The gut microbiota is mainly composed of a diverse population of commensal bacterial species and plays a pivotal role in the maintenance of intestinal homeostasis, immune modulation and metabolism. The influence of the gut microbiota on solid organ transplantation has recently been recognized. In fact, several studies indicated that acute and chronic allograft rejection in small bowel transplantation (SBT) is closely associated with the alterations in microbial patterns in the gut. In this review, we focused on the recent findings regarding alterations in the microbiota following SBTand the potential roles of these alterations in the development of acute and chronic allograft rejection. We also reviewed important advances with respect to the interplays between the microbiota and host immune systems in SBT. Furthermore, we explored the potential of the gut microbiota as a microbial marker and/or therapeutic target for the predication and intervention of allograft rejection and chronic dysfunction. Given that current research on the gut microbiota has become increasingly sophisticated and comprehensive, large cohort studies employing metagenomic analysis and multivariate linkage should be designed for the characterization of host-microbe interaction and causality between microbiota alterations and clinical outcomes in SBT. The findings are expected to provide valuable insights into the role of gut microbiota in the development of allograft rejection and other transplant-related complications and introduce novel therapeutic targets and treatment approaches in clinical practice.
Biomarkers ; Gastrointestinal Microbiome ; Graft Rejection ; immunology ; Humans ; Immunity, Mucosal ; Intestine, Small ; microbiology ; transplantation ; Metagenomics ; Transplantation Tolerance ; immunology

BackgroundImmunosuppressive agents are still inefficient in preventing biopsy-proven acute rejection (BPAR) after expanded criteria donor (ECD) kidney transplantation. The aim of this study was to investigate the relationships between early immunosuppressive exposure and the development of BPAR.

MethodsWe performed a retrospective study of 58 recipients of ECD kidney transplantation treated with enteric-coated-mycophenolate sodium, tacrolimus (Tac), and prednisone. The levels of mycophenolic acid-area under the curve (MPA-AUC) and Tac Cwere measured at the 1 week and the 1 month posttransplant, respectively. The correlation was assessed by multivariate logistic regression.

ResultsThe occurrence rates of BPAR and antibody-mediated rejection were 24.1% and 10.3%, respectively. A low level of MPA-AUC at the 1 week posttransplant was found in BPAR recipients (38.42 ± 8.37 vs. 50.64 ± 13.22, P < 0.01). In addition, the incidence of BPAR was significantly high (P < 0.05) when the MPA-AUClevel was <30 mg·h·L at the 1 week (15.0% vs. 44.4%) or the Tac Cwas <4 ng/ml at the 1 month posttransplant (33.3% vs. 21.6%). Multivariable logistic regression analysis showed that the MPA-AUC at the 1 week (OR: 0.842, 95% CI: 0.784-0.903) and the Tac Cat the 1 month (OR: 0.904, 95% CI: 0.822-0.986) had significant inverse correlation with BPAR (P < 0.05).

ConclusionsLow-level exposure of MPA and Tac Cin the early weeks posttransplant reflects an increased acute rejection risk, which suggested that MPA-AUC <30 mg·h·L and Tac C <4 ng/ml should be avoided in the first few weeks after transplantation.

Adult ; Female ; Graft Rejection ; immunology ; prevention & control ; Humans ; Immunosuppressive Agents ; chemistry ; therapeutic use ; Kidney Transplantation ; adverse effects ; methods ; Male ; Middle Aged ; Mycophenolic Acid ; chemistry ; therapeutic use ; Retrospective Studies ; Tacrolimus ; chemistry ; therapeutic use ; Time Factors

BACKGROUND: The interaction between killer immunoglobulin-like receptors (KIRs) and HLA class I regulates natural killer (NK) cell cytotoxicity and function. The impact of NK cell alloreactivity through KIR in liver transplantation remains unelucidated. Since the frequency of HLA-C and KIR genotypes show ethnic differences, we assessed the impact of HLA-C, KIR genotype, or KIR-ligand mismatch on the allograft outcome of Korean liver allografts. METHODS: One hundred eighty-two living donor liver transplant patients were studied. Thirty-five patients (19.2%) had biopsy-confirmed acute rejection (AR), and eighteen (9.9%) had graft failure. The HLA-C compatibility, KIR genotypes, ligand-ligand, and KIR-ligand matching was retrospectively investigated for association with allograft outcomes. RESULTS: Homozygous C1 ligands were predominant in both patients and donors, and frequency of the HLA-C2 allele in Koreans was lower than that in other ethnic groups. Despite the significantly lower frequency of the HLA-C2 genotype in Koreans, donors with at least one HLA-C2 allele showed higher rates of AR than donors with no HLA-C2 alleles (29.2% vs 15.7%, P=0.0423). Although KIR genotypes also showed ethnic differences, KIR genotypes and the number of activating KIR/inhibitory KIR were not associated with the allograft outcome. KIR-ligand mismatch was expected in 31.6% of Korean liver transplants and had no impact on AR or graft survival. CONCLUSIONS: This study could not confirm the clinical impact of KIR genotypes and KIR-ligand mismatch. However, we demonstrated that the presence of HLA-C2 allele in the donor influenced AR of Korean liver allografts.
Adult ; Alleles ; Asian Continental Ancestry Group/*genetics ; Female ; Genotype ; Graft Rejection ; Graft Survival ; HLA-C Antigens/*genetics ; Homozygote ; Humans ; Killer Cells, Natural/cytology/immunology ; Ligands ; *Liver Transplantation ; Male ; Middle Aged ; Proportional Hazards Models ; Receptors, KIR/chemistry/*genetics/metabolism ; Republic of Korea ; Tissue Donors ; Transplantation, Homologous

OBJECTIVETo investigate the effects of inhibiting TIM-4 function in Kupffer cells (KCs) on liver graft rejection in mice and explore the underlying mechanism.

METHODSMouse models of orthotopic liver transplantation were treated with a control mAb group and TIM-4 mAb. The activated KCs were assayed with immunohistochemistry after operation. The expression of TIM-4 in KCs were assayed with Western blotting and RT-PCR and the levels of AST, ALT, TBIL, TNF-α, IFN-γ and CCL2 were assayed detected. The expression of TIM-4 in KCs was observed with laser confocal microscopy. HE staining was used to observe the microstructure of the liver tissues, and the number of CD25Foxp3T cells was determined using with flow cytometry; the proteins levels of p-P65and p-P38 were assayed with Western blotting. The donor mice were treated with clodronate liposomes to destroy the KCs in the liver before transplantation, and the liver grafts were examined for graft rejection.

RESULTSThe number of activated KCs in the liver graft increased progressively over time. Compared with the sham-operated group, the liver graft showed significantly increased TIM-4 protein and mRNA levels at 1, 3, and 7 days after transplantation (P<0.05) and increased levels of AST, ALT, TBIL, TNF-α, IFN-γ and CCL2 at 7 days (P<0.05). The graft in TIM-4 mAb group showed mild pathological changes with a mean RAI score of 2.67∓0.75, which was significantly lower than that in control mAb group (P<0.05). The mean survival time of the recipient mice was 53.8∓6.4 days in TIM-4 mAb group, significantly longer than that in the control mAB group (14.5∓2.9 days, P<0.05). Donor treatment with clodronate liposomes resulted in comparable RAI scores in TIM-4 mAb and control mAb groups (8.01∓0.64 vs 7.93∓0.56, P>0.05). The protein levels of p-P65 and p-P38 in TIM-4 mAb group were significantly lower than those in control mAb group (P<0.05), and CD25Foxp3T cells in the liver graft increased significantly in TIM-4 mAb group.

CONCLUSIONInhibition of TIM-4 function in KCs reduces the production of inflammatory factors after liver transplantation possibly by inhibiting the NF-κB and MAPK signaling pathways and promoting the proliferation of Foxp3Treg cells to induce allograft tolerance.

Animals ; Antibodies, Monoclonal ; pharmacology ; Graft Rejection ; Immunohistochemistry ; Kupffer Cells ; drug effects ; metabolism ; Liver ; surgery ; Liver Transplantation ; Male ; Membrane Proteins ; antagonists & inhibitors ; Mice ; NF-kappa B ; metabolism ; T-Lymphocytes, Regulatory ; immunology

OBJECTIVE: To evaluate the immunogenicity of self-made sheep skin acellular dermal matrix (ADM).
 METHODS: Both cross-linked and non-crosslinked ADMs were made after the sheep skin ADM was ready. A total of 160 healthy mice were then randomly divided into 4 groups. Group A, cross-linked ADM was implanted under skin; Group B, non-crosslinked ADM was implanted under skin; Group C, allosome skin was embedded under skin; Control group, without any implantation. Any visible changes in implantation region and any apparent rejection was recorded. Any symptoms of inflammatory reaction in implantation region were also observed by microscope. The levels of IL-4 and IFN-γ in serum were measured on the 3rd day, 1 week, 2 weeks and 3 weeks after the operation, respectively.
 RESULTS: Visual study: wound healing in implantation regions were obvious, the immunologic rejection was not significant, and the sheep ADM was absorbed gradually by ambient tissues. Microscope results: the connection between the sheep ADM and surrounding tissues was very tight with infiltration of a few inflammatory cells into the depth of sheep ADM. The structure of sheep ADM was gradually destroyed by inflammatory cells. The levels of IL-4 and IFN-γ were not significant difference between the group of A, B or C and the control group on the 3rd day after the operation. The inflammatory reaction in implantation region of the control group degraded after 3 days, concomitant with a decrease in the levels of IL-4 and IFN-γ. But the levels of IL-4 and IFN-γ in the Group A, B or C remained at high level, suggesting the elevation of IL-4 and IFN-γ levels were related to the immunologic reaction by sheep ADM. The values of IL-4/IFN-γ were significant difference between the group A, B or C and the control group at the end of the 1st week, 2nd week, and 3rd week. However, there were not significantly different among the Group A, B and C.
 CONCLUSION Sheep skin ADMs do not cause apparent rejection from mice after the transplantation because of the low immunogenicity. The cross-linked and non-crosslinked ADMs do not obviously affect the levels of IL-4 and IFN-γ.
Acellular Dermis ; Animals ; Graft Rejection ; blood ; Heterografts ; immunology ; Interferon-gamma ; blood ; Interleukin-4 ; blood ; Mice ; Random Allocation ; Sheep ; Skin Transplantation ; Wound Healing

BACKGROUND: Angiotensin II type 1 receptor (AT1R) is responsible for cardiovascular effects mediated by angiotensin II. This study aimed to investigate the impact of antibodies directed against AT1R (anti-AT1R) in renal allograft rejection. METHODS: We evaluated 53 patients who had biopsy-proven rejection including antibody-mediated rejection (AMR) (N=22), T-cell-mediated rejection (TCMR) (N=29), and mixed AMR and TCMR (N=2). Donor specific HLA antibodies (DSA) and anti-AT1Rs were simultaneously determined. RESULTS: Anti-AT1Rs were detected in 9.4% (5/53) of rejection patients (one with acute AMR, two with chronic active AMR, one with acute TCMR, and one with mixed acute AMR & TCMR). HLA antibodies and DSA were detected in 75.5% (40/53) and 49.1% (26/53) of patients, respectively. There was no significant difference in transplant characteristics between anti-AT1R(+) and anti-AT1R(-) patients except for the association of HLA class-I DSA(+) and anti-AT1R(+). Four of five anti-AT1R(+) patients had DSA and were also found to have AMR. A single anti-AT1R(+)/DSA(-) patient developed acute TCMR. Detection rates of DSA, HLA antibodies, or anti-AT1R were not different between AMR and TCMR. However, DSA(+)/anti-AT1R(+) was more frequently found in AMR than in TCMR (P=0.036). Patients with anti-AT1R showed a greater tendency to develop high-grade rejection as Banff IIA/IIB or AMR. CONCLUSIONS: The presence of anti-AT1R was significantly associated with HLA class-I DSA in renal allograft rejection patients. Both anti-AT1R and DSA positivity was associated with AMR in patients with renal allograft rejection.
Adult ; Antibodies/blood ; Female ; Graft Rejection/*etiology ; HLA Antigens/immunology ; Humans ; Kidney/pathology ; Kidney Transplantation/*adverse effects ; Male ; Middle Aged ; Receptor, Angiotensin, Type 1/*immunology ; Tissue Donors ; Transplantation, Homologous

In allogeneic transplantation, including the B6 anti-BALB.B settings, H60 and H4 are two representative dominant minor histocompatibility antigens that induce strong CD8 T-cell responses. With different distribution patterns, H60 expression is restricted to hematopoietic cells, whereas H4 is ubiquitously expressed. H60-specific CD8 T-cell response has been known to be dominant in most cases of B6 anti-BALB.B allo-responses, except in the case of skin transplantation. To understand the mechanism underlying the subdominance of H60 during allogeneic skin transplantation, we investigated the dynamics of the H60-specific CD8 T cells in B6 mice transplanted with allogeneic BALB.B tail skin. Unexpectedly, longitudinal bioluminescence imaging and flow cytometric analyses revealed that H60-specific CD8 T cells were not always subdominant to H4-specific cells but instead showed a brief dominance before the H4 response became predominant. H60-specific CD8 T cells could expand in the draining lymph node and migrate to the BALB.B allografts, indicating their active participation in the anti-BALB.B allo-response. Enhancing the frequencies of H60-reactive CD8 T cells prior to skin transplantation reversed the immune hierarchy between H60 and H4. Additionally, H60 became predominant when antigen presentation was limited to the direct pathway. However, when antigen presentation was restricted to the indirect pathway, the expansion of H60-specific CD8 T cells was limited, whereas H4-specific CD8 T cells expanded significantly, suggesting that the temporary immunodominance and eventual subdominance of H60 could be due to their reliance on the direct antigen presentation pathway. These results enhance our understanding of the immunodominance phenomenon following allogeneic tissue transplantation.
Animals ; Antigen Presentation ; Antigen-Presenting Cells/immunology/metabolism ; CD8-Positive T-Lymphocytes/*immunology ; Epitopes, T-Lymphocyte/*immunology ; Female ; Graft Rejection/*immunology ; Interferon-gamma ; Lymphocyte Activation/immunology ; Lymphocyte Count ; Mice ; Minor Histocompatibility Antigens/*immunology/metabolism ; *Skin Transplantation ; Transplantation, Homologous

BACKGROUND/AIMS: BK virus-associated nephropathy (BKVAN) is an important cause of allograft dysfunction in kidney transplant recipients. It has an unfavorable clinical course, and no definite treatment guidelines have yet been established. Here, we report our center's experience with biopsy-proven BKVAN and investigate factors associated with its progression. METHODS: From January 2004 to April 2013, 25 patients with BKVAN were diagnosed by biopsy at Seoul St. Mary's Hospital. Of the 25 patients, 10 were deceaseddonor transplant recipients and 15 were living-donor transplant recipients. Three of the patients underwent retransplantation. The primary immunosuppressant used was tacrolimus in 17 patients and cyclosporine in eight patients. RESULTS: BKVAN was observed at a mean duration of 22.8 ± 29.1 months after transplantation. The mean serum creatinine level at biopsy was 2.2 ± 0.7 mg/dL. BKVAN occurred with acute rejection in eight patients (28%). Immunosuppression modification was performed in 21 patients (84%). Additionally, leflunomide and intravenous immunoglobulin were administered to 13 patients (52%) and two (8%), respectively. Allograft loss occurred in five patients (27.8%) during the follow- up period at 0.7, 17.1, 21.8, 39.8, and 41.5 months after the BKVAN diagnosis. Advanced stages of BKVAN, increased creatinine levels, and accompanying acute rejection at the time of BKVAN diagnosis increased the risk of allograft failure. CONCLUSIONS: The clinical outcomes in patients with biopsy-proven BKVAN were unfavorable in the present study, especially in patients with advanced-stage BKVAN, poor renal function, and acute allograft rejection.
Adult ; Allografts ; Antiviral Agents/therapeutic use ; BK Virus/*pathogenicity ; Biomarkers/blood ; Biopsy ; Creatinine/blood ; Disease Progression ; Female ; Graft Rejection/diagnosis/drug therapy/immunology/*virology ; Graft Survival ; Humans ; Immunocompromised Host ; Immunosuppressive Agents/adverse effects ; Kaplan-Meier Estimate ; Kidney Transplantation/*adverse effects ; Male ; Middle Aged ; Opportunistic Infections/diagnosis/drug therapy/immunology/*virology ; Polyomavirus Infections/diagnosis/drug therapy/immunology/*virology ; Republic of Korea ; Retrospective Studies ; Risk Factors ; Time Factors ; Treatment Outcome ; Tumor Virus Infections/diagnosis/drug therapy/immunology/*virology

No abstract available.
Adult ; Female ; Graft Rejection/immunology/*prevention & control ; Graft Survival ; *Hematopoietic Stem Cell Transplantation ; Humans ; *Immune Tolerance ; Immunosuppressive Agents/therapeutic use ; Kidney Failure, Chronic/diagnosis/*surgery ; *Kidney Transplantation ; Living Donors ; Siblings ; Time Factors ; *Transplantation Chimera ; Treatment Outcome

BACKGROUND/AIMS: Patients who undergo repeat kidney transplantations (KTs) are considered at high risk for experiencing immunologic and non-immunologic complications. In this study, we investigated the clinical outcomes, including medical and surgical complications, of patients who underwent a third KT at our center. METHODS: Between March 1969 and December 2012, a total of 2,110 KTs were performed at the Seoul St. Mary's Hospital. Of them, we examined 11 patients who underwent a third KT, and investigated the allograft outcomes and complication rates. RESULTS: The mean follow-up duration after KT was 72.4 ± 78.3 months. The mean age at KT was 38.2 ± 8.0 years, and seven patients (63.6%) were males. Nine patients (81.8%) underwent living-donor KT. A cross-match test yielded positive results in four of the nine patients, and all underwent pretransplant desensitization therapy. After KT, three patients (27.2%) showed delayed graft function. Acute rejection developed in four patients (36.4%), and surgical complications that required surgical correction occurred in three patients. Allograft failure developed due to acute rejection (n = 3) or chronic rejection (n = 1) in four patients. Allograft survival rates at 1, 5, and 10 years were 81.8%, 42.9%, and 42.9%, respectively; however, the allograft survival rate at 5 years was > 80% in patients who underwent KT only after results of the panel reactive antibody test became available. CONCLUSIONS: Thus, a third KT procedure may be acceptable, although aggressive pretransplant immune monitoring and patient selection may be required to reduce the risks of acute rejection and surgical complications.
Acute Disease ; Adult ; Allografts ; Chronic Disease ; Delayed Graft Function/diagnosis/*etiology/therapy ; Female ; Graft Rejection/diagnosis/*immunology/therapy ; Graft Survival ; *Histocompatibility ; Humans ; Immunosuppressive Agents/therapeutic use ; Kidney Transplantation/*adverse effects ; Male ; Middle Aged ; Patient Selection ; Reoperation ; Republic of Korea ; Risk Assessment ; Risk Factors ; Time Factors ; Treatment Outcome