Anticardiolipin antibodies and 12-month graft function in kidney transplant recipients: a prognosis cohort survey.

Background: In kidney transplant recipients, anticardiolipin (ACL) antibodies without antiphospholipid syndrome (APS) are found in up to 38% of patients and could be associated with thrombotic events (TEs). However, the prognostic role of ACL regarding kidney transplant and patients outcomes have still not been well defined. Methods: We conducted an observational, monocentric, retrospective cohort study including 446 kidney transplant recipients and standardized follow-up: 36-month allograft and patient survival, 12-month estimated glomerular filtration rate (eGFR) and 3- and 12-month screening biopsies. Results: ACL tests were run on 247 patients, 101 were positive (ACL+ group, 41%) and 146 were negative (ACL- group, 59%). Allografts and patient survival within 36 months as TE were similar between both groups [hazard ratio (HR) = 1.18 and HR = 0.98, respectively]. The 12-month eGFR was significantly lower in the ACL+ group [median (95% confidence interval) 48.5 (35.1-60.3) versus 51.9 (39.1-65.0) mL/min/1.73 m2, P= 0.042]. ACL+ was independently associated with eGFR decrease (P = 0.04). In 12-month screening biopsies, tubular atrophy was significantly more severe in the ACL+ group compared with the ACL- group (P = 0.02). Conclusions: ACL without APS before kidney transplantation is an independent risk factor of eGFR decline within the first year post-transplant without over-incidence of TEs. Specific immunosuppressive therapy including mammalian target of rapamycin inhibitors should be discussed in the future.

C1q binding is not an independent risk factor for kidney allograft loss after an acute antibody-mediated rejection episode: a retrospective cohort study.

After kidney transplantation, C4d is an incomplete marker of acute antibody-mediated rejection (AMR) and C1q-binding donor-specific antibodies (DSA) have been associated with allograft survival. However, the impact on allograft survival of C1q+ DSA after clinical AMR has not been studied yet. We analysed retrospectively in clinical AMR C4d staining and C1q-binding impact on allograft survival. We compared clinical, histological and serological features of C4d- and C4d+ AMR, C1q+ and C1q- DSA AMR and analysed C4d and C1q-binding impact on allograft survival. Among 500 for-cause kidney allograft biopsies, 48 fulfilled AMR criteria. C4d+ AMR [N = 18 (37.5%)] have significantly higher number class I DSA (P = 0.02), higher microvascular score (P = 0.02) and more transplant glomerulopathy (P = 0.04). C1q+ AMR [N = 20 (44%)] presented with significantly more class I and class II DSA (P = 0.005 and 0.04) and C4d+ staining (P = 0.01). Graft losses were significantly higher in the C4d+ group (P = 0.04) but similar in C1q groups. C4d+ but not C1q+ binding was an independent risk factor for graft loss [HR = 2.65; (1.11-6.34); P = 0.028]. In our cohort of clinical AMR, C4d+ staining but not C1q+ binding is an independent risk factor for graft loss. Allograft loss and patient survival were similar in C1q+ and C1q- AMR.

Development and validation of a prognostic index for allograft outcome in kidney recipients with transplant glomerulopathy.

We studied 92 patients with transplant glomerulopathy to develop a prognostic index based on the risk factors for allograft failure within five years of diagnosis (Development cohort). During 60 months (median) follow-up, 64 patients developed allograft failure. A chronic-inflammation score generated by combining Banff ci, ct and ti scores, serum creatinine and proteinuria at biopsy, were independent risk factors for allograft failure. Based on the Cox model, we developed a prognostic index and classified patients into risk groups. Compared to the low-risk group (median allograft survival over 60 months from diagnosis), patients in the medium risk group had a hazard ratio of 2.83 (median survival 25 months), while those in the high-risk group had a hazard ratio of 5.96 (median survival 3.7 months). We next evaluated the performance of the prognostic index in an independent external cohort of 47 patients with transplant glomerulopathy (Validation cohort). The hazard ratios were 2.18 (median survival 19 months) and 16.27 (median survival 1.6 months), respectively, for patients in the medium and high-risk groups, compared to the low-risk group (median survival 47 months). Our prognostic index model did well in measures of discrimination and calibration. Thus, risk stratification of transplant glomerulopathy based on our prognostic index may provide informative insight for both the patient and physician regarding prognosis and treatment.

Membranous Nephropathy Associated With Immunological Disorder-Related Liver Disease: A Retrospective Study of 10 Cases.

The association between membranous nephropathy (MN) and immunological disorder-related liver disease has not been extensively investigated, and the specific features of this uncommon association, if any, remain to be determined.We retrospectively identified 10 patients with this association. We aimed to describe the clinical, biological, and pathological characteristics of these patients and their therapeutic management. The possible involvement of the phospholipase A2 receptor (PLA2R) in these apparent secondary forms of MN was assessed by immunohistochemistry with renal and liver biopsy specimens.The mean delay between MN and liver disease diagnoses was 3.9 years and the interval between the diagnosis of the glomerular and liver diseases was <1.5 years in 5 patients. MN was associated with a broad spectrum of liver diseases including primary biliary cirrhosis (PBC), autoimmune hepatitis (AIH), and primary sclerosing cholangitis (PSC). AIH whether isolated (n = 3) or associated with PBC (n = 2) or PSC (n = 2) was the most frequent autoimmune liver disease. Circulating PLA2R antibodies were detected in 4 out of 9 patients but the test was performed under specific immunosuppressive treatment in 3 out of 9 patients. Seven of the 9 patients with available renal tissue specimens displayed enhanced expression of PLA2R in glomeruli whereas PLA2R was not expressed in liver parenchyma from these patients or in normal liver tissue. The study of immunoglobulin (Ig) subclasses of deposits in glomeruli revealed that the most frequent pattern was the coexistence of IgG1 and IgG4 immune deposits with IgG4 predominating.Detection of PLA2R antibodies in glomeruli but not in liver parenchyma is a common finding in patients with MN associated with autoimmune liver disease, suggesting that these autoantibodies are not exclusively detected in idiopathic MN.

Minimal change nephrotic syndrome associated with non-Hodgkin lymphoid disorders: a retrospective study of 18 cases.

Few studies have examined the occurrence of minimal change nephrotic syndrome (MCNS) in patients with non-Hodgkin lymphoma (NHL). We report here a series of 18 patients with MCNS occurring among 13,992 new cases of NHL. We analyzed the clinical and pathologic characteristics of this association, along with the response of patients to treatment, to determine if this association relies on a particular disorder. The most frequent NHLs associated with MCNS were Waldenström macroglobulinemia (33.3%), marginal zone B-cell lymphoma (27.8%), and chronic lymphocytic leukemia (22.2%). Other lymphoproliferative disorders included multiple myeloma, mantle cell lymphoma, and peripheral T-cell lymphoma. In 4 patients MCNS occurred before NHL (mean delay, 15 mo), in 10 patients the disorders occurred simultaneously, and in 4 patients MCNS was diagnosed after NHL (mean delay, 25 mo). Circulating monoclonal immunoglobulins were present in 11 patients. A nontumoral interstitial infiltrate was present in renal biopsy specimens from 3 patients without significant renal impairment. Acute kidney injury resulting from tubular lesions or renal hypoperfusion was present in 6 patients. MCNS relapse occurred more frequently in patients treated exclusively by steroid therapy (77.8%) than in those receiving steroids associated with chemotherapy (25%). In conclusion, MCNS occurs preferentially in NHL originating from B cells and requires an aggressive therapeutic approach to reduce the risk of MCNS relapse.

APOL1 polymorphisms and development of CKD in an identical twin donor and recipient pair.

We report an occurrence of progressive loss of transplant function and ultimately transplant failure after living related kidney transplantation involving monozygotic twin brothers of Afro-Caribbean origin who were both heterozygous for the G1 and G2 kidney disease risk alleles in the APOL1 gene, which encodes apolipoprotein L-I. A 21-year-old man with end-stage kidney disease of unknown cause received a kidney from his brother, who was confirmed as a monozygotic twin by microsatellite analysis. Thirty months after transplantation, the patient presented with proteinuria and decreased estimated glomerular filtration rate; a biopsy of the transplant showed typical focal segmental glomerulosclerosis lesions. He received steroid therapy, but progressed to kidney failure 5 years later. The twin brother had normal kidney function without proteinuria at the time of transplantation; however, 7 years later, he was found to have decreased estimated glomerular filtration rate (40mL/min/1.73m(2)) and proteinuria (protein excretion of 2.5g/d). APOL1 genotyping revealed that both donor and recipient were heterozygous for the G1 and G2 alleles. This case is in stark contrast to the expected course of kidney transplantation in identical twins and suggests a role for APOL1 polymorphisms in both the donor and recipient.

Clinicopathological study of glomerular diseases associated with sarcoidosis: a multicenter study.

BACKGROUND: The association between sarcoidosis and glomerular diseases has not been extensively investigated in a large series and the potential features of this uncommon association remain to be determined. METHODS: We retrospectively identified 26 patients with biopsy-proven glomerular lesions that occurred in a sarcoidosis context. Potential remission of glomerular disease and sarcoidosis under specific treatment (steroid and/or immunosuppressive agents) was recorded for all patients. Demographic, clinical and biological characteristics were assessed at the time of kidney biopsy for each patient. Therapeutic data were analyzed for all patients. RESULTS: Glomerular disease occurred after the diagnosis of sarcoidosis in 11 of 26 cases (42%) (mean delay of 9.7 years). In six patients (23%), the glomerulopathy preceded the sarcoidosis diagnosis (mean delay 8 years). In the last nine patients (35%), both conditions occurred simultaneously. The most frequent glomerular disease occurring in sarcoidosis patients was membranous nephropathy in eleven cases. Other glomerular lesions included IgA nephropathy in six cases, focal segmental glomerulosclerosis in four patients, minimal change nephrotic syndrome for three patients and proliferative lupus nephritis in two patients. Granulomatous interstitial nephritis was associated with glomerular disease in six patients and was exclusively found in patients in whom the both disease occurred simultaneously. In nine patients with simultaneous glomerular and sarcoidosis diseases, we observed a strong dissociation between glomerular disease and sarcoidosis in terms of steroid responsiveness. At the end of the follow-up (mean of 8.4 years), six patients had reached end-stage renal disease and three patients had died. CONCLUSIONS: A wide spectrum of glomerular lesions is associated with sarcoidosis. The close temporal relationship observed in some patients suggests common causative molecular mechanisms of glomerular injury but complete remission of both diseases in response to exclusive steroid therapy is infrequent.

Upregulation of c-mip is closely related to podocyte dysfunction in membranous nephropathy.

Membranous nephropathy is a glomerular disease typified by a nephrotic syndrome without infiltration of inflammatory cells or proliferation of resident cells. Although the cause of the disease is unknown, the primary pathology involves the generation of autoantibodies against antigen targets on the surface of podocytes. The mechanisms of nephrotic proteinuria, which reflect a profound podocyte dysfunction, remain unclear. We previously found a new gene, c-mip (c-maf-inducing protein), that was associated with the pathophysiology of idiopathic nephrotic syndrome. Here we found that c-mip was not detected in the glomeruli of rats with passive-type Heymann nephritis given a single dose of anti-megalin polyclonal antibody, yet immune complexes were readily present, but without triggering of proteinuria. Rats reinjected with anti-megalin develop heavy proteinuria a few days later, concomitant with c-mip overproduction in podocytes. This overexpression was associated with the downregulation of synaptopodin in patients with membranous nephropathy, rats with passive Heymann nephritis, and c-mip transgenic mice, while the abundance of death-associated protein kinase and integrin-linked kinase was increased. Cyclosporine treatment significantly reduced proteinuria in rats with passive Heymann nephritis, concomitant with downregulation of c-mip in podocytes. Thus, c-mip has an active role in the podocyte disorders of membranous nephropathy.

c-mip down-regulates NF-κB activity and promotes apoptosis in podocytes.

The mechanisms of podocyte disorders in cases of idiopathic nephrotic syndrome (INS) are complex and remain incompletely elucidated. The abnormal regulation of NF-κB may play a key role in the pathophysiology of these podocyte diseases, but at present, NF-κB has not been thoroughly investigated. In this study, we report that induction of c-mip in podocytes of patients with INS is associated with a down-regulation of RelA, a potent antiapoptotic factor that belongs to the NF-κB family. Overexpression of c-mip in differentiated podocytes promotes apoptosis by inducing caspase-3 activity and up-regulating the proapoptotic protein Bax, whereas the overall levels of the antiapoptotic protein Bcl-2 was concomitantly decreased. The associated overexpression of RelA prevented the proapoptotic effects of c-mip. In addition, the targeted induction of c-mip in podocytes in vivo inhibited the expression of the RelA protein and increased the Bax/Bcl-2 ratio. The expression of both c-mip and active caspase-3 increased in focal and segmental glomerulosclerosis biopsies, and both proteins displayed a close spatial relationship. These results suggest that alterations in NF-κB activity might result from the up-regulation of c-mip and are likely to contribute to podocyte disorders in cases of INS.

Acute interstitial nephritis with predominant plasmacytic infiltration in patients with HIV-1 infection.

We describe a new form of acute interstitial nephritis with predominant plasmacytic infiltration in 2 patients with active human immunodeficiency virus 1 (HIV-1) infection. Clinical features included acute kidney injury and proteinuria, but no sicca syndrome. Acute kidney injury was characterized by a high serum creatinine level and nephrotic syndrome with no hematuria or leukocyturia. Kidney biopsy specimens from both patients showed interstitial infiltration by mononuclear cells composed mainly of CD138(+) plasmacytes and diffuse effacement of podocyte foot processes with no deposits. In one patient with Guillain-Barré syndrome, a sural nerve biopsy showed plasmacyte infiltration and immunohistochemistry was strongly positive for HIV-1 p24 protein. In both patients, minor salivary glands and bone marrow were infiltrated by lymphocytes, consistent with B-cell activation induced by HIV-1 infection. Other common causes of acute interstitial nephritis, including B-cell lymphoma and diffuse infiltrative lymphocytosis syndrome, were actively looked for and excluded. Treatment with highly active antiretroviral therapy was effective; symptoms rapidly improved, serum creatinine level decreased, and proteinuria resolved. Exclusion of other common known causes of acute interstitial nephritis and the dramatic response with highly active antiretroviral therapy suggests HIV-1 as a likely cause. The acute interstitial nephritis probably was induced by HIV-1-driven nonspecific B-cell activation. Further investigations are needed to confirm the direct pathogenic role of HIV-1.

Intrarenal IFN-γ mRNA expression differentiates clinical and subclinical glomerulitis in renal transplant recipients.

BACKGROUND: Transplant glomerulitis, characterized by mononuclear cell infiltration of glomeruli, is likely to occur during clinical or subclinical antibody-mediated rejection. METHODS: To determine whether T-cell phenotype influences the clinical presentation of this pathologic condition, we used reverse transcription quantitative polymerase chain reaction to analyze expression of Treg cells (Foxp3), cytotoxic CD8 T cells (Granzyme B), Th1 cells (INF-γ,T Bet), Th2 cells (GATA3, IL-4), and Th17 pathway (IL-17). Our study included 20 renal transplant recipients exhibiting subclinical glomerulitis (SG) diagnosed after a routine 3-month posttransplant biopsy. Results were compared with those observed in 22 patients with normal routine biopsies at 3 months (N) and 17 patients with clinical glomerulitis occurring during early acute renal dysfunction within the first year after transplantation in a context of acute antibody-mediated rejection. RESULTS: Our results show that expression of IL-4 mRNA was significantly higher in SG patients than in N patients (P = 0.02). Expression of IFN-γ was significantly higher in patients with clinical glomerulitis than in patients with SG (P<0.001) and was associated with a clinical expression of glomerulitis. CONCLUSION: Our results suggest that the balance of Th1/Th2 is likely to differentiate clinical expression of transplant glomerulopathy. They also indicate that therapeutic approaches in cases of SG should be defined with caution and take into account transcriptional criteria.

T-cell phenotype in protocol renal biopsy from transplant recipients treated with belatacept-mediated co-stimulatory blockade.

BACKGROUND: Belatacept is thought to disrupt the interaction between CD80/86 and CD28, thus preventing T-cell activation by blocking the co-stimulatory second signal. However, the consequences on the T-cell profile in human renal transplant cases have not been determined. METHODS: In this study, we analysed intra-graft levels of the mRNAs for Treg (FOXP3), cytotoxic CD8 T cells (Granzyme B), Th1 (INFγ, Tbet), Th2 (GATA3) and Th17 (RORγt and IL-17) in protocol biopsies obtained 12 months after renal transplantation in recipients treated with Belatacept or calcineurin inhibitor (CNI). RESULTS: Only the intra-graft abundance of FOXP3 mRNA was significantly lower (P < 0.001) in the Belatacept group than the CNI group. Conclusions. These results are in agreement with in vitro data suggesting that CD28 is a major co-stimulatory signal of both Tregs development and peripheral homeostasis but contrast with clinical trials showing a better 1-year graft function and a lower incidence of chronic allograft nephropathy in patients receiving Belatacept than patients treated with CNI. They suggest that immune benefits induced by Belatacept are not mediated by Treg expansion and that FOXP3 is not by itself a prognostic marker of long-term graft function in a non-inflammatory context. These results have to be, however, considered as preliminary since the size of our study population is limited.

Renal transplantation in patients with sarcoidosis: a French multicenter study.

BACKGROUND AND OBJECTIVES: Sarcoidosis is a multisystem disorder of unknown etiology. The outcome of renal transplantation on patients with sarcoidosis is not well known. A few case reports have described recurrence of sarcoidosis after transplant. Here, we report for the first time results and outcome of renal transplantation in a series of patients with sarcoidosis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Eighteen patients with sarcoidosis who underwent renal transplantation were identified retrospectively in eight French renal transplantation departments. Patient medical charts, demographics, and the outcome of renal transplantation were reviewed. RESULTS: Initial renal disease was related to sarcoidosis in 10 patients. At the end of the follow-up (median, 42 months), patient and death-censored graft survival were 94.4% and the mean GFR was 60 ml/min per 1.73 m(2). Five patients (27%) experienced recurrence of sarcoidosis including extra-renal involvement in two patients and renal involvement in three patients. Median GFR was lower in the group of patients with renal recurrence compared with that of the entire cohort: 31 ml/min per 1.73 m(2). Recurrence occurred shortly after transplantation (median period, 13 months). Risk factors for recurrence included primary renal disease related to sarcoidosis and a shorter delay between the last episode of sarcoidosis and renal transplantation. CONCLUSIONS: Our results indicate that renal transplantation may be carried out safely in transplant candidates with sarcoidosis. Recurrence is not rare and is likely to affect graft outcome. These results fully justify a specific clinical and histologic monitoring mainly during the early posttransplant period.

c-mip impairs podocyte proximal signaling and induces heavy proteinuria.

Idiopathic nephrotic syndrome comprises several podocyte diseases of unknown origin that affect the glomerular podocyte, which controls the permeability of the filtration barrier in the kidney to proteins. It is characterized by the daily loss of more than 3 g of protein in urine and the lack of inflammatory lesions or cell infiltration. We found that the abundance of c-mip (c-maf inducing protein) was increased in the podocytes of patients with various acquired idiopathic nephrotic syndromes in which the podocyte is the main target of injury. Mice engineered to have excessive c-mip in podocytes developed proteinuria without morphological alterations, inflammatory lesions, or cell infiltration. Excessive c-mip blocked podocyte signaling by preventing the interaction of the slit diaphragm transmembrane protein nephrin with the tyrosine kinase Fyn, thereby decreasing phosphorylation of nephrin in vitro and in vivo. Moreover, c-mip inhibited interactions between Fyn and the cytoskeletal regulator N-WASP (neural Wiskott-Aldrich syndrome protein) and between the adaptor protein Nck and nephrin, potentially accounting for cytoskeletal disorganization and the effacement of foot processes seen in idiopathic nephrotic syndromes. The intravenous injection of small interfering RNA targeting c-mip prevented lipopolysaccharide-induced proteinuria in mice. Together, these results identify c-mip as a key component in the molecular pathogenesis of acquired podocyte diseases.

Arteriolar hyalinization predicts delayed graft function in deceased donor renal transplantation.

Delayed renal graft function (DGF) remains a largely unpredictable and burdensome consequence of deceased donor renal transplantation. There is growing evidence that histologic and molecular analyses of baseline donor kidney biopsies can predict both short- and long-term graft outcome. We performed histologic analyses of 172 preimplantation kidney biopsies to determine reliable histologic risk factors for DGF. Fifty-six recipients presented a DGF (incidence 32%). Univariate analysis revealed that arteriolar hyalinization (P=0.019), arterial intima fibrosis (0.004), donor age (P=0.001), duration of cold ischemia time (P=0.001), and recipient age (P=0.001) were significantly associated with DGF. Multivariate analysis revealed that the only independent histologic factor was arteriolar hyalinization (P=0.036). This histologic predictive factor, together with previously identified clinical risk factors, could guide clinical decisions regarding use, allocation, or immunosuppression protocols for minimization of DGF.

Intragraft levels of Foxp3 mRNA predict progression in renal transplants with borderline change.

The optimal therapeutic management of borderline lymphocytic infiltrates in renal allografts, described by Banff criteria, is unknown, largely because of the inability to predict clinical outcome in these cases. For determination of molecular factors that may predict outcome in cases of borderline change histology, mRNA levels of Foxp3, Granzyme B, IFN-gamma, IL-23, and RORgammat were measured in renal tissue from 46 untreated patients. Twenty-five patients were considered "nonprogressive," defined by a serum creatinine that remained <110% of baseline during the 40 d after biopsy. Twenty-one patients were considered "progressive," defined by an increase in serum creatinine >110% from baseline and by repeat histologic examination within 40 d showing progression toward acute rejection. Only Foxp3 mRNA levels were significantly higher in nonprogressors than in progressors (P = 0.001). Analysis of receiver operating characteristic curves demonstrated that the outcome for patients with biopsies showing borderline change could be predicted with 90% sensitivity and 79.1% specificity using the optimal Foxp3 mRNA cutoff value. Our findings suggest that the measurement of Foxp3 mRNA offers a means of improving prediction of outcome of borderline change.

A 59-kD renal antigen as a new target for rapidly progressive glomerulonephritis.

Anti-glomerular basement membrane (anti-GBM) antibodies are the hallmark of anti-GBM disease, which is characterized by rapidly progressive glomerulonephritis. We describe the case of a 58-year-old woman who presented with rapidly progressive glomerulonephritis with typical anti-GBM staining found by means of direct immunofluorescence microscopy, associated with linear immunoglobin G deposits on tubules. Serum analysis showed circulating anti-tubular basement membrane antibodies, but failed to detect anti-GBM antibodies. Immunoblotting showed that serum antibodies reacted with a 59-kd antigen found along both the GBM and tubular basement membrane.

Risk factors and outcome of focal and segmental glomerulosclerosis recurrence in adult renal transplant recipients.

BACKGROUND: Recurrence of nephrotic syndrome (NS) after renal transplantation for primary focal segmental glomerulosclerosis (FSGS) is a frequent and still unpredictable complication. However, risk factors for recurrence have not yet been clearly identified. METHODS: Data from 33 patients who underwent 35 renal transplantations for FSGS in two French centres are reported. RESULTS: Recurrent NS occurred in 12 transplant recipients (34%). A significantly higher number of patients in the group with recurrence (R group) compared with the group without recurrence (NR group) received cyclosporine for FSGS treatment before transplantation (83.3% vs 43.4%, P<0.02). Donors of R group recipients were significantly older than those of the non-NR group recipients (42.8 years vs 35 years, P<0.05). A higher number of patients from the R group required post-transplantation dialysis (33.3% vs 17.4%, P = 0.002). Surprisingly, acute rejection occurred more frequently in patients of the NR group compared with the R group, although the difference was not significant. Among the 12 patients with NS relapse, 9 were treated with plasmapheresis. Graft loss related to recurrence occurred in 6 cases. The 5-year graft survival was significantly lower in patients with recurrent NS compared with patients without recurrence (57% vs 82%, P<0.001). CONCLUSION: This study confirms the benefit to identify in the future clinical or biological predictive risk factors for NS recurrence after renal transplantation. It also indicates that donor age is a reliable risk factor for recurrence in adult recipients and suggests for the first time a possible opposite relationship between recurrent FSGS and acute rejection.

Acute graft pyelonephritis: a potential cause of acute rejection in renal transplant.

Acute graft pyelonephritis is a common complication in renal transplant recipients. The consequences of this complication on kidney allograft survival remain controversial. Bacterial infection is likely to activate the immune system, potentially leading to acute or chronic rejection. Here, we report for the first time two documented cases of acute rejection occurring shortly after acute graft pyelonephritis, suggesting that pyelonephritis can initiate acute rejection. The immunologic process leading to the alloimmune response is discussed. These reports suggest that acute rejection should be questioned in case of atypical graft outcome in the context of acute graft pyelonephritis.

Molecular diagnosis of renal-allograft rejection: correlation with histopathologic evaluation and antirejection-therapy resistance.

BACKGROUND: Because histopathologic criteria cannot always predict the pathogenesis and response to curative antirejection therapy, new hope derives from the molecular analysis of intragraft immunologic markers. We studied whether the cutoff of intragraft expression level of T-cell activation markers may define subgroups of acute rejection differing either in type of rejection or clinical outcome. METHODS: Forty-three human renal-allograft biopsies were quantified for mRNA expression of granzyme B, Fas ligand, interferon (IFN)gamma, interleukin (IL)-4, and IL-6 with a reverse-transcriptase real-time quantitative polymerase chain reaction (RT-PCR) method. Expression levels were correlated with the histopathologic rejection type according to the Banff 1997 classification criteria, and with the sensitivity to the antirejection immunosuppressive therapy, by means of receiver operating-characteristic (ROC) curves. RESULTS: Granzyme B and Fas ligand mRNA expression up-regulation correlated with all allograft rejection types (P<0.01 for all). Moreover, granzyme B showed the highest sensitivity (90%) and specificity (78%) for the potential detection of histologic borderline changes that will require immunosuppressive therapy (area under the curve [AUC]=0.856, P<0.01). Curative antirejection-therapy resistance of overt, acute-rejection episode was significantly associated with higher Fas ligand gene expression (AUC=0.764, P<0.01, sensitivity [71%], specificity [99.5%]). CONCLUSIONS: Real-time RT-PCR quantification of the over-expression of the granzyme B gene in kidney-graft biopsies has proved to be as reliable in detecting acute rejection as histologic assessment. Furthermore, we demonstrate that the simultaneous measurement of the mRNA up-regulation of Fas ligand might represent an efficient new tool for the prediction of pejorative outcome of acute rejection.