International consensus on post-transplantation diabetes mellitus

Post-transplantation diabetes mellitus (PTDM) remains a leading complication after solid organ transplantation. Previous international PTDM consensus meetings in 2003 and 2013 provided standardized frameworks to reduce heterogeneity in diagnosis, risk stratification and management. However, the last decade has seen significant advancements in our PTDM knowledge complemented by rapidly changing treatment algorithms for management of diabetes in the general population. In view of these developments, and to ensure reduced variation in clinical practice, a 3rd international PTDM Consensus Meeting was planned and held from 6-8 May 2022 in Vienna, Austria involving global delegates with PTDM expertise to update the previous reports. This update includes opinion statements concerning optimal diagnostic tools, recognition of prediabetes (impaired fasting glucose and/or impaired glucose tolerance), new mechanistic insights, immunosuppression modification, evidence-based strategies to prevent PTDM, treatment hierarchy for incorporating novel glucose-lowering agents and suggestions for the future direction of PTDM research to address unmet needs. Due to the paucity of good quality evidence, consensus meeting participants agreed that making GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) recommendations would be flawed. Although kidney-allograft centric, we suggest that these opinion statements can be appraised by the transplantation community for implementation across different solid organ transplant cohorts. Acknowledging the paucity of published literature, this report reflects consensus expert opinion. Attaining evidence is desirable to ensure establishment of optimized care for any solid organ transplant recipient at risk of, or who develops, PTDM as we strive to improve long-term outcomes.

Glucometabolism in Kidney Transplant Recipients with and without Posttransplant Diabetes: Focus on Beta-Cell Function

Posttransplant diabetes mellitus (PTDM) is a common complication after kidney transplantation. Pathophysiologically, whether beta-cell dysfunction rather than insulin resistance may be the predominant defect in PTDM has been a matter of debate. The aim of the present analysis was to compare glucometabolism in kidney transplant recipients with and without PTDM. To this aim, we included 191 patients from a randomized controlled trial who underwent oral glucose tolerance tests (OGTTs) 6 months after transplantation. We derived several basic indices of beta-cell function and insulin resistance as well as variables from mathematical modeling for a more robust beta-cell function assessment. Mean ± standard deviation of the insulin sensitivity parameter PREDIM was 3.65 ± 1.68 in PTDM versus 5.46 ± 2.57 in NON-PTDM. Model-based glucose sensitivity (indicator of beta-cell function) was 68.44 ± 57.82 pmol∙min-1∙m-2∙mM-1 in PTDM versus 143.73 ± 112.91 pmol∙min-1∙m-2∙mM-1 in NON-PTDM, respectively. Both basic indices and model-based parameters of beta-cell function were more than 50% lower in patients with PTDM, indicating severe beta-cell impairment. Nonetheless, some defects in insulin sensitivity were also present, although less marked. We conclude that in PTDM, the prominent defect appears to be beta-cell dysfunction. From a pathophysiological point of view, patients at high risk for developing PTDM may benefit from intensive treatment of hyperglycemia over the insulin secretion axis.

Biomarkers of alcohol abuse potentially predict delirium, delirium duration and mortality in critically ill patients

Carbohydrate-deficient transferrin (CDT) and the γ-glutamyltransferase-CDT derived Anttila-Index are established biomarkers for sustained heavy alcohol consumption and their potential role to predict delirium and mortality in critically ill patients is not clear. In our prospective observational study, we included 343 consecutive patients admitted to our ICU, assessed the occurrence of delirium and investigated its association with biomarkers of alcohol abuse measured on the day of ICU admission. 35% of patients developed delirium during ICU stay. We found significantly higher CDT levels (p = 0.011) and Anttila-Index (p = 0.001) in patients with delirium. CDT above 1.7% (OR 2.06), CDT per percent increase (OR 1.26, AUROC 0.75), and Anttila-Index per unit increase (OR 1.28, AUROC 0.74) were associated with delirium development in adjusted regression models. Anttila-Index and CDT also correlated with delirium duration exceeding 5 days. Additionally, Anttila-Index above 4, Anttila-Index per unit increase, and CDT per percent increase were independently associated with hospital mortality.

COVID-19 outcomes in patients with a history of immune-mediated glomerular diseases

Introduction

Patients with immune-mediated glomerular diseases are considered at high risk for severe COVID-19 outcomes. However, conclusive evidence for this patient population is scarce.

Methods

We created a global registry and retrospectively collected clinical data of patients with COVID-19 and a previously diagnosed immune-mediated glomerular disease to characterize specific risk factors for severe COVID-19 outcomes.

Results

Fifty-nine patients with a history of immune-mediated glomerular diseases were diagnosed with COVID-19 between 01.03.2020 and 31.08.2021. Over a mean follow-up period of 24.79 ± 18.89 days, ten patients (16.9%) developed acute kidney injury. Overall, 44.1% of patients were managed in an outpatient setting and therefore considered as having "non-severe" COVID-19, while 55.9% of patients had severe COVID-19 requiring hospitalization including worse outcomes. Comparing both groups, patients with severe COVID-19 were significantly older (53.55 ± 17.91 versus 39.77 ± 14.95 years, p = .003), had lower serum albumin levels at presentation (3.00 ± 0.80 g/dL versus 3.99 ± 0.68 g/dL, p = .016) and had a higher risk of developing acute kidney injury (27% versus 4%, p = .018). Male sex (p <.001) and ongoing intake of corticosteroids at presentation (p = .047) were also significantly associated with severe COVID-19 outcomes, while the overall use of ongoing immunosuppressive agents and glomerular disease remission status showed no significant association with the severity of COVID-19 (p = .430 and p = .326, respectively).

Conclusion

Older age, male sex, ongoing intake of corticosteroids and lower serum albumin levels at presentation were identified as risk factors for severe COVID-19 outcomes in patients with a history of various immune-mediated glomerular diseases.

Reduced COVID-19 morbidity and mortality in hemodialysis patients across the various Omicron sublineages-A retrospective analysis

Introduction

Hemodialysis (HD) patients are a COVID-19 high risk population due to comorbidities and impaired immune response. Vaccines, advent of effective treatment and the emergence of novel variants have fundamentally changed the pandemic. We aimed to assess temporal changes of COVID-19 in HD patients of our catchment area, and risk factors for severe and fatal course.

Methods and materials

We retrospectively collected data from 274 patients admitted to the Medical University Graz, Austria for HD between 1st of May 2020 and 31st of August 2022. We analyzed clinical and demographic data between different COVID-19 waves and assessed factors associated with hospitalization, ICU admission and mortality by logistic regression. To further evaluate the dialysis at-risk population, we collected demographic and vaccination data between August 2021 and August 2022.

Results

Time of infection and SARS-CoV-2 sequencing data allowed for distinction of five separate waves of infection with different impact on the dialysis population: While in the initial four waves frequencies of hospitalization, necessity of critical care and mortality were around 60%, 10% and 20%, respectively. These events became rare during the large fifth wave, when Omicron had become the dominant variant. Although only 16.9% had to be hospitalized, this resulted in 29 hospital admissions, due to the high prevalence of COVID-19 during the Omicron era. Furthermore, we observed similar clinical outcomes with BA.4/5 as with BA.1/BA.2 Omicron sublineages. The proportion of previously infected increased simultaneously with the number of vaccination doses in our dialysis population. Vaccination at time of positivity and infection with an Omicron variant conferred protection against hospitalization and mortality in univariate analysis, but only infection with an Omicron variant remained a robust predictor for these outcomes in multivariable analysis.

Discussion

While a fourth of our at-risk population became infected during the Omicron wave, mortality was almost non-existent. Several concomitant factors have contributed to the decrease of COVID-19 severity in HD patients. This trend appears to be continued with BA.4/5, which was equally mild as BA.1 and BA.2 in our well vaccinated dialysis population.

Influence of Early Postoperative Basal Insulin Treatment and Post-Transplant Diabetes Mellitus Risk on Health-Related Quality of Life in Kidney Transplant Recipients-An Analysis of Data From a Randomized Controlled Trial

Health-related quality of life (HRQOL) improves after kidney transplantation (KT) but declines over time. Studies on the effect of early postoperative basal insulin therapy on HRQOL after KT, especially KTRs at high risk of developing post-transplant diabetes mellitus (PTDM) are missing. Data from a randomized controlled trial on 148 non-diabetic KTRs were analyzed. HRQOL using the KDQOL-SF™ was compared in KTRs who either received early postoperative basal insulin therapy or standard-of-care and in KTRs at risk of developing PTDM. Determinants of HRQOL outcomes were investigated using multivariable linear regression analysis. In total, 148 patients completed the KDQOL-SF at baseline. Standard-of-care or early basal insulin therapy after KT did not influence HRQOL. Overall, KT improved the mental (MCS) and physical component summary (PCS) scores at 6-month after KT, which remained stable during further follow-up visits. However, patients at high-risk for PTDM had significantly greater impairment in the PCS score (baseline, 24 months) without differences in MCS scores. In the multivariable regression analysis, allograft function and hemoglobin levels were associated with decreased MCS and PCS scores, respectively. A limitation of the study is the fact that only around 50% of the ITP-NODAT study patients participated in the HRQOL evaluation. Still, our data clearly show that early basal insulin therapy does not affect HRQOL after KT but is negatively influenced by classical clinical factors and PTDM-risk at 24 months after KT. The latter might be influenced by older age.

[Diagnosis and therapy of granulomatosis with polyangiitis and microscopic polyangiitis-2023: consensus of the Austrian society of nephrology (ÖGN) and Austrian society of rheumatology (ÖGR)]

ANCA-associated vasculitides (AAV) are rare, complex systemic diseases that are often difficult to diagnose, because of unspecific clinical symptoms at presentation. However, the clinical course may be very dramatic and even life-threatening, necessitating prompt diagnosis and treatment.Therefore, it is important to increase disease awareness among physicians and support colleagues who are not confronted with these rare diseases on a regular basis. Here, the Austrian Society of Nephrology (ÖGN) and the Austrian Society of Rheumatology (ÖGR) provide a joint consensus on how to best diagnose and manage patients with granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA).

[Diagnosis and treatment of focal-segmental glomerulosclerosis-2023]

The histopathological term focal-segmental glomerulosclerosis comprises different pathogenic processes with the unifying features of a high proteinuria and the name-giving glomerular lesion pattern seen on light microscopy. A differentiation according to the underlying cause into primary, secondary and genetic forms is therefore of utmost importance. The pathogenesis of primary focal-segmental glomerulosclerosis remains unknown but, like minimal-change disease, an autoimmune-mediated process leading to podocyte damage is assumed. Consequently, the unifying term "podocytopathy" is increasingly being used for both entities. Supportive treatment measures to preserve kidney function are important in all subtypes. In contrast, immunosuppressive treatment is only indicated in primary focal-segmental glomerulosclerosis. Steroid-dependence, steroid-resistance and frequently relapsing disease often complicate disease management and necessitate alternative treatment strategies. Here, the Austrian Society of Nephrology (ÖGN) provides consensus recommendations on how to best diagnose and manage patients with focal-segmental glomerulosclerosis.

[Diagnosis and treatment of Minimal Change Disease in adults-2023]

Minimal change disease is a glomerulopathy that clinically manifests as acute onset nephrotic syndrome. A diagnosis is made by renal biopsy, implying the absence of glomerular lesions on light microscopy but detection of extensive podocyte foot process effacement on electron miscroscopy. Considering the typically excellent response to immunosuppressive measures (especially to glucocorticoids), an autoimmune pathogenesis is assumed. Although general prognosis is overall beneficial, steroid-dependent, steroid-resistant and frequently-relapsing disease courses may complicate the management of these patients and necessitate the use of alternative immunosuppressive treatment strategies. Here, the Austrian Society of Nephrology (ÖGN) provides a consensus on how to best diagnose and manage adult patients with minimal change disease.

[Diagnosis and Treatment of IgA Nephropathy-2023]

Immunoglobulin A nephropathy (IgAN) is the most common glomerulonephritis. It leads to end-stage kidney disease in about a third of the patients within 10 to 20 years. The pathogenesis of IgAN is incompletely understood. It is believed that a dysregulation of the mucosal immune system leads to undergalactosylation of IgA, followed by formation of IgG autoantibodies against undergalactosylated IgA, circulation of these IgG-IgA immune complexes, deposition of the immune complexes in the mesangium, ultimately resulting in glomerular inflammation. IgAN can occasionally be triggered by other diseases, these secondary causes of IgAN should be identified or ruled out (chronic inflammatory bowel disease, infections, tumors, rheumatic diseases). Characteristic findings of IgAN of variable extent are a nephritic urinary sediment (erythrocytes, acanthocytes, erythrocyte casts), proteinuria, impaired renal function, arterial hypertension, or intermittent painless macrohematuria, especially during infections of the upper respiratory tract. However, the diagnosis of IgAN can only be made by a kidney biopsy. A histological classification (MEST‑C score) should always be reported to be able to estimate the prognosis. The most important therapeutic measure is an optimization of the supportive therapy, which includes, among other things, a consistent control of the blood pressure, an inhibition of the RAS, and the administration of an SGLT2 inhibitor. A systemic immunosuppressive therapy with corticosteroids is discussed controversially, should be used restrictively and only administered after an individual benefit-risk assessment under certain conditions that speak for a progressive IgAN. New promising therapeutics are enteral Budesonide or the dual angiotensin-II-receptor- and endothelin-receptor-antagonist Sparsentan. Rapidly progressive IgAN should be treated with corticosteroids and cyclophosphamide like ANCA-associated vasculitis.

[Diagnosis and treatment of glomerular diseases with a membranoproliferative glomerulonephritis (MPGN) pattern of injury]

Membranoproliferative glomerulonephritis (MPGN) represents a heterogeneous group of diseases. The common feature of a membranoproliferative lesion pattern in the kidney biopsy can either be idiopathic/primary or-much more frequently-have a secondary cause. The historical classification into MPGN types I to III has largely been abandoned and replaced in recent years by a pathogenesis-oriented classification. A MPGN with C1q, C3 and/or C4 deposits on light microscopy is referred to as immune complex GN (IC-GN), while a MPGN with dominant C3 deposits is referred to as C3 glomerulopathy (C3G). C3G is further divided into C3 glomerulonephritis (C3GN) and dense deposit disease (DDD). These diagnoses can only be made by a kidney biopsy. Possible causes of MPGN are chronic infections (especially hepatitis B and C, bacterial infections, infections with protozoa), autoimmune diseases (especially lupus, rheumatoid arthritis) or malignancies (especially hematological malignancies). Particularly in the case of C3G a comprehensive analysis of the complement system components is strongly recommended. Due to the low incidence and the heterogeneous clinical appearance of MPGN therapeutic decisions must be made individually; an optimal general therapy is unknown, except that supportive treatment as with other glomerular diseases should be optimized. In the case of a secondary MPGN it is generally recommended to treat the potential cause of the MPGN. If significant proteinuria persists and eGFR remains > 30 ml/min/1.73 m2, treatment with systemic steroids and mycophenolate mofetil is recommended. Other treatment options on an individual level after evaluation and discussion of the risk-benefit ratio with the patient are rituximab and eculizumab. Rapidly progressive MPGN should be treated like ANCA-associated vasculitis. The recurrence rates after kidney transplantation are very high and treatment is challenging.

[Diagnostic and therapy of lupus nephritis - 2023]

The manuscript summarizes the consensus of the Austrian Society of Nephrology on the diagnosis and therapy of lupusnephritis, which is built on existing studies and literature. We discuss in detail the immunosuppressive treatment in proliferative forms of lupusnephritis (III and IV ± V) and in pure lupusnephritis V with nephrotic-range proteinuria. Furthermore, the supportive medication in lupusnephritis is summarized in the consensus. The figures were designed to provide the reader a guidance through the therapeutical approach in lupusnephritis for the daily practice.

[Diagnosis and therapy of membranous nephropathy-2023]

Membranous nephropathy (MN) is an immune-complex glomerulonephritis and is one of the most common causes of nephrotic syndrome in adults and is also one of the autoimmune kidney diseases with the highest rate of spontaneous remission. The most common autoantigen (> 70% of cases) is directed against the phospholipase A2 receptor (PLA2-R) and, with its detection and clinical course, allows for excellent diagnostics as well as optimal therapy monitoring. Other autoantigens are constantly being published and will enable an autoantigen-based diagnostic and therapeutic algorithm for MN in the future. In the absence of spontaneous remission, a specific B‑cell-directed therapy, especially with rituximab, is the initial therapy of choice. Calcineurininhibitors or cyclophosphamide should only be used if they are carefully indicated in the respective clinical context and if there are serious clinical consequences both from the nephrotic syndrome and from loss of kidney function. Since immune complexes within the kidney often require a long time to be degraded, proteinuria response can follow the immunological remission after many months. The therapy of MN represents the favorable case of a precision medicine-based therapy in nephrology, whereby new therapeutic B‑cell antibodies for the rare but difficult forms of MN will find their way into clinical routine in the not-too-distant future.

[General recommendations for the management of glomerular diseases-2023]

Glomerular diseases are associated with extrarenal complications, such as thromboembolism, cardiovascular events and particularly infections. A thorough knowledge of the various immunosuppressants and their associated toxicity profile is therefore of great importance. While nephrologists usually have extensive experience with calcineurin inhibitors and antimetabolites, two other compounds (rituximab, in severe cases cyclophosphamide) are used comparatively infrequently and will be discussed in more detail. Moreover, practical recommendations for the prevention of thromboembolism in states of nephrosis and for the prophylaxis of Pneumcystic jirovecii pneumonia are provided.

Hospitalizations, emergency room visits and causes of death in 198 patients with permanent hypoparathyroidism: a retrospective Austrian study (2005-2022)

OBJECTIVE

Chronic hypoparathyroidism (HP) is associated with acute and chronic complications, especially those related to hypocalcemia. We aimed to analyze details on hospital admissions and the reported deaths in affected patients.

DESIGN AND METHODS

In a retrospective analysis, we reviewed the medical history of 198 patients diagnosed with chronic HP over a continuous period of up to 17 years at the Medical University Graz.

RESULTS

The mean age in our mostly female cohort (70.2%) was 62.6 ± 18.7 years. The etiology was predominantly postsurgical (84.8%). About 87.4% of patients received standard medication (oral calcium/vitamin D), 15 patients (7.6%) used rhPTH1-84/Natpar® and 10 patients (4.5%) had no/unknown medication. Two hundred and nineteen emergency room (ER) visits and 627 hospitalizations were documented among 149 patients, and 49 patients (24.7%) did not record any hospital admissions. According to symptoms and decreased serum calcium levels, 12% of ER (n = 26) visits and 7% of hospitalizations (n = 44) were likely attributable to HP. A subgroup of 13 patients (6.5%) received kidney transplants prior to the HP diagnosis. In eight of these patients, parathyroidectomy for tertiary renal hyperparathyroidism was the cause of permanent HP. The mortality was 7.8% (n = 12), and the causes of death appeared to be unrelated to HP. Although the awareness for HP was low, calcium levels were documented in 71% (n = 447) of hospitalizations.

CONCLUSIONS

Acute symptoms directly related to HP did not represent the primary cause of ER visits. However, comorbidities (e.g. renal/cardiovascular diseases) associated with HP played a key role in hospitalizations and deaths.

SIGNIFICANCE STATEMENT

Hypoparathyroidism (HP) is the most common complication after anterior neck surgery. Yet, it remains underdiagnosed as well as undertreated, and the burden of disease and long-term complications are usually underestimated. There are few detailed data on emergency room (ER) visits hospitalizations and death in patients with chronic HP, although acute symptoms due to hypo-/hypercalcemia are easily detectable. We show that HP is not the primary cause for presentation but that hypocalcemia is a typical laboratory finding (when ordered) and thus may contribute to subjective symptoms. Patients often present with renal/cardiovascular/oncologic illness for which HP is known to be a contributing factor. A small but very special group (n = 13, 6.5%) are patients after kidney transplantations who showed a high ER hospitalization rate. Surprisingly, HP was never the cause for their frequent hospitalizations but rather the result of chronic kidney disease. The most frequent cause for HP in these patients was parathyroidectomy due to tertiary hyperparathyroidism. The causes of death in 12 patients appeared to be unrelated to HP, but we found a high prevalence of chronic organ damages/comorbidities related to it in this group. Less than 25% documented HP correctly in the discharge letters, which indicates a high potential for improvement.

A multicentre, patient- and assessor-blinded, non-inferiority, randomised and controlled phase II trial to compare standard and torque teno virus-guided immunosuppression in kidney transplant recipients in the first year after transplantation: TTVguideIT

BACKGROUND

Immunosuppression after kidney transplantation is mainly guided via plasma tacrolimus trough level, which cannot sufficiently predict allograft rejection and infection. The plasma load of the non-pathogenic and highly prevalent torque teno virus (TTV) is associated with the immunosuppression of its host. Non-interventional studies suggest the use of TTV load to predict allograft rejection and infection. The primary objective of the current trial is to demonstrate the safety, tolerability and preliminary efficacy of TTV-guided immunosuppression.

METHODS

For this purpose, a randomised, controlled, interventional, two-arm, non-inferiority, patient- and assessor-blinded, investigator-driven phase II trial was designed. A total of 260 stable, low-immunological-risk adult recipients of a kidney graft with tacrolimus-based immunosuppression and TTV infection after month 3 post-transplantation will be recruited in 13 academic centres in six European countries. Subjects will be randomised in a 1:1 ratio (allocation concealment) to receive tacrolimus either guided by TTV load or according to the local centre standard for 9 months. The primary composite endpoint includes the occurrence of infections, biopsy-proven allograft rejection, graft loss, or death. The main secondary endpoints include estimated glomerular filtration rate, graft rejection detected by protocol biopsy at month 12 post-transplantation (including molecular microscopy), development of de novo donor-specific antibodies, health-related quality of life, and drug adherence. In parallel, a comprehensive biobank will be established including plasma, serum, urine and whole blood. The date of the first enrolment was August 2022 and the planned end is April 2025.

DISCUSSION

The assessment of individual kidney transplant recipient immune function might enable clinicians to personalise immunosuppression, thereby reducing infection and rejection. Moreover, the trial might act as a proof of principle for TTV-guided immunosuppression and thus pave the way for broader clinical applications, including as guidance for immune modulators or disease-modifying agents.

TRIAL REGISTRATION

EU CT-Number: 2022-500024-30-00.

Salivary potassium measured by genetically encoded potassium ion indicators as a surrogate for plasma potassium levels in hemodialysis patients-a proof-of-concept study

BACKGROUND

Hyperkalemia is a common complication in cardiorenal patients treated with agents interfering with renal potassium (K+) excretion. It frequently leads to discontinuation of potentially life-saving medication, which has increased the importance of K+ monitoring. Non-invasive means to detect hyperkalemia are currently unavailable, but would be of potential use for therapy guidance. The aim of the present study was to assess the analytical performance of genetically encoded potassium-ion indicators (GEPIIs) in measuring salivary [K+] ([K+]Saliva) and to determine whether changes of [K+]Saliva depict those of [K+]Plasma.

METHODS

We conducted this proof-of-concept study: saliva samples from 20 healthy volunteers as well as plasma and saliva from 29 patients on hemodialysis (HD) before and after three consecutive HD treatments were collected. We compared [K+]Saliva as assessed by the gold standard ion-selective electrode (ISE) with GEPII measurements.

RESULTS

The Bland-Altmann analysis showed a strong agreement (bias 0.71; 95% limits of agreement from -2.79 to 4.40) between GEPII and ISE. Before treatment, patients on HD showed significantly higher [K+]Saliva compared with healthy controls [median 37.7 (30.85; 48.46) vs 23.8 (21.63; 25.23) mmol/L; P < .05]. [K+]Plasma in HD patients decreased significantly after dialysis. This was paralleled by a significant decrease in [K+]Saliva, and both parameters increased until the subsequent HD session. Despite similar kinetics, we found weak or no correlation between [K+]Plasma and [K+]Saliva.

CONCLUSION

GEPIIs have shown an excellent performance in determining [K+]Saliva. [K+]Plasma and [K+]Saliva exhibited similar kinetics. To determine whether saliva could be a suitable sample type to monitor [K+]Plasma, further testing in future studies are required.

Factors influencing kidney transplantation rates: a study from the ERA Registry

BACKGROUND

Large international differences exist in kidney transplantation (KT) rates. We aimed to investigate which factors may explain the total, deceased donor, and living donor KT rates over the last decade.

METHODS

KT experts from 39 European countries completed the Kidney Transplantation Rate Survey on measures and barriers and their potential effect on the KT rate in their country. In the analyses, countries were divided into low, middle, and high KT rate countries based on the KT rate at the start of study period in 2010.

RESULTS

Experts from low KT rate countries reported more frequently to have taken measures regarding staff, equipment and facilities to increase total KT rate compared with middle and high KT rate countries. For donor type specific KT, the largest international differences in measures taken were reported for deceased donor KT, with middle and high KT rate countries taking more measures, such as the use of expanded criteria donor kidneys, the presence of transplantation coordinators, and (inter)national exchange of donor kidneys. Once a measure was taken, experts' opinion on its success was similar across the low, middle and high KT rate countries. Experts from low KT rate countries more often reported potential barriers, such as patients' lack of knowledge and distrust in the health care system.

CONCLUSIONS

In particular in low KT rate countries, KT rate might be stimulated by optimizing staff, equipment, and facilities. In addition, all countries may benefit from deceased and living donor specific measures.

Criteria for prediabetes and posttransplant diabetes mellitus after kidney transplantation: A 2-year diagnostic accuracy study of participants from a randomized controlled trial

Posttransplant diabetes mellitus (PTDM) and prediabetes (impaired glucose tolerance [IGT] and impaired fasting glucose [IFG]) are associated with cardiovascular events. We assessed the diagnostic performance of fasting plasma glucose (FPG) and HbA_1c as alternatives to oral glucose tolerance test (OGTT)-derived 2-hour plasma glucose (2hPG) using sensitivity and specificity in 263 kidney transplant recipients (KTRs) from a clinical trial. Between visits at 6, 12, and 24 months after transplantation, 28%-31% of patients switched glycemic category (normal glucose tolerance [NGT], IGT/IFG, PTDM). Correlations of FPG and HbA_1c against 2hPG were lower at 6 months (r = 0.59 [FPG against 2hPG]; r = 0.45 [HbA_1c against 2hPG]) vs. 24 months (r = 0.73 [FPG against 2hPG]; r = 0.74 [HbA_1c against 2hPG]). Up to 69% of 2hPG-defined PTDM cases were missed by conventional HbA_1c and FPG thresholds. For prediabetes, concordance of FPG and HbA_1c with 2hPG ranged from 6%-9%. In conclusion, in our well-defined randomized trial cohort, one-third of KTRs switched glycemic category over 2 years and although the correlations of FPG and HbA_1c with 2hPG improved with time, their diagnostic concordance was poor for PTDM and, especially, prediabetes. Considering posttransplant metabolic instability, FPG's and HbA_1c 's diagnostic performance, the OGTT remains indispensable to diagnose PTDM and prediabetes after kidney transplantation.

Low-Dose rIL-15 Protects from Nephrotoxic Serum Nephritis via CD8+ T Cells

Rapid progressive glomerulonephritis (GN) often leads to end-stage kidney disease, driving the need for renal replacement therapy and posing a global health burden. Low-dose cytokine-based immunotherapies provide a new strategy to treat GN. IL-15 is a strong candidate for the therapy of immune-mediated kidney disease since it has proven to be tubular-protective before. Therefore, we set out to test the potential of low-dose rIL-15 treatment in a mouse model of nephrotoxic serum nephritis (NTS), mimicking immune complex-driven GN in humans. A single low-dose treatment with rIL-15 ameliorated NTS, reflected by reduced albuminuria, less tissue scarring, fewer myeloid cells in the kidney, and improved tubular epithelial cell survival. In addition, CD8⁺ T cells, a primary target of IL-15, showed altered gene expression and function corresponding with less cytotoxicity mediated by rIL-15. With the use of transgenic knock-out mice, antibody depletion, and adoptive cell transfer studies, we here show that the beneficial effects of rIL-15 treatment in NTS depended on CD8⁺ T cells, suggesting a pivotal role for them in the underlying mechanism. Our findings add to existing evidence of the association of IL-15 with kidney health and imply a potential for low-dose rIL-15 immunotherapies in GN.

Alterations in the Kynurenine-Tryptophan Pathway and Lipid Dysregulation Are Preserved Features of COVID-19 in Hemodialysis

Coronavirus disease 2019 (COVID-19)-induced metabolic alterations have been proposed as a source for prognostic biomarkers and may harbor potential for therapeutic exploitation. However, the metabolic impact of COVID-19 in hemodialysis (HD), a setting of profound a priori alterations, remains unstudied. To evaluate potential COVID-19 biomarkers in end-stage kidney disease (CKD G5), we analyzed the plasma metabolites in different COVID-19 stages in patients with or without HD. We recruited 18 and 9 asymptomatic and mild, 11 and 11 moderate, 2 and 13 severely affected, and 10 and 6 uninfected HD and non-HD patients, respectively. Plasma samples were taken at the time of diagnosis and/or upon admission to the hospital and analyzed by targeted metabolomics and cytokine/chemokine profiling. Targeted metabolomics confirmed stage-dependent alterations of the metabolome in non-HD patients with COVID-19, which were less pronounced in HD patients. Elevated kynurenine levels and lipid dysregulation, shown by an increase in circulating free fatty acids and a decrease in lysophospholipids, could distinguish patients with moderate COVID-19 from non-infected individuals in both groups. Kynurenine and lipid alterations were also associated with ICAM-1 and IL-15 levels in HD and non-HD patients. Our findings support the kynurenine pathway and plasma lipids as universal biomarkers of moderate and severe COVID-19 independent of kidney function.

Myocardial infarction with non-obstructive coronary arteries in a patient double-seropositive for anti-glomerular basement membrane and anti-neutrophil cytoplasmic antibodies: A case report

We report a case of a patient double-seropositive for anti-glomerular basement membrane (anti-GBM) and anti-neutrophil cytoplasmic antibodies (ANCA) who reported retrosternal chest pain during a regular hemodialysis session associated with ST-segment depression in electrocardiogram and an increase of serum high-sensitivity troponin T. Urgent coronary angiography excluded obstructive coronary artery disease, suggesting the diagnosis of ischemia with non-obstructive coronary arteries. This case illustrates an unusual presentation of cardiovascular involvement in a patient with double-positive ANCA/anti-GBM disease, emphasizing the possible relevance of coronary microvascular dysfunction and the need for close cardiovascular follow-up in this patient population.

ScoMorphoFISH: A deep learning enabled toolbox for single-cell single-mRNA quantification and correlative (ultra-)morphometry

Increasing the information depth of single kidney biopsies can improve diagnostic precision, personalized medicine and accelerate basic kidney research. Until now, information on mRNA abundance and morphologic analysis has been obtained from different samples, missing out on the spatial context and single‐cell correlation of findings. Herein, we present scoMorphoFISH, a modular toolbox to obtain spatial single‐cell single‐mRNA expression data from routinely generated kidney biopsies. Deep learning was used to virtually dissect tissue sections in tissue compartments and cell types to which single‐cell expression data were assigned. Furthermore, we show correlative and spatial single‐cell expression quantification with super‐resolved podocyte foot process morphometry. In contrast to bulk analysis methods, this approach will help to identify local transcription changes even in less frequent kidney cell types on a spatial single‐cell level with single‐mRNA resolution. Using this method, we demonstrate that ACE2 can be locally upregulated in podocytes upon injury. In a patient suffering from COVID‐19‐associated collapsing FSGS, ACE2 expression levels were correlated with intracellular SARS‐CoV‐2 abundance. As this method performs well with standard formalin‐fixed paraffin‐embedded samples and we provide pretrained deep learning networks embedded in a comprehensive image analysis workflow, this method can be applied immediately in a variety of settings.

MO223: Contribution of Interstitial CD138 + Plasma Cells on the Renal Outcome in Patients with Anca-Associated Vasculitis

BACKGROUND AND AIMS

Plasma cells (PC) are the most differentiated antibody and cytokine-producing B lineage cells and are thought to contribute to the perpetuation of inflammation in patients with ANCA-associated vasculitis (AAV). Agents targeting PCs are of interest in AAV, however, little is known about the role of interstitial CD138 + PCs in these patients. In this study, we aim to demonstrate the impact of this cell population in the prediction of renal outcomes in patients with AAV.

METHOD

Forty AAV patients with glomerulonephritis, diagnosed between 2014 and 2018 at the Division of Nephrology of the Medical University of Graz were included and followed for 36 months. Histological assessments using the kidney allograft Banff classification were performed to describe the tubulointerstitial (TI) damages. Immunohistochemistry analysis was performed in 29 patients to assess the renal interstitial CD138 + cell expression. More than ten CD138 + cells per high power field were stated as high expression (excluding CD138 staining of renal tubular epithelial cells). Changes in kidney function, the incidence of renal relapses (RR), and end-stage renal disease (ESRD) were analyzed.

RESULTS

In the kidney biopsies, N = 21 (72%) patients had a high expression of CD138 + plasma cells. No significant difference was observed in PR3 and MPO serotypes in the group of patients with high CD138 + cell expression (43% versus 57%, P = .793). In addition, no significant difference was seen in the changes in kidney function and the incidence of RR or ESRD between the groups with high and low expression of CD138 + cells during the follow-up period. However, patients with more severe TI damage had more severe proteinuria {urinary albumin/creatinine ratio: 51 [interquartile range (IQR) 42–123] versus 360 (IQR 202–1112) mg/g Creatinine; P = .016} at 3-year follow-up, and tended to have a higher rate of RR and ESRD [i0/i1: N = 2/18 (11%) versus i2/i3: N = 6/22 (27%), P = .258 and i0/i1: N = 2/18 (11%) versus i2/i3: N = 6/22 (27%), P = .258, respectively].

CONCLUSION

Our data indicate a significant proportion of CD138 + PCs in kidney specimens of patients with AAV. Despite the lack of association between this cell population and our cohort’s renal outcome, these results provide additional insights on the renal B-cell clusters in patients with AAV. In addition, our findings go along with already existing data on the association between extended TI damage and worse renal outcome.

MO171: Chronic Inflammation Might Protect Haemodialysis Patients from Severe COVID-19

BACKGROUND AND AIMS

Patients on haemodialysis (HD) are expected to have excess mortality in coronavirus disease 2019 (COVID-19). This was challenged by a recent study reporting HD patients to have comparable mortality and decreased ICU admissions when hospitalized with COVID-19. It was speculated that an altered immune system due to chronic inflammation might protect HD patients from severe COVID-19. Therefore, we designed a study to describe the peripheral blood immune phenotype in HD patients and respective controls with COVID-19.

METHOD

Sixty-four patients (31 HD, 33 non-HD) with PCR-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and 16 control patients (10 HD, 6 non-HD) were prospectively included. According to symptoms, COVID-19 patients were categorized as asymptomatic/mild and moderate/severe COVID-19 phenotypes. Cytokine profiling and immune phenotyping were performed.

RESULTS

Th1 and Th17 plasma cytokine levels were highly increased in HD patients without SARS-CoV-2 infection and were not significantly regulated during COVID-19. In non-HD COVID-19 patients, these cytokines increased significantly with disease severity. While all patients with moderate/severe COVID-19 showed hallmarks of COVID-19 such as decreased CD3⁺ CD4⁺ and CD8⁺ and CD4⁺CD25^hiFoxP3⁺ regulatory T cells, significantly increased CD38⁺CD8⁺ effector memory and CD38⁺CD8⁺ TEMRA T cells were detected in HD compared to non-HD patients with moderate/severe COVID-19. Furthermore, CD161⁺CD8⁺ T cells decreased significantly in non-HD COVID-19 patients dependent on disease severity, but not in HD patients. Dynamics of B cells and subtypes were comparable in HD and non-HD COVID-19 patients. Significantly fewer moderate/severe COVID-19 HD patients needed ICU treatment [1/13 (7.7%) HD, 12/24 (50%) non-HD], whereas no difference in mortality was observed [4/31 (12.9%) HD, 6/33 non-HD (18.2%)].

CONCLUSION

HD patients might be protected from severe COVID-19 due to their chronic inflammatory state with increased CD38⁺CD8⁺ effector memory and TEMRA T cells as well as CD161⁺CD8⁺ T cells.

MO238: Erythroid ACKR1 Expression has a Protective Effect on the Development of Experimental Glomerulonephritis

BACKGROUND AND AIMS

The overwhelming majority of individuals of West African ancestry carry an ‘erythroid silent’ FyB(ES) SNP in the promoter region of ACKR1 that causes a selective loss of ACKR1 in erythroid cells but does not affect its expression in endothelial cells. The FyB(ES) polymorphism is of a special interest for understanding human kidney disease as individuals of West African ancestry have higher incidence of chronic kidney disease. Moreover, multiple chemokine ligands of ACKR1 are known to contribute to the inflammatory pathology in experimental nephrotoxic serum nephritis (NTS), a murine model of immune complex glomerulonephritis.

METHOD

We developed two humanized transgenic mouse strains that are genetically deficient for mouse ACKR1 but instead carry either West African FyB(ES) or Caucasian FyB human polymorphic ACKR1 variants. These strains as well as ACKR1-deficient and WT mice were subjected to NTS. The parameters of immunopathogenesis and kidney disease were evaluated after 14 days after the induction of NTS.

RESULTS

Albuminuria, PAS and tubular injury scores were significantly increased in FyB(ES)tg and ACKR1-deficient mice as compared with their respective control strains. While monocytes were unchanged in peripheral blood, we found significantly increased numbers of macrophages and neutrophils infiltrating the kidneys of FyB(ES)tg and ACKR1-deficient mice. Interestingly, T cell numbers in the draining lymph nodes were comparable between FyB(ES)tg and ACKR1-deficient mice and their respective controls.

CONCLUSION

We found that NTS was more severe in ACKR1-deficient and FyB(ES) mice as compared with their respective controls. Our results show that ACKR1 expression in the erythroid compartment has a significant impact on the development of kidney disease. These findings have important implications for the pathomechanisms of glomerulonephritis in individuals of West African ancestry who lack ACKR1 selectively in the erythroid lineage.

MO932: Same But Different? Covid-19 Metabolome in Hemodialysis

BACKGROUND AND AIMS

The ongoing coronavirus disease 2019 (COVID-19) pandemic presents a major health and economical challenge. Chronic kidney disease (CKD) patients on haemodialysis (HDp) are at a particularly high risk of severe and fatal courses [1]. The COVID-19 metabolome is distinct [2] and may harbour potential prognostic markers and therapeutic targets. However, the metabolome in SARS-CoV-2 infected HDp remains unstudied.

METHOD

Untargeted and targeted metabolomics via high-performance liquid chromatography and tandem mass spectrometry of EDTA-plasma were performed in 39 individuals without CKD (non-HDp) and 41 HDp. Individuals were further grouped according to COVID-19 disease status and severity: negative, asymptomatic/mild (no or mild symptoms) and moderate/severe (requiring hospitalization).

RESULTS

Principal component analysis shows a clear separation of non-HDp and HDp alongside PC2, independent of COVID-19. Non-HDp with moderate/severe courses are shifted to the right of PC1. The influence of COVID-19 is less pronounced in HDp (Figure 1). Free fatty acids are main contributors to PC1, whereas PC2 reflects the complex metabolic disarray as seen in uraemia (Table 1).

CONCLUSION

Our data underlines the fundamental metabolic differences between non-HDp and HDp [3]. Furthermore, moderate/severe COVID-19 leads to a distinct metabolite signature in non-HDp. This effect is less pronounced in HDp, which could be indicative of a decreased capability to adapt to infectious challenges. In summary, these findings warrant caution when extrapolating COVID-19 metabolomics from otherwise healthy individuals, as the validity of prognostic markers and/or effectiveness of therapeutic approaches based on the metabolome may be limited in HDp.

Chronic Inflammation Might Protect Hemodialysis Patients From Severe COVID-19

Hemodialysis patients (HD) are expected to have excess mortality in coronavirus disease 2019 (COVID-19). This was challenged by a recent study reporting HD patients to have comparable mortality and less ICU admissions when hospitalized with COVID-19. An altered immune system due to chronic inflammation might protect HD-patients from severe COVID-19. Therefore, we aimed to describe the peripheral blood immune phenotype in HD-patients and respective controls with COVID-19.

Membranous nephropathy associated with immunoglobulin G4-related disease successfully treated with obinutuzumab

Immunoglobulin G4 (IgG4)-releated disease is typically associated with interstitial nephritis, but rare cases of idiopathic membranous nephropathy as a renal manifestation have been described. Obinutuzumab was successfully used in refractory membranous nephropathy, but evidence for the treatment of IgG4-related disease with obinutuzumab is lacking. We report one patient's case with membranous nephropathy associated with IgG4-related disease who was treated with obinutuzumab following an anaphylactic reaction to rituximab. Obinutuzumab treatment resulted in a sustained complete remission of membranous nephropathy and a decrease of IgG4 to the normal range. This case demonstrates that membranous nephropathy associated with IgG4-related disease can be treated successfully with obinutuzumab.

B Cell Composition Is Altered After Kidney Transplantation and Transitional B Cells Correlate With SARS-CoV-2 Vaccination Response

Background

The COVID-19 pandemic has major implications on kidney transplant recipients (KTRs) since they show increased mortality due to impaired immune responses to SARS-CoV-2 infection and a reduced efficacy of SARS-CoV-2 vaccination. Surprisingly, dialysis patients have shown superior seroconversion rates after vaccination compared to KTRs. Therefore, we investigated peripheral blood B cell (BC) composition before and after kidney transplantation (KT) and aimed to screen the BC compartment to explain impaired antibody generation.

Methods

A total of 105 patients were recruited, and multicolor flow cytometric phenotyping of peripheral venous blood BC subpopulations was performed before and 1 year after KT. Complete follow-up was available for 71 individuals. Anti-SARS-CoV-2 antibodies were collected retrospectively and were available for 40 subjects, who had received two doses of an mRNA-based vaccine (BNT162b2 or mRNA-1273).

Results

Overall, relative BC frequencies within lymphocytes decreased, and their absolute counts trended in the same direction 1 year after KT as compared to CKD G5 patients. Frequencies and absolute numbers of naïve BCs remained stable. Frequencies of double negative BCs, a heterogeneous subpopulation of antigen experienced BCs lacking CD27 expression, were increased after KT, yet their absolute counts were similar at both time points. Transitional BCs (TrBCs) and plasmablasts were significantly reduced after KT in absolute and relative terms. Memory BCs were affected differently since class-switched and IgM-only subsets decreased after KT, but unswitched and IgD-only memory BCs remained unchanged. CD86⁺ and CD5⁺ expression on BCs was downregulated after KT. Correlational analysis revealed that TrBCs were the only subset to correlate with titer levels after SARS-CoV-2 vaccination. Responders showed higher TrBCs, both absolute and relative, than non-responders.

Conclusion

Together, after 1 year, KTRs showed persistent and profound compositional changes within the BC compartment. Low TrBCs, 1 year after KT, may account for the low serological response to SARS-CoV-2 vaccination in KTRs compared to dialysis patients. Our findings need confirmation in further studies as they may guide vaccination strategies.

The basement membrane in the cross-roads between the lung and kidney

The basement membrane (BM) is a specialized layer of extracellular matrix components that plays a central role in maintaining lung and kidney functions. Although the composition of the BM is usually tissue specific, the lung and the kidney preferentially use similar BM components. Unsurprisingly, diseases with BM defects often have severe pulmonary or renal manifestations, sometimes both. Excessive remodeling of the BM, which is a hallmark of both inflammatory and fibrosing diseases in the lung and the kidney, can lead to the release of BM-derived matrikines, proteolytic fragments with distinct biological functions. These matrikines can then influence disease activity at the site of liberation. However, they are also released to the circulation, where they can directly affect the vascular endothelium or target other organs, leading to extrapulmonary or extrarenal manifestations. In this review, we will summarize the current knowledge of the composition and function of the BM and its matrikines in health and disease, both in the lung and in the kidney. By comparison, we will highlight, why the BM and its matrikines may be central in establishing a renal-pulmonary interaction axis.

The Risk of Severe Infections Following Rituximab Administration in Patients With Autoimmune Kidney Diseases: Austrian ABCDE Registry Analysis

Objective

To characterize the incidence, type, and risk factors of severe infections (SI) in patients with autoimmune kidney diseases treated with rituximab (RTX).

Methods

We conducted a multicenter retrospective cohort study of adult patients with immune-related kidney diseases treated with at least one course of RTX between 2015 and 2019. As a part of the ABCDE Registry, detailed data on RTX application and SI were collected. SI were defined by Common Terminology Criteria for Adverse Events v5.0 as infectious complications grade 3 and above. Patients were dichotomized between “nephrotic” and “nephritic” indications. The primary outcome was the incidence of SI within 12 months after the first RTX application.

Results

A total of 144 patients were included. Twenty-five patients (17.4%) presented with SI, mostly within the first 3 months after RTX administration. Most patients in the nephritic group had ANCA-associated vasculitis, while membranous nephropathy was the leading entity in the nephrotic group. Respiratory infections were the leading SI (n= 10, 40%), followed by urinary tract (n=3, 12%) and gastrointestinal infections (n=2, 8%). On multivariable analysis, body mass index (BMI, 24.6 kg/m²versus 26.9 kg/m², HR: 0.88; 95%CI: 0.79-0.99; p=0.039) and baseline creatinine (HR: 1.25; 95%CI: 1.04-1.49; p=0.017) were significantly associated with SI. All patients in the nephritic group (n=19; 100%) who experienced a SI received oral glucocorticoid (GC) treatment at the time of infection. Hypogammaglobulinemia was frequent (58.5%) but not associated with SI.

Conclusions

After RTX administration, impaired kidney function and lower BMI are independent risk factors for SI. Patients with nephritic glomerular diseases having concomitant GC treatment might be at higher risk of developing SI.

Evaluation of Endothelial Dysfunction and Inflammatory Vasculopathy After SARS-CoV-2 Infection-A Cross-Sectional Study

Background: Rising data suggest that COVID-19 affects vascular endothelium while the underlying mechanisms promoting COVID-19-associated endothelial dysfunction and inflammatory vasculopathy are largely unknown. The aim was to evaluate the contribution of COVID-19 to persisting vascular injury and to identify parameters linked to COVID-19-associated endothelial dysfunction and inflammatory vasculopathy. Methods: In a cross-sectional design, flow-mediated dilation (FMD), nitroglycerine-related dilation (NMD), pulse-wave velocity (PWV), augmentation index, intima-media thickness (IMT), compounds of the arginine and kynurenine metabolism, homocysteine, von Willebrand factor (vWF), endothelial microparticles (EMP), antiendothelial cell antibodies, inflammatory, and immunological parameters, as well as nailfold capillary morphology were measured in post-COVID-19 patients, patients with atherosclerotic cardiovascular diseases (ASCVD) and healthy controls without prior or recent SARS-CoV-2 infection. Results: Post-COVID-19 patients had higher values of PWV, augmentation index, IMT, asymmetric and symmetric dimethylarginine, vWF, homocysteine, CD31+/CD42b- EMP, C-reactive protein, erythrocyte sedimentation rate, interleukin-6, and β-2-glycoprotein antibodies as well as lower levels of homoarginine and tryptophan compared to healthy controls (all with p < 0.05). A higher total number of pathologically altered inflammatory conditions and higher rates of capillary ramifications, loss, caliber variability, elongations and bushy capillaries with an overall higher microangiopathy evolution score were also observed in post-COVID-19 patients (all with p < 0.05). Most parameters of endothelial dysfunction and inflammation were comparably altered in post-COVID-19 patients and patients with ASCVD, including FMD and NMD. Conclusion: COVID-19 may affect arterial stiffness, capillary morphology, EMP and selected parameters of arginine, kynurenine and homocysteine metabolism as well as of inflammation contributing to COVID-19-associated endothelial dysfunction and inflammatory vasculopathy.

Early Postoperative Basal Insulin Therapy versus Standard of Care for the Prevention of Diabetes Mellitus after Kidney Transplantation: A Multicenter Randomized Trial

BACKGROUND

Post-transplantation diabetes mellitus (PTDM) might be preventable.

METHODS

This open-label, multicenter randomized trial compared 133 kidney transplant recipients given intermediate-acting insulin isophane for postoperative afternoon glucose ≥140 mg/dl with 130 patients given short-acting insulin for fasting glucose ≥200 mg/dl (control). The primary end point was PTDM (antidiabetic treatment or oral glucose tolerance test-derived 2 hour glucose ≥200 mg/dl) at month 12 post-transplant.

RESULTS

In the intention-to-treat population, PTDM rates at 12 months were 12.2% and 14.7% in treatment versus control groups, respectively (odds ratio [OR], 0.82; 95% confidence interval [95% CI], 0.39 to 1.76) and 13.4% versus 17.4%, respectively, at 24 months (OR, 0.71; 95% CI, 0.34 to 1.49). In the per-protocol population, treatment resulted in reduced odds for PTDM at 12 months (OR, 0.40; 95% CI, 0.16 to 1.01) and 24 months (OR, 0.54; 95% CI, 0.24 to 1.20). After adjustment for polycystic kidney disease, per-protocol ORs for PTDM (treatment versus controls) were 0.21 (95% CI, 0.07 to 0.62) at 12 months and 0.35 (95% CI, 0.14 to 0.87) at 24 months. Significantly more hypoglycemic events (mostly asymptomatic or mildly symptomatic) occurred in the treatment group versus the control group. Within the treatment group, nonadherence to the insulin initiation protocol was associated with significantly higher odds for PTDM at months 12 and 24.

CONCLUSIONS

At low overt PTDM incidence, the primary end point in the intention-to-treat population did not differ significantly between treatment and control groups. In the per-protocol analysis, early basal insulin therapy resulted in significantly higher hypoglycemia rates but reduced odds for overt PTDM-a significant reduction after adjustment for baseline differences-suggesting the intervention merits further study.Clinical Trial registration number: NCT03507829.

Immunologically relevant aspects of the new COVID-19 vaccines-an ÖGAI (Austrian Society for Allergology and Immunology) and AeDA (German Society for Applied Allergology) position paper

BACKGROUND

The vaccines against the coronavirus disease 2019 (COVID-19) approved in the European Union represent a decisive step in the fight against the pandemic. The application of these available vaccines to patients with pre-existing immunological conditions leads to a multitude of questions regarding efficacy, side effects and the necessary patient information.

RESULTS

This review article provides insight into mechanisms of action of the currently available severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines and summarises the current state of science as well as expert recommendations regarding tolerability of the vaccines. In addition, the potential to develop protective immune responses is determined. A special focus is given on patients under immunosuppression or in treatment with immunomodulatory drugs. Special groups of the population such as children, pregnant women and the elderly are also considered.

CONCLUSION

Despite the need for a patient-specific risk-benefit assessment, the consensus among experts is that patients with immunological diseases in particular benefit from the induced immune protection after COVID-19 vaccination and do not have an increased risk of side effects.

Effect of short-interval rituximab and high-dose corticosteroids on kidney function in systemic sclerosis: Long-term experience of a single centre

INTRODUCTION

Scleroderma renal crisis (SRC) is a rare but one of the most recognised complications of systemic sclerosis (SSc). Corticosteroid (CS) use has been considered as a major risk factor for SRC. Several studies reported the efficacy of rituximab (RTX) with an acceptable safety profile in SSc. However, data on the long-term effect of high-dose CS concomitant to RTX on kidney function are lacking.

METHODS

We retrospectively analysed SSc patients (n = 35) treated with a lower dosage and short-interval RTX and concomitant high-dose CS at the Department of Internal Medicine at the Medical University of Graz between 2010 and 2019. The kidney function was assessed using the estimated glomerular filtration rate (eGFR) at every RTX admission. The annual decline of kidney function was evaluated by linear mixed model analysis.

RESULTS

At the RTX initiation, one patient had a decreased kidney function indicated by eGFR < 60 mL/min/1.73 m² (median: 96 mL/min/1.73 m² ; interquartile range (IQR): 43-136). Patients received RTX and complementary high-dose CS for a median follow-up time of 3.4 years (range 0.6-9.5). A linear mixed model analysis with the patient as random effect and time from first RTX as fixed effect estimated an annual decline of 1.98 mL/min/1.73 m² of the eGFR (95% confidence interval: [-2.24, -1.72]; P <.001). During the follow-up period, no patient experienced SRC or a significant drop in kidney function.

CONCLUSIONS

A regular, high-dose CS given contemporary to RTX seems to be a safe option for kidney function in patients with SSc. Our findings provide additional knowledge in risk evaluation and planning of individualised therapies or designing clinical studies using RTX.

FC 057SALIVARY POTASSIUM FOLLOWS PLASMA POTASSIUM DYNAMICS IN HEMODIALYSIS PATIENTS

Background and Aims

Hyperkalemia is common in patients on hemodialysis (HD) and in cardiorenal patients on RAAS inhibitors. Frequently, hyperkalemia is a leading reason to withdraw potentially lifesaving therapy in cardiorenal patients. Out-patient monitoring of plasma K+ levels due to preanalytical problems has proven problematic. The present pilot-study examined salivary K+ levels and kinetics based on plasma K+ measurements in HD patients employing a novel class of genetically-encoded fluorescent potassium-ion indicators, the GEPIIs (Bischof et al. Nat. Commun. 2017). HD patients represent a unique population in whom significant K+ derangements and rapid K+ level changes predictably occur and where these phenomena can be safely investigated.

Method

K+ assessments were performed in healthy individuals (n=20) and HD patients (n=30). Study-related procedures were approved by the local Institutional Review Board. Healthy individuals were recruited on a voluntary basis and provided only saliva samples. HD patients were recruited from our HD unit. Blood and saliva samples for K+ assessment were collected simultaneously during three consecutive HD sessions (HD1-3) prior to and directly after each session (pre/post HD). Blood was drawn in a standardized procedure directly from the HD access line and plasma K+ was measured immediately using standardized ion-selective electrodes (ISE). Saliva samples were gathered in a standardized procedure using a commercially available collection device (SuperSALTM). Of note, gaining adequate amounts of saliva from chronic HD patients, who frequently suffer from xerostomia, has proven challenging in some cases. The K+ content of saliva samples was measured by ISE and GEPII-technique. For the latter, samples were mixed with purified GEPIIs and were inserted into a fluorescent plate-reader. Probes were illuminated at 430 nm and emission light were collected at 475 nm and 525 nm, respectively. The ratio of the fluorescent intensities (F535/F480) after appropriate calibration is a direct measure of the K+ concentration sensed by GEPIIs.

Results

K+ determination in saliva samples using the GEPII-technique and ISE showed a strong agreement ((Figure 1A), Bias 0,71; 95% limits of agreement from -2.79 to 4.40). Pre-dialytic [K+]saliva of HD patients compared to healthy individuals, was higher (40,64±1,50 vs. 23,15±0,76 mmol/l, p&lt;0.05). As expected, each HD session (HD1-3) led to a significant reduction in [K+]plasma, which is followed by a similar, significant reduction of [K+]saliva (Figure 1B). Dynamics of plasma and salivary [K+] showed a very similar pattern: strong reduction during a HD session followed by a marked increase in the dialysis-free period until the next session 48-72h later (Figure 1C). Although basal [K+]saliva shows individual variations, [K+]Saliva and [K+]plasma exhibited a tendency of linear association (Figure 1D). Correlation analysis in each HD session (HD1-3 pre/post) revealed however no or weak correlation of pre- and post-dialytic saliva and plasma K+ values (Figure 1E).

Conclusion

The GEPII-technique is an easy to use, reliable and suitable method for salivary K+ determination in healthy individuals and in HD patients with accuracy and precision comparable to that of ISE. Despite heterogeneous baselines, changes of [K+]saliva represent a sensitive marker of K+ derangements as well as hyper- and normokalemia in HD patients. Although we observed that [K+]saliva dynamically follows [K+]plasma , an exact quantification - most likely due to the low number of cases per HD sessions in this pilot-study – was not possible. Additionally, how closely [K+]saliva tracks [K+]plasma in patients with hypokalemia was not addressed in this study. To confidently answer whether [K+]saliva measurement can potentially be used in the care of patients at increased risk of hyperkalemia, further studies in a larger number of patients need to be conducted.

Rituximab in Membranous Nephropathy

Membranous nephropathy (MN) is the most common cause of primary nephrotic syndrome among adults. The identification of phospholipase A2 receptor (PLA2R) as target antigen in most patients changed the management of MN dramatically, and provided a rationale for B-cell depleting agents such as rituximab. The efficacy of rituximab in inducing remission has been investigated in several studies, including 3 randomized controlled trials, in which complete and partial remission of proteinuria was achieved in approximately two-thirds of treated patients. Due to its favorable safety profile, rituximab is now considered a first-line treatment option for MN, especially in patients at moderate and high risk of deterioration in kidney function. However, questions remain about how to best use rituximab, including the optimal dosing regimen, a potential need for maintenance therapy, and assessment of long-term safety and efficacy outcomes. In this review, we provide an overview of the current literature and discuss both strengths and limitations of "the new standard."

Blockade of tumor necrosis factor superfamily members CD30 and OX40 abrogates disease activity in murine immune-mediated glomerulonephritis

Co-stimulation is a prerequisite for pathogenic activity in T cell-mediated diseases and has been demonstrated to achieve tolerance in organ-specific autoimmunity as a therapeutic target. Here, we evaluated the involvement of the tumor necrosis factor family members CD30 and OX40 in immune-complex mediated kidney disease. In vitro stimulation and proliferation studies were performed with CD4⁺ cells from wild type and CD30/OX40 double knock-out (CD30OX40^-/-) mice. In vivo studies were performed by induction of nephrotoxic serum nephritis in wild type, CD30OX40^{- /-} , CD30^-/-, OX40^-/-, reconstituted Rag1^-/- and C57Bl/6J mice treated with αCD30L αOX40L antibodies. CD30, OX40 and their ligands were upregulated on various leukocytes in nephrotoxic serum nephritis. CD30OX40^-/- mice, but not CD30^-/- or OX40^-/- mice were protected from nephrotoxic serum nephritis. Similar protection was found in Rag1^-/- mice injected with CD4⁺ T cells from CD30OX40^-/- mice compared to Rag1^-/- mice injected with CD4⁺ T cells from wild type mice. Furthermore, CD4⁺ T cells deficient in CD30OX40^-/- displayed decreased expression of CCR6 in vivo. CD30OX40^-/- cells were fully capable of differentiating into disease mediating T helper cell subsets, but showed significantly decreased levels of proliferation in vivo and in vitro compared to wild type cells. Blocking antibodies against CD30L and OX40L ameliorated nephrotoxic serum nephritis without affecting pan-effector or memory T cell populations. Thus, our results indicate disease promotion via CD30 and OX40 signaling due to facilitation of exaggerated T cell proliferation and migration of T helper 17 cells in nephrotoxic serum nephritis. Hence, co-stimulation blockade targeting the CD30 and OX40 signaling pathways may provide a novel therapeutic strategy in autoimmune kidney disease.

Agonism of Prostaglandin E2 Receptor 4 Ameliorates Tubulointerstitial Injury in Nephrotoxic Serum Nephritis in Mice

Selectively targeting the E-type prostanoid receptor 4 (EP4) might be a new therapeutic option in the treatment of glomerulonephritis (GN), since the EP4 receptor is expressed on different immune cells, resident kidney cells, and endothelial cells, which are all involved in the pathogenesis of immune-complex GN. This study aimed to evaluate the therapeutic potential and to understand the mode of action of EP4 agonist in immune-complex GN using the murine model of nephrotoxic serum nephritis (NTS). In vivo, NTS mice were treated two times daily with two different doses of an EP4 agonist ONO AE1-329 or vehicle for 14 days total. The effect of PGE2 and EP4 agonism and antagonism was tested on murine distal convoluted tubular epithelial cells (DCT) in vitro. In vivo, the higher dose of the EP4 agonist led to an improved NTS phenotype, including a reduced tubular injury score and reduced neutrophil gelatinase-associated lipocalin (NGAL) and blood urea nitrogen (BUN) levels. EP4 agonist treatment caused decreased CD4+ T cell infiltration into the kidney and increased proliferative capacity of tubular cells. Injection of the EP4 agonist resulted in dose-dependent vasodilation and hypotensive episodes. The low-dose EP4 agonist treatment resulted in less pronounced episodes of hypotension. In vitro, EP4 agonism resulted in cAMP production and increased distal convoluted tubular (DCT) proliferation. Taken together, EP4 agonism improved the NTS phenotype by various mechanisms, including reduced blood pressure, decreased CD4+ T cell infiltration, and a direct effect on tubular cells leading to increased proliferation probably by increasing cAMP levels.

Successful treatment of severe interstitial pneumonia by removal of circulating autoantibodies: a case series

Background

There is only limited clinical data on the benefit of intense immunosuppression in patients with severe interstitial pneumonia associated with autoimmune features or new-onset connective tissue disease.

Case presentation

We here report a series of three consecutive patients suffering from severe interstitial lung disease necessitating endotracheal intubation and mechanical ventilation. The first two patients fulfilled many diagnostic criteria for new-onset antisynthetase syndrome, the third patient for systemic lupus erythematosus. We decided to implement aggressive immunosuppressive strategies in these critically-ill patients including therapeutic plasma exchange, immunoadsorption, cyclophosphamide and rituximab. All three patients improved from respiratory failure, were successfully weaned from the respirator, and eventually dismissed from hospital with ongoing immunosuppressive therapy.

Conclusion

Patients suffering from severe connective tissue disease-associated interstitial lung disease and respiratory failure may benefit from an aggressive immunosuppressive regimen and extracorporeal blood purification with rapid reduction of circulating autoantibodies. The impressive clinical responses in this small case series warrant a controlled clinical trial.

Management of post-transplant diabetes: immunosuppression, early prevention, and novel antidiabetics

Post‐transplant diabetes mellitus (PTDM) shows a relationship with risk factors including obesity and tacrolimus‐based immunosuppression, which decreases pancreatic insulin secretion. Several of the sodium–glucose‐linked transporter 2 inhibitors (SGLT2is) and glucagon‐like peptide 1 receptor agonists (GLP1‐RAs) dramatically improve outcomes of individuals with type 2 diabetes with and without chronic kidney disease, which is, as heart failure and atherosclerotic cardiovascular disease, differentially affected by both drug classes (presumably). Here, we discuss SGLT2is and GLP1‐RAs in context with other PTDM management strategies, including modification of immunosuppression, active lifestyle intervention, and early postoperative insulin administration. We also review recent studies with SGLT2is in PTDM, reporting their safety and antihyperglycemic efficacy, which is moderate to low, depending on kidney function. Finally, we reference retrospective case reports with GLP1‐RAs that have not brought forth major concerns, likely indicating that GLP1‐RAs are ideal for PTDM patients suffering from obesity. Although our article encompasses PTDM after solid organ transplantation in general, data from kidney transplant recipients constitute the largest proportion. The PTDM research community still requires data that treating and preventing PTDM will improve clinical conditions beyond hyperglycemia. We therefore suggest that it is time to collaborate, in testing novel antidiabetics among patients of all transplant disciplines.

Drug Crystal-Related Gastrointestinal Complications Involve Crystal-Induced Release of Neutrophil and Monocyte Extracellular Traps

Ion-exchange resins are commonly used to manage complications of chronic kidney disease, such as hyperphosphatemia, hyperkalemia, and hypercholesterolemia. Occasionally, these drugs can irritate the gastrointestinal lining and cause life-threatening intestinal necrosis. Currently, the pathophysiology of drug crystal-induced intestinal necrosis is not well understood. We hypothesized that crystals of ion-exchange resins like sevelamer, polystyrene sulfonate, and cholestyramine can trigger the formation of neutrophil and monocyte extracellular traps by contributing to intestinal barrier dysfunction. Light and fluorescence microscopy of the colonic resection specimen from a patient with chronic kidney disease revealed severe intestinal necrosis, ulceration, sevelamer crystals, and inflammation upon oral intake of sevelamer, as well as the formation of neutrophil extracellular traps in proximity to small sevelamer crystals. Indeed, drug crystals reduced metabolic activity and induced barrier dysfunction and cell death in human intestinal epithelial cells in vitro. In addition, drug crystals triggered the release of neutrophil and monocyte extracellular traps. Taken together, these data raise the possibility that besides other factors including chronic kidney disease, diabetes mellitus, and hypertension, drug crystals may further amplify a pre-existing barrier dysfunction and necroinflammation in a crescendo of local intestinal necrosis and systemic inflammation/infection, as occasionally observed in patients on ion-exchange resin therapy.