Onset Of Acute Rejection Research Articles

Association between time in therapeutic range of tacrolimus blood concentration and acute rejection within the first three months after lung transplantation

BackgroundTacrolimus is a key drug in immunosuppressive therapy following lung transplantation. The blood tacrolimus levels are likely to fluctuate in the early postoperative period, and failure to maintain the tacrolimus trough level in target ranges is a risk factor for rejection. However, there is little information about the relationship between the time in therapeutic range (TTR) of the tacrolimus trough level (tacrolimus TTR) and clinical outcomes. This study aimed to evaluate the association between tacrolimus TTR and acute rejection (AR) within the first three months after lung transplantation.MethodsThis was a retrospective study of patients who underwent lung transplantation at a single center. The target tacrolimus trough levels were 10–15 ng/mL, and tacrolimus TTR was calculated using the Rosendaal method. The cut-off value of the tacrolimus TTR was estimated by receiver operating characteristic analysis based on AR.ResultsThe study included 90 patients. AR was observed in 26 patients. In this study, ‘‘early-AR’’ was defined as any AR within 2 weeks post-transplant (n = 22) and ‘‘late-AR’’ was defined as any AR after 1-month post-transplant (n = 4). For early AR, the relationship between tacrolimus TTR and the onset of AR was examined. There were no differences in the tacrolimus TTR between the early-AR group and non-AR group (35.7 ± 22.4 vs 31.5 ± 19.9%, P = 0.416). For late-AR, the relationship with tacrolimus TTR was examined every 10 d. The tacrolimus TTR during postoperative days (POD) 21–30 and POD 31–onset was significantly lower in the late-AR group than the no-AR group (50.0 ± 7.1 vs. 71.8 ± 18.0% and 37.0 ± 26.6 vs. 68.9 ± 31.5%, P < 0.05, respectively). The cutoff value of the tacrolimus TTR during POD 21–30 was estimated as 55.0%.ConclusionsOur findings suggest that a lower tacrolimus TTR is a predictor of late AR. A tacrolimus TTR of 55% or higher is necessary to reduce the risk of AR during this period after lung transplantation.

Patients with Bronchiolitis Obliterans Syndrome (BOS) Have Later Onset of Acute Rejection Than BOS-Free Patients

Purpose Chronic lung allograft dysfunction (CLAD) is the most important complication after lung transplantation (LTx), which is classified bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS). Acute rejection (AR) is a high potential risk factor for BOS. Therefore, we have analyzed our clinical database to search the missing link between AR and BOS. Methods From January 2015 to March 2020, 746 patients underwent LTx in our institute. In this cohort, 88 patients suffered from AR (11.8%). These patients were divided in patients with BOS and without BOS. Results Our AR incident was also a risk factor of BOS (p=0.003). Mean age AR patients amounted to 47.1 years old. Forty-five patients were male (51.1%). Transplant indication was lung fibrosis (n=32, 36.4%), COPD (n=27, 30.7%), cystic fibrosis (n=13, 14.8%), bronchiectasis (n=4, 4.5%), pulmonary hypertension (n=3, 3.4%), sarcoidosis (n=2, 2.3%), re-transplantation (n=4, 4.5%) and others (n=3). Nine (10.2%) patients showed primary graft dysfunction (PGD) Grade 2-3. At follow-up, 29 (33%) patients developed BOS. Transplant indications did not differ between BOS patients and BOS-free patients. Similarly, age, gender, and PGD Grade 2-3 did not differ between groups. Incidence of infection was significantly higher in BOS than BOS-free patients (p=0.0002). The infections occurred before the AR (n=12) after AR (n=12) and after BOS episode (n=7) in BOS patients (There were repeated infection episodes in 6 patients). Moreover, the first episode of AR occurred earlier in BOS-free patients than that of BOS patients (5.5 months vs. 14.6 months, respectively: p=0.003) Conclusion In our cohort, infection is a risk factor for BOS in patients with AR. However, the infection episode occurred not only after AR but also before AR and after BOS. That means, it could not be related between AR and BOS. The most significant difference was in the first AR phase.

Immune Checkpoint Espression Associates with Rejection in Lung Transplant Recipients

Purpose The outcome of lung transplantion (LuTx) suffers from a high rejection rate, and there are still huge gaps of knowledge about immune-mediated rejection mechanisms. Acute rejection (AR) can lead to chronic lung allograft dysfunction (CLAD), the main cause of poor survival and low quality of life. The standardized morphologic evaluation of rejection is based on histopathologic diagnostic criteria at a given time-point, but it has a limited prognostic value towards clinical outcome and the likelihood to develop CLAD. We analyzed immune-check point proteins in lung tissues of patients who received a LuTx and who were or were not undergoing rejection in the attempt to define novel immunological markers that could predict rejection. Methods We conducted an observational retrospective study on eight consecutive explanted grafts for chronic rejection and on transbronchial cryobiopsies (TCB) obtained from 24 consecutive patients during the first year LuTx follow-up. A broad spectrum of immunohistochemical analysis was carried out (PD1/CD279, PDL1/CD274, CTLA4/CD152, CD4, CD8, hFoxp3, TIGIT, TOX, B-Cell-Specific Activator Protein). Of those TCB-patients we recorded at least 1 year follow up of survival, infections and rejections (acute and chronic) rate. Results Exhausted (PD1+/TOX+) as well as Treg (PD1+/FOXP3+) lymphocytes were significantly reduced in restrictive allograft syndrome (RAS)-compared to bronchiolitis-obliterans-syndrome (BOS)-rejected lungs. PD1-expressing T-lymphocytes in TCBs correlated (sensitivity 0.69; specificity 1) with the presence of AR and were highly suggestive of CLAD development (sensitivity 0.86; specificity 0.82; overall 10 times higher risk of developing CLAD) at one-year follow-up. Conclusion Results herein for the first time show the importance of immunological checkpoints in the setting of LuTx rejection and indicate that the evaluation of the expression of such proteins could offer a distinct prognostic advantage in monitoring the onset of AR in patients who underwent LuTx. Longitudinal analyses in ampler cohorts will be needed to confirm these data.

A Novel Injury Site-Targeted Complement Inhibitor Which Protects against Lung Transplant Ischemia Reperfusion Injury

Purpose Self-reactive natural Abs initiate complement activation and injury following ischemia and reperfusion of certain tissues, but their role in post-ischemic lung injury is unknown. Here, we investigated the expression of two previously identified post-ischemic neoepitopes, namely a modified annexin IV epitope recognized by B4 IgM mAb, and an epitope consisting of a subset of phospholipids recognized by C2 IgM mAb, and additionally determined their role in lung transplant ischemia reperfusion injury (IRI). Methods Lungs from C57Bl/6 mice were orthotopically transplanted into Rag1-/- (antibody-deficient) mice reconstituted with either B4 and C2 mAbs. Results Rag1-/- mice were protected from lung IRI, but reconstitution with either B4 or C2 natural IgM mAbs restored lung IRI. The C2 mAb was more effective than the B4 mAb at restoring injury, as determined by histological and micro-CT analysis. Based on this information, we developed and characterized a therapeutic strategy that exploited the post-ischemia recognition system of natural antibodies. We constructed a single-chain antibody (scFv) derived from C2 mAb and linked it to Crry, an inhibitor of C3 activation (C2scFv-Crry). In models of syngeneic (B6-B6) and allogeneic (Balb/c-B6) lung transplant models in which recipients contain a full natural antibody repertoire, a single post-transplant injection of C2scFv-Crry blocked the binding of endogenous IgM to the graft, inhibited complement activation, and significantly reduced graft inflammation and injury as determined by histology, μCT, and immunhistochemical analysis. The severity of IRI is associated with the onset of acute rejection. Conclusion We identified pathophysiologically important epitopes expressed within the lung after lung ischemia and reperfusion post transplantation. We further describe a novel translatable strategy for complement inhibition that is specifically targeted to the transplanted lung, and that has several advantages over currently available approaches that rely on systemic complement inhibition. Significantly, the C2 epitope has been identified in both mouse and man, increasing the translational relevance of the approach.

Impact of Interleukin-17F Gene Polymorphisms in Outcome of Kidney Transplantation in Tunisian Recipients

BackgroundGenetic polymorphisms of interleukin (IL)-17F, associated with functional and/or quantitative change in this glycoprotein, have been described as predisposing to various autoimmune diseases. The proinflammatory IL-17 has some roles in renal transplantation. In this context, the relationship between the most common IL-17F polymorphisms with acute renal allograft rejection susceptibility in Tunisian renal recipients has been investigated. MethodsWe examined 93 renal transplant recipients who were enrolled and classified as follows: GI, 48 transplant recipients who developed at least one episode of acute rejection; and GII, 45 controls, kidney recipients who also were followed for at least 1 year and had stable renal function. Single nucleotide polymorphisms (SNPs) of IL-17F gene, including -1507 C/T (rs18889570), 7384 A/G (rs2397084), 7469 C/T (rs11465553), and 7489 A/G (rs763780), were evaluated using direct sequencing. ResultsNo statistically significant association of the IL-17F SNPs studied with the onset of acute rejection was observed. However, AA genotype on 7489A/G SNP showed anti-HLA antibodies less than other genotypes and a higher graft survival time (P = .017). ConclusionThe AA genotype on 7489A/G SNP of IL-17F and the A allele might be associated with a lower risk of acute rejection with better graft survival.

Expression of T lymphocyte cytokines in peripheral blood of renal transplant recipients

To evaluate the clinical values of T-lymphocyte cytokines in renal transplant acute rejection. A total of 31 recipients with renal transplantation and 15 healthy volunteers from January 2010 to January 2012 were enrolled and divided into acute rejection group (n = 11) and stable renal allograft function group (n = 20) according to the inclusion criteria. Peripheral blood was collected from the patients before transplantation, 1, 7, 14, 28 day after transplantation and acute rejection onset. Cytometric bead array (CBA) was used to monitor the levels of interleukin-17 (IL-17), interferon-gamma (IFN-γ), tumor necrosis factor (TNF), interleukin(IL)-10, IL-6, IL-4 and IL-2. The associations of the changes and levels of cytokines in 3 groups were examined with Pearson correlation analysis. The levels of IL-17A, TNF, IL-10 and IL-2 in recipients before transplantation were (3.40 ± 1.29) , (1.79 ± 0.53) , (2.73 ± 0.65) and (1.79 ± 1.02) ng/L respectively and decreased significantly compared to healthy volunteers ((4.52 ± 2.01), (3.36 ± 1.09) , (3.91 ± 0.42) , (3.12 ± 1.07) ng/L respectively, all P < 0.05). However the levels of IFN-γ, IL-6 and IL-4 showed no significant changes between two groups (all P > 0.05). In acute rejection group after transplantation, the levels of IL-17A, IFN-γ, IL-10 and IL-6 were (9.47 ± 4.75) , (5.01 ± 2.23) , (12.20 ± 5.79) , (6.55 ± 3.45) ng/L respectively and increased significantly compared to the renal allograft function group ((4.39 ± 1.26), (2.90 ± 0.87),(5.68 ± 2.25) and (2.10 ± 0.70) ng/L respectively, all P < 0.05); the level of IL-17A was correlated with those of IFN-γ and IL-4 (Pearson r = 0.519, 0.395, both P < 0.01), the level of IFN-γ was correlated with those of IL-4 and IL-2 (r = 0.276, 0.335, all P < 0.05) , the level of TNF was correlated with that of IL-4 (r = 0.423, P < 0.05) and the level of IL-10 was correlated with that of IL-6 (r = 0.361, P < 0.05). Cytokines play an important role in acute rejection of renal transplant. And further understanding of its mechanism may provide experimental and preventive rationales.

Linkage Disequilibrium Between TNF-α-308 G/A Promoter and Histocompatibility Leukocyte Antigen Alleles in Han-Nationality Lung Transplant Recipients From Eastern China

Genes encoding histocompatibility leukocyte antigen (HLA) and proinflammatory cytokines are involved in rejection after organ transplant. The authors explored the association between HLA alleles and the tumor necrosis factor (TNF)- α-308 G/A promoter region in lung transplant recipients of Han nationality from East China. They also evaluated the correlation between TNF-α-308 G/A and the onset of acute rejection after lung transplant. All lung transplant recipients of Han nationality who were admitted into our hospital between August 2004 and July 2011 were included. Patients were divided into 2 groups according to the presence or absence of acute rejection episodes. Genotypes of HLA and single nucleotide polymorphisms of TNF-α-308 G/A were determined using polymerase chain reaction-single specific primer kits. A total of 106 lung transplant recipients were investigated. HLA-A*2 allele was in linkage disequilibrium with TNF-α-308 G allele. HLA-A*33, -B*58 and -DRB1*03 alleles were in linkage disequilibrium with TNF-α-308 A allele. Notably, TNF-α-308 A allele was in complete linkage disequilibrium with HLA-B*58 allele. Furthermore, TNF-α-308 A allele was in linkage disequilibrium with the HLA-A*33-DRB1*03 and HLA-B*58-DRB1*03 haplotypes. Clinical analysis indicated that TNF-α-308 G/A was not associated with onset of acute rejection after lung transplant. TNF-α-308 G/A polymorphism was strongly associated with HLA-A*2, -A*33, -B*58, and -DRB1*03 alleles in our population. HLA genotyping can identify lung transplant recipients carrying the highly productive phenotype of TNF-α-308 A allele, which may provide information on rejection after transplant. However, the authors found that TNF-α-308 A subtype has no correlation with acute rejection after lung transplant.

Proliferation of CD8-Positive T Cells in Blood Vessels of Rat Renal Allografts

It is still disputed in which anatomical compartments of allograft recipients T-cells proliferate. After experimental renal transplantation, host monocytes and lymphocytes accumulate in the lumina of graft blood vessels. In this study, we test the hypothesis that T lymphocytes proliferate in the vascular bed of the graft. Kidneys were transplanted in the Dark Agouti to Lewis rat strain combination, an established experimental model for acute rejection. Isogeneic transplantation was performed as a control. Cells in the S-phase of mitosis were detected in situ three days posttransplantation by pulse-labeling with BrdU and by immunohistochemical detection of the proliferating cell nuclear antigen (PCNA). More than 20% of all T-cells in the lumina of allograft blood vessels incorporated BrdU and approximately 30% of them expressed PCNA. In the blood vessels of isografts as well as in other organs of allograft recipients, only few BrdU(+) cells were detected. A majority of the BrdU(+) cells in graft blood vessels expressed CD8. In conclusion, we demonstrate that CD8(+) T lymphocytes proliferate in the lumina of the blood vessels of renal allografts during the onset of acute rejection.

Usefulness of 3-month protocol biopsy of kidney allograft to detect subclinical rejection under triple immunosuppression with basiliximab: a single center experience

Theoretically, an early protocol biopsy (PB) serves to detect subclinical rejection (SCR), allowing early treatment and prevention of acute rejection (AR) and chronic graft injuries. In this retrospective study, we investigated the incidence of biopsy-proven AR (BPAR) and the usefulness of a 3-month PB in detecting SCR in kidney transplant (KT) and simultaneous pancreas-kidney transplant (SPKT) recipients who received triple immunosuppression and basiliximab. Between January 2007 and September 2009, 116 patients received transplantation (KT=112, SPKT=4). In August 2008, we changed our PB policy and started to collect PB after 3 months instead of a pre-discharge biopsy performed 1month after transplantation. Here we compare the incidence of SCR (defined as Banff grade Ia or higher) between the pre-discharge PB group and the 3-month PB group. PB was obtained from 41 patients before discharge (pre-discharge PB group), and from 49 patients 3 months after transplantation (3-month PB group). Among all recipients, 21 patients were diagnosed with BPAR (estimated incidence of BPAR 20.1%); including 13 (62.0%) diagnosed from 31 to 180 postoperative days (POD), and only 3 (14.3%) within 30 POD. The incidence of BPAR was not different between the two groups (19.5 and 20.8%, respectively); however, 4 of 8 recipients in the 3-month PB group were diagnosed with SCR, compared to none in the pre-discharge PB group (P<0.05). Since the use of triple immunosuppression and basiliximab delayed the onset of AR, we recommend that in order to detect SCR, PB should be obtained 3 months postoperatively.

Finding the right time for weaning off immunosuppression in solid organ transplant recipients

Solid organ transplantation (SOT) requires lifelong immunosuppression (IS) to prevent rejection and graft loss. The currently adopted immunosuppressive protocols are numerous and are based on the administration of at least two molecules with diverse mechanisms of action. Owing to the fact that the majority of immunosuppressants act non-selectively, the immune system is normally oversuppressed, and as a result is less able to both defend the host against infection and to control the spread of malignant cells. Consequently, long-term IS is burdened by chronic toxicity, which may be highly invalidating and may significantly influence patient’s quality of life, compliance to treatment, overall success rate, and patient and graft survival. In an ideal scenario, SOT recipients should initially receive just enough IS to favor the onset of clinical operational tolerance (COT), a condition where the immune system of the host does not attack the graft in the absence of any immunosuppressant. COT has been documented after liver transplantation (LT) and renal transplantation (RT). First, COT was accidentally detected in patients who were nonadherent to treatment and who spontaneously decided to stop all IS without any medical guidance or surveillance. Later, it was described in recipients who required IS withdrawal following the occurrence of malignant diseases. Based on strikingly convincing experimental data, several tolerogenic protocols have recently been applied in patients but overall the results have been disappointing. The current literature demonstrates that COT can be safely achieved in stable LT recipients, with completely different strategies. Importantly, the onset of an episode of acute rejection during the attempt of IS withdrawal would not worsen the clinical outcome. On the contrary, COT remains a major challenge after RT because the onset of acute rejection will substantiate in graft loss. Currently, a major field of investigation aims to define markers of COT, which will allow the selection of individuals who are more prone to develop COT. Preliminary results in both RT and LT have just been announced; however, these markers will require validation in prospective studies.

152: Humoral Immune Responses in Acute Phase of Living Double Lobar Lung Transplantation: Donor-Specific IgM Can Predict Onset of Acute Rejection

152: Humoral Immune Responses in Acute Phase of Living Double Lobar Lung Transplantation: Donor-Specific IgM Can Predict Onset of Acute Rejection

Expression of human leucocyte antigen G in peripheral blood of kidney transplantation recipients

To investigate the expression of non-classical major histocompatibility complex (MHC)-I molecule, human leucocyte antigen (HLA) G, including membrane-bound HLA-G (mHLA-G), intracellular HLA-G (iHLA-G) and soluble HLA-G (sHLA-G), in peripheral blood of surviving kidney transplantation recipients and understand the relevance between HLA-G and the function of transplanted organ, as well as the onset of acute rejection. A longitudinal study was performed on 175 kidney transplantation recipients. Three groups were involved in this study, including acute rejection group (n = 36), function stable group (n = 139) and healthy control group (n = 30). The expression of mHLA-G1 and iHLA-G1 in the T lymphocytes of peripheral blood was detected by flow cytometry analysis and the sHLA-G5 level detected by ELISA. The average rate of CD4(+)mHLA-G1(+), CD8(+)mHLA-G1(+), CD4(+)iHLA-G1(+), CD8(+)iHLA-G1(+) in T lymphocytes of healthy control group was 0.43% +/- 0.19%, 1.23% +/- 0.41%, 27% +/- 13% and 36% +/- 14% respectively. That of acute rejection group was 0.57% +/- 0.34%, 1.31% +/- 0.56%, 26% +/- 8% and 37% +/- 17%; that of function stable group was 0.61% +/- 0.43%, 1.39% +/- 0.47%, 26% +/- 9% and 37% +/- 17% respectively. There was no significant difference among the three groups (all P > 0.05). The average of sHLA-G5 levels in plasma of control group was (25 +/- 14) ng/ml, acute rejection group (24 +/- 15) ng/ml (pre-operative) and (34 +/- 21) ng/ml (post-operative), function stable group (25 +/- 11) ng/ml (pre-operative) and (56 +/- 32) ng/ml (post-operative). There was no significant difference among the three groups (pre-operative, P > 0.05). The average of sHLA-G5 levels in plasma of function stable group was higher than that of acute rejection group (post-operative, P < 0.05). There is a subset of CD4(+)HLA-G1(+) and CD8(+)HLA-G1(+)T lymphocytes with low percentage in peripheral blood of those surviving kidney transplantation recipients. The expressions of mHLA-G1 and iHLA-G1 have no relevance with the onset of acute rejection. sHLA-G5 is correlated with acute rejection in peripheral blood of surviving transplantation recipients.

A Transient Increase of Calcineurin Phosphatase Activity in Living-Donor Kidney Transplant Recipients with Acute Rejection

We describe the longitudinal follow-up of calcineurin activity and its clinical relevance in 4 de novo living-donor kidney transplant recipients treated with cyclosporine (n=1) or tacrolimus (n=3). The calcineurin activity in peripheral blood mononuclear cells was measured in combination with therapeutic drug monitoring during hospitalization. Serial blood samplings were performed after the oral administration of each drug to evaluate the temporal pharmacokinetic and pharmacodynamic profiles. Significant changes in enzyme activity were evaluated in relation to clinical outcomes. A nadir of calcineurin activity occurred at the maximum blood drug concentration within 4 h post-dose in most cases. Unlike cyclosporine, tacrolimus partially suppressed calcineurin activity throughout the dosing interval compared to the pre-dose level (cyclosporine, 62-67% inhibition; tacrolimus, 13-35% inhibition). Notably, calcineurin activity rapidly increased a few days before the onset of acute rejection in 2 patients, 1 receiving cyclosporine and 1 receiving tacrolimus, despite the achievement of therapeutic trough blood concentrations. These preliminary findings indicate that therapeutic monitoring of calcineurin activity in addition to the measurement of blood drug concentrations may be helpful to evaluate the pharmacodynamic effects of cyclosporine and tacrolimus early after renal transplantation.

Acute Rejection in Allogeneic Rodent Small Bowel Transplantation Causes Smooth Muscle Dysfunction via an Inflammatory Response Within the Intestinal Muscularis

Introduction Isogeneic intestinal transplantation elicits an inflammatory response within the intestinal muscularis that is associated with dysmotility. Usually the inflammation and the postoperative motor dysfunction resolve within a few days after small bowel transplantation (SBTx). However, the onset of acute rejection in allogeneic SBTx is again associated with dysmotility. We hypothesized that dysmotility during acute rejection is based on coexpression of kinetically active mediators by the alloreactive leucocyte infiltrate. Materials and methods Rat SBTx (BN to Lew and BN to BN) was performed without immunosuppression. Animals were sacrificed at 1, 4, and 7 days after SBTx. Leukocyte infiltration was investigated in muscularis whole mounts by immunohistochemistry. Mediator mRNA expression was determined by reverse transcriptase polymerase chain reaction. Muscle contractility was assessed in a standard organ bath. Results Transplanted animals showed a significant inflammatory response within the muscularis at day 1 after SBTx. However, allogeneic transplanted animals exhibited a significant second inflammatory peak at day 7 (mRNA induction: iNOS 150-fold; tumor necrosis factor-α 18-fold; interferon-γ 397-fold), parallel to the onset of rejection. This change was associated with a significant leukocyte infiltration. Compared to controls, allogeneic transplanted animals showed a 29% decrease in smooth muscle contractility on days 1 and 4 and a 71% decrease of contractility on postoperative day 7. Conclusions The motor dysfunction of transplanted small bowel during acute rejection is associated with an inflammatory reaction in the intestinal muscularis. The initial unspecific inflammation process immediately after transplantation is reactivated and intensified during acute rejection.

One year complete follow-up of a porspective randomized international investigator driven study comparing Tac and CsA (+MMF/steroids) after lung transplantation in 274 patients

induction in lung transplantation. Methods: The initial randomized, prospective study included fortyfour lung recipients assigned to receive either RATG induction (locally developed preparation dosed at 1.5 mg/kg/d for 3 days) with conventional immunosuppression or conventional immunosuppression alone. These 2 groups were retrospectively analyzed for episodes of biopsy-proven acute rejection, BOS development, and survival. Results: Patients receiving RATG suffered fewer early rejections ( 6 months posttransplant) Grade 2 or higher (5%), compared to those with conventional therapy alone (41%; Fisher’s Test, p 0.01). With a mean follow-up of 4.4 years, the overall incidence of acute rejection between groups did not differ (RATG 62%, Conventional 68%; p 0.52). Median time to rejection was 614 days for the RATG group and 206 days for recipients without induction therapy (p 0.52). Freedom from BOS and survival at five years was 62% and 41% for the RATG group, compared to 34% and 46% for recipients treated conventionally (log-rank, p 0.14 and 0.48, respectively). Conclusion: Although RATG delays the onset of acute rejection and is associated with a trend towards delayed onset of BOS, significant differences were not observed in long-term allograft survival.

Pathological study on the relationship between C4d, CD59 and C5b-9 in acute renal allograft rejection.

In order to evaluate the activation or inhibition of the later phases of classical complement cascade in renal allograft presenting with acute rejection, particularly with C4d deposition on the peritubular capillary (PTC), we observed the expression of CD59 and C5b-9 on the PTC. Subjective cases were divided into two groups, an acute rejection group, of 4 males and 6 females, and a normal donor group, of 5 males and 5 females. Renal biopsies were performed at the onset of acute rejection and at the transplant operation, before reperfusion. C4d deposition on PTC was found in three of 10 cases (30%) with biopsy proven acute rejection, whereas CD59 on PTC was positively expressed in all of the rejection cases. Although C5b-9 was not observed on PTC in the acute rejection group, it was intensively deposited on the tubular basement membrane (TBM) in five cases, including the three with positive C4d on PTC. In the normal donor group, CD59 on PTC was intensively observed, whereas C5b-9 was weakly expressed on TBM. CD59, a complement regulatory factor, works as an inhibitory factor against the formation of C5b-9, a membrane attack complex. From our data, we noted the dissociation between the depositions of C4d and C5b-9 on PTC. The substantially expressed CD59 on PTC may affect this dissociation between C4d and C5b-9 on PTC. The intensive deposition of C5b-9 on TBM in acute rejection cases may suggest an independent immunological injury attacking tubular cells.

Recurrent hepatitis C in liver allografts: prospective assessment of diagnostic accuracy, identification of pitfalls, and observations about pathogenesis.

The accuracy of a prospective histopathologic diagnosis of rejection and recurrent hepatitis C (HCV) was determined in 48 HCV RNA-positive liver allograft recipients enrolled in an "immunosuppression minimization protocol" between July 29, 2001 and January 24, 2003. Prospective entry of all pertinent treatment, laboratory, and histopathology results into an electronic database enabled a retrospective analysis of the accuracy of histopathologic diagnoses and the pathophysiologic relationship between recurrent HCV and rejection. Time to first onset of acute rejection (AR) (mean, 107 days; median, 83 days; range, 7-329 days) overlapped with the time to first onset of recurrent HCV (mean, 115 days; median, 123 days; range, 22-315 days), making distinction between the two difficult. AR and chronic rejection (CR) with and without co-existent HCV showed overlapping but significantly different liver injury test profiles. One major and two minor errors occurred (positive predictive values for AR = 91%; recurrent HCV = 100%); all involved an overdiagnosis of AR in the context of recurrent HCV. Retrospective analysis of the mistakes showed that major errors can be avoided altogether and the impact of unavoidable minor errors can be minimized by strict adherence to specific histopathologic criteria, close clinicopathologic correlation including examination of HCV RNA levels, and a conservative approach to the use of additional immunosuppression. In addition, histopathologic diagnoses of moderate and severe AR and CR were associated with relatively low HCV RNA levels, whereas relatively high HCV RNA levels were associated with a histopathologic diagnosis of hepatitis alone, particularly the cholestatic variant of HCV. Liver allograft biopsy interpretation can rapidly and accurately distinguish between recurrent HCV and AR/CR. In addition, the histopathologic observations suggest that the immune mechanism responsible for HCV clearance overlap with those leading to significant rejection.

Surveillance biopsies are superior to functional studies for the diagnosis of acute and chronic renal allograft pathology in children.

In this report of our 3-yr protocol biopsy program, we describe the evolution of acute rejection (AR) and chronic renal allograft nephropathy (CAN) in a cohort of 21 children treated with antibody induction, tacrolimus, mycophenolate mofetil, and prednisone. The aims of this study were to compare the pathogenicity of clinical acute rejection (CAR) and subclinical acute rejection (SAR), and to determine whether functional studies accurately represent acute and chronic renal allograft pathology in pediatric recipients with disproportionately large grafts. Using concurrent biopsies, we evaluated: (i) the utility of changes in the baseline sCr (DeltasCr) to predict both the onset of AR and the response to immunosuppressive therapy; and (ii) the relationship of the calculated creatinine clearance and the presence of pathologic proteinuria to the severity of CAN. We performed 112 biopsies: 11 donor, 73 protocol, 16 acute graft dysfunction and 12 1-month follow-up AR therapy. CAR and SAR were similar in incidence, timing and histologic severity. Progression of CAN was associated with the first episode of CAR (p < 0.02) and the cumulative number of episodes of CAR (p < 0.01), SAR (p < 0.05), CAR plus SAR (p < 0.002) and borderline SAR (B-SAR) (p < 0.006). One-month post-treatment DeltasCrs could not distinguish 1-month follow-up biopsies with histologically confirmed worsened or unchanged AR from those with improved histology (35.2 +/- 74.8% vs. 23.8 +/- 24.9%, p = NS). These findings led to the addition of anti-lymphocyte antibody therapy in five of 10 (50%) cases. Despite 100% 3-yr actuarial graft survival and excellent function (GFR = 111 +/- 36 mL/min/1.73 m(2)), 18 of 21 (86%) patients had grade I CAN or greater chronic histology at a mean +/- sd follow-up period of 18.2 +/- 13.1 months. Thirteen of 21 (62%) patients progressed to grade I CAN at 5.2 +/- 3.6 months and five (38%) of these patients progressed to grade II CAN at 17.8 +/- 11.3 months. Schwartz GFR did not differ between patients with or without CAN (108 +/- 38 mL/min/1.73 m(2) vs. 127 +/- 8 mL/min/1.73 m(2), p = NS). In biopsies with CAN and no associated AR, neither the Banff chronic tubulointerstitial (Banff ci) score nor the Banff chronic grade correlated with the GFR. Proteinuria was not associated with CAN. Clinical AR and SAR are similar histologic lesions with a capacity for CAN progression. In pediatric renal transplant recipients, longitudinal protocol biopsies are superior to functional studies for the diagnosis and post-therapeutic monitoring of AR and for the surveillance of CAN.

Contribution of late acute rejection to long-term renal allograft survival in patients with chronic allograft nephropathy

CHRONIC allograft nephropathy (CAN) is the primary cause of late renal allograft loss, but the pathogenesis of this condition is not fully understood. A previous episode of acute rejection (AR) is a major alloantigendependent risk factor for later development of CAN. Several studies have shown that kidney recipients who do not experience AR have better long-term survival than those with a history of this problem. Although AR is principally a feature of the early posttransplant period, it may also occur in the late ( 1 year) stage. Late-onset AR may contribute to the development of CAN and graft loss. In this study, we aimed to assess how the timing of AR onset impacts the development of CAN and late renal allograft loss.

Transfection of NFkappaB-decoy oligodeoxynucleotides using efficient ultrasound-mediated gene transfer into donor kidneys prolonged survival of rat renal allografts.

Nuclear factor kappaB (NFkappaB) plays a pivotal role in the coordinated transactivation of a series of genes of cytokines and adhesion molecules that are highly involved in the onset of acute rejection in organ transplantation. We previously developed decoy cis-elements oligo deoxyribonucleic acid against NFkappaB (NFkappaB-decoy) that effectively inhibited the activation of major inflammatory mediators in vitro and in vivo. Accordingly, we hypothesized that transfection of NFkappaB-decoy into the donor kidney would prevent acute rejection and prolong graft survival, and thus provide effective therapy for renal acute rejection. To transfect NFkappaB-decoy, we employed a novel approach using ultrasound exposure with an echocardiographic contrast agent, Optison, and clearly demonstrated successful transfection of NFkappaB-decoy into renal tissue. The therapeutic effect of NFkappaB-decoy on renal allografts was then evaluated in a rat renal allograft model (Wistar-Lewis). In the control group, graft function significantly deteriorated with marked destruction of renal tissue, accompanied by increased production of major inflammatory mediators, and all animals died of renal failure by 9 days. In contrast, graft function (serum creatinine on day 2, NFkappaB-treated: 0.97+/-0.16 versus control: 1.84+/-0.23 mg/dl, P<0.01) and histological structure were well preserved with significantly decreased expression of NFkappaB-regulated cytokines and adhesion molecules, including IL-1, iNOS, MCP-1, TNF-alpha, and ICAM-1, in allografts transfected with NFkappaB-decoy. As a result, animal survival was significantly prolonged in this group as compared to controls (14.2+/-5.2 versus 7.1+/-1.2 days, P<0.01). Thus, we established a novel ultrasound-Optison-mediated gene transfection approach and demonstrated the significant prolongation of graft survival by the successful transfection of NFkappaB-decoy into the donor kidney in a rat renal allograft model.