The role of liver transplantation in COACH syndrome (Joubert syndrome with congenital hepatic fibrosis): A review of the literature.

BACKGROUND: COACH syndrome is a rare autosomal recessive genetic disease characterized by liver fibrosis, which leads to severe complications related to portal hypertension. However, only a few patients with COACH syndrome undergoing liver transplantation (LT) have been reported. MATERIALS AND METHODS: We herein report the outcomes of four children who underwent LT for COACH syndrome at our institute and review three previously reported cases to elucidate the role of LT in COACH syndrome. RESULTS: All four patients in our institute were female, and three received living donors LT. All patients were diagnosed with COACH syndrome by genetic testing. LT was performed in these patients at 3, 7, 9, and 14 years old. The indication for LT was varices related to portal hypertension in all patients. One showed an intrapulmonary shunt. Blood tests revealed renal impairment due to nephronophthisis in three patients, and one developed renal insufficiency after LT. The liver function was maintained in all patients. A literature review revealed detailed information for three more patients. The indication for LT in these three cases was portal hypertension, such as bleeding from esophageal varices. One patient had chronic renal failure on hemodialysis at LT and underwent combined liver and kidney transplantation. Of these three previous patients, one died from hepatic failure due to de novo HCV infection 3 years after LT. CONCLUSIONS: LT should be considered an effective treatment for COACH syndrome in patients with severe portal hypertension. However, a detailed follow-up of the renal function is necessary.

Living-donor liver transplantation for methylmalonic acidemia patient with hepatocellular carcinoma: A case report and literature review.

BACKGROUND: Methylmalonic acidemia (MMA) is an autosomal recessive disorder caused by defects in propionyl-CoA (P-CoA) catabolism; of note, liver neoplasms rarely occur as a long-term complication of the disorder. Herein, we report the case of a patient with MMA and hepatocellular carcinoma (HCC) who was successfully treated with a living-donor liver transplant (LDLT) following prior kidney transplantation. CASE REPORT: A 25-year-old male patient with MMA underwent LDLT with a left lobe graft because of metabolic instability and liver neoplasms. He had presented with chronic symptoms of MMA, which had been diagnosed by genetic testing. Additionally, he had undergone living-donor kidney transplantation with his father as the donor due to end-stage kidney disease 6 years before the LDLT. He had an episode of metabolic decompensation triggered by coronavirus disease in 2019. Imaging studies revealed an intrahepatic neoplasm in the right hepatic lobe. Due to concerns about metabolic decompensation after hepatectomy, LDLT was performed using a left lobe graft obtained from the patient's mother. Pathological findings were consistent with the characteristics of well-to-moderately differentiated HCC. The postoperative course was uneventful, and the patient was discharged 48 days after the LDLT without any complications. At the 9-month follow-up, the patient's condition was satisfactory, with sufficient liver graft function and without metabolic decompensation. CONCLUSION: This case indicates that although HCC is a rare complication in patients with MMA, clinicians should be aware of hepatic malignancies during long-term follow-up.

Successful pediatric liver transplantation case with a positive SARS-CoV-2 test at the time of transplant.

AIM: We report a successful liver transplantation (LT) in a child with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. CASE PRESENTATION: A 3-year-old female patient with decompensated cirrhosis due to Alagille syndrome underwent a split LT with a left lateral segment graft. She had a history of SARS-CoV-2 infection 4 months before LT. She was exposed to SARS-CoV-2 after the decision for organ acceptance. We repeatedly confirmed the negative SARS-CoV-2 test by polymerase chain reaction (PCR) before LT. Liver transplantation was carried out in the negative pressure operational theater with full airborne, droplet, and contact precautions as the patient was considered to be within the incubation period of SARS-CoV-2. The SARS-CoV-2 PCR test became positive in the nasopharyngeal swab specimen at the operation. Remdesivir, the antiviral treatment, was held off due to potential hepatotoxicity and no exacerbation of COVID-19. She received tacrolimus and low-dose steroids per protocol. She remained SARS-CoV-2 positive on postoperative days (PODs) 1, 2, and 5. The presence of antibodies for SARS-CoV-2 at LT was confirmed later. On POD 53, she was discharged without any symptomatic infection. CONCLUSION: This case demonstrated that a positive SARS-CoV-2 result was not an absolute contraindication for a life-saving LT. Liver transplantation could be safely performed in a pediatric patient with asymptomatic COVID-19 and S-immunoglobulin G antibodies for SARS-CoV-2.

Optimal liver transplant procedure in progressive familial intrahepatic cholestasis type 1 treated with biliary diversion or intestinal transplantation: Lessons learned from three cases treated with different approaches.

BACKGROUND: Progressive familial intrahepatic cholestasis type 1 (PFIC1) is an autosomal recessive cholestatic liver disorder caused by ATP8B1 gene mutations. Although liver transplantation (LT) is indicated for progressive liver disease, postoperative complications, including severe diarrhea and graft steatohepatitis leading to graft loss, have been reported. CASES: The first patient had jaundice, pruritus, diarrhea, and growth retardation (weight z-score: -2.5; height z-score: -3.7). She underwent LT with total internal biliary diversion (TIBD) to the colon at 2 years of age. Graft biopsy at the 7-year follow-up examination revealed microvesicular steatosis (60%). Her diarrhea improved, and her growth failure was recovering (weight z-score: -1.0; height z-score: -1.7). The second patient underwent sequential intestine-liver transplantation at 8 years of age due to end-stage liver disease (ESLD) and short bowel syndrome caused by massive bowel resection for internal hernia after partial external biliary diversion (PEBD) at 21 months of age. She developed severe pancreatitis induced by steroid-bolus therapy for rejection after transplantation. She died 1.7 years after intestinal transplantation due to an uncontrollable pancreatic abscess and acute respiratory distress syndrome. The third patient underwent PEBD at 15 months of age and received LT with TEBD at 15 years of age due to ESLD with hepatic encephalopathy. Throughout the perioperative period, she showed no abdominal symptoms, including diarrhea and pancreatitis. Graft biopsy at the 2-year follow-up examination revealed macrovesicular steatosis (60%) with inflammation. CONCLUSIONS: The patients showed different outcomes. Effective therapeutic options to mitigate post-LT complications in patients with PFIC1 must be considered individually.

Gallstone ileus at 17 years after living donor liver transplantation: A case report.

BACKGROUND: Gallstone ileus (GI) occurs in <0.1% of all cases of mechanical bowel obstruction. There have been a few reports of GI occurring after Kasai procedures or Roux-en-Y anastomosis for bariatric surgery. We herein report a case of GI that occurred over 17 years after liver transplantation (LT). CASE REPORT: A 33-year-old woman who had undergone living donor LT for biliary atresia at 16 years old and had been regularly followed on an outpatient basis in our hospital presented with the sudden onset of increased abdominal distension, pain, and nausea. Enhanced abdominal computed tomography showed dilatation of the intrahepatic bile duct and the whole intestinal tract of the Roux limb as well as ischemic changes near the jejuno-jejunal anastomosis. On laparotomy, a movable and hard foreign body was palpated in the intestinal tract close to the jejuno-jejunal anastomosis site. Enterotomy was performed, and a 4-cm gallstone was removed. The patient had a good postoperative course and was discharged on postoperative day 12. CONCLUSIONS: Although GI after LT is a rare complication, it may need to be differentiated as a cause of ileus. An accurate differential diagnosis and early reliable intervention for stone removal will help prevent serious bowel complication, which may lead to graft dysfunction.

Preemptive liver transplant in two patients with primary hyperoxaluria type 1: Clinical significance of nephrolithiasis and nephrocalcinosis.

BACKGROUND: Although nephrolithiasis (NL) and nephrocalcinosis (NC) are very common features of primary hyperoxaluria type 1 (PH1), the long-term prognosis of NL and NC after preemptive liver transplantation (PLT) has not been elucidated. MATERIAL AND METHODS: We describe the cases of two chronic kidney disease (CKD) stage three patients with different clinical courses after PLT for PH1. RESULTS: The first patient underwent PLT at 7 years of age with an estimated glomerular filtration rate (eGFR) of 47.8 ml/min/1.73 m2 . Two years later, she experienced several episodes of obstructive pyelonephritis due to urolithiasis, and developed septic shock in one of these episodes. At the same time as these episodes, preexisting NL and NC progressively improved, with disappearance on X-ray disappeared at 8 years after transplantation. Her renal function has been maintained with an eGFR of 58.7 ml/min/1.73 m2 . The second patient received PLT at 10 years of age with an eGFR of 58.9 ml/min/1.73 m2 . Her renal function has been maintained with an eGFR of 65.9 ml/min/1.73 m2 . She had repeated urolithiasis which started to appear at 3 years after LT. The radiological findings still show bilateral NL and NC, but the stones in the renal pelvis have shown mild improvement. CONCLUSIONS: Regardless of the regression in NC seen on X-ray, long-term maintenance of the renal function in patients with PH1 with CKD stage 3 can be achieved with PLT. In patients with NL, there is a risk of serious complications due to posttransplant immunosuppressive therapy when obstructive pyelonephritis occurs after LT.

Effect of microscopy-assisted portoenterostomy (MAPE) for biliary atresia.

PURPOSE: Portoenterostomy (PE) is the standard treatment for biliary atresia (BA). However, micro-bile ducts are difficult to identify with surgical loupes and dissect systematically. We report the effects of our attempts to dissect hilar tissue using a surgical microscope. METHODS: Microscopy-assisted portoenterostomy (MAPE) was initiated in 2014. Patients born between 2000 and 2013 who underwent PE until day 70 without a surgical microscope for BA were gathered as historical control. MAPE in re-do PE cases (Re-MAPE) was evaluated in the same manner. RESULTS: Ten patients underwent MAPE for BA during the study period. 17 patients in the conventional PE group were gathered. In the MAPE group, the jaundice clearance rate was 80%, compared with 53% in the conventional PE group. Re-MAPE was performed in four patients, who had a jaundice clearance rate of 75%, essentially identical to the rate with initial MAPE. At age 4 years, the native liver survival rate was 58% in the MAPE group and 38% in the conventional PE group. The native liver survival rate in the Re-MAPE group was 75%. CONCLUSION: MAPE is useful for sharing the surgical field during open PE in patients with BA. It may improve the rate of jaundice clearance.

Serum Mac-2-binding protein (M2BPGi) as a marker of chronological liver fibrosis in biliary atresia patients with cirrhosis.

PURPOSE: Biliary atresia (BA) is characterized by progressive liver fibrosis, but it is difficult to assess the progression after the patient develops cirrhosis. Mac-2-binding protein glycosylation isomer (M2BPGi) is a new marker for hepatic fibrosis. We examined the chronological changes in M2BPGi levels in BA patients with cirrhosis. METHODS: Patients with cirrhosis were selected from among pediatric BA patients who had their native livers. Serum M2BPGi levels and Child-Pugh classification were evaluated. A total of 11 pediatric BA patients with cirrhosis were recruited. RESULTS: Initial M2BPGi level after diagnosis of liver cirrhosis based on liver biopsy was on average 3.4, and the most recent M2BPGi level under observation was on average 4.3. The follow-up period from the initial M2BPGi measurement averaged 22.6 months. The ratio of the initial and most recent values (M2BPGi ratio) was on average 1.3 (0.5-2.4). Three cases with improved fibrosis (M2BPGi ratio < 1.0) remained in Child A, as did six cases (1.0 ≤ M2BPGi ratio < 2.0), but two cases with marked fibrosis progression (2.0 ≤ M2BPGi ratio) advanced to decompensated cirrhosis Child B. CONCLUSION: M2BPGi is useful as a prognostic factor for BA patients with liver cirrhosis. In addition, fibrosis improved even after the development of cirrhosis.

Postoperative decrease in plasma acyl ghrelin levels after pediatric living donor liver transplantation in association with hepatic damage due to ischemia and reperfusion injury.

PURPOSE: Ghrelin was recently reported to promote recovery from hepatic injury. We hypothesized that it could also be associated with clinical recovery of the transplanted liver from ischemia and reperfusion injury. Our aims were to investigate perioperative ghrelin changes following pediatric living donor liver transplantation (LDLT) and to analyze the association of these changes with postoperative hepatic function. METHODS: We measured plasma acyl ghrelin (AG) concentrations before surgery, at the end of surgery and on postoperative days (PODs) 1, 3 and 7 in 12 children who underwent LDLTs, and, as controls, pre- and post-operatively and on POD1 in 7 children who underwent benign abdominal mass resection. The correlations between the participants' ghrelin profiles and hepatic function-related data were evaluated. RESULTS: AG levels significantly declined to 15.6% of preoperative levels after LDLT and almost returned to baseline on POD3. Post-operative AG levels were significantly reduced to a greater extent following LDLT than benign abdominal mass resection. AG levels on POD1 inversely correlated with aspartate aminotransferase levels and cold/total ischemia time (P < 0.05). CONCLUSION: These results suggest that reduced AG levels on POD1 may reflect the degree of damage to the transplanted liver due to ischemia and reperfusion injury.

The effect of maternal grafts in early acute cellular rejection after pediatric living-donor liver transplantation.

PURPOSE: Living-donor liver transplantations (LDLTs) with maternal grafts can be more successful than those with paternal grafts because of their tolerance to non-inherited maternal antigens. We reviewed LDLT patients to investigate the relationship between acute rejection and donor sex. METHODS: LDLT patients between January 2010 and November 2015 were enrolled. ACR was defined by a rejection activity index of > 3. RESULTS: Forty-six patients (22 males and 24 females), of whom 28 had biliary atresia, were enrolled. The median age of the patients was 2.8 years and the donor types were maternal (n = 25) and paternal (n = 21). Acute cellular rejection (ACR) was observed in 22 patients. Twelve (48%) of the 25 patients in the maternal group had at least one episode of rejection compared with 10 (48%) of the 21 in the paternal group. Among the patients with ACR, the first rejection in the maternal group occurred significantly earlier than that in the paternal group (p < 0.01). In the multivariable analysis, the only variable significantly related to the first rejection day after LDLT was donor sex (male) (p < 0.005). CONCLUSION: Our results showed that maternal grafts had an effect on causing earlier ACR in LDLT.

Human CD31 on porcine cells suppress xenogeneic neutrophil-mediated cytotoxicity via the inhibition of NETosis.

BACKGROUND: Xenotransplantation is one of the promising strategies for overcoming the shortage of organs available for transplant. However, many immunological obstructions need to be overcome for practical use. Increasing evidence suggests that neutrophils contribute to xenogeneic cellular rejection. Neutrophils are regulated by activation and inhibitory signals to induce appropriate immune reactions and to avoid unnecessary immune reactivity. Therefore, we hypothesized that the development of neutrophil-targeted therapies may have the potential for increased graft survival in xenotransplantation. METHODS: A plasmid containing a cDNA insert encoding the human CD31 gene was transfected into swine endothelial cells (SEC). HL-60 cells were differentiated into neutrophil-like cells by culturing them in the presence of 1.3% dimethyl sulfoxide for 48 hours. The cytotoxicity of the differentiated HL-60 cells (dHL-60) and peripheral blood-derived neutrophils was evaluated by WST-8 assays. To investigate the mechanism responsible for hCD31-induced immunosuppression, citrullinated histone 3 (cit-H3) and phosphorylation of SHP-1 were detected by a cit-H3 enzyme-linked immunosorbent assay (ELISA) and Western blotting, respectively. RESULTS: A significant decrease in dHL-60 and neutrophil-mediated cytotoxicity in SEC/hCD31 compared with SEC was seen, as evidenced by a cytotoxicity assay. Furthermore, the suppression of NETosis and the induction of SHP-1 phosphorylation in neutrophils that had been co-cultured with SEC/CD31 were confirmed by cit-H3 ELISA and Western blotting with an anti-phosphorylated SHP-1. CONCLUSION: These data suggest that human CD31 suppresses neutrophil-mediated xenogenic cytotoxicity via the inhibition of NETosis. As CD31 is widely expressed in a variety of inflammatory cells, human CD31-induced suppression may cover the entire xenogeneic cellular rejection, thus making the generation of human CD31 transgenic pigs very attractive for use in xenografts.

Human CD200 suppresses macrophage-mediated xenogeneic cytotoxicity and phagocytosis.

PURPOSE: Various strategies, such as the generation of alpha-1,3-galactosyltransferase knocked-out pigs and CD55 transgenic pigs, have been investigated to inhibit pig to human xenogeneic rejection. Our aim is to develop strategies to overcome the hurdle of not only hyper acute rejection, but also that of cellular xenogeneic rejection (CXR). Although macrophages have been well known to play a critical role in CXR, monocyte/macrophage-mediated xenogeneic rejection has not been well studied. In this study, we evaluated the effect of CD200 in xenogeneic rejection by macrophages. METHODS: Naïve swine endothelial cells (SEC) and SEC/CD200 were co-cultured with M0 macrophages and the cytotoxicity was measured by a WST-8 assay. The phagocytosis of SEC and SEC/CD200 by macrophages was analyzed by flow cytometry. RESULTS: While CD200 failed to suppress a significant amount of cytotoxicity against SEC by monocytes, M0 macrophage-mediated cytotoxicity was significantly suppressed by human CD200. The phagocytosis by M0 macrophages was also tested. The phagocytosis assay revealed that human CD200 suppresses M0 macrophage-mediated phagocytosis. CONCLUSIONS: Our findings indicate that human CD200 suppresses the xenogeneic rejection by CD200R+ macrophages and that the generation of hCD200 transgenic pigs for use in xenografts is very attractive for preventing the macrophage-mediated rejection.

Correction to: Human CD200 suppresses macrophage-mediated xenogeneic cytotoxicity and phagocytosis.

In the original publication, the fifth author name was erroneously published as "Patmika Jiaravuthiasan". The correct author name should read as, "Patmika Jiaravuthisan". The original article was corrected.

Clinical implications of serum Mac-2-binding protein (M2BPGi) during regular follow-up of patients with biliary atresia.

PURPOSE: The Mac-2-binding protein glycosylation-modified isomer (M2BPGi) is a new marker for progression of hepatic fibrosis. We examined the relationship between serum M2BPGi levels and liver histological findings in patients with biliary atresia (BA) who were not transplant candidates. METHODS: Patients with BA who were not transplant candidates with good liver function were included. We examined M2BPGi levels and histological findings in relation to other laboratory markers of liver fibrosis, including aspartate aminotransferase (AST) to platelet ratio index, fibrosis-4 index, and type IV collagen 7s domain. Liver fibrosis was evaluated based on the METVIR score. RESULTS: 37 patients were included. The median age was 18 years (range 3-38 years). M2BPGi values ranged from 0.3 to 6.9 cutoff index (COI) (median 1.6). The degree of liver fibrosis varied with M2BPGi level. For predicting cirrhosis (F4) and advanced liver fibrosis (≥ F3), M2BPGi had higher areas under the curve (AUCs; 0.93, respectively) with cutoff COIs of 1.84 and 1.67, respectively, than for the four conventional markers for fibrosis. CONCLUSION: M2BPGi is a novel marker for liver fibrosis in patients with BA. It is especially useful for following patients with BA with a native liver and supporting liver biopsy interpretation findings.

"Reduced Size Liver Grafts in Pediatric Liver Transplantation; Technical Considerations".

Liver transplantation (LT) has become a vital treatment option for children with end-stage liver disease. Left lateral segment (LLS) grafts are particularly common in split and living donor LT for pediatric patients. However, challenges arise in small infants receiving LLS grafts, primarily due to graft-size mismatches, resulting in "large-for-size" grafts. To overcome this issue, the practice of further reducing grafts from the LLS to diminish graft thickness has been explored. Currently, the indication for reducing the thickness of LLS grafts includes recipients with a body weight (BW) under 5.0 kg, neonates with acute liver failure, or those with metabolic liver disease. At the National Center for Child Health and Development in Tokyo, Japan, among 131 recipients of reduced-size LLS grafts, a remarkable 15-year graft survival rate of 89.9% has been achieved in small infants. This success indicates that with experience and refinement of the technique, there's a trend towards improved graft survival in recipients with reduced-thickness LLS grafts. This advancement underscores the importance of BW-appropriate methods in graft selection to ensure exceptional outcomes in vulnerable pediatric patients in need of LT. These techniques' ongoing development and refinement are crucial in enhancing the survival rates and overall outcomes for these young patients.

Strategy for hepatoblastoma with major vascular involvement: A guide for surgical decision-making.

BACKGROUND: Surgical management of tumor thrombus extending to the major vascular system for children with hepatoblastoma is challenging and insufficiently discussed. METHODS: We conducted a retrospective review of hepatoblastoma with tumor thrombus extending to the major vascular system (inferior vena cava, 3 hepatic veins, and portal vein trunk) treated at our center between May 2010 and June 2021. We describe our preoperative assessment, surgical strategies, and outcomes. RESULTS: We identified 9 patients (median age at the diagnosis: 3.4 years). All patients received chemotherapy before liver surgery. At the time of the diagnosis, tumor thrombus extended to the portal vein trunk (n = 6), inferior vena cava (n = 3), and 3 hepatic veins (n = 2). Among the 9 patients, 4 underwent liver resection. Liver transplantation was performed in 5 patients. The inferior vena cava wall was circumferentially resected for tumor removal in 1 patient and partially resected in 2 patients. One patient underwent liver transplantation using veno-venous bypass. Patients with tumor thrombus extending to the portal vein trunk were more likely to be managed by liver transplantation in comparison to those with tumor thrombus spreading to the inferior vena cava. The median follow-up period was 5.5 years. One patient underwent transhepatic balloon dilatation for biliary stricture after liver resection. Tumor recurrence was seen in 3 patients (33.3%; lung, n = 2; lymph node and liver, n = 1). No patients died during the follow-up period. CONCLUSION: Surgical intervention for pediatric hepatoblastoma with tumor thrombus extending into the major vascular system is safe, feasible, and achieves excellent outcomes.

Clinical outcomes of surgical management for rare types of progressive familial intrahepatic cholestasis: a case series.

BACKGROUND: Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of genetic autosomal recessive diseases that cause severe cholestasis, which progresses to cirrhosis and liver failure, in infancy or early childhood. We herein report the clinical outcomes of surgical management in patients with four types of PFIC. CASE PRESENTATION: Six patients diagnosed with PFIC who underwent surgical treatment between 1998 and 2020 at our institution were retrospectively assessed. Living-donor liver transplantation (LDLT) was performed in 5 patients with PFIC. The median age at LDLT was 4.8 (range: 1.9-11.4) years. One patient each with familial intrahepatic cholestasis 1 (FIC1) deficiency and bile salt export pump (BSEP) deficiency died after LDLT, and the four remaining patients, one each with deficiency of FIC1, BSEP, multidrug resistance protein 3 (MDR3), and tight junction protein 2 (TJP2), survived. One FIC1 deficiency recipient underwent LDLT secondary to deterioration of liver function, following infectious enteritis. Although he underwent LDLT accompanied by total external biliary diversion, the patient died because of PFIC-related complications. The other patient with FIC1 deficiency had intractable pruritus and underwent partial internal biliary diversion (PIBD) at 9.8 years of age, pruritus largely resolved after PIBD. One BSEP deficiency recipient, who had severe graft damage, experienced recurrence of cholestasis due to the development of antibodies against BSEP after LDLT, and eventually died due to graft failure. The other patient with BSEP deficiency recovered well after LDLT and there was no evidence of posttransplant recurrence of cholestasis. In contrast, recipients with MDR3 or TJP2 deficiency showed good courses and outcomes after LDLT. CONCLUSIONS: Although LDLT was considered an effective treatment for PFIC, the clinical courses and outcomes after LDLT were still inadequate in patients with FIC1 and BSEP deficiency. LDLT accompanied by total biliary diversion may not be as effective for patients with FIC1 deficiency.

Effect of a C5a receptor antagonist on macrophage function in an intestinal transplant rat model.

BACKGROUND: C5a promotes alloreactivity via the C5a receptor 1 (C5aR1) on immune cells, but this has not been confirmed in the case of small intestine transplantation immunity. In the present study, we examined the effect of C5aR1 antagonist (PMX53) on macrophage function in small intestinal transplantation. METHODS: The model was created by heterotopic intestinal transplantation using donor Dark Agouti and recipient Lewis rats. PMX53 was administered starting on the day of operation until postoperative day 7. The graft survivals were compared, and HE staining of grafts, lymphocyte mixed reaction test (MLR, mixed culture of T cells from lymph nodes and spleen cells from donors), and changes in macrophage and T cell accumulation in grafts on day 6 after transplantation were evaluated. In addition, the effect of PMX53 on macrophage differentiation and activation was assessed using macrophages derived from bone marrow (BMDM). RESULTS: Graft survival was significantly prolonged in the therapeutic group compared to the untreated group. Histological evaluation showed that PMX53 inhibited the shortening of the graft villus, and the stimulation index of MLR was significantly lower in the therapeutic group compared to the untreated group. In the therapeutic group, the accumulation of macrophages in intestinal graft and monocyte in blood were reduced, compared with the untreated group. PMX53 decreased the differentiation in BMDM and the mRNA expression of IL-1ß and TNF-α in activated BMDM. CONCLUSION: Inhibition of C5a/C5aR1 signaling appears to regulate macrophage differentiation and suppress rejection in small intestine transplantation immunity.