The Immunohistochemical Expression of the Von Willebrand Factor: A Potential Tool to Predict Kidney Allograft Outcomes.

Few reports assessed endothelial activation biomarkers in kidney allograft biopsies using immunohistochemistry. This retrospective cohort study evaluated the association between posttransplant outcomes and the immunohistochemistry expression of Caveolin-1, Von Willebrand Factor (Vwf), and T-Cadherin in for-cause biopsies diagnosed as interstitial fibrosis and tubular atrophy of unknown etiology. Samples with antibody-mediated changes were excluded. The patients were followed for 3 years after the biopsy or until graft loss/death. Seventy-one (71) samples from 66 patients were included. Eighteen (25.4%) patients lost their grafts, mainly due to chronic rejection (33.3%). Caveolin-1 and T-Cadherin were not associated with graft loss. Vwf had good accuracy in predicting graft failure (AUC 0.637, 95% CI 0.486 to 0.788 P =0.101). The presence of more than 10% of Vwf positivity in the microvasculature (Vwf >10%) was associated with reduced death-censored graft survival (58.2% vs. 85.4% P =0.006), and this result was also observed in the subgroup presenting mild interstitial fibrosis (ci=1) (65.7% vs. 88.6% P =0.033). The multivariate analysis showed that Vwf >10% was an independent risk factor for graft loss (HR=2.88, 95% CI 1.03 to 8.02 P =0.043). In conclusion, Vwf might be an additional tool to predict allograft outcomes in kidney transplant recipients with interstitial fibrosis and tubular atrophy of unknown etiology, probably reflecting immune endothelial activation.

Temporal Reduction in COVID-19-Associated Fatality Among Kidney Transplant Recipients: The Brazilian COVID-19 Registry Cohort Study.

Data from the general population suggest that fatality rates declined during the course of the pandemic. This analysis, using data extracted from the Brazilian Kidney Transplant COVID-19 Registry, seeks to determine fatality rates over time since the index case on March 3rd, 2020. Data from hospitalized patients with RT-PCR positive SARS-CoV-2 infection from March to August 2020 (35 sites, 878 patients) were compared using trend tests according to quartiles (Q1: <72 days; Q2: 72-104 days; Q3: 105-140 days; Q4: >140 days after the index case). The 28-day fatality decreased from 29.5% (Q1) to 18.8% (Q4) (pfor-trend = 0.004). In multivariable analysis, patients diagnosed in Q4 showed a 35% reduced risk of death. The trend of reducing fatality was associated with a lower number of comorbidities (20.7-10.6%, p for-trend = 0.002), younger age (55-53 years, pfor-trend = 0.062), and better baseline renal function (43.6-47.7 ml/min/1.73 m2, pfor-trend = 0.060), and were confirmed by multivariable analysis. The proportion of patients presenting dyspnea (pfor-trend = 0.001) and hypoxemia (pfor-trend < 0.001) at diagnosis, and requiring intensive care was also found reduced (pfor-trend = 0.038). Despite possible confounding variables and time-dependent sampling differences, we conclude that COVID-19-associated fatality decreased over time. Differences in demographics, clinical presentation, and treatment options might be involved.

Procurement Biopsies Can Predict Unfavorable Outcomes in Kidneys With Low MAPI Score Values.

BACKGROUND: There are few reports about the usefulness of Maryland Aggregate Pathology Index (MAPI) score in procurement biopsies. This study aimed to evaluate the association between histopathological analysis according to MAPI and unfavorable outcomes in the first year after kidney transplantation (KT). METHODS: This retrospective study included deceased-donor KT patients whose grafts were biopsied before transplantation and had low MAPI scores (<8) in frozen sections (FSs). Paraffin sections (PSs) were analyzed after KT. MAPI parameters were global glomerulosclerosis in more than 15% (2 patients), periglomerular fibrosis (4 patients), wall-lumen ratio of arteries >0.5 (2 patients), arteriolar hyalinosis (4 patients), and interstitial scar (3 patients). Multivariable models were used to analyze risk factors for delayed graft function (DGF), prolonged DGF, inferior renal function, and graft loss (P < .05). RESULTS: One hundred fifty-nine KTs were included. Donors (n = 120) were predominantly men (70%) and young adults (37.68 ± 12.50 years old) who suffered a traumatic death (55.8%). Recipients were predominantly men (62.26%) and adults (45.70 ± 15.80 years old) with kidney disease of unknown etiology (39.6%). Low rates of agreement between FS and PS were observed for all MAPI criteria, with kappa values ranging from 0.28 to 0.51. Using FS, no histologic parameter was independently associated with outcomes. After adjustment, glomerulosclerosis was an independent risk factor for prolonged DGF (odds ratio = 6.18: 95% confidence interval, 1.27-30.18) and wall-lumen ratio >0.5 for inferior renal function at 1 year (odds ratio = 4.08; 95% confidence interval, 1.21-13.76). CONCLUSION: Procurement biopsies can be useful to predict inferior outcomes even in kidneys with low MAPI scores.

The immunohistochemical expression of von Willebrand factor, T-cadherin, and Caveolin-1 is increased in kidney allograft biopsies with antibody-mediated injury.

BACKGROUND: There are only a few reports evaluating the applicability of endothelial-damage markers analysis by immunohistochemistry (IHC) in kidney allograft samples. This study analyzed the expression of Caveolin-1 (Cav), von Willebrand factor (Vwf), and T-cadherin (Cad) in kidney biopsies and their association with antibody-mediated injury. METHODS: In this retrospective study, 114 cases with antibody-mediated changes (Banff, 2020) and 72 with interstitial fibrosis/tubular atrophy were selected. IHC for Cav, Vwf and Cad was performed and evaluated according to their qualitative expression in peritubular capillaries. The cases were grouped according to the presence of microvascular inflammation (MVI), donor-specific antibodies (DSA), C4d positivity and antibody-mediated rejection (AMR). A level of significance < 0.05 was adopted. RESULTS: Vwf expression was associated with MVI (p < 0.001), DSA (p = 0.016), C4d (p < 0.001) and AMR (p < 0.001), and was higher in DSA+/C4d+ cases despite MVI (p < 0.001). The expression of Cad correlated with MVI (p = 0.015), C4d (p = 0.005) and AMR (p = < 0.001). Cad was more expressed in chronic AMR compared with acute/active cases (p = 0.001). Cav expression was associated with MVI (p = 0.029) and AMR (p = 0.016) and was also higher in chronic AMR (p = 0.049). A combined score of Vwf and Cad was higher in AMR when compared with C4d without rejection and IF/TA cases (p < 0.001). CONCLUSION: Vwf, Cad and Cav expression shows association with antibody-mediated injury and may be helpful to support AMR diagnosis.

Lessons from SARS-CoV-2 screening in a Brazilian organ transplant unit.

Protecting immunosuppressed patients during infectious disease outbreaks is crucial. During this novel coronavirus disease 2019 pandemic, preserving "clean areas" in hospitals assisting organ transplant recipients is key to protect them and to preserve transplantation activity. Evidence suggests that asymptomatic carriers might transmit the SARS-CoV-2, challenging the implementation of transmission preventive strategies. We report a single-center experience using universal SARS-CoV-2 screening for all inpatients and newly admitted patients to an Organ Transplant Unit located in a region with significantly high community-based transmission.

The impact of everolimus in reducing cytomegalovirus events in kidney transplant recipients on steroid-avoidance strategy: 3-year follow-up of a randomized clinical trial.

There is no evidence of whether everolimus (EVR) reduces cytomegalovirus (CMV) events in patients receiving steroid-free regimens. Besides, studies evaluating a tacrolimus (TAC) and EVR regimen are limited to 1-year follow-up. In this single-center prospective randomized trial, the incidence of CMV and 3-year efficacy and safety outcomes of EVR were compared to those of mycophenolate sodium (MPS) in a steroid-free regimen based on low-exposure TAC. Both groups received rabbit anti-thymocyte globulin (r-ATG) induction (6 mg/kg) and the steroids were withdrawn at day 7. Maintenance immunosuppression consisted of TAC (4-7 ng/ml until month 3 and 2-4 ng/ml thereafter) plus EVR (3-8 ng/ml) in the EVR group (n = 59); and TAC (4-7 ng/ml during all follow-up) plus MPS (1440 mg) in the MPS group (n = 56). The EVR group presented with a lower incidence of CMV events (18.6% vs. 50%, P = 0.001). No differences were observed in biopsy-proven acute rejection (6.8% vs. 3.6%, P = 0.680),graft loss (0.0% vs. 1.8%, P = 0.487),death (6.8% vs. 1.8%, P = 0.365), or estimated glomerular filtration rate at 36 months (61.1 ± 25.4 vs. 66.3 ± 24 ml/min/1.73 m2 , P = 0.369). A higher proportion of patients discontinued MPS treatment (8.5% vs. 26.8%, P = 0.013) for safety issues. In conclusion, EVR was associated with lower rates of CMV events in patients induced with standard dose r-ATG and a maintenance steroid-free regimen based on TAC. This regimen effectively prevented acute rejection and demonstrated a more favorable safety profile. (ClinicalTrials.gov:NCT02084446).

Genetic diversity of Pneumocystis jirovecii from a cluster of cases of pneumonia in renal transplant patients: Cross-sectional study.

Pneumocystis jirovecii can cause severe potentially life-threatening pneumonia (PCP) in kidney transplant patients. Prophylaxis of patients against PCP in this setting is usually performed during 6 months after transplantation. The aim of this study is to describe the molecular epidemiology of a cluster of PCP in renal transplant recipients in Brazil. Renal transplant patients who developed PCP between May and December 2011 had their formalin-fixed paraffin-embedded (FFPE) lung biopsy samples analysed. Pneumocystis jirovecii 23S mitochondrial large subunit of ribosomal RNA (23S mtLSU-rRNA), 26S rRNA, and dihydropteroate synthase (DHPS) genes were amplified by polymerase chain reaction (PCR), sequenced, and analysed for genetic variation. During the study period, 17 patients developed PCP (only four infections were documented within the first year after transplantation) and six (35.3%) died. Thirty FFPE samples from 11 patients, including one external control HIV-infected patient, had fungal DNA successfully extracted for further amplification and sequencing for all three genes. A total of five genotypes were identified among the 10 infected patients. Of note, four patients were infected by more than one genotype and seven patients were infected by the same genotype. DNA extracted from FFPE samples can be used for genotyping; this approach allowed us to demonstrate that multiple P. jirovecii strains were responsible for this cluster, and one genotype was found infecting seven patients. The knowledge of the causative agents of PCP may help to develop new initiatives for control and prevention of PCP among patients undergoing renal transplant and improve routine PCP prophylaxis.

Tuberculosis after kidney transplantation is associated with significantly impaired allograft function.

BACKGROUND: This study aimed to evaluate renal function before, during, and after the course of tuberculosis (TB) disease in kidney transplant recipients, and assess the risk factors for non-recovery of baseline renal function. METHODS: We performed a retrospective, single-center cohort study, including all patients with confirmed or presumed TB diagnosis after kidney transplant (n=34, 2.1%). Renal function was assessed by serum creatinine (Cr) and glomerular filtration rate (GFR) adjusted for deaths and graft losses. RESULTS: A significant increase was seen in serum Cr during TB disease and treatment: 1.5 mg/dL at baseline (Crbase ), 1.7 mg/dL at diagnosis (P<.001 vs. Crbase ), and 2.4 mg/dL during the peak (P<.001 vs. Crbase ). According to acute kidney injury (AKI) Kidney Disease: Improving Global Outcomes (KDIGO) classification, 29 (85%) patients had AKI: 16 stage 1, 2 stage 2, and 11 stage 3. Three months after the end of the TB treatment, five patients (14.7%) had lost their graft and two others (5.9%) had died. The GFR was lower than the baseline (42.4 mL/min vs 51.6 mL/min, P=.007). In the univariate analysis, peak Cr (odds ratio [OR] 1.276, 95% confidence interval [CI] 0.955-1.705, P=.100), AKI KDIGO stages 2 or 3 (OR 4.958, 95% CI 1.062-23.157, P=.042), severe disease (OR 5.700, 95% CI 1.147-28.330, P=.033), and acute rejection (AR) episodes after TB diagnosis (OR 3.937, 95% CI 0.551-28.116, P=.172) were associated with non-recovery of baseline renal function. No variable was identified in the multivariable model. CONCLUSION: Post-transplantation TB was associated with a high incidence of AKI, and complete recovery of baseline renal function was not achieved after treatment. The severity of TB disease, AKI, and AR episodes that occurred after TB diagnosis are potential causes for this outcome.

The diagnostic yield and complications of open lung biopsies in kidney transplant patients with pulmonary disease.

BACKGROUND: The purpose of this study was to assess the efficacy of open lung biopsy (OLB) in determining the specific diagnosis and the related complications in patients with undiagnosed diffuse pulmonary infiltrates. METHODS: This single center, retrospective study included adult kidney transplant patients who underwent OLB. The patients had diffuse pulmonary infiltrates without definitive diagnoses and failed to respond to empiric antibiotic treatment. We analyzed the number of specific diagnoses, changes in treatment and the occurrence of complications in these patients. A logistic regression was used to determine which variables were predictors of hospital mortality. RESULTS: From April 2010 to April 2014, 87 patients consecutively underwent OLB. A specific diagnosis was reached in 74 (85.1%) patients. In 46 patients (53%), their therapeutic management was changed after the OLB results. Twenty-five (28.7%) patients had complications related to the OLB. The hospital mortality rate was 25.2%. Age, SAPS3 score and complications related to the procedure were independent predictors of all-cause mortality. CONCLUSIONS: OLB is a high-risk procedure with a high diagnostic yield in kidney transplant patients with diffuse pulmonary infiltrates who did not have a definitive diagnosis and who failed to respond to empiric antibiotic treatment. Complications related to OLB were common and were independently associated with intra-hospital mortality.

Subclinical Lesions and Donor-Specific Antibodies in Kidney Transplant Recipients Receiving Tacrolimus-Based Immunosuppressive Regimen Followed by Early Conversion to Sirolimus.

BACKGROUND: There is no evidence on the incidence of subclinical inflammation and scaring lesions in patients receiving tacrolimus (TAC) minimization and elimination immunosuppressive regimens. METHODS: This study analyzed preimplantation, 3 and 24 months protocol biopsies and anti-HLA donor-specific antibodies (DSA) in 140 low immunological risk kidney transplant recipients receiving reduced TAC exposure, prednisone, and mycophenolate, randomized at 3 months to be converted or not to sirolimus (SRL). RESULTS: Mean TAC concentrations were 6.0 ± 2.4 ng/mL and 5.8 ± 2.2 ng/mL at 3 and 24 months. The incidence of subclinical inflammation lesions at 3 months was 9.3%. The incidence of (interstitial fibrosis) IF/(tubular atrophy) TA at month 24 was 57.6%, higher in SRL compared to TAC group (68.8 vs 44.4%; P = 0.022). Patients converted to SRL showed higher incidence of acute rejection (7.3% vs 0%), proteinuria (59.6% vs 25%; P = 0.001), and DSA (17.8% vs 7.3%; P = 0.201), respectively. Biopsy-proven acute rejection (odds ratio [OR] 2.32, 95% confidence interval [95% CI], 0.979-5.518, P = 0.056), subclinical inflammation lesions at 3 months (OR, 11.75; 95% CI, 1.286-107.474; P = 0.029) and conversion to SRL (OR, 2.72; 95% CI, 1.155-6.383; P = 0.022) were associated with IF/TA at month 24. Black ethnicity (OR, 0.22; 95% CI, 0.058-0.873; P = 0.031), donor age (OR, 2.74; 95% CI, 1.329-5.649; P = 0.006), and conversion to SRL (OR, 2.34; 95% CI, 1.043-5.267; P = 0.039) were associated with inferior renal function at 24 months. CONCLUSIONS: In kidney transplant recipients receiving reduced TAC exposure, subclinical inflammation lesions at 3 months were associated with IF/TA at 24 months. Conversion from TAC to SRL was associated with inferior renal function, higher incidence of IF/TA, and trends to higher incidence of DSA at 24 months.

IgA NEPHROPATHY IN PATIENTS RECEIVING A RENAL TRANSPLANT.

BACKGROUND: IgA nephropathy (IgAN) is the third most frequent cause of renal graft loss among patients with primary glomerulonephritis. OBJECTIVES: To assess clinical and laboratorial profile of patients with pre and/or post transplant IgAN, in addition to patient and graft survival in both groups. DESIGN: Data from 146 patients who had received a renal transplant were retrospectively collected and were divided in two groups: group 1-patients with biopsy-documented IgAN as the underlying native kidney disease (n = 128); group 2-patients who developed post-transplant IgAN independent of the underlying disease (n = 18). PARTICIPANTS: Patients submitted to renal transplantation (1998-2010) with pre and/or post transplant IgAN. MEASUREMENTS: Clinical and laboratorial evaluation of renal function of 146 post transplant IgAN patients. RESULTS: Recipients and deceased donors exhibited a higher degree of HLA compatibility (1.0 vs. 2.5 mismatches for groups 1 and 2, respectively). The main post-transplant IgAN presentation was haematuria associated with non-nephrotic proteinuria (44.4%). A histological pattern of focal segmental glomerulosclerosis was observed in 59.2% of biopsy samples. The 10-year patient survival was 93.5% in group 1 and 100% in group 2, and the graft survival rates were 58.5 and 87.2%, respectively. CONCLUSION: The rate of post-transplant IgA diagnosis in our case series was 11%, and IgAN was diagnosed late in the course of transplantation. In most cases, IgAN manifested as haematuria and non-nephrotic proteinuria, without renal graft dysfunction, and this picture might explain late indication of graft biopsies. The 10-year patient survival rates were excellent.

Steroid or tacrolimus withdrawal in renal transplant recipients using sirolimus.

BACKGROUND: Calcineurin inhibitor (CNI) and steroid (ST) withdrawal are strategies under investigation to reduce long-term toxicities associated with current immunosuppressive regimens. We conducted a single center, prospective trial comparing the efficacy and safety of CNI or ST withdrawal in kidney transplant recipients receiving sirolimus-based immunosuppressive regimen. METHODS: Forty-seven recipients of first renal transplant with non-HLA-identical living donors received sirolimus (SRL), tacrolimus (TAC), and ST without induction therapy and were randomized to undergo ST (TAC/SRL group, n = 24) or TAC (SRL/ST group, n = 21) withdrawal 3 months after transplantation. Primary efficacy and safety endpoints were the incidence of biopsy-confirmed acute rejection (BCAR) and renal function at 12 months. RESULTS: No differences were observed in the incidence of BCAR (4.2% vs. 9.5%), graft (95.8% vs. 95.6%), and patient (95.8% vs. 95.6%) survivals or in renal function (60 ± 11.5 vs. 63.4 ± 10.5 ml/min, P = 0.361). Higher mean cholesterol concentration was observed in the SRL/ST group (191.9 ± 63.3 vs. 241.6 ± 61.5 mg/dl, P = 0.019). Treatment discontinuation due to adverse events occurred in 12.5% of patients in TAC/SRL group and 21.7% in SRL/ST group. CONCLUSION: Within this short period of observation, our study was unable to detect any significant difference in major transplant outcomes comparing CNI and ST elimination strategies.