMR was 0.87, 0.91, and 0.89, respectively, significantly higher than those of the other noninvasive tests (P < 0.001). Furthermore, miRNA 155-5p identified all patients who presented TCMR during the first 2 weeks after transplant. miRNA plasmatic expression differentiates TCMR from other causes of GD in patients who have undergone LT and may be a useful tool in clinical practice.

Primary graft dysfunction after liver transplantation

BACKGROUND

Primary graft dysfunction (PGD) causes complications in liver transplantation, which result in poor prognosis. Recipients who develop PGD usually experience a longer intensive care unit and hospital stay and have higher mortality and graft loss rates compared with those without graft dysfunction. However, because of the lack of universally accepted definition, early diagnosis of graft dysfunction is difficult. Additionally, numerous factors affect the allograft function after transplantation, making the prediction of PGD more difficult. The present review was to analyze the literature available on PGD and to propose a definition.

DATA SOURCE

A search of PubMed (up to the end of 2012) for English-language articles relevant to PGD was performed to clarify the characteristics, risk factors, and possible treatments or interventions for PGD.

RESULTS

There is no pathological diagnostic standard; many documented definitions of PGD are different. Many factors, such as donor status, procurement and transplant process and recipient illness may affect the function of graft, and ischemia-reperfusion injury is considered the direct cause. Potential managements which are helpful to improve graft function were investigated. Some of them are promising.

CONCLUSIONS

Our analyses suggested that the definition of PGD should include one or more of the following variables: (1) bilirubin ≥ 10 mg/dL on postoperative day 7; (2) international normalized ratio ≥ 1.6 on postoperative day 7; and (3) alanine aminotransferase or aspartate aminotransferase >2000 IU/L within 7 postoperative days. Reducing risk factors may decrease the incidence of PGD. A majority of the recipients could recover from PGD; however, when the graft progresses into primary non-function, the patients need to be treated with re-transplantation.

Histopathology of post-transplant liver biopsies, the first report from iran

BACKGROUND

Evaluation of a transplanted liver by Imaging techniques and enzyme changes is sensitive to hepatocellular or biliary problems, but in most instances liver allograft biopsies are performed in order to find out the final reason for these changes.

OBJECTIVES

It's been about 17 years (with more than 1326 cases) since the first liver transplantation in the Namazi Hospital of Shiraz University of Medical Sciences while during the last five years the number of post liver transplant biopsies have increased. Until now there has been no report of the pathological results of post liver transplant needle biopsies from Iran.

MATERIALS AND METHODS

During the last 5 years, there have been 382 post liver transplant biopsies. We studied the clinical charts and pathological results of all needle biopsies.

RESULTS

A total of 382 needle biopsies were performed on 287 patients aged between 1 and 64 years old. The earliest specimen was obtained within the first few hours following transplantation, and the last was gathered 3209 days (261 ± 523) post-transplantation. Acute rejection was the most common diagnosis, which occurred in 180 (47%) of specimens. Among other complications were vascular problems (8.6%), preservation/reperfusion (I/R) injury (7%), chronic rejection (5.2%), biliary injury/obstruction (3.4%), recurrence of primary disease (2.6%), drug-induced hepatic injury (1.8%), cirrhosis (1.6%), sepsis (1.4%), cytomegalovirus hepatitis (1.4%), post-transplantation lymphoproliferative disease (1%) and Venous outflow obstruction (0.5%).

CONCLUSIONS

The most common pathological diagnosis of post-transplant liver needle biopsies has been acute rejection, followed by ischemia due to hepatic artery thrombosis, preservation/reperfusion injury, and chronic rejection.

Doppler sonography of patients with and without acute cellular rejection after right-lobe living donor liver transplantation

OBJECTIVES

To compare percent interval changes in the portal blood flow velocity (%PBV) and venous pulsatility index (%VPI), as determined by Doppler sonography, in patients with and without acute cellular rejection after right-lobe living donor liver transplantation.

METHODS

Forty-seven patients with biopsy-proven acute cellular rejection underwent Doppler sonography. The control group consisted of 47 age- and sex-matched patients without acute cellular rejection. Doppler spectrograms of the portal vein and right hepatic vein were used to calculate mean peak PBVs and VPIs for the first 3 days after right-lobe living donor liver transplantation, defined as PBV(Baseline) and VPI(Baseline). The PBV and VPI closest in time to biopsy in the patient group or at a matched time in the control group were determined as PBV(Event) and VPI(Event), and %PBV and %VPI values were calculated.

RESULTS

The mean PBV(Baseline) values ± SD in the rejection and control groups were 46.0 ± 21.8 and 44.4 ± 20.5 cm/s, respectively; the PBV(Event) values were 32.2 ± 14.5 and 34.4 ± 17.1 cm/s; and the %PBV values were 19.4% ± 39.9% and 2.2% ± 75.4% (P = .73; P = .38; P = .17, respectively). The VPI(Baseline) values were 0.92 ± 0.34 and 0.93 P = .94; P < .001); and the ± 0.38; the VPI(Event) values were 0.46 ± 0.33 and 0.84 ± 0.44 (%VPI values were 45.5% ± 40.1% and 5.6% ± 47.3%, with a greater than 50% VPI observed more frequently in the rejection than in the control group (61.7% versus 12.8%; P < .001).

CONCLUSIONS

The VPI(Event) was significantly lower and a greater than 50% VPI was significantly more frequent in patients with than without acute cellular rejection after right-lobe living donor liver transplantation.

Recurrent hepatitis C and acute allograft rejection: clinicopathologic features with emphasis on the differential diagnosis between these entities

Chronic hepatitis C virus infection is the leading etiology for liver transplantation in the United States. Recurrent hepatitis C occurs nearly universally in these patients and represents a serious posttransplantation complication. Despite the detailed characterization of the histologic features of both recurrent hepatitis C and acute cellular rejection (ACR) over the last decades, the pathologic distinction between these 2 conditions remains one of the greatest diagnostic challenges in liver pathology. An accurate diagnosis, nevertheless, plays an essential role in patient management, as different therapeutic strategies are used for these conditions. In this review, the clinicopathologic features of posttransplantation recurrent hepatitis C and ACR are discussed, with emphasis on distinguishing histopathologic features, morphologic variants, ancillary techniques, and diagnostic pitfalls.