Higher Levels of SARS-CoV-2 Genetic Variation in Immunocompromised Patients: A Retrospective Case-Control Study.

BACKGROUND: A severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection lasts longer in immunocompromised hosts than in immunocompetent patients. Prolonged infection is associated with a higher probability of selection for novel SARS-CoV-2 mutations, particularly in the spike protein, a critical target for vaccines and therapeutics. METHODS: From December 2020 to September 2022, respiratory samples from 444 immunocompromised patients and 234 health care workers positive for SARS-CoV-2, diagnosed at 2 hospitals in Paris, France, were analyzed using whole-genome sequencing using Nanopore technology. Custom scripts were developed to assess the SARS-CoV-2 genetic diversity between the 2 groups and within the host. RESULTS: Most infections were SARS-CoV-2 Delta or Omicron lineages. Viral genetic diversity was significantly higher in infections of immunocompromised patients than those of controls. Minor mutations were identified in viruses sequenced from immunocompromised individuals, which became signature mutations for newer SARS-CoV-2 variants as the epidemic progressed. Two patients were coinfected with Delta and Omicron variants. The follow-up of immunocompromised patients revealed that the SARS-CoV-2 genome evolution differed in the upper and lower respiratory tracts. CONCLUSIONS: This study found that SARS-CoV-2 infection in immunocompromised patients is associated with higher genetic diversity, which could lead to the emergence of new SARS-CoV-2 variants with possible immune evasion or different virulence characteristics.

Rituximab as maintenance therapy for ANCA-associated vasculitides: pooled analysis and long-term outcome of 277 patients included in the MAINRITSAN trials.

OBJECTIVE: To compare the long-term efficacy and safety of azathioprine (AZA), 18-month fixed-schedule rituximab (RTX), 18-month tailored RTX and 36-month RTX in preventing relapses in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis who achieved a complete remission after induction therapy. Patients treated with 36-month RTX received either a fixed or a tailored regimen for the first 18 months and a fixed regimen for the last 18 months (36-month fixed/fixed RTX and 36-month tailored/fixed RTX, respectively). METHODS: The Maintenance of Remission using Rituximab in Systemic ANCA-associated Vasculitis (MAINRITSAN) trials sequentially compared: 18-month fixed-schedule RTX versus AZA (MAINRITSAN); 18-month fixed-schedule RTX versus 18-month tailored-RTX (MAINRITSAN2); and extended therapy to 36 months with four additional RTX infusions after MAINRITSAN2 versus placebo (MAINRITSAN3). Patients were then followed prospectively through month 84 and their data were pooled to analyse relapses and adverse events. The primary endpoint was relapse-free survival at month 84. RESULTS: 277 patients were enrolled and divided in 5 groups: AZA (n=58), 18-month fixed-schedule RTX (n=97), 18-month tailored-RTX (n=40), 36-month tailored/fixed RTX (n=42), 36-month fixed/fixed RTX (n=41). After adjustment for prognostic factors, 18-month fixed-schedule RTX was superior to AZA in preventing major relapses at month 84 (HR 0.38, 95% CI 0.20 to 0.71). The 18-month tailored-RTX regimen was associated with an increased risk of major relapse compared with fixed-schedule regimen (HR 2.92, 95% CI 1.43 to 5.96). The risk of major relapse was similar between 36-month fixed/fixed and 18-month fixed-RTX (HR 0.69, 95% CI 0.38 to 1.25). CONCLUSIONS: According to these results, it appears that the 84-month remission rate is higher with an 18-month fixed RTX regimen compared with AZA and 18-month tailored RTX. Also, extending RTX to 36 months does not appear to reduce the long-term relapse rate compared with the 18-month fixed RTX regimen. However, as this study was underpowered to make this comparison, further prospective studies are needed to determine the potential long-term benefits of extending treatment in these patients.

Lupus activity and outcomes in lupus patients undergoing maintenance dialysis.

OBJECTIVES: Lupus activity has long been considered to decline after initiation of maintenance dialysis (MD). This assumption is based on limited historical data. We aimed to describe the natural history of lupus in patients undergoing MD. METHODS: We assembled a national retrospective cohort of lupus patients who started dialysis between 2008 and 2011, included in the REIN registry with a 5-year follow-up. We analysed healthcare consumption from the National Health Data System. We evaluated the proportion of patients 'off-treatment' (i.e. receiving 0-5 mg/d of corticosteroids, without any immunosuppressive therapy) after the start of MD. We describe the cumulative incidences of non-severe and severe lupus flares, cardiovascular events, severe infections, kidney transplantation and survival. RESULTS: We included 137 patients (121 females and 16 males), with a median age of 42 years. The proportion of patients 'off-treatment' at dialysis initiation was 67.7% (95% CI: 61.8, 73.8%), and increased to 76.0% (95% CI: 73.3, 78.8) at 1 year and 83.4% (95% CI: 81.0, 85.9%) at 3 years, with a lower proportion in younger patients. Lupus flares mainly occurred in the first year after MD initiation, and at 12 months 51.6% of patients had presented a non-severe lupus flare and 11.6% a severe lupus flare. In addition, 42.2% (95% CI: 32.9, 50.3%) and 23.7% (95% CI: 16.0, 30.7%) of patients at 12 months had been hospitalized for cardiovascular events or infections, respectively. CONCLUSION: The proportion of lupus patients off-treatment increases after MD initiation, but non-severe and severe lupus flares continue to occur, mainly during the first year. This calls for the continued follow-up of lupus patients by lupus specialists after dialysis initiation.

Lower access to kidney transplantation for women in France is not explained by comorbidities and social deprivation.

BACKGROUND: Access to kidney transplantation (KT) remains challenging for patients with end-stage kidney disease. This study assessed women's access to KT in France by considering comorbidities and neighborhood social deprivation. METHODS: All incident 18-85-year-old patients starting dialysis in France between January 1, 2017 and December 31, 2019 were included. Three outcomes were assessed: (i) access to the KT waiting list after dialysis start, (ii) KT access after waitlisting, and (iii) KT access after dialysis start. Cox and Fine and Gray models were used. Gender-EDI and gender-age interactions were tested and analyses were performed among strata if required. RESULTS: 29,395 patients were included (35% of women). After adjusting for social deprivation and comorbidities, women were less likely to be waitlisted at 1 (adjHR: 0.91 [0.87-0.96]) and 3 years (adjHR: 0.87 [0.84-0.91]) post-dialysis initiation. This disparity concerned mainly ≥60-year-old women (adjHR: 0.76 [0.71-0.82] at 1 year and 0.75 [0.71-0.81] at 3 years). Access to KT, after 2 years of waitlisting was similar between genders. Access to KT was similar between genders at 3 years after dialysis start, but decreased for women after 4 years (adjHR: 0.93 [0.88-0.99]) and longer follow-up (adjHR: 0.90 [0.85-0.96]). CONCLUSIONS: In France, women are less likely to be waitlisted and undergo kidney transplantation. This is driven by the ≥60-year-old group and is not explained by comorbidities or social deprivation level.

Glomerular diseases in pregnancy: pragmatic recommendations for clinical management.

Our understanding of the various aspects of pregnancy in women with kidney diseases has significantly improved in the last decades. Nevertheless, little is known about specific kidney diseases. Glomerular diseases are not only a frequent cause of chronic kidney disease in young women, but combine many challenges in pregnancy: immunologic diseases, hypertension, proteinuria, and kidney tissue damage. An international working group undertook the review of available current literature and elicited expert opinions on glomerular diseases in pregnancy with the aim to provide pragmatic information for nephrologists according to the present state-of-the-art knowledge. This work also highlights areas of clinical uncertainty and emphasizes the need for further collaborative studies to improve maternal and fetal health.

C3 Glomerulopathy With Concurrent Thrombotic Microangiopathy: Clinical and Immunological Features.

RATIONALE & OBJECTIVE: C3 glomerulopathy (C3GN) and atypical hemolytic uremic syndrome (aHUS) are 2 distinct rare kidney diseases caused by dysregulation of the alternative complement pathway. Patients with C3GN and concurrent kidney lesions of thrombotic microangiopathy (TMA) have been rarely reported. We characterized the clinical features and underlying immunological abnormalities in these patients. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Patients with C3GN and concomitant TMA lesions on biopsy registered from 2009 to 2019 in the French National Registry of C3GN. FINDINGS: Among 278 registered patients with C3GN, 16 (6%) had biopsy-proven glomerular and/or vascular TMA lesions. Their median age at diagnosis was 39 years (range, 7-76), and 59% were female. Fourteen of the 16 patients (88%) had an estimated glomerular filtration rate of<30mL/min/1.73m2 and 3 of 16 (19%) required dialysis. Twelve of the 14 evaluated patients (86%) showed evidence of mechanical hemolysis. Fifty percent of the patients had low C3 levels. Six of the 14 evaluated patients had a rare variant in complement genes, and 4 of the 16 patients (25%) had monoclonal gammopathy. Among the 16 patients, 10 (63%) received eculizumab, 5 (31%) received immunosuppressive therapy, and 4 (25%) received clone-targeted chemotherapy. Median kidney survival was 49 months. LIMITATIONS: Small retrospective case series with a limited number of biopsies including electron microscopy. CONCLUSIONS: Concomitant C3GN and TMA is extremely rare and is associated with poor kidney outcomes. Genetic or acquired abnormalities of the alternative complement pathway are common as is the presence of monoclonal gammopathy, which may inform the selection of treatment approaches.

Efficacy and safety of methylprednisolone pulse followed by oral prednisone vs. oral prednisone alone in sarcoidosis tubulointerstitial nephritis: a randomized, open-label, controlled clinical trial.

BACKGROUND: We determine the benefit of pulsed methylprednisolone for improving kidney function in patients with sarcoidosis tubulointerstitial nephritis. METHODS: We conducted a multicenter, prospective, randomized, open-label, controlled trial in patients with biopsy-proven acute tubulointerstitial nephritis caused by sarcoidosis at 21 sites in France. Patients were randomly assigned to receive a methylprednisolone pulse 15 mg/kg/day for 3 days, then oral prednisone (MP group) or oral prednisone 1 mg/kg/day alone (PRD group). The primary end point was a positive response at 3 months, defined as a doubling of estimated glomerular filtration rate (eGFR) compared with the eGFR before randomization. RESULTS: We randomized 40 participants. Baseline eGFR before PRD was 22 mL/min/1.73m2 {interquartile range [IQR], 16-44} and before MP was 25 mL/min/1.73m2 (IQR, 22-36) (P = .3). The two groups did not differ in underlying pathological lesions, including mean percentage of interstitial fibrosis and intensity of interstitial infiltrate. In the intent-to-treat population, the median eGFR at 3 months did not significantly differ between the PRD and MP groups: 45 (IQR, 34-74) and 46 (IQR, 39-65) mL/min/1.73m2. The primary end point at 3 months was achieved in 16 of 20 (80%) PRD patients and 10 of 20 (50%) MP patients (P = .0467). The eGFR was similar between the two groups after 1, 3, 6, and 12 months of treatment. For both groups, eGFR at 1 month was strongly correlated with eGFR at 12 months (P < .0001). The two groups did not differ in severe adverse events. CONCLUSION: Compared with a standard oral steroid regimen, intravenous MP may have no supplemental benefit for renal function in patients with tubulointerstitial nephritis caused by sarcoidosis.Trial Registration: ClinicalTrials.gov: NCT01652417; EudraCT: 2012-000149-11.

Endopeptidase Cleavage of Anti-Glomerular Basement Membrane Antibodies in vivo in Severe Kidney Disease: An Open-Label Phase 2a Study.

BACKGROUND: The prognosis for kidney survival is poor in patients presenting with circulating anti-glomerular basement membrane (GBM) antibodies and severe kidney injury. It is unknown if treatment with an endopeptidase that cleaves circulating and kidney bound IgG can alter the prognosis. METHODS: An investigator-driven phase 2a one-arm study (EudraCT 2016-004082-39) was performed in 17 hospitals in five European countries. A single dose of 0.25 mg/kg of imlifidase was given to 15 adults with circulating anti-GBM antibodies and an eGFR <15 ml/min per 1.73m2. All patients received standard treatment with cyclophosphamide and corticosteroids, but plasma exchange only if autoantibodies rebounded. The primary outcomes were safety and dialysis independency at 6 months. RESULTS: At inclusion, ten patients were dialysis dependent and the other five had eGFR levels between 7 and 14 ml/min per 1.73m2. The median age was 61 years (range 19-77), six were women, and six were also positive for anti-neutrophil cytoplasmic antibodies. Then 6 hours after imlifidase infusion, all patients had anti-GBM antibodies levels below the reference range of a prespecified assay. At 6 months 67% (ten out of 15) were dialysis independent. This is significantly higher compared with 18% (nine out of 50) in a historical control cohort (P<0.001, Fisher's exact test). Eight serious adverse events (including one death) were reported, none assessed as probably or possibly related to the study drug. CONCLUSIONS: In this pilot study, the use of imlifidase was associated with a better outcome compared with earlier publications, without major safety issues, but the findings need to be confirmed in a randomized controlled trial.Clinical Trial registration number: EUDRACT 2016-004082-39 https://www.clinicaltrialsregister.eu/ctr-search/trial/2007-001377-28/results.

Results from a nationwide retrospective cohort measure the impact of C3 and soluble C5b-9 levels on kidney outcomes in C3 glomerulopathy.

C3 glomerulopathy (C3G) is a rare complement-mediated disease. Specific treatments are not yet available and factors predictive of kidney survival such as age, kidney function and proteinuria are not specific to C3G. The prognostic value of biomarkers of complement activation, which are pathognomonic of the diseases, remains unknown. In a large cohort of 165 patients from the French National registry, we retrospectively assess the prognostic value of C3, soluble C5b-9 (sC5b-9), C3 nephritic factor, and rare disease-predicting variants in complement genes in predicting clinical outcome of patients. By multivariate analysis age (adult onset), reduced kidney function (defined by estimated glomerular filtration rate under 60ml/min) and presence of rare disease-predicting variants in complement genes predicted risk of progression to kidney failure. Moreover, by multivariate analysis, normal C3/high sC5b-9 levels or low C3/normal sC5b-9 levels remained independently associated with a worse kidney prognosis, with the relative risk 3.7- and 8-times higher, respectively. Subgroup analysis indicated that the complement biomarker profiles independently correlated to kidney prognosis in patients with adult but not pediatric onset. In this subgroup, we showed that profiles of biomarkers C3 and/or sC5b-9 correlated with intra glomerular inflammation and may explain kidney outcomes. In children, only the presence of rare disease-predicting variants correlated with kidney survival. Thus, in an adult population, we propose a three-point C3G prognostic score based on biomarker profiles at risk, estimated glomerular filtration rate at presentation and genetic findings, which may help stratify adult patients into subgroups that require close monitoring and more aggressive therapy.

Weaning of maintenance immunosuppressive therapy in lupus nephritis (WIN-Lupus): results of a multicentre randomised controlled trial.

OBJECTIVES: Lupus nephritis (LN) is a frequent complication of systemic lupus erythematosus (SLE). Severe (proliferative) forms of LN are treated with induction immunosuppressive therapy (IST), followed by maintenance IST, to target remission and avoid relapses. The optimal duration of maintenance IST is unknown. The WIN-Lupus trial tested whether IST discontinuation after 2‒3 years was non-inferior to IST continuation for two more years in proliferative LN. METHODS: WIN-Lupus was an investigator-initiated multicentre randomised controlled trial. Patients receiving maintenance IST with azathioprine or mycophenolate mofetil for 2-3 years, and hydroxychloroquine, were randomised (1:1) into two groups: (1) IST continuation and (2) IST discontinuation. The primary endpoint was the relapse rate of proliferative LN at 24 months. Main secondary endpoints were the rate of severe SLE flares, survival without renal relapse or severe flare, adverse events. RESULTS: Between 2011 and 2016, 96 patients (out of 200 planned) were randomised in WIN-Lupus: IST continuation group (n=48), IST discontinuation group (n=48). Relapse of proliferative LN occurred in 5/40 (12.5%) patients with IST continuation and in 12/44 (27.3%) patients with IST discontinuation (difference 14.8% (95% CI -1.9 to 31.5)). Non-inferiority was not demonstrated for relapse rate; time to relapse did not differ between the groups. Severe SLE flares (renal or extrarenal) were less frequent in patients with IST continuation (5/40 vs 14/44 patients; p=0.035). Adverse events did not differ between the groups. CONCLUSIONS: Non-inferiority of maintenance IST discontinuation after 2‒3 years was not demonstrated for renal relapse. IST discontinuation was associated with a higher risk of severe SLE flares. TRIAL REGISTRATION NUMBER: NCT01284725.

ANCA-Negative Pauci-immune Necrotizing Glomerulonephritis: A Case Series and a New Clinical Classification.

RATIONALE & OBJECTIVE: Pauci-immune necrotizing glomerulonephritis (PING) is usually associated with the presence of antineutrophil cytoplasmic antibodies (ANCA). However, a minority (2%-3%) of patients with PING do not have detectable ANCA. We assessed the clinical spectrum and outcome of patients with ANCA-negative PING. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: 74 patients with ANCA-negative PING diagnosed in 19 French nephrology centers between August 2006 and December 2018 were included in the series. Patients' medical files were reviewed, and kidney biopsies were centrally reexamined by pathologists who were masked to the diagnosis. FINDINGS: Median age at diagnosis was 69 (IQR, 61-76) years. The clinical and pathological features were remarkable for a high frequency of extrarenal manifestations (54%), nephrotic syndrome (32%), and endocapillary hypercellularity (31%). Three main subtypes of ANCA-negative PING were observed: infection-associated (n=9[12%]), malignancy-associated (n=6[8%]), and primary (n=57[77%]). For patients with primary PING, induction treatment included mainly corticosteroids (n=56[98%]), cyclophosphamide (n=37[65%]), and rituximab (n=5[9%]). Maintenance treatment consisted mainly of corticosteroids (n=42[74%]), azathioprine (n=18[32%]), and mycophenolate mofetil (n=11[19%]). After a median follow-up period of 28 months, 28 (38%) patients had died and 20 (27%) developed kidney failure (estimated glomerular filtration rate<15mL/min/1.73m2). Eleven (21%) patients (9 with primary and 2 with malignancy-associated PING) relapsed. LIMITATIONS: Retrospective study and limited number of patients; electron microscopy was not performed to confirm the absence of glomerular immune deposits. CONCLUSIONS: Within the spectrum of ANCA-negative PING, infection and malignancy-associated forms represent a distinct clinical subset. This new clinical classification may inform the management of ANCA-negative PING, which remains a severe form of vasculitis with high morbidity and mortality rates despite immunosuppressive treatments.

Basophils and IgE contribute to mixed connective tissue disease development.

BACKGROUND: Mixed connective tissue disease (MCTD) is a rare and complex autoimmune disease that presents mixed features with other connective tissue diseases, such as systemic lupus erythematosus, systemic sclerosis, and myositis. It is characterized by high levels of anti-U1 small nuclear ribonucleoprotein 70k autoantibodies and a high incidence of life-threatening pulmonary involvement. The pathophysiology of MCTD is not well understood, and no specific treatment is yet available for the patients. Basophils and IgE play a role in the development of systemic lupus erythematosus and thus represent new therapeutic targets for systemic lupus erythematosus and other diseases involving basophils and IgE in their pathogenesis. OBJECTIVE: We sought to investigate the role of basophils and IgE in the pathophysiology of MCTD. METHODS: Basophil activation status and the presence of autoreactive IgE were assessed in peripheral blood of a cohort of patients with MCTD and in an MCTD-like mouse model. Basophil depletion and IgE-deficient animals were used to investigate the contribution of basophils and IgE in the lung pathology development of this mouse model. RESULTS: Patients with MCTD have a peripheral basopenia and activated blood basophils overexpressing C-C chemokine receptor 3. Autoreactive IgE raised against the main MCTD autoantigen U1 small nuclear ribonucleoprotein 70k were found in nearly 80% of the patients from the cohort. Basophil activation and IgE anti-U1 small nuclear ribonucleoprotein 70k were also observed in the MCTD-like mouse model along with basophil accumulation in lymph nodes and lungs. Basophil depletion dampened lung pathology, and IgE deficiency prevented its development. CONCLUSIONS: Basophils and IgE contribute to MCTD pathophysiology and represent new candidate therapeutic targets for patients with MCTD.

Shiga Toxin-Associated Hemolytic Uremic Syndrome in Adults, France, 2009-2017.

We conducted a retrospective study on hemolytic uremic syndrome caused by Shiga toxin-producing Escherichia coli (STEC) in 96 adults enrolled in the cohort of the National Reference Center for Thrombotic Microangiopathies network in France during 2009-2017. Most infections were caused by STEC strains not belonging to the O157 or O104 serogroups. Thirty (31.3%) patients had multiple risk factors for thrombotic microangiopathy. In total, 61 (63.5%) patients required dialysis, 50 (52.1%) had a serious neurologic complication, 34 (35.4%) required mechanical ventilation, and 19 (19.8%) died during hospitalization. We used multivariate analysis to determine that the greatest risk factors for death were underlying immunodeficiency (hazard ratio 3.54) and severe neurologic events (hazard ratio 3.40). According to multivariate analysis and propensity score-matching, eculizumab treatment was not associated with survival. We found that underlying conditions, especially immunodeficiency, are strongly associated with decreased survival in adults who have hemolytic uremic syndrome caused by STEC.

CD62L on blood basophils: a first pre-treatment predictor of remission in severe lupus nephritis.

BACKGROUND: Basophils were recently shown to contribute to lupus nephritis (LN). This study assessed blood basophil activation markers (BAMs) for the diagnosis of LN severity and as pre-treatment prognostic markers of the response to treatment in patients with severe LN. METHOD: The diagnostic study included all the patients of a monocentric prospective observational cohort built with consecutive patients diagnosed with LN on the basis of a renal biopsy. The prognostic study selected patients of this cohort according to the following inclusion criteria: ≥18 years old, Class III or IV A ± C ± Class V or pure Class V LN at the time of inclusion and treated with an induction treatment for LN. Clinical data and BAMs were obtained at the time of the kidney biopsy. LN remission status was recorded 12 months after induction therapy initiation. Associations between baseline data and histological severity of LN or LN remission were assessed using logistic regression. RESULTS: No significant association was found between BAMs and the histological severity of LN in 101 patients. Among the 83 patients included in the prognostic study, 64 reached renal remission. CD62L expression on blood basophils at baseline was independently negatively associated with remission at 12 months [odds ratio = 0.26, 95% confidence interval 0.08-0.82, P = 0.02 for quantitative CD62L expression >105 (geometric fluorescent intensity) gMFI]. CD62L <105 gMFI was associated with a probability of 0.87 of LN remission in the next 12 months after the start of induction therapy. CONCLUSION: Pre-treatment CD62L expression on blood basophils could be a first predictive biomarker of renal response to induction therapy at 12 months in patients with severe LN.

The spectrum of kidney biopsies in hospitalized patients with COVID-19, acute kidney injury, and/or proteinuria.

We report a multicentric retrospective case series of patients with COVID-19 who developed acute kidney injury and/or proteinuria and underwent a kidney biopsy in the Paris and its metropolitan area. Forty-seven patients (80.9% men) with COVID-19 who underwent a kidney biopsy between March 08 and May 19, 2020 were included. Median age was 63 years IQR [52-69]. Comorbidities included hypertension (66.0%), diabetes mellitus (27.7%), obesity (27.7%), history of chronic kidney (25.5%), cardiac (38.6%) and respiratory (27.3%) diseases. Initial symptoms were fever (85.1%), cough (63.8%), shortness of breath (55.3%), and diarrhea (23.4%). Almost all patients developed acute kidney injury (97.9%) and 63.8% required renal replacement therapy. Kidney biopsy showed two main histopathological patterns, including acute tubular injury in 20 (42.6%) patients, and glomerular injury consisting of collapsing glomerulopathy and focal segmental glomerulosclerosis in 17 (36.2%) patients. Two (4.3%) patients had acute vascular nephropathy, while eight (17%) had alternative diagnosis most likely unrelated to COVID-19. Acute tubular injury occurred almost invariably in the setting of severe forms of COVID-19, whereas patients with glomerular injury had various profiles of COVID-19 severity and collapsing glomerulopathy was only observed in patients harboring a combination of APOL1 risk variants. At last follow-up, 16 of the 30 patients who initially required dialysis were still on dialysis, and 9 died. The present study describes the spectrum of kidney lesions in patients with COVID-19. While acute tubular injury is correlated with COVID-19 severity, the pattern of glomerular injury is intimately associated with the expression of APOL1 risk variants.

COVID-19 Infection in Kidney Transplant Recipients: Disease Incidence and Clinical Outcomes.

BACKGROUND: COVID-19 has been associated with high morbidity and mortality in kidney transplant recipients. However, risk factors for COVID-19 disease in patients with kidney transplants remain poorly defined. METHODS: We enrolled patients who underwent kidney transplantation and were actively followed up in two hospitals in Paris on March 1st, 2020. Patients were screened for baseline and transplant characteristics, functional parameters, comorbidities, and immunosuppressive therapies. COVID-19 disease was assessed. Patients were followed up during the pandemic until April 30th, 2020 by the COVID-19 SLS KT survey program, including teleconsulting, at-home monitoring for patients with COVID-19, and a dedicated phone hotline platform. RESULTS: Among 1216 patients with kidney transplants enrolled, 66 (5%) patients were identified with COVID-19 disease, which is higher than the incidence observed in the general population in France (0.3%). Their mean age was 56.4±12.5 years, and 37 (56%) patients were men. The following factors were independently associated with COVID-19 disease: non-White ethnicity (adjusted odds ratio [OR], 2.17; 95% confidence interval [95% CI], 1.23 to 3.78; P=0.007), obesity (OR, 2.19; 95% CI, 1.19 to 4.05; P=0.01), asthma and chronic pulmonary disease (OR, 3.09; 95% CI, 1.49 to 6.41; P=0.002), and diabetes (OR, 3.33; 95% CI, 1.92 to 5.77; P<0.001). The mortality rate related to COVID-19 disease was 1% in the overall study population and 24% in COVID-19-positive patients. CONCLUSIONS: Patients with kidney transplants display a high risk of mortality. Non-White ethnicity and comorbidities such as obesity, diabetes, asthma, and chronic pulmonary disease were associated with higher risk of developing COVID-19 disease. It is imperative that policy makers urgently ensure the integration of such risk factors on response operations against COVID-19.

Mast cell chymase protects against acute ischemic kidney injury by limiting neutrophil hyperactivation and recruitment.

Here we investigated the role of murine mast cell protease 4 (MCPT4), the functional counterpart of human mast cell chymase, in an experimental model of renal ischemia reperfusion injury, a major cause of acute kidney injury. MCPT4-deficient mice had worsened kidney function compared to wildtype mice. MCPT4 absence exacerbated pathologic neutrophil infiltration in the kidney and increased kidney myeloperoxidase expression, cell death and necrosis. In kidneys with ischemia reperfusion injury, when compared to wildtype mice, MCPT4-deficient mice showed increased surface expression of adhesion molecules necessary for leukocyte extravasation including neutrophil CD162 and endothelial cell CD54. In vitro, human chymase mediated the cleavage of neutrophil expressed CD162 and also CD54, P- and E-Selectin expressed on human glomerular endothelial cells. MCPT4 also dampened systemic neutrophil activation after renal ischemia reperfusion injury as neutrophils expressed more CD11b integrin and produced more reactive oxygen species in MCPT4-deficient mice. Accordingly, after renal injury, neutrophil migration to an inflammatory site distal from the kidney was increased in MCPT4-deficient versus wildtype mice. Thus, contrary to the described overall aggravating role of mast cells, one granule-released mediator, the MCPT4 chymase, exhibits a potent anti-inflammatory function in renal ischemia reperfusion injury by controlling neutrophil extravasation and activation thereby limiting associated damage.

Mast Cell Chymase and Kidney Disease.

A sizable part (~2%) of the human genome encodes for proteases. They are involved in many physiological processes, such as development, reproduction and inflammation, but also play a role in pathology. Mast cells (MC) contain a variety of MC specific proteases, the expression of which may differ between various MC subtypes. Amongst these proteases, chymase represents up to 25% of the total proteins in the MC and is released from cytoplasmic granules upon activation. Once secreted, it cleaves the targets in the local tissue environment, but may also act in lymph nodes infiltrated by MC, or systemically, when reaching the circulation during an inflammatory response. MC have been recognized as important components in the development of kidney disease. Based on this observation, MC chymase has gained interest following the discovery that it contributes to the angiotensin-converting enzyme's independent generation of angiotensin II, an important inflammatory mediator in the development of kidney disease. Hence, progress regarding its role has been made based on studies using inhibitors but also on mice deficient in MC protease 4 (mMCP-4), the functional murine counterpart of human chymase. In this review, we discuss the role and actions of chymase in kidney disease. While initially believed to contribute to pathogenesis, the accumulated data favor a more subtle view, indicating that chymase may also have beneficial actions.

Recruitment of CXCR3+ T cells into injured tissues in adult IgA vasculitis patients correlates with disease activity.

OBJECTIVES: Adult immunoglobulin A vasculitis (IgAV) is an immune complex small vessel vasculitis. So far, the involvement of T cells in this pathology has been poorly studied. The aim of this study was to analyze T-cell homeostasis as well as cytokine and chemokine concentrations in the blood and tissues of IgAV patients. METHODS: T cells, cytokine and chemokine concentrations were analyzed in peripheral blood using flow cytometry and multiplex assays. T-cell infiltrates in the kidney and the skin were characterized by immunohistochemistry. This study prospectively included 44 adult patients with biopsy-proven IgAV and 24 age- and sex-matched healthy controls. RESULTS: We observed reduced proportions of circulating CXCR5-and CXCR3-expressing memory CD4 T cells at diagnosis but normal values at remission. The plasma levels of Th1-related cytokines (IL-12, IL-27 and IFNγ) and of the TFH-related cytokine, IL-21, were paradoxically not reduced in patients. We observed increased plasma concentrations of the CXCR5 ligand, CXCL13, and of the CXCR3 ligands, CXCL10/11, suggesting a potential relocation of the corresponding T cells into inflamed tissues. We then confirmed the recruitment of CXCR3-expressing T cells into the skin and kidneys. In the skin, T-cell infiltrates mainly co-localized with damaged dermal small vessels. Finally, patients with the largest kidney T-cell infiltrates were also those with the highest proteinuria. CONCLUSION: Altogether, our results strongly suggest that, in IgAV patients, CXCL10/11 orchestrate the recruitment of CXCR3-expressing T cells in injured tissues, contributing to tissue damage and disease activity.

Basophil involvement in lupus nephritis: a basis for innovation in daily care.

Lupus nephritis (LN) affects a large proportion of patients with systemic lupus erythematosus (SLE). LN can lead to end-stage renal disease depending on when it is diagnosed and on the adequacy of the treatment administered to the patient based on the class of LN. Determination of the class and activity of LN is only possible by histological analysis of kidney biopsies. In this context, the development of non-invasive early diagnostic tools for determining the class of LN and biomarkers predicting the response to treatment would greatly benefit patients with SLE. Basophils, which are one of the rarest types of circulating leucocytes, are well-established effectors of allergic and parasitic diseases. Recent advances in the understanding of the immune regulatory role of basophils in several auto immune conditions, including SLE and LN, have demonstrated their involvement in the amplification of auto-antibody production and LN pathogenesis in both human SLE and lupus-like mouse models. The present review summarizes the currently available literature describing dysregulation of basophil counts, basophil activation status and basophil activating factors in patients with SLE and the involvement of basophils in the pathogenesis of SLE. We also discuss the potential utility of these biological and immunological parameters as diagnostic and prognostic biomarkers, used alone or in combination with other known SLE and LN activity biomarkers. Finally, considering basophils as contributors to the disease, they may also constitute a future treatment target for the management of SLE and LN.