How histopathological diagnosis interacts with kidney ultrasound parameters and glomerular filtration rate.

The evaluation of estimated GFR (eGFR) is a pivotal staging step in patients with chronic kidney disease (CKD), and renal ultrasound plays an important role in diagnosis, prognosis and progression of CKD. The interaction between histopathological diagnosis and ultrasound parameters in eGFR determination has not been fully investigated yet. The study examined the results of native kidney biopsies performed in 48 Italian centers between 2012 and 2020. The primary goal was if and how the histopathological diagnosis influences the relationship between ultrasound parameters and eGFR. After exclusion of children, patients with acute kidney injury and patients without measure of kidney length or parenchymal thickness, 2795 patients have been selected for analysis. The median values were 52 years for patient age, 11 cm for bipolar kidney diameter, 16 mm for parenchymal thickness, 2.5 g/day for proteinuria and 70 ml/min/1.73 m2 for eGFR. The bipolar kidney diameter and the parenchymal thickness were directly related with eGFR values (R square 0.064). Diabetes and proteinuria were associated with a consistent reduction of eGFR, improving the adjusted R square up to 0.100. Addition of histopathological diagnosis in the model increased the adjusted R square to 0.216. There is a significant interaction between histopathological diagnosis and longitudinal kidney diameter (P 0.006). Renal bipolar length and parenchymal thickness are directly related with eGFR. The magnitude of proteinuria and histopathological kidney diagnosis are associated with eGFR. The relationship between kidney length and the level of eGFR depends on the nature of the kidney disease.

"Eculizumab First" in the Management of Posttransplant Thrombotic Microangiopathy.

Introduction: Posttransplant thrombotic microangiopathy (PT-TMA) is an uncommon event that characterizes approximately 3% to 14% of kidney transplants (KTs), and that is associated with a higher risk of delayed graft function and graft loss. PT-TMA occurs more frequently within the first 3 months after transplant and can be a manifestation of de novo disease or the recurrence of previous atypical hemolytic uremic syndrome (aHUS). Abnormalities in complement regulation genes could explain the increased susceptibility of some patients to PT-TMA. Eculizumab is a humanized monoclonal antibody that inhibits the formation of the membrane attack complex C5b-9. The aim of this study is to evaluate the efficacy of eculizumab as treatment for PT-TMA. Methods: We retrospectively analyzed clinical records of 45 KT patients who received eculizumab immediately after the clinical diagnosis of PT-TMA. Results: Kidney biopsy was performed in 91.1% of patients, and complement genetic study was performed in 64.4%. Of the kidney biopsies, 85.4% showed signs of TMA; genetic analysis revealed 1 pathogenetic variant, 2 variants of uncertain significance, 1 likely benign variant, 8 risk polymorphisms, and 27 risk haplotypes. After 2 weeks from the treatment starting, hemoglobin and platelets significantly increased. A remarkable improvement in kidney function was also observed. After 6 months, 28.8% of patients had a complete renal recovery whereas 44.4% had a partial recovery. Conclusion: This is, to our knowledge, the largest series of KT patients with PT-TMA treated with eculizumab. These data suggest that eculizumab is associated with a normalization of hemolysis indices and an important and progressive improvement of graft function.

Rituximab as possible therapy in TNF inhibitor-induced IgA vasculitis with severe renal involvement.

BACKGROUND: We observe the increasing use of tumor necrosis factor (TNF) inhibitors in patients affected by chronic inflammatory diseases. These drugs provide good control of symptoms, contributing to significant improvement in the quality of life in individuals with high disease burden. On the other hand, along with their wider use and longer follow-up periods the number of reports regarding their adverse effects is also increasing. The reported complications include drug-induced vasculitis with possible kidney involvement. In the literature we can distinguish more frequently described ANCA-associated vasculitis and more rarely occurring immunoglobulin A vasculitis. Although uncommon, such complications may present with potentially life-threatening vital organ dysfunction; therefore, adequate monitoring and effective therapy are necessary. CASE PRESENTATION: We report two cases of TNF inhibitor-induced vasculitis with severe acute worsening of renal function and significant proteinuria. The first patient was receiving golimumab therapy for ankylosing spondylitis and the second patient was treated with adalimumab for psoriasis and psoriatic arthritis. In the second case dialysis treatment was necessary and the patient presented recurrence of vasculitis after rechallenge with adalimumab. Both patients underwent renal biopsy which showed findings compatible with drug-induced IgA vasculitis and both were treated successfully with corticosteroids and rituximab. CONCLUSIONS: To the best of our knowledge this is the first report of rituximab use in drug-induced IgA vasculitis with renal involvement. Combination of corticosteroids and rituximab can be an effective therapy in case of vasculitis with kidney failure and a preferable option for selected patients with drug-induced IgA vasculitis compared to cyclophosphamide. More studies are necessary to establish suitable short- and long-term treatment. Given the rarity of this disorder, case reports and case series can provide practical guidance until additional studies become available.

Caveolin-1 in situ expression in glomerular and peritubular capillaries as a marker of ultrastructural progression and severity of renal thrombotic microangiopathy.

BACKGROUND: Thrombotic microangiopathy is a severe and potentially life-threatening condition inducing severe endothelial injury in many organs, particularly native and transplanted kidneys. Current pathological studies by our group have identified the use of Caveolin-1 immunohistochemistry as a potential marker of endothelial damage and progression degree of thrombotic microangiopathy. The aim of the present work was to evaluate Caveolin-1 as a marker of severity in thrombotic microangiopathy kidney disease, according to the ultrastructural progression of the disease evaluated by transmission electron microscopy. MATERIALS AND METHODS: Twenty-nine patients (17 non-transplanted and 12 transplanted) were retrospectively selected, biopsied for suspected or histologically-confirmed thrombotic microangiopathy. Transmission electron microscopy was performed in all cases, and an ultrastructural score of thrombotic microangiopathy-related glomerular disease was assessed (from 0 to 3+). Immunohistochemistry for Caveolin-1 was automatically performed. RESULTS: The mean percentage of Caveolin-1-positive glomerular capillaries was 53.2 ± 40.6% and 28.0 ± 42.8% in the active thrombotic microangiopathy versus previous thrombotic microangiopathy cases (p = 0.085), considering both native and transplanted kidneys. The presence of progressive disease correlated with diffuse Caveolin-1 immunoreactivity (p = 0.031), and ultrastructural score correlated with glomerular Caveolin-1 positivity, progressively increasing from 22.5% of the Score 0 group to 95.5% of the Score 3 group (p = 0.036). DISCUSSION: Caveolin-1 proved to be a very useful marker of early endothelial damage in the course of thrombotic microangiopathy for both native and transplanted kidneys, therefore worth considering in routine practice. Diffuse glomerular Caveolin-1 immunoreactivity correlates with the severity of the thrombotic disease and it can appear very early, even before ultrastructurally evident endothelial damage.

Acute myeloma kidney and SARS-COV2 infection with dialysis need: never say never - a case report.

BACKGROUND: Older individuals with multiple comorbidities and especially patients with multiple myeloma are at higher risk of contracting SARS-CoV-2. When patients with multiple myeloma (MM) are also affected by SARS-CoV-2 the time to start immunosuppressants is still a clinical dilemma especially when urgent hemodialysis is required for acute kidney injury (AKI). CASE PRESENTATION: We present a case of an 80-year-old woman who was diagnosed with AKI in MM. The patient began hemodiafiltration (HDF) with free light chain removal combined with bortezomib and dexamethasone. The reduction of free light chains concurrently was obtained by means of HDF using poly ester polymer alloy (PEPA) high-flux filter: 2 PEPA filters were used in series during each 4-h length HDF session. A total of 11 sessions was carried out. The hospitalization was complicated with acute respiratory failure caused by SARS-CoV-2 pneumonia successfully treated with both pharmacotherapy and respiratory support. Once the respiratory status stabilized MM treatment was resumed. The patient was discharged in stable condition after 3 months of hospitalization. The follow up showed significant improvement of the residual renal function which allowed interruption of hemodialysis (HD). CONCLUSIONS: The complexity of patients affected by MM, AKI, and SARS-CoV-2 should not discourage the attending physicians to offer the adequate treatment. The cooperation of different specialists can lead to a positive outcome in those complicated cases.

Histology for nephrology, from pre-implantation to post-transplant kidney biopsy. Lesson learned from ReBIrth (Renal BIopsy for Kidney Transplantation Therapy).

A meeting entitled Renal BIopsy for Kidney Transplantation Therapy (ReBIrth) took place on May 31st, 2022 in Bologna, Italy. The meeting drew together nephrologists, surgeons, and pathologists and recognized as experts in the field of kidney transplantation in Italy. In this paper, we present our experience working with kidney transplants in the current era of immunosuppression therapy. The primary aim is to report the histopathological characteristics of failed kidney allografts after a consensus of experts reviewed the cases on a wholeslide imaging digital platform. Regardless of the cases discussed, digital pathology was reliable in identifying all the morphological and immunohistochemical features required to improve the correct use of immunosuppressive therapy to prevent graft failure and optimize patient management.

Double glomerulopathies or two-faced janus? A challenging case in the COVID-19 era.

SARS-CoV-2 very often causes kidney involvement through various mechanisms including: acute tubular injury, virus cell invasion, vascular damage due to hypercoagulability and finally dysregulation of the immune system. Even though there are no pathognomonic morphologic features that can rule out or confirm direct damage by SARS-CoV-2, the latest literature suggests that there may be some association. SARS-CoV-2 infection represents a poor prognostic factor, regardless of pulmonary involvement. We report a challenging case with complex renal biopsy findings suggestive of collapsing glomerulopathy and focal proliferative IgA-dominant glomerulonephritis in a patient affected by active hepatitis C virus (HCV), SARS-CoV-2 infection and personal history of cocaine abuse.

DNAJB11 Mutation in ADPKD Patients: Clinical Characteristics in a Monocentric Cohort.

Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a late-onset cilia-related disorder, characterized by progressive cystic enlargement of the kidneys. It is genetically heterogeneous with PKD1 and PKD2 pathogenic variants identified in approximately 78% and 15% of families, respectively. More recently, additional ADPKD genes, such as DNAJB11, have been identified and included in the diagnostic routine test for renal cystic diseases. However, despite recent progress in ADPKD molecular approach, approximately ~7% of ADPKD-affected families remain genetically unresolved. We collected a cohort of 4 families from our center, harboring heterozygous variants in the DNAJB11 gene along with clinical and imaging findings consistent with previously reported features in DNAJB11 mutated patients. Mutations were identified as likely pathogenetic (LP) in three families and as variants of uncertain significance (VUS) in the remaining one. One patient underwent to kidney biopsy and showed a prevalence of interstitial fibrosis that could be observed in ~60% of the sample. The presence in the four families from our cohort of ADPKD characteristics together with ADTKD features, such as hyperuricemia, diabetes, and chronic interstitial fibrosis, supports the definition of DNAJB11 phenotype as an overlap disease between these two entities, as originally suggested by the literature.

Patterns of renal toxicity from the combination of pemetrexed and pembrolizumab for advanced nonsquamous non-small-cell lung cancer (NSCLC): A single-center experience.

OBJECTIVES: The combination of immune-checkpoint inhibitors (ICI) and platinum-pemetrexed chemotherapy (CT) in first-line setting improved survival outcomes of advanced non-small cell lung cancer (NSCLC) patients. Among the various adverse events, renal toxicity can be a relevant safety issue. MATERIALS AND METHODS: We conducted a single-center, observational retrospective study including consecutive patients treated with upfront CT-ICI for advanced nonsquamous NSCLC to investigate incidence and clinical characteristics of acute kidney injury (AKI) using 'Acute Kidney Injury Working Group of Kidney Disease: Improving Global Outcomes' (KDIGO) definition. RESULTS: A total of 89 patients received a first-line CT/ICI. The median age was 69 years. 60.7 % were male, and 87.6 % had an ECOG PS of 0-1. 92.1 % had a baseline glomerular filtration rate of at least 60 ml/min. According to KDIGO criteria, 25 (28 %) patients developed AKI. Considering risk factors for AKI onset, patients receiving >10 cycles of CT/ICI were more likely to experience AKI (p < 0.001). No other associations were found with other variables, including concomitant medications. Any component of the treatment was discontinued (pemetrexed pembrolizumab or both) in 10 (40 %) patients, and 9 patients (36 %) were addressed to nephrological consultation. These patients had higher mean creatinine variation from baseline (1 vs 0.6 mg/dl, p = 0.025) and creatine level (1.8 vs 1.4 mg/dl, p = 0.015), but lower eGFR (35.7 vs 54.2 ml/min, p = 0.011) in comparison to patients not addressed. No patients had microscopic hematuria or pyuria, but mild proteinuria (<0.8 g/24 h) was found in 4 patients. A renal biopsy was performed on 3 patients, revealing acute tubule interstitial nephritis (ATIN), karyomegalic interstitial nephritis, and acute tubular necrosis (ATN). CONCLUSION: Renal toxicity represents a challenging adverse event that could negatively impact outcomes of metastatic nonsquamous NSCLC patients receiving CT/ICI demanding a multidisciplinary approach.

Sickle Cell Trait and SARS-CoV-2-Induced Rhabdomyolysis: A Case Report.

BACKGROUND Rhabdomyolysis is a syndrome characterized by muscle necrosis and the subsequent release of intracellular muscle constituents into the bloodstream. Although the specific cause is frequently evident from the history or from the immediate events, such as a trauma, extraordinary physical exertion, or a recent infection, sometimes there are hidden risk factors that have to be identified. For instance, individuals with sickle cell trait (SCT) have been reported to be at increased risk for rare conditions, including rhabdomyolysis. Moreover, there have been a few case reports of SARS-CoV-2 infection-related rhabdomyolysis. CASE REPORT We present a case of a patient affected by unknown SCT and admitted with SARS-CoV-2 pneumonia, who suffered non-traumatic non-exertional rhabdomyolysis leading to acute kidney injury (AKI), requiring acute hemodialysis (HD). The patients underwent 13 dialysis session, of which 12 were carried out using an HFR-Supra H dialyzer. He underwent kidney biopsy, where rhabdomyolysis injury was ascertained. No viral traces were found on kidney biopsy samples. The muscle biopsy showed the presence of an "open nucleolus" in the muscle cell, which was consistent with virus-infected cells. After 40 days in the hospital, his serum creatinine was 1.62 mg/dL and CPK and Myoglobin were 188 U/L and 168 ng/mL, respectively; therefore, the patient was discharged. CONCLUSIONS SARS-CoV-2 infection resulted in severe rhabdomyolysis with AKI requiring acute HD. Since SARS-CoV-2 infection can trigger sickle-related complications like rhabdomyolysis, the presence of SCT needs to be ascertained in African patients.

Rituximab Followed by Belimumab Controls Severe Lupus Nephritis and Bullous Pemphigoid in Systemic Lupus Erythematosus Refractory to Several Combination Therapies.

Systemic lupus erythematosus (SLE) and bullous pemphigoid (BP) are chronic autoimmune diseases in which B cells play an important pathogenic role in the different stages of the disease. B cell-targeted therapies have been suggested as a new rational approach for treating SLE. Rituximab (RTX), an anti-CD20 chimeric monoclonal antibody, failed to achieve primary endpoints in two clinical trials (EXPLORER and LUNAR) despite multiple observational and retrospective studies showing its beneficial effect on SLE. Moreover, RTX is recommended in cases of BP that is unresponsive to conventional treatments. Belimumab (BLM), a human immunoglobulin G1 λ monoclonal antibody that inhibits soluble B-lymphocyte stimulator (BlyS)/B-cell activating factor (BAFF), is the only biological treatment approved for standard therapy of refractory autoantibody-positive active SLE. Animal models and a few case reports have supported the efficacy of the combined use of RTX followed by BLM as maintenance therapy in severe lupus nephritis (LN), suggesting that their combined use may be more effective than their single use, without compromising safety. In this study, we describe the clinical case of a SLE patient with predominant renal involvement in overlap with BP, refractory to conventional therapy including RTX alone, achieving significant steroid sparing and clinical remission under sequential treatment of RTX-BLM. Moreover, we describe the first case of BP successfully treated with BLM. This case report may encourage further clinical research studies in B lymphocyte targeted combination therapy in patients affected by SLE with major organ involvement or with refractory disease, suggesting that RTX and BLM sequential therapy may be a valid option for the treatment of SLE manifestations, including conventional therapy and RTX-resistant LN.

Deterioration in Clinical Status Is Not Enough to Suspend Eculizumab: A Genetic Complement-Mediated Atypical Hemolytic Uremic Syndrome Case Report.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is characterized by microangiopathic hemolytic anemia, thrombocytopenia, and renal failure. Mutations in CFI gene coding for complement regulation factors and in THBD gene coding for endothelial cell receptor thrombomodulin could predispose to the disease and hypertension can trigger the onset. CASE PRESENTATION: A 51-year-old female patient who had received kidney transplant eighteen years ago presented with hypertensive peak and hemolysis pattern. Normal ADAMTS13 levels as well as negative culture and serology for Shiga-toxin excluded, respectively, thrombotic thrombocytopenic purpura (TTP) and typical HUS caused by Shiga toxin-producing Escherichia coli (STEC-HUS). In suspicion of aHUS, we administered eculizumab and hemodialysis sessions were started as the patient showed severe renal failure. After an initial response, the patient developed cerebral hemorrhage. After last eculizumab administration, according to hematological parameters, an unsatisfactory response was observed: given the worsening clinical scenario, we withdrew eculizumab. Pathogenic mutations in CFI and THBD genes were found. After eculizumab reinitiation, looking at hemolysis indexes, we observed a suboptimal response as well as an otherwise adequate renal one: renal graft function was recovered despite persistence of hemolysis signs, after 6 months on regular dialysis. CONCLUSION: For the first time, we report an aHUS case in which a peculiar combination of mutations in CFI and THBD is found. We describe the importance of continuing eculizumab despite deterioration of patient's clinical conditions.

MALDI-MSI Pilot Study Highlights Glomerular Deposits of Macrophage Migration Inhibitory Factor as a Possible Indicator of Response to Therapy in Membranous Nephropathy.

PURPOSE: Membranous nephropathy (MN) is the most frequent cause of nephrotic syndrome in adults and the disease course is characterized by the "rule of third", with one-third of patients experiencing complete remission and the remaining experiencing relapses or progression of the disease. Additionally, the therapeutic approach is not standardized, leading to further heterogeneity in terms of response and outcome. EXPERIMENTAL DESIGN: In this pilot study, MALDI-MSI analysis is performed on renal biopsies (n = 13) obtained from two homogeneous groups of patients, which differentially responded to the immunosuppressive treatments (Ponticelli regimen). RESULTS: A signal at m/z 1303 displays the greatest discriminatory power when comparing the two groups and is observed to be of higher intensity in the glomeruli of the non-responding patients. The corresponding tryptic peptide is identified as macrophage migration inhibitory factor (MIF). CONCLUSIONS AND CLINICAL RELEVANCE: Despite much effort being made in recent years to understand the pathogenesis of MN, a biomarker able to predict the outcome of these patients following therapeutic treatment is still lacking. Here, a protein (MIF), verified by immunohistochemistry, that can differentiate between these MN patients and could be a valuable starting point for a further study focused on verifying its predictive role in therapy response is highlighted.

Inhibition of heparanase protects against chronic kidney dysfunction following ischemia/reperfusion injury.

Renal ischemia/reperfusion (I/R) injury occurs in patients undergoing renal transplantation and with acute kidney injury and is responsible for the development of chronic allograft dysfunction as characterized by parenchymal alteration and fibrosis. Heparanase (HPSE), an endoglycosidase that regulates EMT and macrophage polarization, is an active player in the biological response triggered by ischemia/reperfusion (I/R) injury. I/R was induced in vivo by clamping left renal artery for 30 min in wt C57BL/6J mice. Animals were daily treated and untreated with Roneparstat (an inhibitor of HPSE) and sacrificed after 8 weeks. HPSE, fibrosis, EMT-markers, inflammation and oxidative stress were evaluated by biomolecular and histological methodologies together with the evaluation of renal histology and measurement of renal function parameters. 8 weeks after I/R HPSE was upregulated both in renal parenchyma and plasma and tissue specimens showed clear evidence of renal injury and fibrosis. The inhibition of HPSE with Roneparstat-restored histology and fibrosis level comparable with that of control. I/R-injured mice showed a significant increase of EMT, inflammation and oxidative stress markers but they were significantly reduced by treatment with Roneparstat. Finally, the inhibition of HPSE in vivo almost restored renal function as measured by BUN, plasma creatinine and albuminuria. The present study points out that HPSE is actively involved in the mechanisms that regulate the development of renal fibrosis arising in the transplanted organ as a consequence of ischemia/reperfusion damage. HPSE inhibition would therefore constitute a new pharmacological strategy to reduce acute kidney injury and to prevent the chronic pro-fibrotic damage induced by I/R.

Defective activation of the MAPK/ERK pathway, leading to PARP1 and DNMT1 dysregulation, is a common defect in IgA nephropathy and Henoch-Schönlein purpura.

Studies on IgA nephropathy (IgAN) have identified, through GWAS, linkage analysis, and pathway scanning, molecular defects in familial and sporadic IgAN patients. In our previous study, we identified a novel variant in the SPRY2 gene that segregates with the disease in one large family. The functional characterization of this variant led us to discover that the MAPK/ERK pathway was defective not only in this family, but also in two sporadic IgAN patients wild type for SPRY2. In the present study, we have deepened the molecular analysis of the MAPK/ERK pathway and extended our evaluation to a larger cohort of sporadic patients and to one additional family. We found that the ERK pathway is defective in IgAN patients and in patients affected by another IgA-mediated disorder, Henoch-Schönlein purpura (HSP). Furthermore, we found that two other proteins, PARP1 and DNMT1, respectively involved in DNA repair and in antibody class switching and methylation maintenance duties, were critically downregulated in IgAN and HSP patients. This study opens up the possibility that defective ERK activation, in some patients, leads to PARP1 and DNMT1 downregulation suggesting that IgAN could be the consequence of a dysregulated epigenetic maintenance leading to the upregulation of several genes. In particular, PARP1 could be used as a potential biomarker for the disease.