Liver Histology Predicts Liver Regeneration and Outcome in ALPPS: Novel Findings From A Multicenter Study.

BACKGROUND AND AIMS: Alterations in liver histology influence the liver's capacity to regenerate, but the relevance of each of the different changes in rapid liver growth induction is unknown. This study aimed to analyze the influence of the degree of histological alterations during the first and second stages on the ability of the liver to regenerate. METHODS: This cohort study included data obtained from the International ALPPS Registry between November 2011 and October 2020. Only patients with colorectal liver metastases were included in the study. We developed a histological risk score based on histological changes (stages 1 and 2) and a tumor pathology score based on the histological factors associated with poor tumor prognosis. RESULTS: In total, 395 patients were included. The time to reach stage 2 was shorter in patients with a low histological risk stage 1 (13 vs 17 days, P ˂0.01), low histological risk stage 2 (13 vs 15 days, P <0.01), and low pathological tumor risk (13 vs 15 days, P <0.01). Regarding interval stage, there was a higher inverse correlation in high histological risk stage 1 group compared to low histological risk 1 group in relation with future liver remnant body weight ( r =-0.1 and r =-0.08, respectively), and future liver remnant ( r =-0.15 and r =-0.06, respectively). CONCLUSIONS: ALPPS is associated with increased histological alterations in the liver parenchyma. It seems that the more histological alterations present and the higher the number of poor prognostic factors in the tumor histology, the longer the time to reach the second stage.

Impact of rapid hypertrophy of tourniquet associating liver partition and portal vein ligation in the tumor progression pathways compared to two stage hepatectomy in patients with colorectal liver metastases.

BACKGROUND: It is not known if the inflammatory phenomena related to highly accelerated regeneration activate any signaling pathways that are associated with a major stimulus to colorectal liver metastases (CRLM) disease in tourniquet associating liver partition and portal vein ligation for staged hepatectomy (T-ALPPS) compared to two stage hepatectomy (TSH). METHODS: Between January 2012 and April 2018, we prospectively performed biopsies from future liver remnant and deportalized lobe in CRLM patients undergoing T-ALPPS in both stages. Immunohistopathological analysis was performed on the above tissue samples and compared to biopsy samples from patients who underwent TSH for CRLM at our center between September 2000 and August 2011. RESULTS: A total of 42 patients (20 TSH and 22 T-ALPPS) were included. There were no differences in the rates of recurrence, overall survival or any of the factors analyzed relating to tumor progression between stages 1 and 2. Regarding the anti-tumor effect, there was a significant reduction in the number of T-CD8 infiltrates in the second stage of TSH (12.5 vs. 5.5, p = 0.02). CONCLUSION: The results suggest that liver regeneration with T-ALPPS does not induce higher tumor progression or significant immunological changes in the tumor environment when compared to classical TSH.

Efficiency of Machine Learning Algorithms for the Determination of Macrovesicular Steatosis in Frozen Sections Stained with Sudan to Evaluate the Quality of the Graft in Liver Transplantation.

Liver transplantation is the only curative treatment option in patients diagnosed with end-stage liver disease. The low availability of organs demands an accurate selection procedure based on histological analysis, in order to evaluate the allograft. This assessment, traditionally carried out by a pathologist, is not exempt from subjectivity. In this sense, new tools based on machine learning and artificial vision are continuously being developed for the analysis of medical images of different typologies. Accordingly, in this work, we develop a computer vision-based application for the fast and automatic objective quantification of macrovesicular steatosis in histopathological liver section slides stained with Sudan stain. For this purpose, digital microscopy images were used to obtain thousands of feature vectors based on the RGB and CIE L*a*b* pixel values. These vectors, under a supervised process, were labelled as fat vacuole or non-fat vacuole, and a set of classifiers based on different algorithms were trained, accordingly. The results obtained showed an overall high accuracy for all classifiers (>0.99) with a sensitivity between 0.844 and 1, together with a specificity >0.99. In relation to their speed when classifying images, KNN and Naïve Bayes were substantially faster than other classification algorithms. Sudan stain is a convenient technique for evaluating ME in pre-transplant liver biopsies, providing reliable contrast and facilitating fast and accurate quantification through the machine learning algorithms tested.

Fungal cholangitis of the hepatobiliary tract: a case report.

We report the case of a 52-year-old male diagnosed with primary sclerosing colangitis, mainly of the extrahepatic bile duct, with a long evolution. After liver transplantation, the explanted liver showed necrosis of the bile duct wall, with fungal structures inside the bile duct that was compatible with Candida. The patient was treated with mesalazine and ursodeoxycholic acid and does not have a stent in the bile duct.

Utility of 18 fludeoxyglucose in preoperative positon-emission tomography-computed tomography (PET-CT) in the early diagnosis of exocrine pancreatic cancer: A study of 139 resected cases. / Utilidad de la 18-fluorodeoxiglucosa en la tomografía por emisión de positrones-tomografía computarizada (PET-TC) preoperatoria en el diagnóstico precoz del cáncer de páncreas exocrino: estudio en 139 casos resecados.

INTRODUCTION: In pancreatic ductal adenocarcinoma (PDA), surgical resection is the only curative treatment, but due to its late clinical presentation only 15-25% patients are candidates for curative resection. The aim of this prospective, single-center study is to determine the diagnostic utility of preoperative PET-CT for early detection of PDA and early panIN lesions. METHODS: We studied the histopathological features of PDA and different panIN lesions in 139 surgical samples from patients undergoing pancreatic resection (from 2010-2014), comparing these results with preoperative PET-CT and MDCT study. For tumor diagnosis in PET-CT maximum standard SUV 2.5 was used. Pancreatic baseline SUVmax is the maximum uptake of the radiotracer 18-2FDG on the ROI curve determined for the area of the normal pancreas after pathological reassessment with areas not affected by tumours or preneoplastic lesions. Tumour Uptake Index is the ratio between the tumour SUVmax and pancreatic baseline SUVmax. RESULTS: Using an standard maximum SUV value of 2.5, PET-CT sensitivity was 77.7% (108 of the 139 cases) against 75.5% (105 of the 139 cases) of MDCT. But when we combined this value with maximum SUV of normal pancreatic tissue from each patient, PET-CT sensitivity improved its value to 94.9%. CONCLUSION: A combination of studies of PET-CT in tumor and non-tumor tissue of each patient might be a very useful diagnostic tool not only for preoperative diagnosis of PDA, but also for early panIN lesions.

Prognostic factors in resected pancreatic neuroendocrine tumours: Experience in 95 patients. / Factores pronósticos de los tumores neuroendocrinos de páncreas resecados. Experiencia en 95 pacientes.

INTRODUCTION: The aim of this study was to analyze prognostic factors for survival and recurrence in patients with resected pancreatic neuroendocrine tumors (PNT). METHODS: Medical records of 95 patients with resected PNT were retrospectively reviewed. The variables studied were: age, sex, form of presentation (sporadic/familial tumors), functionality, type of tumor, localization, type of surgery, tumor size, multifocal tumors and recurrent rate. The new WHO classification (2010) was used. RESULTS: There were 45 men and 50 women. Mean age was 46.8 years. Regarding the mode of presentation, it was sporadic in 66 patients (69.8%) and 29 cases were familial neuroendocrine tumors (30.2%) in association with MEN 1 syndrome. The 59% of patients suffered from non-functional tumors and 41% were functional: 20 insulinoma, 16 gastrinoma, and 3 glucagonoma. Distal pancreatectomy was the most common surgical procedure, followed by tumor enucleation in 19 patients. According to the WHO classification, 59 patients had a PNT G1, 24 PNT G2 and 12 with a poorly-differentiated carcinoma, respectively. The 5-year survival in well-differentiated tumors was 100%, regardless of the functionality. Sporadic PNT are more commonly unifocal (P<0.001), associating liver metastasis. Survival and recurrence rates after a mean follow-up of 85.3 months were 65.8 and 24%, respectively. CONCLUSIONS: In our experience, WHO classification was an independent prognostic factor in PNT survival.

Groove pancreatitis vs. pancreatic adenocarcinoma: A review of 8 cases. / Pancreatitis del surco versus adenocarcinoma de páncreas: a propósito de 8 casos.

INTRODUCTION: Groove pancreatitis (PS) is an uncommon clinical situation and radiologically it can mimic carcinoma of the periampullary area. The aim of this paper is to study a series of 8 patients who underwent surgery with preoperative diagnosis of pancreatic head mass and subsequent pathological diagnosis of PS. METHODS: In our series, 6 were men and 2 women, with an average age of 51,9 years. Before surgery, all patients had epigastric abdominal pain requiring analgesia at high doses. The preoperative analytical CEA and Ca 19.9 were normal in all patients. Imaging studies showed intrapancreatic solid lesions in 6 of the 8 patients, and in the remaining 2 one papillary mass of 5 and 6cm, respectively, that caused stenosis in the duodenal luz. EUS neoplastic cells were negative in all patients. RESULTS: The immediate postoperative evolution was satisfactory, there are no complications. In our series, no patients have died. The long-term follow-up, in 7 of the 8 patients, has been excellent with disappearance of abdominal pain and improvement of nutritional status. The remaining patient had frequent recurrent episodes of acute pancreatitis, and at 60 months, presented a pseudocyst that has required a Roux-en-Y cystojejunostomy. CONCLUSIONS: PS must be included in the differential diagnosis of pancreatic lesions, which may include carcinoma of the periampullary area and other causes of chronic pancreatitis.

Acute cellular rejection versus recurrent hepatitis C after liver transplantation: Clinical and pathological features driving a rational diagnostic approach.

AIM: The aim of our study was develop and validate an algorithm system based on morphological features for finding the differences between recurrent hepatitis C virus (HCV) and acute cellular rejection (ACR) in liver biopsies of HCV-transplanted patients. METHODS: Two hundred and eighty-eight liver biopsies were analyzed from 121 patients transplanted for HCV. A diagnostic consensus was reached between clinicians and pathologists in 214 biopsies for the diagnosis of recurrent HCV or ACR. A random sample of 114 liver biopsies (derivation cohort) was taken to generate the diagnostic tree and was subsequently evaluated using the validation cohort in 100 liver biopsies by recursive partitioning analysis of morphological variables and time since transplantation. RESULTS: The presence of endotheliitis together with a time of less than 6 weeks since LT definitely excluded recurrent HCV. After obtaining the regression tree, diagnostic accuracy was 96% and 93% in the derivation and validation cohort, respectively. Both cases surpassed the pathologist's original diagnosis, which had a diagnostic accuracy of 91% (P < 0.05, for both comparisons). CONCLUSION: A recursive partitioning analysis of the morphological features in liver biopsies from HCV-transplanted patients may be useful for easily distinguishing between recurrent HCV and ACR.

[A new surgical technique for extended right hepatectomy: tourniquet in the umbilical fissure and right portal vein occlusion (ALTPS). Clinical case]. / Una nueva técnica quirúrgica para la hepatectomía derecha extendida: torniquete en la cisura umbilical y oclusión portal derecha (ALTPS). Caso clínico.

ALPPS (associating liver partition and portal vein ligation for staged hepatectomy), in 2-stage liver resections, achieves hypertrophy of the functional liver remnant (FLR) in 7 days, and the objective of this technique is the occlusion of the intrahepatic collaterals. In March 2012 we published a new surgical technique associating the insertion of a tourniquet in Cantlie' line and right portal vein ligation (ALTPS: Associating liver tourniquet and right portal vein occlusion for staged hepatectomy). In this paper we present this ALTPS technique placing the tourniquet in the umbilical fissure to obtain hypertrophy of segments II-III. It was performed in a 51 year-old patient with a recurrent right renal hypernephroma which involved all the anatomic right lobe and inferior vena cava. Preoperative FLR was 380 ml (20% of the total volume) increasing 150% at 7 days (to 953 ml, 31% of the total). In the second step, we performed a right trisectionectomy and retrohepatic inferior vena cava resection, replacing it by a 2 cm-ring goretex graft.

Clinical Significance of the Pre-Transplant CXCR3 and CCR6 Expression on T Cells In Kidney Graft Recipients.

BACKGROUND: T cells play a fundamental role in the processes that mediate graft rejection, tolerance, and defense against infections. The CXCR3 and CCR6 receptors, highly expressed in Th1 (type 1 T helper cells)/Tc1 (T cytotoxic cells, type 1), Th1-Tc1, and Th17-Tc17 lymphocytes, respectively, participate in cell migration toward inflamed tissues. The altered expression level of CXCR3 and CCR6 has been associated with different clinical events after renal transplantation, such as acute rejection (AR) and chronic graft dysfunction, but data are still limited. In this study, we evaluated the expression of the receptor CXCR3 and CCR6 in peripheral blood T lymphocytes from kidney transplant recipients (KTR) and their association with viral infections, AR, and allograft function. METHODS: Through flow cytometry, the peripheral blood expression of CXCR3 and CCR6 in T cells was evaluated in a pretransplant collection of KTR. The levels of these T subpopulations and their association with the incidence of AR, kidney graft function, viral infections, cytomegalovirus, and BK virus were studied. Adverse clinical events and graft function were monitored during the first year post transplant. RESULTS: KTRs with low pretransplantation levels of Th17 (CD4+CXCR3-CCR6+) (tertile 1, Th17<16.4%) had a higher risk of suffering AR during the first year post transplantation (P = .033). KTRs with viral infections or reactivations during the first 3 months post transplantation had significantly lower levels of Tc17 (CD8+CXCR3-CCR6+) and higher levels of Th1 (CD4+CXCR3+CCR6-). In patients with cytomegalovirus reactivations, the viral peak correlates negatively with the pretransplant levels of Th1 (r = -0.606, P = .037). CONCLUSIONS: Pretransplantation assessment of Th1-Th17 and Tc1-Tc17 levels may help predict post-transplant clinical events such as AR and reactivation of viral infections.

Monitoring of Soluble Forms of BAFF System (BAFF, APRIL, sR-BAFF, sTACI and sBCMA) in Kidney Transplantation.

BAFF system plays an essential role in B cells homeostasis and tolerance, although it has widely not been tested in transplantation with doubtful results. The main purpose was to study the BAFF soluble forms and their correlation with acute rejection (AR) and donor-specific antibodies production. Serum levels of BAFF, APRIL, and soluble forms of their receptors were analyzed in renal recipients with and without acute rejection (AR/NAR) appearance. All molecules were evaluated at pre- and post-transplantation. sTACI showed a significant correlation with BAFF and sR-BAFF levels, and sBCMA also showed a positive correlation with sAPRIL levels. A significant increase in sAPRIL levels in patients suffering AR was also found, and ROC curves analysis showed an AUC = 0.724, a concentration of 6.05 ng/ml (sensitivity: 66.7%; specificity: 73.3%), the best cutoff point for predicting AR. In the post-transplant dynamics of sAPRIL levels in the longitudinal cohort, we observed a significant decrease at 3 and 6 month post-transplantation compared to pretransplantation status. We also observed that recipients with high pre-transplant levels of sAPRIL generated antibodies earlier than those with lower sAPRIL levels, although their long-term post-transplantation was not different. Our results show that elevated serum levels of APRIL may be helpful as a biomarker for the diagnosis of AR, although the longitudinal study shows that it is not helpful as a prognostic biomarker.

Evaluating the Link between BAFF System Gene Expression and Acute Rejection Development in Kidney Transplantation.

B-cell activating factor (BAFF) system signaling is critical for B-cell homeostasis, effector functions, and tolerance maintenance in transplants, but it has not been studied in kidney transplant recipients (KTRs). The aim was to analyze the changes in BAFF system expression in KTRs with/without acute rejection (AR/NAR). The BAFF system expression was analyzed by qPCR in 40 KTRs. A meta-analysis of BAFF system expression and histological renal damage was identified by the Chronic Allograft Damage Index (CADI) and performed from the GEO database. Proliferation-inducing ligand (APRIL) expression increased at three- and six-months post-KT (p = 0.014 and p < 0.001). B-cell maturation antigen (BCMA) expression increased at six-months post-KT (p = 0.038). BAFF expression remained stable in NAR-KTRs, but was increased in CADI concerning the No-CADI group at one year (p = 0.008). BCMA expression increased in the CADI group at one- (p = 0.001) and six-years post-KT (p = 0.024). At three months, the transmembrane activator and calcium modulator interactor (TACI) gene significantly elevated KTRs with DSAs (donor-specific antibody; p = 0.034). KTRs with DSAs significantly increase the B-cell activating factor receptor (R-BAFF; p = 0.021) and TACI (p = 0.018) between pre- and three-month post-KT. Changes in the expression of the BAFF system increase during post-KTR in the development of AR and chronic allograft damage, and could be an important pathological tool to detect and prevent kidney graft outcomes.

Monitoring of B Cell in Kidney Transplantation: Development of a Novel Clusters Analysis and Role of Transitional B Cells in Transplant Outcome.

BACKGROUND: B lymphocytes (BL) seem to play an important role in transplantation, although the and role of different subpopulations in monitoring and outcome is not clear. Our aim was to monitoring immunological profiles based on BL subpopulations in kidney recipients (KR) with the risk of acute rejection (AR). METHODS: Monitoring of BL subpopulations was performed by flow cytometry in PBLs before transplantation and three and six months after transplantation (PTX). We used two methodological approaches, a traditional analysis, and a novel cluster analysis, to determine the association between BL subpopulations, AR incidence, and graft function. RESULTS: After three months of PTX, KRs with a B phenotype enriched in transitional BL and plasmablasts had better kidney function and lower AR incidence. KRs with decreased transitional BL and plasmablasts were associated with lower kidney function and higher AR PTX. KRs that had an increase in transitional BL PTX had a better clinical outcome. The increase in transitory BL during PTX was also associated with an increase in Tregs. Indeed, KRs receiving thymoglobulin as induction therapy showed a slight decrease in the relative frequency of naive BLs after three months of PTX. CONCLUSION: The monitoring of BL subpopulations may serve as a non-invasive tool to improve immunological follow-up of patients after kidney transplantation. However, further studies are needed to confirm the obtained results, define cut-off values, and standardize more optimal and even custom/customized protocols.

PCR Array Technology in Biopsy Samples Identifies Up-Regulated mTOR Pathway Genes as Potential Rejection Biomarkers After Kidney Transplantation.

Background: Antibody-mediated rejection (AMR) is the major cause of kidney transplant rejection. The donor-specific human leukocyte antigen (HLA) antibody (DSA) response to a renal allograft is not fully understood yet. mTOR complex has been described in the accommodation or rejection of transplants and integrates responses from a wide variety of signals. The aim of this study was to analyze the expression of the mTOR pathway genes in a large cohort of kidney transplant patients to determine its possible influence on the transplant outcome. Methods: A total of 269 kidney transplant patients monitored for DSA were studied. The patients were divided into two groups, one with recipients that had transplant rejection (+DSA/+AMR) and a second group of recipients without rejection (+DSA/-AMR and -DSA/-AMR, controls). Total RNA was extracted from kidney biopsies and reverse transcribed to cDNA. Human mTOR-PCR array technology was used to determine the expression of 84 mTOR pathway genes. STRING and REVIGO software were used to simulate gene to gene interaction and to assign a molecular function. Results: The studied groups showed a different expression of the mTOR pathway related genes. Recipients that had transplant rejection showed an over-expressed transcript (≥5-fold) of AKT1S1, DDIT4, EIF4E, HRAS, IGF1, INS, IRS1, PIK3CD, PIK3CG, PRKAG3, PRKCB (>12-fold), PRKCG, RPS6KA2, TELO2, ULK1, and VEGFC, compared with patients that did not have rejection. AKT1S1 transcripts were more expressed in +DSA/-AMR biopsies compared with +DSA/+AMR. The main molecular functions of up-regulated gene products were phosphotransferase activity, insulin-like grown factor receptor and ribonucleoside phosphate binding. The group of patients with transplant rejection also showed an under-expressed transcript (≥5-fold) of VEGFA (>15-fold), RPS6, and RHOA compared with the group without rejection. The molecular function of down-regulated gene products such as protein kinase activity and carbohydrate derivative binding proteins was also analyzed. Conclusions: We have found a higher number of over-expressed mTOR pathway genes than under-expressed ones in biopsies from rejected kidney transplants (+DSA/+AMR) with respect to controls. In addition to this, the molecular function of both types of transcripts (over/under expressed) is different. Therefore, further studies are needed to determine if variations in gene expression profiles can act as predictors of graft loss, and a better understanding of the mechanisms of action of the involved proteins would be necessary.

MicroRNA Expression Changes in Kidney Transplant: Diagnostic Efficacy of miR-150-5p as Potential Rejection Biomarker, Pilot Study.

BACKGROUND: The kidney allograft biopsy is considered the gold standard for rejection diagnosis but is invasive and could be indeterminate. Several publications point to the role of miRNA expression in suggesting its involvement in the acceptance or rejection of organ transplantation. This study aimed to analyze microRNAs involved in the differentiation and activation of B and T lymphocytes from kidney transplant (KT) patients' peripheral blood leukocytes to be used as biomarkers of acute renal rejection (AR). METHODS: A total of 15 KT patients with and without acute rejection (AR/NAR) were analyzed and quantified by miRNA PCR array. A total of 84 miRNAs related to lymphocyte differentiation and activation B and T were studied. The functions and biological pathways were analyzed to predict the potential targets of differential expressed miRNAs. RESULTS: Six miRNA were increased in the AR group (miR-191-5p, miR-223-3p, miR-346, miR-423-5p, miR-574-3p, and miR-181d) and miR-150-5p was increased in the NAR group. In silico studies showed a total of 2603 target genes for the increased miRNAs in AR, while for the decrease miRNA, a total of 1107 target-potential genes were found. CONCLUSIONS: Our results show that KT with AR shows a decrease in miR-150-5p expression compared to NAR, suggesting that the decrease in miR-150-5p could be related to an increased MBD6 whose deregulation could have clinical consequences.

A high concentration of TGF-ß correlates with opportunistic infection in liver and kidney transplantation.

Transforming growth factor-ß (TGF-ß) has been associated with numerous human infections, but its role in the occurrence of opportunistic infection (OI) after solid organ transplantation remains unexplored. This study aimed to assess the utility of the TGF-ß following in vitro stimulation of whole peripheral blood (WPB) as a surrogate biomarker of post-transplant OI in a cohort of liver and kidney recipients. Thirty liver and thirty-one kidney transplant recipients were recruited to be prospectively monitored for one-year post-transplantation. Enzyme-linked immunosorbent assay (ELISA) was performed to calculate IFN-γ, IL-17, IL-10 and TGF-ß concentration in the supernatant from the activated WPB. Recipients showed higher TGF-ß concentrations compared to IFN-γ, IL-17, IL-10 at baseline, although these differences were not significant between INF and NoINF. However, recipients who developed an OI within the first sixth months had a higher concentration of TGF-ß than those without OI. A concentration of TGF-ß > 363.25 pg/ml in liver and TGF-ß > 808.51 pg/ml in kidney recipients were able to stratify patients at high risk of OI with a sensitivity and specificity above 70% in both types of solid organ transplantations. TGF-ß could provide valuable information for the management of liver and kidney recipients at risk of post-transplant infection.

A comparative analysis of oral and maxillofacial pathology over a 16-year period, in the north of Portugal.

OBJECTIVES: To determine the frequency and spectrum of oral and maxillofacial lesions biopsied in a hospital population in the northern region of Portugal. METHODS: We conducted descriptive analyses of pathology reports from biopsies of oral and maxillofacial lesions performed between 1990 and 2006, in Oporto Hospital Center. Information on gender and age of patient, location of the lesions and the histopathological diagnosis were analysed. RESULTS: The analyses revealed that 1,520 (47.7%) patients were male and 1,666 (52.3%) were female. They had a mean age ± standard deviation of 47.8 ± 18.6 years. The site most frequently biopsied was the labial mucosa (17.5%). A non-neoplastic diagnosis was established in 2,162 (63.3%) cases, potentially malignant disorders in 163 (5.1%) and neoplasms in 886 (27.6%) (403 benign and 483 malignant). The most commonly reported diagnosis was fibroepithelial polyp (n = 186; 15.9%), followed by squamous cell carcinoma (SCC) (n = 158; 13.6%). SCC was the lesion most commonly found in male patients (n = 279; 18.4%) whilst fibroepithelial polyp was the lesion most commonly found in female patients (n = 268; 16.1%). The most common lesion in patients 0-17 years of age was a follicular cyst (n = 25; 12.8%), whereas in patients 18-64 years of age it was a fibroepithelial polyp (n = 299; 13%). SCC was the most common type of lesion found in patients ≥ 65 years of age (n = 160; 24.6%). CONCLUSION: This large sample provides useful information about the incidence and distribution of oral biopsies over a period of 16 years, allowing valuable comparison with other countries. Non-neoplastic lesions were the types of lesion most commonly reported, with fibroepithelial polyp being most frequent. SCC was the second most common diagnosis.

Influence of human leukocyte antigen mismatching on rejection development and allograft survival in liver transplantation: is the relevance of HLA-A locus matching being underestimated?

The influence of HLA matching on liver transplant is still controversial, as studies have failed to demonstrate an adverse effect of HLA mismatching on transplant outcome. We examined the effect of HLA mismatching on transplant outcome in a series of 342 consecutive liver transplants (224 finally analyzed). HLA typing was performed by serological and molecular methods. HLA-A matching was associated with an increased chronic rejection incidence (P=0.04). Indeed, HLA-A match also demonstrated a significant impact on allograft survival (P=0.03), confirming previous observation concerning to rejection, as complete HLA-A mismatching favored a better liver transplant outcome. Analysis of HLA-A+B+DR matching also demonstrated a significant impact on graft survival (P<0.05). Multivariate Cox regression analysis confirmed the effect of HLA-A and DPB1 matching as independent risk factors for graft loss. Another independent factor was a positive pre-transplant crossmatch. In conclusion, liver transplant outcome has not been found to be improved by HLA matching, however a poorer HLA compatibility favored a better graft survival and decreased rejection incidence, with a special relevance for HLA-A matching.