Myeloproliferative neoplasms cause glomerulopathy

A Case of Myeloproliferative Neoplasm-Related Glomerulopathy Secondary to Primary Myelofibrosis With Acute Leukaemic Transformation

Glomerular diseases associated with myeloproliferative neoplasms (MPN) are rare, and most often present with proteinuria and kidney impairment. Its natural history is not well described, although it has been associated with poor prognosis in described cases. Here, we present a case of MPN-related focal segmental glomerulosclerosis (FSGS) secondary to primary myelofibrosis (PMF) and describe its progression with transformation of PMF to leukaemia. A 52-year-old gentleman was referred for lower limb swelling on a background of primary myelofibrosis requiring splenectomy 3 months prior. Kidney function was normal, but there was nephrotic-range proteinuria of 3.6 g (normal range, NR < 0.15 g) and mild hypoalbuminaemia of 29 g/L (NR 33-48 g/L). Urine microscopy was bland with no haematuria or pyuria. A kidney biopsy confirmed secondary FSGS with dysmorphic megakaryocytes in the glomerular capillaries, as well as immunohistochemistry demonstrating the presence of megakaryocytes and erythroid precursors in the interstitium, indicating the presence of extramedullary haematopoiesis. No deposits were seen on immunofluorescence or electron microscopy. Despite an initial response to high-dose corticosteroids, a relapse in proteinuria to 10.9 g was seen 5 months after diagnosis. This coincided with leukaemic transformation, which was confirmed on bone marrow biopsy. We describe a case of FSGS secondary to PMF presenting with normal kidney function and nephrotic syndrome. As far as the authors are aware, this is the first case to detail the progression of kidney disease before and after leukaemic transformation. Ongoing follow-up may provide useful insights into the natural history of this infrequent association.

Clonal monocytosis of renal significance

Clonal monocytosis reflects a preneoplastic or neoplastic sustained increase in the absolute monocyte count in the absence of reactive causes. Causes of clonal monocytosis include clonal cytopenias with monocytosis and acute and chronic myeloid neoplasms. Chronic myelomonocytic leukemia is a prototypical myelodysplastic/myeloproliferative overlap neoplasm in adults, characterized by sustained peripheral blood monocytosis. Kidney abnormalities, including acute kidney injury and chronic kidney disease, are frequent in patients with chronic myelomonocytic leukemia and are predictors of worse outcomes. In addition, acute kidney injury/chronic kidney disease often limits eligibility for allogeneic stem cell transplantation or enrollment in clinical trials. In this review, we highlight clonal monocytosis-related etiologies that give rise to acute kidney injury and chronic kidney disease, with special emphasis on chronic myelomonocytic leukemia and lysozyme-induced nephropathy. Monocytes produce lysozyme, which, in excess, can accumulate in and damage the proximal renal tubular epithelium. Early identification of this etiology and a timely reduction in monocyte counts can salvage kidney function. Other etiologies of kidney injury associated with clonal monocytosis include direct renal infiltration by monocytes, renal extramedullary hematopoiesis, myeloproliferative neoplasm-associated glomerulopathy, autoimmune (membranous nephropathy, minimal change disease) and paraneoplastic manifestations, thrombotic microangiopathy, obstructive nephropathy due to myeloproliferation, and urate nephropathy due to tumor lysis syndrome. We propose to group these mechanistic etiologies of kidney injury as clonal monocytosis of renal significance and provide guidance on their diagnosis and management.

Renal tubular necrosis associated with anagrelide administration: a case report

A 62-year-old female patient with essential thrombocythemia experienced rapid renal dysfunction and was subsequently referred to our hospital. Further investigations did not reveal any significant abnormalities except for a slight increase in urinary β2-microglobulin levels. A renal biopsy was performed to investigate the cause of her renal dysfunction, revealing acute tubular necrosis, interstitial edema, and arteriosclerosis. No significant glomerular lesions were observed. Immunofluorescence staining and electron microscopy showed no abnormalities. She had been using anagrelide for 4 years, and her dosage was increased from 2.0 to 3.0 mg/day 10 months before her initial admission. Her renal function began to deteriorate 2 months after the anagrelide dosage increase. Although 0.625 mg of bisoprolol was initiated for tachycardia 3 months after the anagrelide dosage adjustment, we suspected that the acute tubular necrosis was associated with anagrelide administration. After transitioning from anagrelide to hydroxyurea and discontinuing bisoprolol, her renal function improved. This case suggests the importance of considering anagrelide as a potential cause of renal dysfunction in patients using this medication. Therefore, renal biopsy, combined with a comprehensive medical history, is crucial for evaluating the etiology of renal injury in such cases.

Optimization of cardiovascular risk factor management in patients with BCR::ABL1 negative chronic myeloproliferative neoplasms, current knowledge, and perspectives

The exact prognostic role of cardiovascular (CV) risk factors in patients with BCR::ABL1 negative chronic myeloproliferative neoplasms (MPNs) remains unknown as it is often masked by other MPN-related features that bear strong prognostic impact on thrombotic risk. Therefore, current MPN treatment is not primarily guided by presence of CV risk factors. Treatment of CV risk factors in MPN patients usually mirrors that from the general population, despite the fact that CV risk factors in MPNs have their own specificities. Moreover, the optimal target levels for different metabolic deflections in MPNs (i.e., low-density lipoprotein, serum uric acid, or glycated hemoglobin levels) have not been defined. In the current review, we separately discuss the most important aspects of every individual CV risk factor (arterial hypertension, hyperlipidemia, chronic kidney disease, smoking, diabetes mellitus, hyperuricemia, and obesity and cachexia) in MPNs, summarize recent advances in the field, and propose future directions and research areas which may be needed to appropriately manage CV risk factors in MPNs.

Evaluation of Absolute Neutrophil, Lymphocyte and Platelet Count and Their Ratios as Predictors of Thrombotic Risk in Patients with Prefibrotic and Overt Myelofibrosis

AIM

To investigate the prognostic contribution of absolute neutrophil (ANC), lymphocyte (ALC), platelet count and their ratios, neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR), to thrombotic risk in patients with prefibrotic and overt fibrotic myelofibrosis (MF).

METHODS

We retrospectively analyzed a cohort of 256 patients with prefibrotic (85 patients) and overt fibrotic MF (171 patients) treated in six Croatian hematological centers.

RESULTS

Prefibrotic compared to overt fibrotic MF patients presented with significantly higher ALC, platelet count and PLR, and experienced longer time to thrombosis (TTT). Among prefibrotic patients, ANC > 8.33 × 109/L (HR 13.08, p = 0.036), ALC > 2.58 × 109/L (HR 20.63, p = 0.049) and platelet count > 752 × 109/L (HR 10.5, p = 0.043) remained independently associated with shorter TTT. Among overt fibrotic patients, ANC > 8.8 × 109/L (HR 4.49, p = 0.004), ALC ≤ 1.43 × 109/L (HR 4.15, p = 0.003), platelet count ≤ 385 × 109/L (HR 4.68, p = 0.004) and chronic kidney disease (HR 9.07, p < 0.001) remained independently associated with shorter TTT.

CONCLUSIONS

Prognostic properties of ANC, ALC and platelet count are mutually independent and exceed those of NLR and PLR regarding thrombotic risk stratification. ALC and platelet count associate in opposite directions with thrombotic risk in prefibrotic and overt fibrotic MF patients.

Presence and Onset of Chronic Kidney Disease as a Factor Involved in the Poor Prognosis of Patients with Essential Thrombocythemia

Chronic kidney disease (CKD) is an important risk factor for cardiovascular disease, thrombosis, and all-cause death. However, few studies have examined the association between CKD and the prognosis of patients with essential thrombocythemia (ET). We collected ET patients who met the WHO classification 2017 and performed a retrospective clinical study to clarify the association between the presence and onset of CKD and prognosis. Of 73 patients who met the diagnostic criteria, 21 (28.8%) had CKD at the time of ET diagnosis. The age of patients with CKD was significantly higher, and a high proportion of these patients had the JAK2V617F gene mutation. The presence of CKD was a risk factor for the prognosis (hazard ratio (HR): 3.750, 95% confidence interval (CI): 1.196-11.760, P=0.023), and the survival curve was significantly poorer. Furthermore, we analyzed patients without CKD at the time of ET diagnosis using the onset of CKD as a time-dependent variable and identified the onset of CKD as a risk factor for the prognosis (HR: 9.155, 95% CI: 1.542-54.370, P=0.005). In patients with renal hypofunction at the time of ET diagnosis or those with a reduction in the kidney function during follow-up, strict renal function monitoring at regular intervals is necessary.

Kidney and Urinary Tract Involvement in Chronic Myelomonocytic Leukemia

Chronic myelomonocytic leukemia (CMML) is a hematologic malignancy affecting the bone marrow and resulting in peripheral blood monocytosis. Kidney and urinary tract involvement is common and can present dramatically with life-threatening consequences. Kidney involvement can be the result of direct or indirect mechanisms, including prerenal azotemia, glomerular disease, tubulointerstitial involvement, and renovascular disorders. Urinary tract involvement, electrolyte and acid-base disorders, as well as nephrotoxicity from treatment of the disorder can also occur. Given this multifactorial pathogenesis involving several mechanisms concomitantly, nephrologists must exercise heightened awareness and maintain a low threshold for kidney biopsy. There is a pressing need for future research endeavors to elucidate and target the manifestations of CMML that involve the kidneys with the ultimate goal of augmenting overall prognosis and therapeutic outcomes.

Focal Crescentic Glomerulonephritis Superimposed on Myeloproliferative Disease-Related Glomerulopathy in a Case of Myelofibrosis

Proliferative glomerulonephritis in myelofibrosis is a very rare. Mesangial proliferation and sclerosis with changes of chronic thrombotic microangiopathy have been reported, but pauci-immune focal crescentic glomerulonephritis has not been described so far. Herein, we present a 68-year-old male who was a known case of myelofibrosis and presented with rapidly progressive glomerulonephritis and nephrotic range proteinuria. He was diagnosed as anti-neutrophil cytoplasmic antibody (ANCA)-negative focal crescentic glomerulonephritis, and he responded well to a course of intravenous methylprednisolone and cyclophosphamide. Pauci-immune focal crescentic glomerulonephritis may occur in myelofibrosis without ANCA and may be related to unknown pathogenetic mechanisms in myeloproliferative disorders or suggest any superimposed pathology that might respond well to immunosuppressants.

The spectrum of glomerular and vascular kidney pathology associated with myeloproliferative neoplasms

A high prevalence of chronic kidney disease (CKD) occurs in patients with myeloproliferative neoplasms (MPN). However, MPN-related glomerulopathy (MPN-RG) may not account for the entirety of CKD risk in this population. The systemic vasculopathy encountered in these patients raises the hypothesis that vascular nephrosclerosis may be a common pattern of injury in patients with MPN and with CKD. In an exhaustive, retrospective, multicenter study of MPN kidney biopsies in four different pathology departments, we now describe glomerular and vascular lesions and establish clinicopathologic correlations. Our study encompassed 47 patients with MPN who underwent a kidney biopsy that included 16 patients with chronic myeloid leukemia (CML) and 31 patients with non-CML MPN. Fourteen cases met a proposed definition of MPN-RG based on mesangial sclerosis and hypercellularity, as well as glomerular thrombotic microangiopathy. MPN-RG was significantly associated with both myelofibrosis and poorer kidney survival. Thirty-three patients had moderate-to-severe arteriosclerosis while 39 patients had moderate-to-severe arteriolar hyalinosis. Multivariable models that included 188 adult native kidney biopsies as controls revealed an association between MPN and chronic kidney vascular damage, which was independent of established risk factors such as age, diabetes mellitus and hypertension. Therefore, MPN-RG is associated with myelofibrosis and has a poor kidney prognosis. Thus, our findings suggest that the kidney vasculature is a target during MPN-associated vasculopathy and establish a new link between MPN and CKD. Hence, these results may raise new hypotheses regarding the pathophysiology of vascular nephrosclerosis in the general population.

Patient-Specific Pharmacokinetics and Dasatinib Nephrotoxicity

BACKGROUND

Dasatinib has been associated with nephrotoxicity. We sought to examine the incidence of proteinuria on dasatinib and determine potential risk factors that may increase dasatinib-associated glomerular injury.

METHODS

We examined glomerular injury through urine albumin-creatinine ratio (UACR) in 82 patients with chronic myelogenous leukemia who were on tyrosine-kinase inhibitor therapy for at least 90 days. t tests were used to compare mean differences in UACR, while regression analysis was used to assess the effects of drug parameters on proteinuria development while on dasatinib. We assayed plasma dasatinib pharmacokinetics using tandem mass spectroscopy and further described a case study of a patient who experienced nephrotic-range proteinuria while on dasatinib.

RESULTS

Participants treated with dasatinib ( n =32) had significantly higher UACR levels (median 28.0 mg/g; interquartile range, 11.5-119.5) than participants treated with other tyrosine-kinase inhibitors ( n =50; median 15.0 mg/g; interquartile range, 8.0-35.0; P < 0.001). In total, 10% of dasatinib users exhibited severely increased albuminuria (UACR >300 mg/g) versus zero in other tyrosine-kinase inhibitors. Average steady-state concentrations of dasatinib were positively correlated with UACR ( ρ =0.54, P = 0.03) and duration of treatment ( P = 0.003). There were no associations with elevated BP or other confounding factors. In the case study, kidney biopsy revealed global glomerular damage with diffuse foot process effacement that recovered on termination of dasatinib treatment.

CONCLUSIONS

Exposure to dasatinib was associated with a significant chance of developing proteinuria compared with other similar tyrosine-kinase inhibitors. Dasatinib plasma concentration significantly correlated with higher risk of developing proteinuria while receiving dasatinib.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_09_08_CJN0000000000000219.mp3.

Revisiting Circulating Extracellular Matrix Fragments as Disease Markers in Myelofibrosis and Related Neoplasms

Philadelphia chromosome-negative chronic myeloproliferative neoplasms (MPNs) arise due to acquired somatic driver mutations in stem cells and develop over 10-30 years from the earliest cancer stages (essential thrombocythemia, polycythemia vera) towards the advanced myelofibrosis stage with bone marrow failure. The JAK2V617F mutation is the most prevalent driver mutation. Chronic inflammation is considered to be a major pathogenetic player, both as a trigger of MPN development and as a driver of disease progression. Chronic inflammation in MPNs is characterized by persistent connective tissue remodeling, which leads to organ dysfunction and ultimately, organ failure, due to excessive accumulation of extracellular matrix (ECM). Considering that MPNs are acquired clonal stem cell diseases developing in an inflammatory microenvironment in which the hematopoietic cell populations are progressively replaced by stromal proliferation-"a wound that never heals"-we herein aim to provide a comprehensive review of previous promising research in the field of circulating ECM fragments in the diagnosis, treatment and monitoring of MPNs. We address the rationales and highlight new perspectives for the use of circulating ECM protein fragments as biologically plausible, noninvasive disease markers in the management of MPNs.

Clinicopathologic Spectrum of Lysozyme-Associated Nephropathy

Introduction

Lysozyme-associated nephropathy (LyN), a rare cause of kidney injury in patients with chronic myelomonocytic leukemia (CMML), has not been well described to date. We report the clinicopathologic spectrum of LyN from a multi-institutional series.

Method

We identified 37 native kidney biopsies with LyN and retrospectively obtained clinicopathologic data.

Results

Thirty-seven patients had a median age of 74 years and included 78% males. Their most common presentation was acute kidney injury (AKI) or AKI on chronic kidney disease (CKD) (66%) with median estimated glomerular filtration rate (eGFR) of 21.7 ml/min per 1.73 m2, and proteinuria of 1.7 g. A minority (15%) had partial Fanconi syndrome. Serum lysozyme levels were elevated in all tested. Hematologic disorder (n = 28, 76%) was the most common etiology, including CMML (n = 15), acute myeloid leukemia (n = 5), and myelodysplastic syndrome (MDS) (n = 5). Nonhematologic causes (n = 5, 14%), included metastatic neuroendocrine carcinoma (n = 3), sarcoidosis, and leprosy. Etiology was unknown in 4 (11%). Pathology showed proximal tubulopathy with abundant hypereosinophilic intracytoplasmic inclusions, with characteristic staining pattern by lysozyme immunostain. Mortality was high (8/30). However, among the 22 alive, including 85% treated, 7 had improved kidney function, including 1 who discontinued dialysis and 6 with increase in eGFR >15 ml/min per 1.73 m2 compared with eGFR at the time of biopsy.

Conclusion

Increased awareness of the full clinicopathologic spectrum of LyN may lead to prompt diagnosis, earlier treatment, and potentially improved outcome of this rare entity.

Dasatinib nephrotoxicity correlates with patient-specific pharmacokinetics

Introduction

Dasatinib has been associated with nephrotoxicity. We sought to examine the incidence of proteinuria on dasatinib and determine potential risk factors that may increase dasatinib-associated glomerular injury.

Methods

We examine glomerular injury via urine albumin-to-creatinine ratio (UACR) in 101 chronic myelogenous leukemia patients who were on tyrosine-kinase inhibitor (TKI) therapy for at least 90 days. We assay plasma dasatinib pharmacokinetics using tandem mass spectroscopy, and further describe a case study of a patient who experienced nephrotic-range proteinuria while on dasatinib.

Results

Patients treated with dasatinib (n= 32) had significantly higher UACR levels (median 28.0 mg/g, IQR 11.5 - 119.5) than patients treated with other TKIs (n=50; median 15.0 mg/g, IQR 8.0 - 35.0; p < 0.001). In total, 10% of dasatinib users exhibited severely increased albuminuria (UACR > 300 mg/g) versus zero in other TKIs. Average steady state concentrations of dasatinib were positively correlated with UACR (ρ = 0.54, p = 0.03) as well as duration of treatment ( p =0.003). There were no associations with elevated blood pressure or other confounding factors. In the case study, kidney biopsy revealed global glomerular damage with diffuse foot process effacement that recovered upon termination of dasatinib treatment.

Conclusions

Exposure to dasatinib is associated a significant chance of developing proteinuria compared to other similar TKIs. Dasatinib plasma concentration significantly correlates with increased risk of developing proteinuria while receiving dasatinib. Screening for renal dysfunction and proteinuria is strongly advised for all dasatinib patients.

Secondary IgA Nephropathy and IgA-Associated Nephropathy: A Systematic Review of Case Reports

Primary (pIgAN), secondary IgA nephropathy (sIgAN), and IgA-associated nephropathy can be distinguished. While pIgAN has been thoroughly studied, information about the etiology of sIgAN remains scarce. As concerns sIgAN, several studies suggest that different etiologic factors play a role and ultimately lead to a pathophysiologic process similar to that of pIgAN. In this article, we review a vast number of cases in order to determine the novel putative underlying diseases of sIgAN. Moreover, updates on the common pathophysiology of primary disorders and sIgAN are presented. We identified liver, gastrointestinal, oncological, dermatological, autoimmune, and respiratory diseases, as well as infectious, iatrogenic, and environmental factors, as triggers of sIgAN. As novel biological therapies for listed underlying diseases emerge, we suggest implementing drug-induced sIgAN as a new significant category. Clinicians should acknowledge the possibility of sIgAN progression in patients treated with TNF-α inhibitors, IL-12/IL-23-inhibitors, immune checkpoint inhibitors, CTLA-4, oral anticoagulants, thioureylene derivatives, and anti-vascular endothelial growth factor drugs.

Significance of reduced renal function in patients with chronic myelomonocytic leukemia

In a retrospective study, we analyzed the prevalence of increased creatinine levels in 166 patients with chronic myelomonocytic leukemia (CMML), their potential prognostic impact, and potential correlations with laboratory and molecular features. Increased creatinine values (> 1.1 mg/dl) were found in 71 of 166 (43%) patients. The median survival of patients with increased creatinine values was significantly shorter than in patients without impairment of renal function (20 vs. 52 months, p < 0.001). Patients with increased creatinine values were older, were more often male, had higher leukocyte counts, higher monocyte counts, and higher lactatdehydrogenase (LDH) values. There was a trend toward a higher prevalence of CBL and ASXL1 mutations in patients with renal impairment. Our findings show a high prevalence of renal abnormalities in patients with CMML. Increased creatinine values were identified as a new prognostic marker. These findings may be important for the individualized management of this heterogenous group of patients.

Myeloproliferative Neoplasm and Myelodysplastic Syndrome-Associated Renal Disease: A Histopathological Report of Two Cases

Myeloproliferative neoplasms (MPN) are clonal disorders of hematopoietic stem cells with a proliferation of one or more myeloid lineage and mature cell overproduction, while myelodysplastic syndrome (MDS)/MPN simultaneously show aspects of MDS and MPN, leading to partially ineffective hematopoiesis with associated dysplastic changes. This spectrum of disorders includes chronic myeloid leukemia, polycythemia vera, primary myelofibrosis, and essential thrombocythemia. MDS/MPN are classically not associated with renal complications; however, an accumulating body of evidence suggests that multiple growth factors, cytokines, endothelial damage, and an activated complement system in these patients can induce glomerulopathy, as nearly a third of these patients present with advanced renal disease on diagnosis, which is unlikely to be age or hypertension-related. In this report, we present two cases of patients with MPN/MDS, a 45-year-old male with essential thrombocythemia and a 73-year-old male with polycythemia vera, both of whom developed generalized edema and were referred to our institution from their outpatient nephrologists due to accompanying proteinuria. Renal biopsy of the first patient revealed mesangiocapillary and mesangioproliferative MPN-associated glomerulopathy. In contrast, the second patient was diagnosed with MPN/MDS-associated segmental mesangial proliferative glomerulonephritis and renal vasculature drug toxicity. Both patients were started on treatment - corticosteroid as per consensus.

Clonal haematopoiesis of indeterminate potential and impaired kidney function-A Danish general population study with 11 years follow-up

The myeloproliferative neoplasms are associated with chronic kidney disease but whether clonal haematopoiesis of indeterminate potential (CHIP) is associated with impaired kidney function is unknown. In the Danish General Suburban Population Study (N = 19 958) from 2010 to 2013, 645 individuals were positive for JAK2V617F (N = 613) or CALR (N = 32) mutations. Mutation-positive individuals without haematological malignancy were defined as having CHIP (N = 629). We used multiple and inverse probability weighted (IPW)-adjusted linear regression analysis to estimate adjusted mean (95% confidence interval) differences in estimated glomerular filtration rate (eGFR; ml/min/1.73 m² ) by mutation status, variant allele frequency (VAF%), blood cell counts, and neutrophil-to-lymphocyte ratio (NLR). We performed 11-year longitudinal follow-up of eGFR in all individuals. Compared to CHIP-negative individuals, the mean differences in eGFR were -5.6 (-10.3, -0.8, p = .02) for CALR, -11.9 (-21.4, -2.4, p = 0.01) for CALR type 2, and -10.1 (-18.1, -2.2, p = .01) for CALR with VAF ≥ 1%. The IPW-adjusted linear regression analyses showed similar results. NLR was negatively associated with eGFR. Individuals with CALR type 2 had a worse 11-year longitudinal follow-up on eGFR compared to CHIP-negative individuals (p = .004). In conclusion, individuals with CALR mutations, especially CALR type 2, had impaired kidney function compared to CHIP-negative individuals as measured by a lower eGFR at baseline and during 11-year follow-up.

A Case of Focal Segmental Glomerulosclerosis Associated With Essential Thrombocythemia

A 72-year-old man was admitted for examination of proteinuria (9.14 g/day) and leg edema. Essential thrombocythemia (ET) was diagnosed because of thrombocytosis (platelet count, 57.9×10⁴/μL), elevated megakaryocytes in bone marrow biopsy, and JAK2 V617 mutation. Kidney biopsy led to a diagnosis of focal segmental glomerulosclerosis (FSGS) cellular variant (characterized by glomerular capillaries filled with swollen endothelial cells containing foam cells) in 6 glomeruli, FSGS tip variant in 5 glomeruli, and additional FSGS variants in other glomeruli. Affected glomeruli had anti-CD61 antibody staining-positive megakaryocyte infiltrations. ET mayinduce FSGS because megakaryocyte infiltration increases intraglomerular pressure, resulting in hypertension and proteinuria.

Hematological Malignancies and the Kidney

The incidence of hematologic malignancies is on the rise worldwide. Kidney disease is ubiquitous in patients with hematologic malignancies, encompassing a wide spectrum of disorders involving each kidney compartment, including the vasculature, tubules, interstitium, and glomerulus, and there is significant overlap of kidney involvement with each hematologic malignancy. Vascular disorders include both microvascular and macrovascular damage, via thrombotic microangiopathy, hyperleukocytosis, hyperviscosity, and cryoglobulinemia. The tubulointerstitial compartment may be affected by prerenal azotemia and acute tubular injury, but malignant infiltration, tumor lysis syndrome, extramedullary hematopoiesis, cast nephropathy, granulomatous interstitial nephritis, and lysozymuria should be considered in certain populations. Obstructive uropathy may occur due to nephrolithiasis or retroperitoneal fibrosis. Glomerular disorders, including membranoproliferative, membranous, minimal change, and focal segmental glomerulosclerosis, can rarely occur. By understanding how each compartment may be affected, care can best be optimized for these patients. In this review, we summarize the widely varied etiologies of kidney diseases stratified by kidney compartment and hematologic malignancy, focusing on demographics, pathology, pathophysiology, mechanism, and outcomes. We conclude with common electrolyte abnormalities associated with hematologic malignancies.

Paraneoplastic Glomerular Diseases

Paraneoplastic glomerular diseases (GNs) are rare manifestations in patients with underlying hematologic and solid organ malignancies and can occur before or after the detection of cancer. In the absence of established algorithms for investigation and reliable tests, they remain difficult to diagnose. Given the heterogeneity and infrequency of cases, the pathogenesis of most paraneoplastic GNs is poorly understood. Most of our recent understanding of paraneoplastic GNs has emerged from the discovery of target antigens in membranous nephropathy such as thrombospondin type-1 domain-containing protein 7A and neural epidermal growth factor-like 1 protein that appear to be promising in differentiating a primary vs paraneoplastic cause of membranous nephropathy. Treatment of paraneoplastic GNs is usually directed at the underlying malignancy. This review will focus on the epidemiology, pathogenesis, and diagnosis of paraneoplastic glomerular processes.

The Myeloid-Kidney Interface in Health and Disease

Kidney homeostasis is highly dependent upon the correct functioning of myeloid cells. These cells form a distributed surveillance network throughout the kidney, where they play an integral role in the response to organ threat. Dysregulation of resident proinflammatory and profibrotic macrophages leads to kidney structural damage and scarring after kidney injury. Fibrosis throughout the kidney parenchyma contributes to the progressive functional decline observed in CKD, independent of the etiology. Circulating myeloid cells bearing intrinsic defects also affect the kidney substructures, such as neutrophils activated by autoantibodies that cause GN in ANCA-associated vasculitis. The kidney can also be affected by disorders of myelopoiesis, including myeloid leukemias (acute and chronic myeloid leukemias) and myelodysplastic syndromes. Clonal hematopoiesis of indeterminate potential is a common, newly recognized premalignant clinical entity characterized by clonal expansion of hyperinflammatory myeloid lineage cells that may have significant kidney sequelae. A number of existing therapies in CKD target myeloid cells and inflammation, including glucocorticoid receptor agonists and mineralocorticoid receptor antagonists. The therapeutic indications for these and other myeloid cell-targeted treatments is poised to expand as our understanding of the myeloid-kidney interface evolves.

Renal post-mortem findings in myeloproliferative and myelodysplastic/myeloproliferative neoplasms

Myeloproliferative neoplasms (MPN) are a heterogeneous group of hematological disorders presenting with an increased proliferation in one or several hematological cell lines. Renal manifestations of MPN have not been fully characterized so far. To morphologically assess the potential renal involvement in MPN patients, we analyzed histomorphological findings of a post-mortem cohort (n = 57) with a disease history of Philadelphia-negative MPN including polycythaemia vera, primary myelofibrosis, essential thrombocythemia, or chronic myelomonocytic leukemia (CMML). Seven (12.2%) patients presented with a pattern of diffuse glomerulosclerosis not attributable to diabetic or hypertensive nephropathy. Weak C4d staining suggestive for chronic thrombotic microangiopathy (TMA) was observed in 4/7 cases. Glomerulonephritis was excluded by light microscopy and immunohistochemistry. Patients with a pattern of diffuse glomerulosclerosis did not differ from the rest of the cohort regarding MPN subtype, disease duration, age, or sex. No significant proteinuria had been observed before death. Further findings attributed to MPNs were extramedullary hematopoiesis (n = 5; 8.8%) and tumor involvement in advanced disease (n = 4; 7.0%). Other common findings included arteriolosclerosis (n = 18; 31.6%) and signs of shock (n = 8; 14.0%). To our knowledge, this study is so far the largest investigating renal findings in MPN patients. There may be a causal relationship between idiopathic diffuse glomerular sclerosis and MPN, although its clinical significance and pathophysiology remain uncertain with TMA probably being relevant in a subgroup of cases. Our findings demonstrate the spectrum of renal findings in MPN from early to terminal disease of which hematologists should be aware of in daily clinical practice.

Clinical and Pathological Features of Renal Presentations in Polycythemia Vera

BACKGROUND

Polycythemia vera (PV) is a common type of Philadelphia chromosome-negative chronic myeloproliferative disorder. PV-associated kidney disease is rarely reported and remains poorly understood. It has been observed that chronic kidney disease could be a risk factor for poor prognosis in PV.

METHODS

We retrospectively analyzed the clinicopathological features of renal presentations in eight patients with confirmed PV-associated kidney disease.

RESULTS

The eight patients were 6 males and 2 females, with a mean age of 46.4±16.8 years. Six patients had a history of PV, with a duration range 0.5-16 years. The other two patients were newly diagnosed with PV simultaneously with glomerular disease. Seven patients conducted a JAK2 V617F mutation test, with a positive result in five. Proteinuria and renal dysfunction were the patients' main complaints, with only one having nephrotic syndrome and three having microscopic hematuria. The level of proteinuria ranged from 0.52-10.96 g/day. Three patients had advanced chronic kidney disease (CKD), two in stage 3b and one in stage 4, but only one patient had anemia. Three patients had monoclonal immunoglobulinemia, one patient with immunoglobulin (Ig) G kappa plus light chain lambda, one patient with IgG kappa, and one patient with IgG lambda. Five patients underwent a renal biopsy. The pathological diagnosis was IgA nephropathy in three, non-IgA mesangial proliferative glomerulopathy in one, and glomerular hypertrophy with ischemic renal injury in one patient. Glomerular ischemia, ischemic shrinkage, focal segmental sclerosis, and glomerulomegaly were common pathological features. Glomerular crescents and endocapillary proliferation were also observed. All patients were administered hydroxyurea, and seven were administered renin-angiotensin system inhibitors. During follow-up, one patient with uncontrolled PV developed secondary myelofibrosis and died, three patients were lost to follow-up, and four patients remained alive with CKD.

CONCLUSIONS

Patients with untreated or uncontrolled PV could have massive proteinuria and advanced CKD, pathologically showing ischemic, sclerosing glomerular lesions with hypercellurity, glomerular crescents and endocapillary proliferation. IgA nephropathy was most commonly diagnosed. These findings deserve attention because early screening and effective control of PV may benefit the long-term kidney prognosis.

Advanced extramedullary hematopoiesis with a marked increase in reticulin fibers and hemorrhage on various organs: the first autopsy case report

Myelofibrosis is characterized by stem cell-derived clonal proliferation potentially resulting in bone marrow fibrosis. As the disease progresses, extramedullary hematopoiesis is frequently detected in the spleen and the liver but rarely in other organs. We report a case of a 68-year-old woman with myelofibrosis with a JAK2 mutation, showing extramedullary hematopoiesis (EMH) in various organs with a marked increase in reticulin fibers, and myeloproliferative neoplasm (MPN)-related necrotizing crescent glomerulonephritis. She was admitted to our hospital owing to respiratory discomfort. Computed tomography revealed a mass in the anterior mediastinum. Ten days later, the patient died owing to respiratory distress. At autopsy, EMH were detected in the anterior mediastinum, heart, lung, spleen, and the kidney with a marked increase in reticulin fibers. We considered that respiratory distress was partially caused by EMH. In the kidney, necrotizing crescent glomerulonephritis was observed. Immunohistochemically, the glomerular basement and mesangial area were IgA- and C3d-positive. Ultrastructural examination revealed the presence of dense deposits in the subendothelial space and the mesangial and paramesangial areas. Thus, we suspected that MPN-related necrotizing crescentic glomerulonephritis harbored a pathogenesis similar to that of IgA-dominant post-infectious glomerulonephritis or IgA nephropathy. This case report could widen the spectrum of MPN- or EMH-related lesions.

Renal Diseases Associated with Hematologic Malignancies and Thymoma in the Absence of Renal Monoclonal Immunoglobulin Deposits

In addition to kidney diseases characterized by the precipitation and deposition of overproduced monoclonal immunoglobulin and kidney damage due to chemotherapy agents, a broad spectrum of renal lesions may be found in patients with hematologic malignancies. Glomerular diseases, in the form of paraneoplastic glomerulopathies and acute kidney injury with various degrees of proteinuria due to specific lymphomatous interstitial and/or glomerular infiltration, are two major renal complications observed in the lymphoid disorder setting. However, other hematologic neoplasms, including chronic lymphocytic leukemia, thymoma, myeloproliferative disorders, Castleman disease and hemophagocytic syndrome, have also been associated with the development of kidney lesions. These renal disorders require prompt recognition by the clinician, due to the need to implement specific treatment, depending on the chemotherapy regimen, to decrease the risk of subsequent chronic kidney disease. In the context of renal disease related to hematologic malignancies, renal biopsy remains crucial for accurate pathological diagnosis, with the aim of optimizing medical care for these patients. In this review, we provide an update on the epidemiology, clinical presentation, pathophysiological processes and diagnostic strategy for kidney diseases associated with hematologic malignancies outside the spectrum of monoclonal gammopathy of renal significance.

Kidney injury and disease in patients with haematological malignancies

Acute kidney injury (AKI) is common in patients with cancer, especially in those with haematological malignancies. Kidney injury might be a direct consequence of the underlying haematological condition. For example, in the case of lymphoma infiltration or extramedullary haematopoiesis, it might be caused by a tumour product; in the case of cast nephropathy it might be due to the presence of monoclonal immunoglobulin; or it might result from tumour complications, such as hypercalcaemia. Kidney injury might also be caused by cancer treatment, as many chemotherapeutic agents are nephrotoxic. High-intensity treatments, such as high-dose chemotherapy followed by haematopoietic stem cell transplantation, not only increase the risk of infection but can also cause AKI through various mechanisms, including viral nephropathies, engraftment syndrome and sinusoidal obstruction syndrome. Some conditions, such as thrombotic microangiopathy, might also result directly from the haematological condition or the treatment. Novel immunotherapies, such as immune checkpoint inhibitors and chimeric antigen receptor T cell therapy, can also be nephrotoxic. As new therapies for haematological malignancies with increased anti-tumour efficacy and reduced toxicity are developed, the number of patients receiving these treatments will increase. Clinicians must gain a good understanding of the different mechanisms of kidney injury associated with cancer to better care for these patients.

Treatment of Essential Thrombocythemia with Anagrelide Is Associated with an Increased Risk of Worsened Kidney Function

BACKGROUND AND PURPOSE

When choosing a cytoreduction method for patients suffering from essential thrombocythemia (ET), it is important to know the safety profile of the medicine used. Few articles have been published about the effects of hydroxycarbamide (hydroxyurea, HU) and anagrelide (ANA) on renal function in ET patients. This study is the largest analysis of nephrotoxicity of cytoreductive drugs used in ET therapy so far, which additionally includes risk factors for the progression of kidney disease and coexisting genetic mutation.

EXPERIMENTAL APPROACH

The retrospective study included 310 patients diagnosed with ET. Demographic data, comorbidities, Cr, and estimated glomerular filtration rate (eGFR) were all taken into account prior to diagnosis and after 6 months of HU and ANA treatment.

KEY RESULTS

A statistically significant difference was found between Cr and eGFR levels at baseline and after 6 months of treatment (p < 0.001). The applied treatment (HU and ANA) had the greatest impact on kidney function. ANA significantly increased the risk of worsening renal function in contrary to hydroxycarbamide after 6 months of treatment (eGFR change: median +1 mL/min/1.73 m2 [interquartile range (IQR) (-4)-(+7)] in the HU group vss. median -13 mL/min/1.73 m2 [IQR (-18)-(-6)] in the ANA group, odds ratio [OR] 7.92 95% confidence interval [95% CI] [4.17-15.08], p < 0.001). Lowering of eGFR <60 mL/min/1.73 m2 occurred in 31 patients (31.0%) from the ANA group and 10 people (4.8%) treated with HU (p = 0.000). In 1 patient from the ANA group, >50% decrease in eGFR was observed. The chance for an increase in Cr levels was higher in people with pre-existing arterial hypertension (OR 1.92 CI = 95% [1.21-3.05], p = 0.006). Sex, type of mutation found (JAK2 V617F or CALR), and previous renal impairment did not affect renal function after 6 months of treatment. In addition, there was no difference in the efficacy of ET treatment between HU and ANA (p = 0.998).

CONCLUSIONS AND IMPLICATIONS

The observations indicate that ANA should be used in patients with ET with great caution and taking into account the risk of worsened kidney function.

Immune Complex Associated Glomerulonephritis in a Patient with Prefibrotic Primary Myelofibrosis: A Case Report

A case of prefibrotic myelofibrosis with immune complex-mediated glomerulonephritis is presented. A 45-year-old female, with history of right subclavian and axillary vein thrombosis, presented with abdominal distension, facial puffiness, and pedal edema. Evaluation revealed deranged renal functions with nephrotic range proteinuria and acute kidney injury. JAK2 mutation evaluated in view of portal vein thrombosis and splenomegaly was positive. Renal biopsy revealed mesangial proliferative glomerulonephritis with full house immune complex deposition on direct immunofluorescence (DIF). The patient had no signs or symptoms of systemic lupus erythematosus and serological markers for autoimmune or collagen vascular disease were negative. Renal involvement in myeloproliferative neoplasms (MPNs) is uncommon and histological patterns of DIF negative mesangial proliferative glomerulonephritis, focal segmental glomerulosclerosis, and immunoglobulin A nephropathy have been reported.

Primary Myelofibrosis-Related Renal Disorders Treated with a Janus Kinase Inhibitor

Extramedullary hematopoiesis is widely known to occur in patients with primary myelofibrosis (PMF). Autopsy studies on individuals with PMF revealed that extramedullary hematopoiesis occurred in the kidneys in 35% of the cases, but there is little awareness regarding such lesions. A 63-year-old man was diagnosed with PMF based on a detailed examination of persistent high white blood cells. An examination of the patient's medical records revealed an increased white blood cell count, deterioration of kidney function, and urinary protein excretion developed simultaneously. Thus, a kidney biopsy was performed. Advanced lymphocyte invasion was recognized in the interstitial tissue, and the tubular structure was highly disrupted. Based on these findings, he was diagnosed with interstitial nephritis. However, because of the large number of cells with nuclear atypia in the stroma, additional immunohistochemical staining was also performed, such as glycophorin A, naphthol AS-D, myeloperoxidase, and CD42b. As a result, invasion of three lineages of immature cells, erythroblasts, megakaryocytes, and granulocytes, was identified. Renal dysfunction resulting from interstitial cellular infiltration due to extramedullary hematopoiesis was therefore diagnosed. Treatment with ruxolitinib was initiated after a renal biopsy and the rate of decline in renal function was slightly reduced. Although, in myeloproliferative disorders, proliferative glomerular lesions are widely considered to be renal disorders, there is little awareness regarding interstitial lesions. Extramedullary hematopoiesis of the kidney in PMF is not uncommon, but 40% of cases are reportedly misdiagnosed as interstitial nephritis. Because extramedullary hematopoiesis can be controlled by ruxolitinib, early detection is important.

A rare cause of acute kidney injury with chronic myelomonocytic leukemia

An 80-year-old man with myelodysplastic syndrome developed acute kidney injury (AKI) and peripheral blood monocyte-dominant leukocytosis. Glomerular disease was suspected from urinalysis, which showed proteinuria and microscopic hematuria with red cell casts. Eventually, he died of respiratory failure, after which a postmortem was performed. In the glomeruli, the extracapillary space was filled with numerous mononuclear cells and erythrocytes. At first interpretation, the glomerular findings appeared to represent cellular crescents. However, immunostaining revealed that the extracapillary mononuclear cells were in fact leukemic cells. Furthermore, tubular injury due to marked accumulation of lysozyme was also recognized together with infiltration of leukemic cells in the interstitium. The diagnosis of kidney infiltration by chronic myelomonocytic leukemia (CMML) and lysozyme-induced tubular injury was eventually made. Our case is the first report showing extracapillary infiltration of leukemic cells by immunostaining. In addition, lysozyme-induced tubular injury is a forgotten cause of kidney injury in patients with CMML. This case teaches us the rare and forgotten causes of AKI with CMML.

Spectrum of Kidney Involvement in Patients with Myelodysplastic Syndromes

Introduction

Myelodysplastic syndromes (MDS) are characterized by a high prevalence of associated autoimmune manifestations. Kidney involvement has been rarely reported in MDS patients. We report on the spectrum of kidney pathological findings in MDS patients.

Methods

We retrospectively identified MDS patients who had undergone a kidney biopsy between 2001 and 2019 in nine Swiss and French nephrology centres.

Results

Nineteen patients (median age 74 years [63-83]) were included. At the time of kidney biopsy, eleven (58%) patients had extra-renal auto-immune manifestations and sixteen (84%) presented with acute kidney injury. Median serum creatinine at diagnosis was 2.8 mg/dL [0.6-8.3] and median urinary protein to creatinine ratio was 1.2 g/g [0.2-11]. Acute tubulo-interstitial nephritis (TIN) was present in seven (37%) patients. Immunofluorescence study in one patient with acute TIN disclosed intense IgG deposits along the tubular basement membrane and Bowman’s capsule. Other kidney pathological features included ANCA-negative pauci-immune necrotizing and crescentic glomerulonephritis (n = 3), membranous nephropathy (n = 2), IgA nephropathy (n = 1), IgA vasculitis (n = 1), immunoglobulin-associated membrano-proliferative glomerulonephritis type I (n=1), crescentic C3 glomerulopathy (n = 1), fibrillary glomerulonephritis (n = 1) and minimal change disease (n = 1). Eleven (58%) patients received immunosuppressive treatments, among whom one developed a severe infectious complication. After a median follow-up of 7 month [1-96], nine (47%) patients had chronic kidney disease stage 3 (n = 6) or 4 (n = 3) and five (26%) progressed to end-stage kidney disease. Three patients died.

Conclusions

MDS are associated to several autoimmune kidney manifestations, predominantly acute TIN. MDS are to be listed among the potential causes of autoimmune TIN.

Renal disease associated with myeloproliferative neoplasms and myelodysplastic syndrome/myeloproliferative neoplasms

AIMS

Renal changes in patients with myeloproliferative neoplasms (MPNs) or myelodysplastic syndrome (MDS)/MPNs have been addressed by few, respectively no, reports. The aim of this study was to focus on a systematic evaluation of renal biopsies in patients with MPNs or MDS/MPNs.

METHODS AND RESULTS

The cohort comprised 29 patients (23 men) aged 67 ± 11 years (mean ± standard deviation), diagnosed with chronic myeloid leukaemia (n = 5), polycythaemia vera (n = 9), primary myelofibrosis (n = 5), essential thrombocythaemia (n = 2), or chronic myelomonocytic leukaemia (n = 4), as well as MPNs or MDS/MPNs not otherwise specified (n = 4). Patients manifested with proteinuria (93%), partially in the nephrotic range (46%), haematuria (72%), and impaired kidney function (93%). The most prominent histological findings included double-contoured glomerular basement membranes (71%), acute endothelial damage (68%), intracapillary platelet aggregation (62%), mesangiolysis (21%), thrombotic microangiopathy (24%), segmental glomerulosclerosis (66%), mesangial hypercellularity and sclerosis, extramedullary haematopoiesis (17%), and also IgA nephropathy (21%) and glomerulonephritis (GN) with features of infection-related GN (21%). MPN and MDS/MPN patients showed significantly more chronic changes than age-matched and sex-matched controls, including global and segmental glomerulosclerosis, mesangial sclerosis, and hypercellularity, whereas the extent of arteriosclerosis was comparable.

CONCLUSIONS

MPN and MDS/MPN patients show glomerular scarring that exceeds age-related phenomena. Ongoing endothelial damage, growth factors released by platelets and deposition of immune complexes are probably the causative mechanisms. Early recognition of renal failure heralded by proteinuria and haematuria, and consequent control of risk factors for kidney failure, should be recommended for MPN and MDS/MPN patients.

Kidney Involvement in Patients With Chronic Myelomonocytic Leukemia or BCR-ABL-Negative Myeloproliferative Neoplasms

Introduction

The identification of specific molecular signatures and the development of new targeted drugs have changed the paradigm of onco-nephrology, now allowing a multiscale approach of kidney involvement related to hematologic malignancies relying on combined hematologic and molecular assessments. In this study, we aimed to refine the spectrum of kidney disorders associated with chronic myelomonocytic leukemia (CMML) or BCR-ABL–negative myeloproliferative neoplasms (MPNs), 2 very rare conditions scarcely described.

Methods

Case series. Patients with myeloid neoplasms who were referred to Toulouse University Hospital Nephrology Unit and were diagnosed with acute kidney injury (AKI), chronic kidney disease (CKD), or urine abnormalities were retrospectively included.

Results

Eighteen patients (males n=13, CMML n=8, essential thrombocytosis [ET] n=7, polycythemia vera [PV] n=1, and myelofibrosis n=2) developed kidney disease 7.7±2 years after the diagnosis of the malignancy. Twelve patients had AKI at presentation. Eight patients had glomerular presentation (high-range proteinuria 33%, microscopic hematuria 56%). Kidney biopsy (n=14) showed various patterns, including pauci-immune glomerulosclerosis (n=5), extramedullary hematopoiesis (n=6), or tubular atrophy and interstitial fibrosis with polymorphic inflammation (n=8). Immunostaining of CD61 confirmed the infiltration of megakaryocytes within glomeruli or interstitium in 5 of 8 patients. Other pictures of glomerulopathy were identified in 3 patients (IgA nephropathy n=2, AA amyloidosis n=1). Massive kidney infiltration by CMML was identified in 1 patient. After a mean follow-up of 24±6 months, malignancy was considered as stable in 11 patients (61%), but 22% of patients had progressed to end-stage renal failure. The remaining had persistently reduced kidney function. No correlation between the malignancy and the renal presentation and outcomes could be identified.

Conclusions

Kidney complications of CMML/MPN are heterogenous, and kidney biopsy may help to identify new molecular targets to prevent the development of kidney fibrosis.

Reduced renal function strongly affects survival and thrombosis in patients with myelofibrosis

We retrospectively investigated a cohort of 176 myelofibrosis patients (128 primary-PMF; 48 secondary-SMF) from five hematology centers. The presence of chronic kidney disease (CKD) was determined in addition to other clinical characteristics. CKD was present in 26.1% of MF patients and was significantly associated with older age (P < 0.001), higher WBC (P = 0.015), and its subsets (neutrophil, monocyte, and basophil counts), higher platelets (P = 0.001), lower albumin (P = 0.018), higher serum uric acid (P = 0.001), higher LDH (P = 0.022), and the presence of CV risk factors (P = 0.011). There was no significant association with driver mutations, degree of bone marrow fibrosis, PMF/SMF, or DIPSS risk categories (P > 0.05 for all analyses). The presence of CKD was significantly associated with shorter time to arterial (HR = 3.49; P = 0.041) and venous thrombosis (HR = 7.08; P = 0.030) as well as with shorter overall survival (HR 2.08; P = 0.009). In multivariate analyses, CKD (HR = 1.8; P = 0.014) was associated with shorter survival independently of the DIPSS (HR = 2.7; P < 0.001); its effect being more pronounced in lower (HR = 3.56; P = 0.036) than higher DIPSS categories (HR = 2.07; P = 0.023). MF patients with CKD should be candidates for active management aimed at the improvement of renal function. Prospective studies defining the optimal therapeutic approach are highly needed.

Chronic kidney disease could be a risk factor for thrombosis in essential thrombocythemia and polycythemia vera

Chronic kidney disease (CKD) is a well-known risk factor for venous thromboembolism and cardiovascular (CV) disease development in the general population, but its role in thrombotic risk in essential thrombocythemia (ET) and polycythemia vera (PV) remains poorly understood. This retrospective multicenter study analyzed clinical correlations and the potential impact of CKD on thrombosis development in ET and PV patients. We included 167 patients (76 ET and 91 PV); 25.7% had CKD at diagnosis, defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² for ≥ 3 months. Lower eGFR correlated with advanced age, female sex, higher granulocytes, higher serum C-reactive protein, history of thrombosis, CV risk factors, and the presence of palpable splenomegaly. CKD was univariately associated with inferior thrombosis-free survival in the entire cohort, as well as in both ET and PV patients. These results remained significant in the multivariate Cox regression models when adjusted to disease-specific risk models. Therefore, CKD could be a risk factor for thrombosis in ET and PV patients. Additional studies on a larger number of patients are needed to confirm our findings and to elucidate whether the addition of CKD to the current risk stratification models might improve prognostication in ET and PV patients.

Does Polycythemia Vera Increase Risk of Postoperative Complications Following Primary Total Joint Arthroplasty? A Retrospective Matched Control Cohort Study of 6932 Polycythemia Vera Patients

BACKGROUND

There is sparsity of data on outcomes following joint arthroplasty among polycythemia vera (PV) patients. The aim of this study is to evaluate postoperative outcomes following primary total knee (TKA) and hip (THA) arthroplasty among PV patients.

METHODS

A retrospective Medicare database review identified 6932 PV patients who underwent a primary total joint arthroplasty (4643 TKAs and 2289 THAs) from 2006 to 2013. A comparison of hospital length of stay, mortality, and the diagnosis of surgical site infections (SSIs), stroke, myocardial infarction, acute pulmonary embolism (PE), deep vein thrombosis (DVT), and other postoperative complications was made between PV patients undergoing TKA and THA and their respective matched control groups.

RESULTS

PV was significantly associated with increased rates of acute PE (2.3% vs 1.6%; odds ratio [OR] 1.44, 95% confidence interval [CI] 1.17-1.75), DVT (4.2% vs 3.6%; OR 1.40, 95% CI 1.20-1.61, P < .001), postoperative hematoma (0.6% vs 0.4%; OR 1.57, 95% CI 1.03-2.28), and SSI (4.5% vs 3.6%; OR 1.25, 95% CI 1.08-1.44, P = .002) following TKA. Among PV patients who underwent a primary THA, PV was significantly associated with increased rate of acute PE (1.9% vs 1.4%; OR 1.40, 95% CI 1.01-1.88, P = .035), DVT (3.5% vs 2.6%; OR 1.32, 95% CI 1.04-1.66, P = .035), postoperative hematoma (1.1% vs 0.6%; OR 1.86, 95% CI 1.22-2.80), and 1-year mortality (2.2% vs 1.6%; OR 1.43, 95% CI 1.06-1.89, P = .016).

CONCLUSION

PV was significantly associated with increased risk for DVT, PE, postoperative hematoma, SSI (TKA only), and 1-year mortality (THA only) following primary total joint arthroplasty.

Pharmacokinetics and tolerability of fedratinib, an oral, selective Janus kinase 2 inhibitor, in subjects with renal or hepatic impairment

PURPOSE

Fedratinib is an oral, selective Janus kinase 2 inhibitor that is approved in the United States for the treatment of patients with intermediate-2 or high-risk myelofibrosis. Pharmacokinetics and tolerability of fedratinib in subjects with renal impairment (RI) and hepatic impairment (HI) were evaluated in two separate studies.

METHODS

In the renal study, male and female subjects with stable, chronic mild, moderate, and severe RI, as well as those with end-stage renal disease, were included. The hepatic study included subjects with stable, chronic mild HI. Both were phase 1, multicenter, open-label, single-dose studies, and included matched healthy subjects. Subjects received a single oral dose of fedratinib 300 mg on day 1, were discharged on day 4, returned for clinical visits on days 5-12, and had their end-of-study visit between days 14 and 16.

RESULTS

Thirty-six and 17 subjects were included in the renal and hepatic studies, respectively. In the renal study, fedratinib area under the plasma concentration-time curve from time 0 to infinity (AUC_inf) was 1.9- and 1.5-fold higher in subjects with severe and moderate RI, respectively, than in matched healthy subjects. In the hepatic study, fedratinib AUC_inf did not appreciably differ between subjects with mild HI and matched healthy subjects. Overall, most treatment-emergent adverse events were gastrointestinal and mild.

CONCLUSION

Mild RI and HI do not necessitate fedratinib dosage adjustments. Subjects with moderate RI should be monitored (with dosage adjustments made as necessary), whereas those with severe RI should receive a daily dose of 200 mg, reduced from the indicated dose of 400 mg.

The evaluation of monoclonal gammopathy of renal significance: a consensus report of the International Kidney and Monoclonal Gammopathy Research Group

The term monoclonal gammopathy of renal significance (MGRS) was introduced by the International Kidney and Monoclonal Gammopathy Research Group (IKMG) in 2012. The IKMG met in April 2017 to refine the definition of MGRS and to update the diagnostic criteria for MGRS-related diseases. Accordingly, in this Expert Consensus Document, the IKMG redefines MGRS as a clonal proliferative disorder that produces a nephrotoxic monoclonal immunoglobulin and does not meet previously defined haematological criteria for treatment of a specific malignancy. The diagnosis of MGRS-related disease is established by kidney biopsy and immunofluorescence studies to identify the monotypic immunoglobulin deposits (although these deposits are minimal in patients with either C3 glomerulopathy or thrombotic microangiopathy). Accordingly, the IKMG recommends a kidney biopsy in patients suspected of having MGRS to maximize the chance of correct diagnosis. Serum and urine protein electrophoresis and immunofixation, as well as analyses of serum free light chains, should also be performed to identify the monoclonal immunoglobulin, which helps to establish the diagnosis of MGRS and might also be useful for assessing responses to treatment. Finally, bone marrow aspiration and biopsy should be conducted to identify the lymphoproliferative clone. Flow cytometry can be helpful in identifying small clones. Additional genetic tests and fluorescent in situ hybridization studies are helpful for clonal identification and for generating treatment recommendations. Treatment of MGRS was not addressed at the 2017 IKMG meeting; consequently, this Expert Consensus Document does not include any recommendations for the treatment of patients with MGRS.

This Expert Consensus Document from the International Kidney and Monoclonal Gammopathy Research Group includes an updated definition of monoclonal gammopathy of renal significance (MGRS) and recommendations for the use of kidney biopsy and other modalities for evaluating suspected MGRS

A Case of Essential Thrombocythemia and IgA Nephropathy with Literature Review of the Concurrence

Myeloproliferative neoplasms such as essential thrombocythemia (ET) have been associated with glomerular disease on rare instances. A case of ET associated with immunoglobulin A nephropathy (IgAN) is described in a 57-year-old man with a history of hypertension. Progressively worsening renal function was noted in the patient along with unexplained mild thrombocytosis. Pathological review of renal biopsy identified IgAN concurrently with newly diagnosed JAK2-mutated ET. The patient was started on aspirin therapy and closely monitored for his renal function. A literature review of the association of ET and renal disease revealed nine cases of ET associated with IgAN, focal segmental glomerulosclerosis, and fibrillary glomerulonephritis. Comparison of the pathological features of the renal biopsies within the cases noted mesangial proliferation as a common finding, which has been described to be potentiated by platelet-derived growth factor (PDGF). This commonality may represent a link between ET and glomerular disease which deserves further attention in future cases. Improved management of such cases depends on the recognition of the combined occurrence of ET and glomerular diseases and uncovering the shared pathogenesis between platelets and glomeruli.

Novel Detection of CALR-Mutated Cells in Myeloproliferative Neoplasm-Related Glomerulopathy With Interstitial Extramedullary Hematopoiesis: A Case Report

Myeloproliferative neoplasms (MPNs) are associated with somatic mutations of genes including JAK2, CALR, or MPL in hematopoietic stem cells. Various glomerular lesions are known to be involved in MPN-related glomerulopathy, including mesangial hypercellularity, segmental sclerosis, features of chronic thrombotic microangiopathy, and intracapillary hematopoietic cell infiltration. Renal extramedullary hematopoiesis (EMH) is uncommon, but it is reported to occur in the setting of MPN; however, to our knowledge, there have been no reports of renal EMH with pathologically verified mutations. We report the case of a 65-year-old woman with MPN who had a CALR mutation and developed nephrotic syndrome. Kidney biopsy showed the typical findings of MPN-related glomerulopathy. CALR mutation-specific immunostaining of the kidney revealed immunopositive cells in the EMH lesion of the interstitium, indicating that renal EMH was caused by CALR-mutated cells. Based on these findings, we diagnosed nephrotic syndrome caused by MPN-related glomerulopathy. After initiation of steroid therapy, the patient's proteinuria gradually decreased and she achieved an incomplete remission. Additionally, the patient was prescribed the JAK inhibitor ruxolitinib and maintained incomplete remission. There is no established treatment for MPN-related glomerulopathy; therefore, further studies are needed to elucidate its pathophysiology.

Glomerular basement membrane duplication is a predictor of the prognosis of diabetic nephropathy in patients with type 2 diabetes

BACKGROUND

Several clinical parameters and pathological findings are known to be predictors of the deterioration of diabetic nephropathy (DN). Glomerular basement membrane duplication (GBM-DP) is a pathological feature representing endothelial injury, which is commonly observed in DN. In the present study, we investigated the association between GBM-DP and the renal prognosis in DN.

METHODS

The study enrolled 80 patients with renal biopsy-proven DN who were managed at Chiba-East Hospital from 2005 to 2012. We confirmed the pathological findings according to the Renal Pathology Society classifications, and we further evaluated the GBM-DP, which was defined as double contours of the GBM that expanded more than 10% of capillary loops in the most affected nonsclerotic glomerulus. We used Cox regression models to estimate hazard ratios (HRs) for end-stage renal disease (ESRD), with adjustment for age, sex, systolic blood pressure, HbA1c, estimated glomerular filtration rate (eGFR), and urinary protein excretion (UP) at baseline.

RESULTS

Of the 80 patients, 56 were male (70.0%) and the mean age was 59.1 years. The median eGFR and UP were 42 ml/min/1.73 m² (IQR 30, 59) and 3.1 g/gCr (IQR 1.2, 5.2). Twenty-seven patients progressed to ESRD and one patient died during the median observational period of 2.9 years (IQR 1.5, 4.3). The multivariable analyses showed that GBM-DP was significantly associated with ESRD (HR 3.18 [95% confidence interval (CI): 1.02-9.87], p = 0.045).

CONCLUSION

We newly identified GBM-DP as a strong prognostic predictor in DN patients. Further study is needed to clarify the pathogenic mechanism of GBM-DP in DN.

Development of membranoproliferative glomerulonephritis-like glomerulopathy in a patient with neutrophilia resulting from endogenous granulocyte-colony stimulating factor overproduction: a case report

Background

The pathophysiologic role of exogenous granulocyte-colony stimulating factor (G-CSF) administration is reportedly linked to the progression of glomerulonephritis. However, the relationship between endogenous G-CSF overproduction and the progression of glomerulopathy has not been well investigated.

Case presentation

A 76-year-old woman presented with neutrophilia at a medical check-up and thorough examination revealed a high level of serum G-CSF. She subsequently developed mild renal dysfunction and proteinuria. Her renal biopsy showed lobulation of the glomeruli with mesangial proliferation and glomerular capillary walls with a double contour but no immune complex deposition, suggesting membranoproliferative glomerulonephritis-like glomerulopathy. Thereafter, her proteinuria levels fluctuated in parallel with the changes in her blood neutrophil count and finally reduced considerably in association with her decreased neutrophil count.

Conclusions

The unique features of this case suggest that endogenous overproduction of G-CSF could play an important role in the pathogenesis of active glomerulonephritis.