T cell and antibody responses to SARS-CoV-2: Experience from a French transplantation and hemodialysis center during the COVID-19 pandemic

Immunosuppressed organ-transplanted patients are considered at risk for severe forms of COVID-19. Moreover, exaggerated innate and adaptive immune responses might be involved in severe progression of the disease. However, no data on the immune response to SARS-CoV-2 in transplanted patients are currently available. Here, we report the first assessment of antibody and T cell responses to SARS-CoV-2 in 11 kidney-transplanted patients recovered from RT-PCR-confirmed (n = 5) or initially suspected (n = 6) COVID-19. After reduction of immunosuppressive therapy, RT-PCR-confirmed COVID-19 transplant patients were able to mount vigorous antiviral T cell and antibody responses, as efficiently as two nontherapeutically immunosuppressed COVID-19 patients on hemodialysis. By contrast, six RT-PCR-negative patients displayed no antibody response. Among them, three showed very low numbers of SARS-CoV-2-reactive T cells, whereas no T cell response was detected in the other three, potentially ruling out COVID-19 diagnosis. Low levels of T cell reactivity to SARS-CoV-2 were also detected in seronegative healthy controls without known exposure to the virus. These results suggest that during COVID-19, monitoring both T cell and serological immunity might be helpful for the differential diagnosis of COVID-19 but are also needed to evaluate a potential role of antiviral T cells in the development of severe forms of the disease.

Kidney and contrast media: Common viewpoint of the French Nephrology societies (SFNDT, FIRN, CJN) and the French Radiological Society (SFR) following ESUR guidelines

Contrast medium administration is classically considered to cause or worsen kidney failure, but recent data may moderate this assertion. The European Society of Urogenital Radiology recently published guidelines re-evaluating the precautions before administering contrast media. Kidney injury does not constitute a contra-indication to the administration of iodinated contrast medium, as long as the benefit-risk ratio justifies it. Intravenous hydration with 0.9% NaCl or 1.4% sodium bicarbonate is the only validated measure for the prevention of post-iodine contrast nephropathy. This is necessary for intravenous or intra-arterial administration of iodinated contrast agent without first renal pass when the glomerular filtration rate is less than 30mL/min/1.73m², for intra-arterial administration of iodinated contrast agent with first renal passage when the glomerular filtration rate is less than 45mL/min/1.73m², or in patients with acute renal failure. The use of iodinated contrast medium should allow the carrying out of relevant examinations based on an analysis of the benefit-risk ratio and the implementation of measures to prevent toxicity when necessary.

Is intraoperative heparin during renal transplantation useful to reduce graft vascular thrombosis?

OBJECTIVES

The standard treatment for end-stage renal disease is renal transplantation. As vascular anastomoses are performed during the surgery, it may expose to a risk of vascular thrombosis. This raises the question of using intravenous heparin during the procedure. The purpose of this study was to compare the incidence of renal transplant vascular thrombosis in the perioperative period based on whether the patients received or not intraoperative heparin.

METHODS

A single center retrospective study was conducted on a cohort of consecutive patients who underwent renal transplantation between 2011 and 2015. Patients were divided into two groups: patients not receiving heparin vs. receiving heparin at the dose of 0.5mg/kg. A Doppler ultrasound was performed at day one postoperatively to assess the occurrence of vascular thrombosis. Hemorrhagic complications and the need for postoperative transfusion were also assessed.

RESULTS

In total, 261 patients were included. Fifty-one patients received heparin (19.5%). Patient's baseline characteristics were comparable between the groups. No significant difference was found regarding the incidence of vascular thrombosis (6% for both groups, P=1). In addition, no difference was found regarding hemorrhagic complications requiring surgical revision (P=1) as well as early postoperative transfusion rate (P=0.57).

CONCLUSIONS

Our results suggest that intraoperative IV heparin doesn't improve the risk of vascular thrombosis following renal transplantation. However, intraoperative IV heparin was not significantly associated with a higher rate of hemorrhagic complications suggesting that heparin can be safely used if required in some selected patients at higher risk of thrombosis.

LEVEL OF EVIDENCE

3.

[Cardiovascular disorders in autosomal dominant polycystic kidney disease]

Autosomal dominant polycystic kidney disease is the most frequent genetic kidney disease. Cardiovascular disorders associated with autosomal dominant polycystic kidney disease are multiple and may occur early in life. In autosomal dominant polycystic kidney disease cardiovascular morbidity and mortality are related both to the nonspecific consequences of chronic kidney disease and to the particular phenotype of autosomal dominant polycystic kidney disease. Compared to the general population, patients with autosomal dominant polycystic kidney disease present an increased prevalence of hypertension, left ventricular hypertrophy, atrial fibrillation, valvular diseases, aneurisms and arterial dissections. This review article provides an update on cardiovascular disorders associated with autosomal dominant polycystic kidney disease and recent pathophysiological developments.

IgA nephropathy in association with inflammatory bowel diseases: results from a national study and systematic literature review

BACKGROUND

Little is known about clinical characteristics and kidney outcome in patients with biopsy-proven immunoglobulin A nephropathy (IgAN) in a context of inflammatory bowel disease (IBD).

METHODS

We conducted a retrospective multicenter study with centralized histological review, to analyze the presentation, therapeutic management and outcome of 24 patients suffering from IBD associated IgAN relative to a cohort of 134 patients with primary IgAN without IBD.

RESULTS

Crohn's disease and ulcerative colitis accounted for 75% and 25% of IBD-associated IgAN cases, respectively. IBD was diagnosed before IgAN in 23 cases (a mean of 9 years previously) and was considered active at IgAN onset in 23.6% of patients. Hypertension was present in 41.7% of patients. Urinary protein-to-creatinine ratio exceeded 100 mg/mmol in 70.8% of patients (mean: 254 mg/mmol). Estimated glomerular filtration rate (eGFR) exceeded 60 ml/min/1.73m2 in 13/24 patients and only one patient required dialysis. In the Oxford MEST-C classification of renal biopsies, 57% were M1, 48% E1, 76% S1, 57% T1+T2 and 38% C1+C2. Steroids were administered in 50% of cases. After a mean follow-up of 7.2 years, four patients (16.7%) had a poor kidney outcome: end-stage renal disease (n = 3) or a > 50% decrease in eGFR from initial values (n = 1). A similar evolution was observed in patients with primitive IgAN.

CONCLUSIONS

This first case series suggests that IBD-associated IgAN have frequent inflammatory lesions at onset and variable long-term outcome.

Opportunistic infections after conversion to belatacept in kidney transplantation

BACKGROUND

Belatacept (bela) rescue therapy seems to be a valuable option for calcineurin inhibitor chronic toxicity in kidney transplantation. Nevertheless, the risk of infection associated with bela is not well reported.

METHODS

We report the rate of opportunistic infections (OPI) after a switch to bela in a multicentric cohort of 280 kidney transplant patients.

RESULTS

Forty-two OPI occurred in 34 patients (12.1%), on average 10.8 ± 11.3 months after the switch. With a cumulative exposure of 5128 months of bela treatment, we found an incidence of 0.008 OPI/month of exposure, and 9.8 OPI/100 person-years. The most common OPI was cytomegalovirus (CMV) disease in 18/42 OPI (42.9%) and pneumocystis pneumonia in 12/42 OPI (28.6%). Two patients presented a progressive multifocal leucoencephalopathy and two patients developed a cerebral Epstein-Barr virus-induced post-transplant lymphoproliferative disease. OPI led to death in 9/34 patients (26.5%) and graft failure in 4/34 patients (11.8%). In multivariate analysis, estimated glomerular filtration rate <25/mL/min/1.73 m2 on the day of the switch and the use of immunosuppressive agents before transplantation were associated with the occurrence of OPI. We found a higher rate of infection-related hospitalization (24.1 versus 12.3/100 person-years, P = 0.0007) and also a higher rate of OPI (13.2 versus 6.7/100 person-years, P = 0.005) in the early conversion group (within 6 months).

CONCLUSIONS

The risk of OPI is significant post-conversion to bela and may require additional monitoring and prophylactic therapy, particularly regarding pneumocystis pneumonia and CMV disease. These data need to be confirmed in a larger case-control study.

Organ Transplantation in Hereditary Fibrinogen A α-Chain Amyloidosis: A Case Series of French Patients

RATIONALE & OBJECTIVE

Fibrinogen A α-chain amyloidosis (AFib amyloidosis) is a form of amyloidosis resulting from mutations in the fibrinogen A α-chain gene (FGA), causing progressive kidney disease leading to kidney failure. Treatment may include kidney transplantation (KT) or liver-kidney transplantation (LKT), but it is not clear what factors should guide this decision. The aim of this study was to characterize the natural history and long-term outcomes of this disease, with and without organ transplantation, among patients with AFib amyloidosis and various FGA variants.

STUDY DESIGN

Case series.

SETTING & PARTICIPANTS

32 patients with AFib amyloidosis diagnosed by genetic testing in France between 1983 and 2014, with a median follow-up of 93 (range, 4-192) months, were included.

RESULTS

Median age at diagnosis was 51.5 (range, 12-77) years. Clinical presentation consisted of proteinuria (93%), hypertension (83%), and kidney failure (68%). Manifestations of kidney disease appeared on average at age 57 (range, 36-77) years in patients with the E526V variant, at age 45 (range, 12-59) years in those with the R554L variant (P<0.001), and at age 24.5 (range, 12-31) years in those with frameshift variants (P<0.001). KT was performed in 15 patients and LKT was performed in 4. In KT patients with the E526V variant, recurrence of AFib amyloidosis in the kidney graft was less common than with a non-E526V (R554L or frameshift) variant (22% vs 83%; P=0.03) and led to graft loss less frequently (33% vs 100%). Amyloid recurrence was not observed in patients after LKT.

LIMITATIONS

Analyses were based on clinically available historical data. Small number of patients with non-E526V and frameshift variants.

CONCLUSIONS

Our study suggests phenotypic variability in the natural history of AFib amyloidosis, depending on the FGA mutation type. KT appears to be a viable option for patients with the most common E526V variant, whereas LKT may be a preferred option for patients with frameshift variants.

Adrenocortical carcinoma complicated by renal thrombotic microangiopathy, a case-series

Background

Cancer-related thrombotic microangiopathy (CR-TMA) is a rare entity associated with a dismal prognosis. Usually, CR-TMA is associated with mucin-producing carcinomas among which stomach, breast, prostate, lung and pancreas tumours are the most frequent.

Cases presentation

We describe for the first time three cases of CR-TMA due to adrenocortical carcinoma (ACC). All of them had mechanical hemolytic anemia and thrombocytopenia without any other identifiable cause. Bicytopenia was diagnosed either simultaneously with ACC or at the time of metastatic evolution. Two patients had acute kidney injury (AKI) with severe pathological findings on kidney biopsy. Despite total adrenalectomy, chemotherapy, and specific treatment of TMA with plasma-exchanges, renal failure and hemolytic anemia remained. The only manifestation of CR-TMA in the third patient was hemolytic anemia, which resolved after surgical removal of ACC. The evolutions in these patients suggests ACC-related TMA may be related to a circulating factor.

Conclusions

CR-TMAs are rare. Here we describe the first case series of ACC-related TMA, among which two had renal involvement. This entity is associated with dismal renal prognosis despite specific treatment of TMA. According to patients’ evolution, the persistence of TMA may reflect an uncontrolled malignancy.

Ipilimumab-induced renal granulomatous arteritis: a case report

Background

Immune Checkpoint Inhibitors (ICPIs) are promising new drugs in treatment of advanced tumours targeting cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed cell death protein-1 (PD1) or its ligand (PDL-1). Ipilimumab is a monoclonal antibody targeting the CTLA-4 receptor used in treatment of metastatic melanoma. By increasing activity of the immune system, ICPIs lead to immune-related adverse events, such as dermatitis, colitis or hepatitis. ICPIs-related kidney adverse events are rare and acute tubulointerstitial nephritis with or without granuloma have mainly been reported.

Case presentation

We report a case of acute kidney injury in a patient with melanoma treated by ipilimumab. Kidney biopsy revealed acute interlobular and juxtaglomerular granulomatous arteritis, which has not yet been reported in patients treated by ICPIs. Kidney function partially recovered after ipilimumab discontinuation and oral prednisone. Unfortunately, the patient died a few months later from progression of his melanoma.

Conclusion

This case highlights a new mechanism of acute kidney injury related to ICPIs and supports the interest of kidney biopsy in case of ICPIs related acute renal failure.

[Kidney disease in cobalamin C deficiency]

Cobalamin C deficiency (cblC) is the most common inborn error of vitamin B₁₂ metabolism. This autosomal recessive disease is due to mutations in MMACHC gene, encoding a cyanocobalamin decyanase. It leads to hyperhomocysteinemia associated with hypomethioninemia and methylmalonic aciduria. Two distinct phenotypes have been described : early-onset forms occur before the age of one year and are characterized by a severe multisystem disease associating failure to thrive to neurological and ophthalmological manifestations. They are opposed to late-onset forms, less severe and heterogeneous. CblC deficiency-associated kidney lesions remain poorly defined. Thirty-eight cases have been described. Age at initial presentation varied from a few days to 28 years. Most of the patients presented renal thrombotic microangiopathy (TMA) associated with acute renal failure, and 21 patients presented typical lesions of renal thrombotic microangiopathy on kidney biopsy. Prognosis was poor, leading to death in the absence of treatment, and related to the severity of renal lesions in the early-onset forms. Late-onset disease had better prognosis and most of patients were weaned off dialysis after treatment initiation. We suggest that all the patients with renal TMA be screened for cobalamin metabolism disorder, regardless of age and even in the absence of neurological symptoms, to rapidly initiate the appropriate treatment.

Risk Factors for Early Graft Failure and Death After Kidney Transplantation in Recipients Older Than 70 Years

INTRODUCTION

Although kidney transplantation carries a survival benefit compared with dialysis, mortality, especially the first year after transplantation, is high in recipients older than 70. The aim of this study was to evaluate early death and graft failure, and to determine the risk factors associated with these events in this specific population.

METHODS

All patients older than 70 years who received a kidney transplant between January 2000 and December 2014 in the North-West of France were included (n = 171). Baseline characteristics and outcomes after transplantation were studied. Kaplan-Meier analysis was performed to assess patient and graft survival, and Cox regression analysis to evaluate risk factors for graft failure and patient death.

RESULTS

The mean recipient age was 73.3 ± 2.5 years. Death-censored graft survival at 1, 3, and 5 years were 82.6%, 78.7%, and 75.4%, respectively. Patient survival at 1, 3, and 5 years was 90.1%, 82.5%, and 68.1%, respectively. One year after transplantation, 17 patients (9.9%) were dead, mainly from infectious (58.5%) or cardiovascular disease (29.4%). According to the Cox multivariate analysis, the independent risk factors for death or graft failure during the first year were arrhythmia (odds ratio [OR] 2.26; 95% confidence interval [CI] 1.08-4.8), left-ventricular ejection fraction (LVEF) under 56% (OR 2.38; 95% CI 1.18-4.83), human leucocyte antigen (HLA) antibodies (OR 2.1; 95% CI 1.04-4.2), deceased donor from cardiovascular cause (OR 5.18; 95% CI 1.22-6.3), and acute rejection (OR 2.77; 95% CI 1.2-6.3).

CONCLUSION

In kidney transplant recipients older than 70 years, cardiac evaluation and immunosuppression optimization seem to be crucial to improve short-term patient and graft survival.

Endothelium structure and function in kidney health and disease

The kidney harbours different types of endothelia, each with specific structural and functional characteristics. The glomerular endothelium, which is highly fenestrated and covered by a rich glycocalyx, participates in the sieving properties of the glomerular filtration barrier and in the maintenance of podocyte structure. The microvascular endothelium in peritubular capillaries, which is also fenestrated, transports reabsorbed components and participates in epithelial cell function. The endothelium of large and small vessels supports the renal vasculature. These renal endothelia are protected by regulators of thrombosis, inflammation and complement, but endothelial injury (for example, induced by toxins, antibodies, immune cells or inflammatory cytokines) or defects in factors that provide endothelial protection (for example, regulators of complement or angiogenesis) can lead to acute or chronic renal injury. Moreover, renal endothelial cells can transition towards a mesenchymal phenotype, favouring renal fibrosis and the development of chronic kidney disease. Thus, the renal endothelium is both a target and a driver of kidney and systemic cardiovascular complications. Emerging therapeutic strategies that target the renal endothelium may lead to improved outcomes for both rare and common renal diseases.

Early predictors of one-year mortality in patients over 65 presenting with ANCA-associated renal vasculitis: a retrospective, multicentre study

Background

The risk of early death is particularly high in patients over the age of 65 presenting with antineutrophil cytoplasmic antibody (ANCA)-associated renal vasculitis. We hypothesized that by combining disease severity markers, a comorbidity index and serious adverse event reports, we would be able to identify early predictors of one-year mortality in this population.

Methods

We performed a multicentre, retrospective study in the nephrology and internal medicine departments of six tertiary hospitals in northern France. A total of 149 patients (median [interquartile range (IQR)] age: 72.7 [68.5–76.8] years) presenting with ANCA-associated vasculitis and renal involvement were included between January 2002 and June 2015. The primary endpoint was the one-year mortality rate.

Results

Renal function was severely impaired at presentation (median [IQR] peak serum creatinine (SCr): 337 [211–522] μmol/l), and 45 patients required dialysis. The Five-Factor Score (FFS, scored as + 1 point for each poor prognostic factor (age > 65 years, cardiac symptoms, gastrointestinal involvement, SCr ≥150 μmol/L, and the absence of ear, nose, and throat involvement)) was ≥3 in 120 cases. The one-year mortality rate was 19.5%. Most of the deaths occurred before month 6, and most of these were related to severe infections. In a univariate analysis, age, a high comorbidity index, a performance status of 3 or 4, a lack of co-trimoxazole prophylaxis, early severe infection, and disease activity parameters (such as the albumin level, haemoglobin level, peak SCr level, dialysis status, and high FFS) were significantly associated with one-year mortality. In a multivariable analysis, the best predictors were a high FFS (relative risk (RR) [95% confidence interval (CI)] = 2.57 [1.30–5.09]; p = 0.006) and the occurrence of a severe infection during the first month (RR [95%CI] = 2.74 [1.27–5.92]; p = 0.01).

Conclusions

When considering various disease severity markers in over-65 patients with ANCA-associated renal vasculitis, we found that an early, severe infection (which occurred in about a quarter of the patients) is a strong predictor of one-year mortality. A reduction in immunosuppression, the early detection of infections, and co-trimoxazole prophylaxis might help to reduce mortality in this population.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1102-3) contains supplementary material, which is available to authorized users.

Both Monoclonal and Polyclonal Immunoglobulin Contingents Mediate Complement Activation in Monoclonal Gammopathy Associated-C3 Glomerulopathy

C3 glomerulopathy (C3G) results from acquired or genetic abnormalities in the complement alternative pathway (AP). C3G with monoclonal immunoglobulin (MIg-C3G) was recently included in the spectrum of “monoclonal gammopathy of renal significance.” However, mechanisms of complement dysregulation in MIg-C3G are not described and the pathogenic effect of the monoclonal immunoglobulin is not understood. The purpose of this study was to investigate the mechanisms of complement dysregulation in a cohort of 41 patients with MIg-C3G. Low C3 level and elevated sC5b-9, both biomarkers of C3 and C5 convertase activation, were present in 44 and 78% of patients, respectively. Rare pathogenic variants were identified in 2/28 (7%) tested patients suggesting that the disease is acquired in a large majority of patients. Anti-complement auto-antibodies were found in 20/41 (49%) patients, including anti-FH (17%), anti-CR1 (27%), anti-FI (5%) auto-antibodies, and C3 Nephritic Factor (7%) and were polyclonal in 77% of patients. Using cofactor assay, the regulation of the AP was altered in presence of purified IgG from 3/9 and 4/7 patients with anti-FH or anti-CR1 antibodies respectively. By using fluid and solid phase AP activation, we showed that total purified IgG of 22/34 (65%) MIg-C3G patients were able to enhance C3 convertase activity. In five documented cases, we showed that the C3 convertase enhancement was mostly due to the monoclonal immunoglobulin, thus paving the way for a new mechanism of complement dysregulation in C3G. All together the results highlight the contribution of both polyclonal and monoclonal Ig in MIg-C3G. They provide direct insights to treatment approaches and opened up a potential way to a personalized therapeutic strategy based on chemotherapy adapted to the B cell clone or immunosuppressive therapy.

Antithymocyte globulin-induced hemolytic anemia and thrombocytopenia after kidney transplantation

Antithymocyte globulin is the most widely used lymphocyte-depleting treatment in kidney transplantation. In spite of the frequency of side effects, including anemia and thrombocytopenia, their pathophysiological mechanisms are not clearly established. Here, we report the case of a 21-year-old patient who had a first kidney transplantation and received induction immunosuppressive therapy by thymoglobulin. Immediately after kidney transplantation, he developed a severe hemolytic anemia and thrombocytopenia with a subsequent perirenal hematoma, which lead to a second surgical procedure and a transfer to the intensive care unit. Our patients' anemia and thrombocytopenia had heteroimmune characteristics, and thymoglobulin therapy was suspected to be the cause, via an interaction with a common Fc-receptor epitope in the different cell lines.