Mimicking kidney flow shear efficiently induces aggregation of LECT2, a protein involved in renal amyloidosis.

Aggregation of leukocyte cell-derived chemotaxin 2 (LECT2) causes ALECT2, a systemic amyloidosis that affects the kidney and liver. Previous studies established that LECT2 fibrillogenesis is accelerated by the loss of its bound zinc ion and stirring/shaking. These forms of agitation create heterogeneous shear conditions, including air-liquid interfaces that denature proteins, that are not present in the body. Here, we determined the extent to which a more physiological form of mechanical stress-shear generated by fluid flow through a network of narrow channels-drives LECT2 fibrillogenesis. To mimic blood flow through the kidney, where LECT2 and other proteins form amyloid deposits, we developed a microfluidic device consisting of progressively branched channels narrowing from 5 mm to 20 µm in width. Shear was particularly pronounced at the branch points and in the smallest capillaries. Aggregation was induced within 24 h by shear levels that were in the physiological range and well below those required to unfold globular proteins such as LECT2. EM images suggested the resulting fibril ultrastructures were different when generated by laminar flow shear versus shaking/stirring. Importantly, results from the microfluidic device showed the first evidence that the I40V mutation accelerated fibril formation and increased both the size and the density of the aggregates. These findings suggest that kidney-like flow shear, in combination with zinc loss, acts in combination with the I40V mutation to trigger LECT2 amyloidogenesis. These microfluidic devices may be of general use for uncovering mechanisms by which blood flow induces misfolding and amyloidosis of circulating proteins.

2024 Update on Classification, Etiology, and Typing of Renal Amyloidosis: A Review.

Amyloidosis is a protein folding disease that causes organ injuries and even death. In humans, 42 proteins are now known to cause amyloidosis. Some proteins become amyloidogenic as a result of a pathogenic variant as seen in hereditary amyloidoses. In acquired forms of amyloidosis, the proteins form amyloid in their wild-type state. Four types (serum amyloid A, transthyretin, apolipoprotein A-IV, and ß2-macroglobulin) of amyloid can occur either as acquired or as a mutant. Iatrogenic amyloid from injected protein medications have also been reported and AIL1RAP (anakinra) has been recently found to involve the kidney. Finally, the mechanism of how leukocyte cell-derived chemotaxin 2 (ALECT2) forms amyloid remains unknown. This article reviews the amyloids that involve the kidney and how they are typed.

First case report of PLA2R-related monotypic (IgG-κ positive) membranous nephropathy concurrent with leukocyte chemotactic factor 2 amyloidosis.

BACKGROUND: Membranous nephropathy (MN) is a major pattern of nephrotic syndrome (NS) in adults. Some MN have secondary causes and some may be accompanied with other glomerular diseases. MN patients coexisting with amyloidosis are very rare, and mostly was polytypic MN. Herein, we describe the first report which identifying monotype PLA2R-MN (κ light chain) concurrent with leukocyte chemotactic factor 2 amyloidosis (ALECT2). This rare case highlights the importance of renal pathology for diagnosis. CASE PRESENTATION: We describe a case of a 60-year-old male patient with persistent proteinuria and low serum albumin for nine months. No monoclonal component was revealed by serum and urine immunofixation electrophoresis but serum PLA2R antibody was positive. The patient was empirically treated with Leflunomide and Losartan, but edema was not improved. The diagnosis of renal pathology is PLA2R-related monotypic (IgG-κ positive) MN concurrent with ALECT2. Methylprednisolone, cyclosporine A and anticoagulant (rivaroxaban) were prescribed resulting in a complete remission of NS. CONCLUSIONS: MN patients concurrent with ALECT2 presented massive proteinuria or NS. When nephrotic range proteinuria is present in ALECT2, it is important to consider that it may be due to a concomitant underlying nephropathy especially MN and treated according to MN will get good therapeutic effect.

Loss of bound zinc facilitates amyloid fibril formation of leukocyte-cell-derived chemotaxin 2 (LECT2).

Aggregation of the circulating protein leukocyte-cell-derived chemotaxin 2 (LECT2) causes amyloidosis of LECT2 (ALECT2), one of the most prevalent forms of systemic amyloidosis affecting the kidney and liver. The I40V mutation is thought to be necessary but not sufficient for ALECT2, with a second, as-yet undetermined condition being required for the disease. EM, X-ray diffraction, NMR, and fluorescence experiments demonstrate that LECT2 forms amyloid fibrils in vitro in the absence of other proteins. Removal of LECT2's single bound Zn2+ appears to be obligatory for fibril formation. Zinc-binding affinity is strongly dependent on pH: 9-13 % of LECT2 is calculated to exist in the zinc-free state over the normal pH range of blood, with this fraction rising to 80 % at pH 6.5. The I40V mutation does not alter zinc-binding affinity or kinetics but destabilizes the zinc-free conformation. These results suggest a mechanism in which loss of zinc together with the I40V mutation leads to ALECT2.

Karyomegalic interstitial nephritis with a novel FAN1 gene mutation and concurrent ALECT2 amyloidosis.

BACKGROUND: Karyomegalic interstitial nephritis (KIN) is a rare hereditary cause of chronic kidney disease. It typically causes progressive renal impairment with haemoproteinuria requiring renal replacement therapy before 50 years of age. It has been associated with mutations in the Fanconi anaemia-associated nuclease 1 (FAN1) gene and has an autosomal recessive pattern of inheritance. Leukocyte chemotactic factor 2 amyloidosis (ALECT2) is the third most common cause of amyloid nephropathy presenting with chronic kidney disease and variable proteinuria. We report a novel mutation in the FAN1 gene causing KIN and to our knowledge, the first case of concurrent KIN and ALECT. CASE PRESENTATION: We describe the case of 44 year old Pakistani woman, presenting with stage four non-proteinuric chronic kidney disease, and a brother on dialysis. Renal biopsy demonstrated KIN and concurrent ALECT2. Genetic sequencing identified a novel FAN1 mutation as the cause of her KIN and she is being managed conservatively for chronic kidney disease. Her brother also had KIN with no evidence of amyloidosis and is being worked up for kidney transplantation. CONCLUSION: This case highlights two rare causes of chronic kidney disease considered underdiagnosed in the wider population due to their lack of proteinuria, and may contribute to the cohort of patients reaching end stage renal disease without a renal biopsy. We report a novel mutation of the FAN1 gene causing KIN, and report the first case of concurrent KIN and ALECT2. This case highlights the importance of renal biopsy in chronic kidney disease of unclear aetiology which has resulted in a diagnosis with implications for kidney transplantation and family planning.

LECT2 Amyloidosis in Kidney Transplantation: A Report of 5 Cases.

Leukocyte chemotactic factor 2 (LECT2) amyloidosis is a recently recognized entity that often affects the kidneys. Little information is available regarding kidney transplant outcomes in patients with LECT2 amyloidosis or who received kidney allografts containing LECT2 amyloid. We present clinical findings and allograft outcomes of 5 patients who received kidneys with donor-derived LECT2 amyloidosis. In all 5, LECT2 amyloidosis was discovered during protocol biopsies or in evaluation of suspected rejection. Less than 10% of kidney parenchyma was involved, with mostly interstitial and vascular deposits. Allograft function was not impaired and the amyloid deposits persisted for up to 8 years of follow-up. We conclude that kidneys with limited and localized LECT2 amyloid deposits that are otherwise suitable for transplantation need not be automatically discarded.

De novo leukocyte chemotactic factor 2 amyloidosis in a pediatric renal allograft, 15 years post-transplant.

Leukocyte chemotactic factor 2 amyloidosis (ALECT2) is a recently described form of systemic amyloidosis, which most commonly affects the kidney and liver. The LECT2 protein is produced during inflammatory processes, but its precise function in renal diseases in unclear. ALECT2, however, is known to be a relatively common form of renal amyloidosis, after amyloid light chain and serum amyloid A types and is most often seen in patients of Hispanic ethnicity. ALECT2 can occur de novo or as recurrent disease in kidney transplants. We present the first case, to our knowledge, of de novo ALECT2 in a pediatric kidney transplant patient, 15 years post-transplant.

ALECT2 amyloidosis with concurrent IgG4-related interstitial nephritis, membranous nephropathy and diabetic kidney disease: a case report and literature review.

Leukocyte chemotactic factor-2 amyloidosis (ALECT2) is a recently described subtype of amyloidosis. IgG4-related disease is a rare fibroinflammatory condition characterized by dense interstitial lymphoplasmacytic infiltrates and fibrosis. Membranous nephropathy and diabetic nephropathy are common causes of nephrotic syndrome. Here we report a 49-year-old Hispanic male patient with diabetes mellitus who presented with jaundice and pruritus. IgG4-related autoimmune pancreatitis was diagnosed through laboratory workup and ampulla biopsy. He subsequently presented with marked lower extremity edema and nephrotic syndrome. Kidney biopsy showed severe interstitial IgG4-positive plasma cell-rich inflammatory infiltrates and interstitial storiform fibrosis. Immunofluorescence microscopy revealed diffuse and finely granular glomerular capillary wall staining for IgG and the glomeruli were negative for anti-phospholipase A2 receptor. Congo red stain was positive for birefringent deposits in the interstitium, arteriolar walls, and glomeruli. Electron microscopy demonstrated subepithelial immune complex-type electron-dense deposits, thickening of glomerular basement membranes (GBM), and randomly oriented fibrils in the mesangium, GBM, and interstitium. Mass spectrometry identified a peptide profile consistent with ALECT2 amyloidosis. This is the first report of a case with concurrence of ALECT2 amyloidosis, IgG4-related disease involving the kidney, membranous nephropathy, and early diabetic kidney injury.

Leukocyte Chemotactic Factor 2 Amyloidosis (ALECT2) Distribution in a Mexican Population.

OBJECTIVES: To assess the prevalence of leukocyte cell-derived chemotactic 2 (LECT2), its organ involvement, and its clinical association in autopsies from an ethnically biased population. METHODS: The tissues from all autopsies of individuals diagnosed with amyloidosis were reassessed and typed for amyloid light chain (AL) amyloidosis, amyloid A (AA) amyloidosis, transthyretin amyloidosis (ATTR), and leukocyte chemotactic factor 2 amyloidosis (ALECT2) by immunohistochemistry. Organ involvement was described and correlated with its clinical associations. RESULTS: Of 782 autopsies, 27 (3.5%) had a confirmed diagnosis of amyloidosis. Of these, 14 (52%) corresponded to ALECT2, 5 (19%) to AL amyloidosis, 2 (7%) to ATTR amyloidosis, 1 (4%) to AA amyloidosis, and 5 (21%) as undetermined-type amyloidosis. The LECT2 amyloid deposits were found in the kidneys, liver, spleen, and adrenal glands in most individuals. Except for the kidneys, there were no clinical signs suggestive of amyloid deposition in most of the affected organs. LECT2 amyloidosis was not associated with the cause of death in any case. No cases had heart or brain involvement. Potential subclinical effects of amyloid deposition in organs such as adrenal glands and spleen require further study. CONCLUSIONS: This autopsy study confirms the high prevalence of LECT2 amyloidosis in the Mexican population, with frequent amyloid deposition in the kidneys, liver, spleen, and adrenal glands.

Identification of amyloidosis of the urinary tract and prostate: Opportunities for early diagnosis & intervention in systemic disease.

OBJECTIVES: To determine the prevalence of different amyloid types and frequency of associated systemic amyloidosis in the urinary tract/prostate. METHODS: We studied Congo red-positive prostate (n = 150) and urinary tract (n = 767) specimens typed by a proteomics-based method between 2008 and 2020. Clinical follow up was available for a subset (urinary tract, n = 111; prostate, n = 17). Amyloid types were correlated with various clinicopathologic features. For patients with clinical follow up, chart review was performed to establish localized versus systemic disease, frequency of initial diagnosis of amyloidosis on urinary tract/prostate specimens, presence of cardiac disease, and death from disease-related complications. RESULTS: The most common amyloid types were AL/AH in urinary tract (479/767, 62 %) and localized ASem1 in prostate (64/150, 43 %). Urinary tract AL/AH amyloid was usually localized, but systemic AL amyloidosis occurred in both sites (urinary tract: 5/71, 7 %; prostate: 2/2, 100 %). ATTR amyloidosis was seen in over a third of cases (urinary tract: 286/767, 37 %; prostate: 55/150, 37 %). Urinary tract/prostate was the site of the initial ATTR amyloidosis diagnosis in 44/48 patients (92 %), and 38/48 (79 %) were subsequently found to have cardiac involvement. Seminal vesicle/ejaculatory duct involvement was pathognomonic for ASem1-type amyloidosis (39/39, 100 %). CONCLUSIONS: Over 40 % of patients had systemic amyloidosis, with urinary tract/prostate often the first site in which amyloid was identified. Since early recognition of systemic amyloidosis is critical for optimal patient outcomes, there should be a low threshold to perform Congo red stain. Proteomics-based amyloid typing is recommended since treatment depends on correctly identifying the amyloid type.

Mimicking Kidney Flow Shear Efficiently Induces Aggregation of LECT2, a Protein Involved in Renal Amyloidosis.

Aggregation of leukocyte cell-derived chemotaxin 2 (LECT2) causes ALECT2, a systemic amyloidosis that affects the kidney and liver. Homozygosity of the I40V LECT2 mutation is believed to be necessary but not sufficient for the disease. Previous studies established that LECT2 fibrillogenesis is greatly accelerated by loss of its single bound zinc ion and stirring or shaking. These forms of agitation are often used to facilitate protein aggregation, but they create heterogeneous shear conditions, including air-liquid interfaces that denature proteins, that are not present in the body. Here, we determined the extent to which a more physiological form of mechanical stress-shear generated by fluid flow through a network of artery and capillary-sized channels-drives LECT2 fibrillogenesis. To mimic blood flow through the human kidney, where LECT2 and other proteins form amyloid deposits, we developed a microfluidic device consisting of progressively branched channels narrowing from 5 mm to 20 µm in width. Flow shear was particularly pronounced at the branch points and in the smallest capillaries, and this induced LECT2 aggregation much more efficiently than conventional shaking methods. EM images suggested the resulting fibril structures were different in the two conditions. Importantly, results from the microfluidic device showed the first evidence that the I40V mutation accelerated fibril formation and increased both size and density of the aggregates. These findings suggest that kidney-like flow shear, in combination with zinc loss, acts in combination with the I40V mutation to trigger LECT2 amyloidogenesis. These microfluidic devices may be of general use for uncovering the mechanisms by which blood flow induces misfolding and amyloidosis of circulating proteins.

Donor-Derived ALECT2 Amyloidosis and Recurrent Fibrillary Glomerulonephritis in a Transplant Allograft.

The occurrence of renal amyloidosis and fibrillary glomerulonephritis in the same biopsy specimen is exceptional and poses a diagnostic challenge. We describe the case of a non-Hispanic White patient with end-stage kidney disease due to fibrillary glomerulonephritis who received a second living donor kidney from a Hispanic individual. A 40-month-posttransplantation biopsy performed for an elevated serum creatinine level revealed interstitial congophilic deposits and glomerular noncongophilic fibrillary deposits, in addition to rejection. Separate laser microdissections of the glomerular and interstitial deposits followed by liquid chromatography-tandem mass spectrometry (LC MS/MS) revealed DNAJB9 peptide spectra in glomeruli and a peptide profile consistent with leukocyte chemotactic factor 2 (ALECT2) amyloidosis in the interstitium. Based on these findings, a 2-week-posttransplantation biopsy was re-reviewed and analyzed using LC MS/MS, which revealed a peptide profile consistent with ALECT2 amyloidosis in the interstitium, without peptide spectra for ALECT2 or DNAJB9 in glomeruli. The findings were consistent with donor-derived ALECT2 amyloidosis and recurrent fibrillary glomerulonephritis. At 49 months posttransplantation, allograft function was stable with minimal proteinuria. Thus, LC MS/MS was crucial to establish the accurate diagnosis of these 2 nephropathies characterized by fibrillary deposits. The indolent posttransplantation course suggests that donated kidneys with focal interstitial ALECT2 deposits may be suitable for transplantation but the deposits persist for many years.

Clinically occult amyloidosis derived from leukocyte chemotactic factor 2 (ALECT 2) with cardiac involvement complicating renal transplantation: case report and literature review.

INTRODUCTION: Amyloidosis derived from leukocyte chemotactic factor 2 (ALECT2) may be associated with slowly progressive renal failure that is clinically unsuspected at the time of transplantation. While this is typically clinically insignificant, we report a case with extensive systemic ALECT2 amyloidosis that also involved the myocardium, contributing to perioperative death post renal transplantation. CASE DESCRIPTION: A 72-year-old Hispanic woman presented for renal transplantation due to end-stage renal disease secondary to hypertension. She was bradycardic on admission. Cardiac workup prior to transplantation had not identified an infiltrative process. Post-transplant hypotensive bradycardic arrests lead to multiorgan failure, anoxic brain injury, and death. Autopsy revealed massive amyloid deposition in the native kidneys, adrenals, spleen, and less extensive infiltration of liver and myocardium. Cardiac intramural vasculature from venules to capillaries, arterioles, and arteries showed amyloid deposition. Mass spectrometry revealed ALECT2 as the amyloidogenic protein. DISCUSSION: ALECT2 is a systemic amyloidosis that typically involves kidneys, adrenals, spleen, and liver. It may be clinically unsuspected at the time of renal transplantation and should be considered in older patients, especially from higher ALECT2 amyloid prevalence populations. Complications related to systemic disease may add to morbidity or mortality post-transplantation. Cardiac involvement in ALECT2 amyloidosis has not been previously identified as a significant clinical or autopsy finding, but our case demonstrates that the cardiovascular system may indeed rarely be involved by ALECT2 amyloidosis in cases with extensive systemic disease, and it may be associated with significant clinical sequelae.

Rare, Yet Emerging Cause of Graft Dysfunction-ALECT 2 Amyloidosis.

Amyloidosis is characterized by pathological deposition of abnormal protein aggregates in various tissues, AL protein being the commonest. Amyloidosis derived from leukocyte cell-derived chemotaxin 2 (LECT2) is a recently recognized form of amyloidosis in the United States with predominant involvement of kidney and liver. We present a case of ALECT2 renal amyloid in a transplant recipient who presented with gradual worsening of graft function and subnephrotic proteinuria. To our knowledge, this is first case of LECT2 amyloidosis from Northern India in a transplant recipient. There is no effective therapy for amyloidosis derived from leukocyte cell-derived chemotaxin 2.

Leukocyte Cell-Derived Chemotaxin-2 Amyloidosis (ALECT2) in a Patient With Lung Adenocarcinoma: An Autopsy Report and Literature Review.

Amyloidosis caused by deposition of leukocyte cell-derived chemotaxin-2 amyloidosis (ALECT2) is the most recently described form of systemic amyloidosis and has quickly emerged as a common and possibly underdiagnosed cause of slowly declining renal function, particularly in patients of Hispanic ancestry. We describe the autopsy findings in a 70-year-old Hispanic woman who died of metastatic lung adenocarcinoma and was incidentally found to have extensive amyloid deposition in the kidneys, liver, spleen, adrenal glands, small intestine, gallbladder, lungs, bilateral ovaries, and uterus. The type of amyloid was confirmed to be ALECT2 by mass spectrometry. The pattern of amyloid deposition in the kidneys and the liver was typical for what has been described for ALECT2. In addition, a unique pattern of amyloid deposition was observed in spleen, adrenal glands, small intestine, gallbladder, lungs, ovaries, and uterus. The pattern of amyloid deposition in ALECT2 is distinct from amyloid A and amyloid light-chain and needs to be recognized to avoid misdiagnosis as amyloid light-chain or amyloid A amyloidosis. After recognition, an accurate diagnosis by mass spectrometry and/or immunohistochemical staining is essential to guide treatment and avoid toxic therapies.

Pathology and diagnosis of renal non-AL amyloidosis.

Renal amyloidosis is characterized by acellular Congo red positive deposits in the glomeruli, interstitium and/or arteries. Light chain restriction on immunofluorescence studies is present in AL-amyloidosis, the most common type of amyloidosis involving the kidney. The detection of Congo red positive deposits coupled with negative immunofluorescence studies is highly suggestive of non-AL amyloidosis. Some of the non-AL amyloidosis are common while others are relatively rare. The clinical features, laboratory and renal pathology findings are helpful in the diagnosis and typing of non-AL amyloidosis. Thus, ALECT2 amyloidosis is characterized by diffuse cortical interstitial amyloid deposits, AA amyloidosis shows vascular deposits in addition to the glomerular deposits, AFib amyloidosis is characterized by massive amyloid accumulation limited to the glomeruli resulting in the obliteration of glomerular architecture, AApoA1 and AApoAIV are characterized by large amyloid deposits restricted to the medulla, and AGel shows swirling patterns of amyloid fibrils on electron microscopy. While light microscopy is very helpful, accurate typing of non-AL amyloidosis then requires immunohistochemical or laser microdissection/mass spectrometry studies of the Congo red positive deposits. Immunohistochemical studies are available for some of the non-AL amyloidosis. On the other hand, mass spectrometry analysis is a one stop methodology for confirmation and typing of amyloidosis. The diagnosis and typing of amyloidosis by mass spectrometry is based on finding the signature amyloid peptides, apolipoprotein E and serum amyloid-P component, followed by detection of precursor amyloidogenic protein such as LECT2, fibrinogen-α, gelsolin, etc. To, summarize, non-AL amyloidosis is a group of amyloidosis with distinctive clinical, laboratory and renal pathology findings. Typing of the amyloidosis is best performed using mass spectrometry methodology. Accurate typing of non-AL amyloidosis is imperative for correct management, prognosis, and genetic counseling.

Leukocyte Cell-Derived Chemotaxin 2-Associated Renal Amyloidosis: A Case Report.

Amyloidosis is a disorder characterized by the deposition of abnormal protein fibrils in tissues. Leukocyte cell-derived chemotaxin 2-associated amyloidosis is a recently recognized entity and is characterized by a distinctive clinicopathologic type of amyloid deposition manifested in adults by varying degrees of impaired kidney function and proteinuria. There are only a limited number of cases reported in the literature. We present a 64-year-old Hispanic female with a history of hypertension who was referred for chronic kidney disease management. The review of her laboratory tests revealed a serum creatinine of 1.5-1.8 mg/dL and microalbuminuria (in the presence of a bland urine sediment) in the past year. She denied any history of diabetes, rheumatologic disorders or exposure to intravenous contrast, nonsteroidal anti-inflammatory drugs, herbals, and heavy metals. Serological workup was negative. A renal biopsy showed diffuse infiltration of glomerulus with pale eosinophilic material strongly positive for Congo red stain and a similar eosinophilic material in the interstitium, muscular arteries, and arterioles. Electron microscopy showed marked infiltration of the mesangium, capillary loops, and interstitium with haphazardly arranged fibrillary deposits (9.8 nm thick). Liquid chromatography tandem mass spectrometry confirmed leukocyte cell-derived chemotaxin 2 (LECT2) amyloid deposition. LECT2 amyloidosis (ALECT2) should be suspected in renal biopsy specimens exhibiting extensive and strong mesangial as well as interstitial congophilia. Individuals with LECT2 renal amyloidosis have a varying prognosis. Therapeutic options include supportive measures and consideration of a kidney transplant for those with end-stage renal disease.

Amyloidosis: Insights from Proteomics.

Amyloidoses are a spectrum of disorders caused by abnormal folding and extracellular deposition of proteins. The deposits lead to tissue damage and organ dysfunction, particularly in the heart, kidneys, and nerves. There are at least 30 different proteins that can cause amyloidosis. The clinical management depends entirely on the type of protein deposited, and thus on the underlying pathogenesis, and often requires high-risk therapeutic intervention. Application of mass spectrometry-based proteomic technologies for analysis of amyloid plaques has transformed the way amyloidosis is diagnosed and classified. Proteomic assays have been extensively used for clinical management of patients with amyloidosis, providing unprecedented diagnostic and biological information. They have shed light on the pathogenesis of different amyloid types and have led to identification of numerous new amyloid types, including ALECT2 amyloidosis, which is now recognized as one of the most common causes of systemic amyloidosis in North America.

Leukocyte Cell-Derived Chemotaxin 2-Associated Amyloidosis: A Recently Recognized Disease with Distinct Clinicopathologic Characteristics.

Amyloidosis derived from leukocyte cell-derived chemotaxin 2 is a recently recognized form of amyloidosis, and it has already been established as a frequent form of systemic amyloidosis in the United States, with predominant involvement of kidney and liver. The disease has a strong ethnic bias, affecting mainly Hispanics (particularly Mexicans). Additional ethnic groups prone to develop amyloidosis derived from leukocyte cell-derived chemotaxin 2 include Punjabis, First Nations people in British Columbia, and Native Americans. Most patients are elderly who present with chronic renal insufficiency and bland urinary sediment. Proteinuria is variable, being absent altogether in about one third of patients. Liver involvement is frequently an incidental finding. Amyloidosis derived from leukocyte cell-derived chemotaxin 2 deposits shows a characteristic distribution: in the kidney, there is consistent involvement of cortical interstitium, whereas in the liver, there is a preferential involvement of periportal and pericentral vein regions. Concurrent renal disease is frequent, with diabetic nephropathy and IgA nephropathy being the most common. Patient survival is excellent, likely because of the rarity of cardiac involvement, whereas renal survival is guarded, with a median renal survival of 62 months in those without concurrent renal disease. There is currently no efficacious therapy for amyloidosis derived from leukocyte cell-derived chemotaxin 2 amyloidosis. Renal transplantation seems to be a reasonable treatment for patients with advanced renal failure, although the disease may recur in the allograft. The pathogenesis of amyloidosis derived from leukocyte cell-derived chemotaxin 2 amyloidosis has not yet been elucidated. It could be a result of leukocyte cell-derived chemotaxin 2 overexpression by hepatocytes either constitutively (controlled by yet-uncharacterized genetic defects) or secondary to hepatocellular damage. It is critical not to misdiagnose amyloidosis derived from leukocyte cell-derived chemotaxin 2 amyloidosis as Ig light chain-derived amyloidosis to avoid harmful chemotherapy.

Amyloid nephropathy.

Amyloidosis is an uncommon disease that is characterized by abnormal extracellular deposition of misfolded protein fibrils leading to organ dysfunction. The deposited proteins display common chemical and histologic properties but can vary dramatically in their origin. Kidney disease is a common manifestation in patients with systemic amyloidosis with a number of amyloidogenic proteins discovered in kidney biopsy specimens. The emergence of mass spectrometry-based proteomics has added to the diagnostic accuracy and overall understanding of amyloidosis. This in-depth review discusses the general histopathologic features of renal amyloidosis and includes an in-depth discussion of specific forms of amyloid affecting the kidney.