Biopsy-proven BK virus nephropathy in renal transplant recipients: A multi-central study from Turkey (BK-TURK STUDY).

AIM: BK polyomavirus infection is a challenging complication of renal transplantation. The management is not standardized and is based on reports from transplantation centers' experiences, usually with small sample sizes. Therefore, we aimed to present our countrywide experience with BK virus nephropathy (BKVN) in renal transplant recipients. MATERIALS AND METHODS: Our study was carried out with the participation of 30 transplantation centers from all regions of Turkey. Only cases with allograft biopsy-proven BKVN were included in the study. RESULTS: 13,857 patients from 30 transplantation centers were screened, and 207 BK nephropathy cases were included. The mean age was 46.4 ±  13.1 years, and 146 (70.5%) patients were male. The mean time to diagnosis of BK nephropathy was 15.8 ± 22.2 months after transplantation. At diagnosis, the mean creatinine level was 1.8 ±  0.7 mg/dL, and the mean estimated glomerular filtration rate was 45.8 ± 19.6 mL/min/1.73m2. In addition to dose reduction or discontinuation of immunosuppressive drugs, 18 patients were treated with cidofovir, 11 patients with leflunomide, 17 patients with quinolones, 15 patients with intravenous immunoglobulin (IVIG), 5 patients with cidofovir plus IVIG, and 12 patients with leflunomide plus IVIG. None of the patients receiving leflunomide or leflunomide plus IVIG had allograft loss. During follow-up, allograft loss occurred in 32 (15%) out of 207 patients with BK nephropathy. CONCLUSION: BKVN is still a frequent cause of allograft loss in kidney transplantation and is not fully elucidated. The results of our study suggest that leflunomide treatment is associated with more favorable allograft outcomes.

Concurrent Cobalamin C and Plasminogen Deficiencies in a Patient with Chronic Thrombotic Microangiopathy.

BACKGROUND: Although most patients with atypical hemolytic uremic syndrome (aHUS) have variants in genes participating in alternative complement pathways, rare variants in non-complement pathway-related genes, including DGKE, INF2, MMACHC, PLG, and THBD, have also been described. CASE PRESENTATION: We report an 18-year-old male patient with renal biopsy-proven chronic thrombotic microangiopathy that raised suspicion of aHUS. Whole-exome sequencing revealed a novel pathogenic homozygous MMACHC c.484G>T (p.Gly162Trp) variant. Subsequently, clinical and laboratory findings confirmed cobalamin C (Cbl C) deficiency. Also, homozygous missense c.1112C>T PLG (p.Thr371Ile) variant was detected (it had been reported as a variant of unknown significance). However, the low serum plasminogen (PLG) activity proved the pathogenicity of c.1112C>T. Hence, the patient was diagnosed with concurrent Cbl C and PLG deficiencies. Segregation analysis revealed that the mother and father had the same heterozygous PLG and MMACHC variants. PLG variants have generally been described in aHUS patients concomitant with complement gene variants in the literature; therefore, the association between aHUS and PLG variants is controversial. The possible contribution of PLG deficiency to thrombotic microangiopathy was also discussed in this case. CONCLUSION: Non-complement-mediated aHUS is an exceptional disorder. A limited number of genes are involved in this entity. To our knowledge, this is the first aHUS patient diagnosed with both Cbl C and PLG deficiencies in the literature.

Thromboembolic complications after COVID-19 in kidney transplant recipients.

AIM: Increased venous thrombosis and arterial embolism rates are observed in the general population during or after COVID-19. Data regarding the kidney transplant population are scarce. In this study, we aim to investigate the thrombotic complications and risk factors associated with thrombotic complications in kidney transplant patients. METHODS: This retrospective observational study included adult kidney transplant recipients diagnosed with COVID-19 between March 2020 and June 2022. The endpoint was the occurrence of thromboembolic events. RESULTS: Four hundred and sixty-nine patients were followed for a median of 10.8 months after COVID-19. Forty patients (8.5%) died. Thromboembolic complications developed in 51 (11.9%) of the surviving patients. Twenty-four patients with thromboembolic events were receiving prophylactic anticoagulation before the event. The patients with mild, moderate, and severe COVID-19 were 292, 129, and 48, respectively. Patients with moderate COVID-19 had a significantly higher percentage of thromboembolic complications than patients with mild COVID-19. Older age, prior heart disease, and moderate COVID-19 were significantly associated with thromboembolic events. The incidence of thromboembolic events after COVID-19 is 10.9 per 100 patient-year. CONCLUSION: Thromboembolic complications were observed at increased rates in kidney transplant recipients after COVID-19. Therefore, prospective and cohort studies for post-COVID-19 complications regarding the treatment modalities are urgently needed.

Diagnostic yield and safety of percutaneous native kidney biopsy in pregnancy: 20-years of single-center experience.

BACKGROUND: Percutaneous kidney biopsy is a fundamental procedure in nephrology. Although pregnancy is not a contraindication, a careful risk-benefit assessment is mandatory in pregnancy. We aimed to evaluate safety and diagnostic accuracy of percutaneous kidney biopsy in pregnancy in a single-center retrospective study. METHODS: Percutaneous kidney biopsy was performed in 19 pregnant patients. Demographics, estimated glomerular filtration rates, serum albumin levels, and proteinuria levels at the time of biopsy were evaluated. Biopsy-related complications, diagnoses, and treatments during the follow-up were analyzed. In addition, delivery success, preeclampsia, early delivery, low birth weight rates, and long-term outcomes of the patients were retrieved and analyzed. RESULTS: Mean patient age was 27 (range 16-41) years. Median gestational week at kidney biopsy was 20th. All but one biopsies were diagnostic. Median gestational week of delivery was 35 (range 23-39) gestational weeks. Preterm delivery (< 37 gestational weeks) and low birth weight (< 2500 mg) occurred in 73.7% and 52.6% of cases, respectively. Median weight at birth was 2500 mg. The incidence of preeclampsia was 57.9%. Overall 89.5% of the children survived. Median post-biopsy follow-up was 64 months. Maternal mortality was not observed during the follow-up period. End stage kidney disease developed in one patient. The results of percutaneous kidney biopsy led to therapeutic decisions in 73.7% of cases. CONCLUSIONS: Although percutaneous kidney biopsy is not frequently performed during pregnancy, it is relatively safe and usually diagnostic, and may guide further follow-up.

Outcomes of kidney transplantation in patients with congenital anomalies of the kidney and urinary tract: a propensity-score-matched analysis with case-control design.

BACKGROUND: We compared long-term outcomes after kidney transplantation (KTx) in patients with and without congenital anomalies of the kidney and urinary tract (CAKUT). METHODS: KTx recipients (KTRs) with CAKUT in 1980-2016 were identified; their hard copy and electronic medical records were reviewed and compared to a propensity-score-matched control group (non-CAKUT) from the same period. The primary outcomes were graft loss or death with a functioning graft; secondary outcomes included posttransplant urinary tract infections (UTIs) and biopsy-proven rejection (BPR). RESULTS: : We identified 169 KTRs with CAKUT and 169 matched controls. Median follow-up was 132 (IQR: 75.0-170.0) months. UTIs were more common in CAKUT patients compared to non-CAKUT group (20.7% vs 10.7%; p = 0.01). Rates of BPR were similar between the two groups. In Kaplan-Meier analysis, 10-year graft survival rates were significantly higher in the CAKUT group than in the non-CAKUT group (87.6% vs 69.2%; p < 0.001), while patient survival rates were similar. In multivariate Cox regression analyses, CAKUT (HR: 0.469; 95% CI: 0.320-0.687; p < 0.001) and PRA positivity before transplantation (HR: 3.756; 95% CI: 1.507-9.364; p = 0.005) predicted graft loss. DISCUSSION: Graft survival in KTRs with CAKUT appears superior to KTRs without CAKUT. Transplant centers should develop multidisciplinary educational and social working groups to support and encourage CAKUT patients with kidney failure to seek for transplants.

Propensity score-matched analysis of long-term outcomes for living kidney donation in alternative complement pathway diseases: a pilot study.

BACKGROUND: Atypical hemolytic syndrome (aHUS) and C3 glomerulopathy (C3G) are complement-mediated rare diseases with excessive activation of the alternative pathway. Data to guide the evaluation of living-donor candidates for aHUS and C3G are very limited. The outcomes of living donors to recipients with aHUS and C3G (Complement disease-living donor group) were compared with a control group to improve our understanding of the clinical course and outcomes of living donation in this context. METHODS: Complement disease-living donor group [n = 28; aHUS(53.6%), C3G(46.4%)] and propensity score-matched control-living donor group (n = 28) were retrospectively identified from 4 centers (2003-2021) and followed for major cardiac events (MACE), de novo hypertension, thrombotic microangiopathy (TMA), cancer, death, estimated glomerular filtration rate (eGFR) and proteinuria after donation. RESULTS: None of the donors for recipients with complement-related kidney diseases experienced MACE or TMA whereas two donors in the control group developed MACE (7.1%) after 8 (IQR, 2.6-12.8) years (p = 0.15). New-onset hypertension was similar between complement disease and control donor groups (21.4% vs 25%, respectively, p = 0.75). There were no differences between study groups regarding last eGFR and proteinuria levels (p = 0.11 and p = 0.70, respectively). One related donor for a recipient with complement-related kidney disease developed gastric cancer and another related donor developed a brain tumor and died in the 4th year after donation (2, 7.1% vs none, p = 0.15). No recipient had donor-specific human leukocyte antigen antibodies at the time of transplantation. Median follow-up period of transplant recipients was 5 years (IQR, 3-7). Eleven (39.3%) recipients [aHUS (n = 3) and C3G (n = 8)] lost their allografts during the follow-up period. Causes of allograft loss were chronic antibody-mediated rejection in 6 recipients and recurrence of C3G in 5. Last serum creatinine and last eGFR of the remaining patients on follow up were 1.03 ± 038 mg/dL and 73.2 ± 19.9 m/min/1.73 m2 for aHUS patients and 1.30 ± 0.23 mg/dL and 56.4 ± 5.5 m/min/1.73 m2 for C3G patients. CONCLUSION: The present study highlights the importance and complexity of living related-donor kidney transplant for patients with complement-related kidney disorders and motivates the need for further research to determine the optimal risk-assessment for living donor candidates to recipients with aHUS and C3G.

A comparison of methods of plasmapheresis for the treatment of late antibody mediated rejection in kidney transplant recipients.

INTRODUCTION: We compared the outcomes associated with plasma exchange (PE), double filtration plasmapheresis (DFPP), or immunoadsorption (IA) in the treatment of late antibody mediated rejection (AMR). METHODS: Sixty-nine kidney transplantation (KTx) recipients with late AMR were retrospectively categorized according to management with PE (n = 30), DFPP (n = 22) or IA (n = 17). Allograft loss was compared across treatment groups by Kaplan-Meier analysis and Cox regression. RESULTS: Study groups were similar regarding age, sex, donor type, kidney function, donor specific antibodies, and post-KTx follow-up time. Five-year graft survival trended higher with IA (70.6%) compared to PE (36.7%) and DFPP (27.3%) (p = 0.06). In multivariate Cox regression, baseline eGFR (HR per ml/min/1.73 m2 [95% CI]; 0.96 [0.94-0.99]), rituximab use (HR [95% CI]; 0.42 [0.21-0.84]), interstitial inflammation (i) (HR [95% CI]; 2.05 [1.13-3.69]), and transplant glomerulopathy (cg) (HR [95% CI]; 1.46 [1.13-1.87]) were associated with graft loss. CONCLUSION: These results motivate the need for continued assessment of rituximab and plasmapheresis in larger studies.

Heme oxygenase-1 deficiency as an extremely rare cause of AA-type renal amyloidosis: Expanding the clinical features and review of the literature.

Heme oxygenase-1 (HMOX-1) is an enzyme that regulates heme degradation. Antiinflammatory, antioxidant, and cytoprotective effects of HMOX-1 were also described. It is encoded by the HMOX1 gene, and biallelic mutations cause HMOX-1 deficiency, which is a rare chronic multisystemic inflammatory disorder. This inflammatory status could lead to the development of secondary AA-type amyloidosis theoretically. Here, we report a 30-year-old male with AA-type renal amyloidosis due to a chronic inflammatory condition of unknown origin. Paternal consanguinity and dysmorphic features raised suspicion of a rare genetic disorder. Clinical exome sequencing (CES) confirmed the HMOX-1 deficiency diagnosis related to homozygous missense G139V mutation. To the best of our knowledge, our patient is the eleventh HMOX-1 deficiency case in the literature. Also, HMOX-1 deficiency-related systemic AA-type amyloidosis has not been reported before.

An atypical case of refractory passenger lymphocyte syndrome after renal transplantation.

BACKGROUND: Passenger lymphocyte syndrome (PLS) causes immune-mediated hemolysis in solid and bone marrow transplant recipients. Donor-derived antibodies against the recipient erythrocyte drive the pathogenesis. It is a rare entity in kidney transplantation, and most of the cases are self-limited. CASE PRESENTATION: A 36-year-old woman presented with fatigue 13 days after living donor renal transplantation. The operation was uneventful, and she was discharged with normal graft functions on the 11th day of transplantation Findings were consistent with cold agglutinin disease at her admission. However, the cold agglutinin test was negative. Eventually, she was diagnosed with PLS. Refractory intravascular hemolysis and frank hemoglobinuria were also present in the patient. Hemolysis was resistant to steroids, intravenous immunoglobulin (IVIG), and Rituximab. Because of life-threatening anemia related to refractory PLS, mycophenolate and tacrolimus were interrupted. However, hemolysis persisted. Following that, immunoadsorption (IA) treatment was obtained. Unfortunately, graft loss occurred due to rejection despite the resolution of PLS after IA. CONCLUSION: PLS is a rare and usually self-limited entity. Our case was an atypical refractory PLS that resembled cold agglutinin disease. Also, frank hemoglobinuria was observed related to severe intravascular hemolysis. These features have not been described before in PLS, to the best of our knowledge. Additionally, IA treatment had never been reported in the literature for PLS, as far as we know. Treatment and management could be a challenge in refractory PLS. Rituximab, IVIG, and extracorporeal treatments could be beneficial. It should be borne in mind that refractory PLS can cause graft and patient loss.

Long-Term Outcomes of Living-Related Kidney Donation for Alport Syndrome Spectrum: A Propensity Score-Matched Analysis.

INTRODUCTION: Data to guide the evaluation of living-related donor candidates for kidney transplant recipients with Alport syndrome (AS) spectrum are limited. We aimed to examine a cohort of living-related donors to recipients with AS and compare their outcomes with a control group to improve understanding of the clinical course and outcomes of living donation in this context. METHODS: Living donors (LDs) of AS recipients and propensity score-matched control LDs without any family history of AS (control group) were followed for major cardiac events, death, post-donation estimated glomerular filtration rate (eGFR), and proteinuria. RESULTS: There were 31 LDs (48.4% male), in whom relationship to AS recipient included mother (45.2%), father (32.3%), sibling (16.1%), grandparent (3.2%), and uncle (3.2%). Long-term outcomes over 10.0 (IQR, 3.0-15.0) years were evaluated in 25 and 25 LDs from study and control groups, respectively. During follow-up, 5 LDs (20.0%) in study group developed major cardiac event (acute coronary ischemia [n = 4] and severe congestive heart failure [n = 1]) after 5.5 (IQR, 4.5-10.3) years, whereas only 2 (8.0%) LDs in control group developed major cardiac events (p = 0.221). New-onset hypertension was higher in study group (56.0%) compared to the control group (16.0%) (p = 0.003). Three donors in study and 2 donors in control group who developed new-onset hypertension died during follow-up (p = 0.297). Major cardiac event rate was significantly higher in donors who developed hypertension after donation (0 vs. 28.0%, p < 0.001). There were no differences between study groups regarding last eGFR and proteinuria levels (p = 0.558 and p = 0.120, respectively). DISCUSSION/CONCLUSION: Although the risk of kidney disease can be minimized by careful donor evaluation, our findings suggest that hypertension risk after the donation is higher than expected in related donors of recipients with AS.

Efficacy of intravenous combined immunosuppression with plasmapheresis in adult patients with refractory primary focal segmental glomerulosclerosis.

BACKGROUND: Primary focal segmental glomerulosclerosis (FSGS) treatment is based on immunosuppressive therapies. Since refractory disease is common, alternative methods are emerging. One of these methods is plasmapheresis with intravenous cyclosporine and corticosteroids, and it could be an option in post-transplant recurrent FSGS. We retrospectively investigated the efficacy of this combined treatment in adult patients with refractory primary FSGS. METHODS: Seven refractory primary FSGS patients were included. Demographics, estimated glomerular filtration rates, serum albumin levels, urine protein/creatinine ratios, and previous treatments were evaluated. Also, complications and remission rates were assessed. RESULTS: Median patient age was 23 years. Median duration of diagnosis was 2 years. Median number of plasmapheresis sessions was 14. Five of seven patients (71.4%, one complete, four partial remissions) were responders after the protocol. Changes in serum albumin levels and proteinuria after protocol were statistically significant (P = 0.018 and P = 0.018, respectively). eGFR levels did not change statistically (P = 0.753). Median follow-up duration after the treatment was 17 months. However, two patients experienced disease relapse (28.5%). End-stage kidney disease was developed in two patients. Sustained remission rate was 42.8% during follow-up (One complete and two partial remissions). Also, 42.8% of patients experienced catheter infections. Catheter-associated thrombosis that required surgery was observed in a patient. CONCLUSIONS: Plasmapheresis combined with intravenous cyclosporine and corticosteroids could be an option in refractory primary FSGS. High response rates after this protocol were encouraging. However, the relapsing disease was observed after the cessation of apheresis. Also, complications of the protocol could limit the applicability.

COVID-19 in Kidney Transplant Recipients: A Multicenter Experience from the First Two Waves of Pandemic.

BACKGROUND: Kidney transplant recipients have an increased risk of complications from COVID-19. However, data on the risk of allograft damage or death in kidney transplant recipients recovering from COVID-19 is limited. In addition, the first and second waves of the pandemic occurred at different times all over the world. In Turkey, the Health Minister confirmed the first case in March 2020; after that, the first wave occurred between March and August 2020; afterward, the second wave began in September 2020. This study aims to demonstrate the clinical presentations of kidney transplant recipients in the first two waves of the pandemic in Turkey and explore the impact of COVID-19 on clinical outcomes after the initial episode. METHODS: Patients with COVID-19 from seven centers were included in this retrospective cohort study. Initially, four hundred and eighty-eight kidney transplant recipients diagnosed with COVID-19 between 1 March 2020 to 28 February 2021 were enrolled. The endpoints were the occurrence of all-cause mortality, acute kidney injury, cytokine storm, and acute respiratory distress syndrome. In addition, longer-term outcomes such as mortality, need for dialysis, and allograft function of the surviving patients was analyzed. RESULTS: Four hundred seventy-five patients were followed up for a median of 132 days after COVID-19. Forty-seven patients (9.9%) died after a median length of hospitalization of 15 days. Although the mortality rate (10.1% vs. 9.8%) and intensive care unit admission (14.5% vs. 14.5%) were similar in the first two waves, hospitalization (68.8% vs. 29.7%; p < 0.001), acute kidney injury (44.2% vs. 31.8%; p = 0.009), acute respiratory distress syndrome (18.8% vs. 16%; p = 0.456), and cytokine storm rate (15.9% vs. 10.1%; p = 0.072) were higher in first wave compared to the second wave. These 47 patients died within the first month of COVID-19. Six (1.4%) of the surviving patients lost allografts during treatment. There was no difference in the median serum creatinine clearance of the surviving patients at baseline (52 mL/min [IQR, 47-66]), first- (56 mL/min [IQR, 51-68]), third- (51 mL/min [IQR,48-67]) and sixth-months (52 mL/min [IQR, 48-81]). Development of cytokine storm and posttransplant diabetes mellitus were independent predictors for mortality. CONCLUSIONS: Mortality remains a problem in COVID-19. All the deaths occur in the first month of COVID-19. Also, acute kidney injury is common in hospitalized patients, and some of the patients suffer from graft loss after the initial episode.

Differences in clinical outcomes of COVID-19 among vaccinated and unvaccinated kidney transplant recipients.

INTRODUCTION: The remarkable efficacy and effectiveness of COVID-19 vaccines have been described in healthy individuals, but kidney transplant recipients have been excluded from these studies. Therefore, real-world evidence of these vaccines can guide clinicians in predicting complications in kidney transplant recipients and how many doses of vaccines are protective. In this study, we aimed to investigate the impact of the COVID-19 vaccines on kidney transplant recipients with SARS-CoV-2 infection. MATERIAL AND METHOD: This matched case-control study included vaccinated kidney transplant recipients with COVID-19 from two centers between 1 May and 1 October 2021. All patients in the vaccinated group received a minimum of two doses of the vaccine and were diagnosed with COVID-19 at least one month after the last dose. Each vaccinated patient was matched with an unvaccinated kidney transplant recipient diagnosed with COVID. The endpoints were all-cause mortality, hospitalization, intensive care unit admission, acute kidney injury, cytokine storm, and acute respiratory distress syndrome. RESULTS: The median age of vaccinated seventy-two participants was 45 years, and 41 of the participants were men in the vaccinated group. Four patients in the vaccinated group and nine patients in the control group died during follow-up (p = 0.247). Seventeen patients in the vaccinated group, thirty-four participants in the control group were hospitalized (p = 0.004); five vaccinated patients and ten unvaccinated patients were followed-up in the ICU during follow-up (p = 0.168). Thirteen of the vaccinated and twelve unvaccinated patients developed acute kidney injury (p = 0.16). The occurrence of cytokine storm (n = 4 vs. n = 11; p = 0.061) and acute respiratory distress syndrome (n = 5 vs. n = 10; p = 0.168) was higher in the patient group compared to the control group. CONCLUSION: COVID-19 remains a fatal disease despite advancing treatment modalities and preventive strategies. COVID-19 vaccines can't prevent death in all kidney transplant recipients, but they decrease hospitalization rate and duration in most patients.

Impact of the COVID-19 pandemic on interest in renal diseases.

There is an information gap about the public's interest in nephrological diseases in the COVID-19 era. The objective was to identify public interest in kidney diseases during the pandemic. In this infodemiology study, Google Trends was queried for a total of 50 search queries corresponding to a broad spectrum of nephrological diseases and the term "nephrologist." Two time intervals of 2020 (March 15-July 4 and July 5-October 31) were compared to similar time intervals of 2016-2019 for providing information on interest in different phases of the pandemic. Compared to the prior 4 years, analyses showed significant decreases in relative search volume (RSV) in the majority (76%) of search queries on March 15-July 4, 2020 period. However, RSV of the majority of search queries (≈70%) on July 5-October 31, 2020 period was not significantly different from similar periods of the previous 4 years, with an increase in search terms of amyloidosis, kidney biopsy, hematuria, chronic kidney disease, hypertension, nephrolithiasis, acute kidney injury, and Fabry disease. During the early pandemic, there have been significant decreases in search volumes for many nephrological diseases. However, this trend reversed in the period from July 5 to October 31, 2020, implying the increased need for information on kidney diseases. The results of this study enable us to understand how COVID-19 impacted the interest in kidney diseases and demands/needs for kidney diseases by the general public during the pandemic.