Abstract
AL amyloidosis (light chain; previously also called primary amyloidosis) is a systemic disease characterized by an amyloid deposition process affecting many organs, and which still has ...unsatisfactory survival of patients. The monoclonal light chains kappa (κ) or lambda (λ) or their fragments form the fibrils that deposit and accumulate in different tissues. Renal involvement is very frequent in AL amyloidosis and can lead to the development of nephrotic syndrome followed by renal failure in some cases. AL amyloidosis ultimately leads to destruction of tissues and progressive disease. With recent advances in the treatment, the importance of an early diagnosis of amyloidosis and correct assessment of its type is high. Histologic confirmation is based on Congo red detection of amyloid deposits in tissues but AL amyloidosis must also be distinguished from other systemic forms of amyloidoses with renal involvement, such as AA amyloidosis, amyloidosis with heavy chain deposition, fibrinogen Aα or ALECT2 (leukocyte chemotactic factor 2) deposition. Immunofluorescence (IF) plays a key role here. IF on formalin-fixed paraffin-embedded tissue after protease digestion, immunohistochemistry or laser microdissection with mass spectrometry should complete the diagnosis in unclear cases. Standard treatment with melphalan and prednisolone or with cyclophosphamide and dexamethasone has been replaced with newer drugs used for the treatment of multiple myeloma—bortezomib, carfilzomib and ixazomib or thalidomide, lenalidomide and pomalidomide. High-dose melphalan supported by autologous stem cell transplantation remains the therapeutic option for patients with low-risk status. These new treatment options prolong survival from months to years and improve the prognosis in a majority of patients.
Atypical hemolytic uremic syndrome (aHUS), also called complement-mediated hemolytic uremic syndrome (CM-HUS), is a rare disease caused by dysregulation in the alternative complement activation ...pathway. It is a life-threatening condition causing ischemia of a number of organs, and it typically causes acute kidney injury. This disorder may be triggered by various factors including viral or bacterial infections, pregnancy, surgery, and injuries. In about 60% of cases, the genetic origin of the disease can be identified-commonly mutations affecting complementary factor H and MCP protein. Eculizumab, a monoclonal antibody to the C5 component of the complement, represents the current effective treatment.We describe a case of a young woman with a previous history of polyvalent allergies, who developed atypical hemolytic uremic syndrome after vaccination with mRNA vaccine against SARS-CoV-2. The disease manifested by scleral bleeding, acute renal insufficiency, anemia, and thrombocytopenia. The patient was treated with
without sufficient effect; remission occurred only after starting treatment with eculizumab. Genetic examination showed that the patient is a carrier of multiple inherited risk factors (a rare pathogenic variant in
, MCPggaac haplotype of the
gene, and the risk haplotype
H3). The patient is currently in hematological remission with persistent mild renal insufficiency, continuing treatment with eculizumab/ravulizumab. By this case report, we meant to point out the need for careful monitoring of people after vaccination, as it may trigger immune-mediated diseases, especially in those with predisposing factors.
Activity and chronicity of kidney involvement in ANCA-associated vasculitis (AAV) can be currently reliably evaluated only by kidney biopsy. In this study, we measured a panel of serum and urinary ...biomarkers collected at the time of kidney biopsy and hypothesized that they could reflect specific histopathological parameters in the biopsy and help to predict prognosis.
We examined a cohort of 45 patients with AAV and 10 healthy controls. Biomarker levels (DKK-3, CD163, EGF, PRO-C6 and C3M) were measured in this study by ELISA. Biopsies were scored with a scoring system for AAV (focal x crescentic x sclerotic x mixed class) and interstitial fibrosis was quantified.
Levels of urinary DKK-3, CD163, EGF, PRO-C6 and C3M significantly differed among biopsy classes in AAV, with urinary DKK-3 and PRO-C6 levels being highest in the sclerotic class and lowest in the focal class, urinary CD163 levels highest in the crescentic class and urinary C3M levels highest in the focal class. Moreover, the urinary biomarkers were able to discriminate focal biopsy class from the other classes. Urinary DKK-3, EGF, PRO-C6 and C3M levels measured at the time of biopsy were also significantly related to the extent of fibrosis and to the final kidney function at the end of follow-up.
This small pilot study suggests that selected urinary biomarkers of fibrosis and inflammation may reflect changes in the kidney biopsy and be prognostic of kidney outcome in patients with AAV.
Factor H-related protein 5 (FHR-5) is a member of the complement Factor H protein family. Due to the homology to Factor H, the main complement regulator of the alternative pathway, it may also be ...implicated in the pathomechanism of kidney diseases where Factor H and alternative pathway dysregulation play a role. Here, we report the first observational study on
variations along with serum FHR-5 levels in immune complex-mediated membranoproliferative glomerulonephritis (IC-MPGN) and C3 glomerulopathy (C3G) patients together with the clinical, genetic, complement, and follow-up data.
A total of 120 patients with a histologically proven diagnosis of IC-MPGN/C3G were enrolled in the study. FHR-5 serum levels were measured in ELISA, the
gene was analyzed by Sanger sequencing, and selected variants were studied as recombinant proteins in ELISA and surface plasmon resonance (SPR).
Eight exonic
variations in 14 patients (12.6%) were observed. Serum FHR-5 levels were lower in patients compared to controls. Low serum FHR-5 concentration at presentation associated with better renal survival during the follow-up period; furthermore, it showed clear association with signs of complement overactivation and clinically meaningful clusters.
Our observations raise the possibility that the FHR-5 protein plays a fine-tuning role in the pathogenesis of IC-MPGN/C3G.
Acquired or genetic abnormalities of the complement alternative pathway are the primary cause of C3glomerulopathy(C3G) but may occur in immune-complex-mediated membranoproliferative ...glomerulonephritis (IC-MPGN) as well. Less is known about the presence and role of C4nephritic factor(C4NeF) which may stabilize the classical pathway C3-convertase. Our aim was to examine the presence of C4NeF and its connection with clinical features and with other pathogenic factors.
One hunfe IC-MPGN/C3G patients were enrolled in the study. C4NeF activity was determined by hemolytic assay utilizing sensitized sheep erythrocytes. Seventeen patients were positive for C4NeF with lower prevalence of renal impairment and lower C4d level, and higher C3 nephritic factor (C3NeF) prevalence at time of diagnosis compared to C4NeF negative patients. Patients positive for both C3NeF and C4NeF had the lowest C3 levels and highest terminal pathway activation. End-stage renal disease did not develop in any of the C4NeF positive patients during follow-up period. Positivity to other complement autoantibodies (anti-C1q, anti-C3) was also linked to the presence of nephritic factors. Unsupervised, data-driven cluster analysis identified a group of patients with high prevalence of multiple complement autoantibodies, including C4NeF.
In conclusion, C4NeF may be a possible cause of complement dysregulation in approximately 10-15% of IC-MPGN/C3G patients.
The amyloidoses represent a group of diseases characterized by extracellular deposition of abnormal protein, amyloid, which is formed by insoluble extracellular fibrils in β-pleated sheets. Although ...cardiac involvement may occur in all types of amyloidoses, clinically relevant amyloid cardiomyopathy is a typical feature of AL amyloidosis and transthyretin-related amyloidoses. Congestive heart failure represents the commonest manifestation of amyloid heart disease. Noninvasive imaging techniques, especially echocardiography and cardiac magnetic resonance, play a major role in the diagnosis of amyloid cardiomyopathy; however, histological confirmation and exact typing of amyloid deposits is necessary whether in extracardiac location or directly in the myocardium. Early diagnosis of amyloid heart disease is of utmost importance as the presence and especially the severity of cardiac involvement generally drives the prognosis of affected subjects and plays a major role in determining the intensity of specific treatment, namely in AL amyloidosis. The management of patients with amyloid heart disease is complex. Loop diuretics together with aldosterone antagonists represent the basis for influencing signs of congestion. In AL amyloidosis, high-dose chemotherapy followed by autologous stem cell transplantation is generally considered to be a front-line treatment option, if the disease is diagnosed at its early stage. The combination of mephalan with dexamethasone has been the standard therapy for severely affected individuals; however, the combinations with several novel agents including immunomodulatory drugs and bortezomibe have been tested in clinical trials with promising results. New therapeutic substances with the potential to slow or even stop the progression of transthyretin-related amyloidosis are also extensively studied.
Abstract Cardiac amyloidosis is characterized by clinically significant extracellular amyloid infiltration of the heart that is usually, but not always, associated with the involvement of other ...organs depending on the type of amyloid. Cardiac involvement represents the most important prognostic factor especially in AL amyloidosis and thus early diagnosis of amyloid heart disease is of utmost importance influencing further management of the patients. This review aims to broadly discuss pathogenesis, manifestation and complex diagnostics of amyloidosis with the main focus on amyloid cardiomyopathy. Also, the summary of current therapeutic options that have great potential to improve existing poor prognosis of affected individuals is given.
Primary (AL amyloidosis) is a systemic disease characterized by an amyloid deposition process in many organs, with unsatisfactory survival of patients. The monoclonal light chains form the fibrils ...that deposit and accumulate in tissues. Renal involvement is very frequent in AL amyloidosis and could lead to development of nephrotic syndrome followed by the renal failure in many cases. Classic therapeutic combination melphalan and prednisone has been supplemented with drugs with different mechanisms of action in this group of patients: high-dose dexamethasone, high-dose dexamethasone with melphalan, combination of vincristine, doxorubicin, and dexamethasone or newly high-dose melphalan supported by peripheral blood stem cell transplantation. This progressive therapy leads to the better survival and prognosis in the majority of patients. Alternative therapeutic approaches include thalidomide (alone or in combination with cyclophosphamide), lenalidomide, iododoxorubicin, etanercept and rituximab. The development of immunotherapy is expected in the near future.
Rituximab is being increasingly prescribed for the treatment of autoimmune glomerular diseases. While it is highly effective for some diseases, the response is less predictable for others, which may ...be due to differing requirements in terms of the dosing according to the disease type and variations concerning exposure to the drug.
We compiled novel rituximab dosing schedules according to pharmacokinetic analysis of data gathered from rituximab treated patients in a tertiary referral nephrology centre between May 2020 and June 2023. The population-pharmacokinetic analysis was based on the rituximab dosing, the patients’ characteristics, rituximab levels and anti-rituximab antibodies.
The analysis, which was based on data from 185 patients, clearly highlighted differing rituximab dosing requirements for patients with ANCA associated vasculitis and minimal change disease compared to those with membranous nephropathy, focal-segmental glomerulosclerosis and lupus nephritis. This corresponded to the good treatment response of the first two diseases and the unreliable efficacy for the others. The model predicts the rituximab pharmacokinetics with high degree of accuracy when body weight, proteinuria, type of glomerulonephritis, treatment length and anti-rituximab antibodies formation are used as covariates. We proposed a dosing schedule with shortened dosing intervals for difficult-to-treat diagnoses with high proteinuria.
In order to ensure reliable and comparable exposure of rituximab with respect to the full range of glomerular diseases, the dosing schedule should be adjusted for membranous nephropathy, focal-segmental glomerulosclerosis and lupus nephritis. This is largely, but not solely, due to the enhanced level of unselective proteinuria in these diseases.
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•A population pharmacokinetic model was constructed for rituximab based on real data.•Rituximab elimination is faster in lupus nephritis, FSGS and MN than in AAV and MCD.•Proteinuria and the formation of ADA significantly enhance rituximab elimination.•The clearance (CL) of rituximab decreases with the treatment duration.•The dosing interval must be shortened for selected patients to overcome fast CL.
Amyloid A amyloidosis is a serious clinical condition resulting from the systemic deposition of amyloid A originating from serum amyloid A proteins with the kidneys being the most commonly and ...earliest affected organ. Previously described amyloid A amyloidosis is linked to increased production and deposition of serum amyloid A proteins secondary to inflammatory conditions arising from infectious, metabolic, or genetic causes. Here we describe a family with primary amyloid A amyloidosis due to a chr11:18287683 T>C (human genome version19) mutation in the SAA1 promoter linked to the amyloidogenic SAA1.1 haplotype. This condition leads to a doubling of the basal SAA1 promoter activity and sustained elevation of serum amyloid A levels that segregated in an autosomal dominant pattern in 12 genetically affected and in none of six genetically unaffected relatives, yielding a statistically significant logarithm of odds (LOD) score over 5. Affected individuals developed proteinuria, chronic kidney disease and systemic deposition of amyloid composed specifically of the SAA1.1 isoform. Tocilizumab (a monoclonal antibody against the interleukin-6 receptor) had a beneficial effect when prescribed early in the disease course. Idiopathic forms represent a significant and increasing proportion (15-20%) of all diagnosed cases of amyloid A amyloidosis. Thus, genetic screening of the SAA1 promoter should be pursued in individuals with amyloid A amyloidosis and no systemic inflammation, especially if there is a positive family history.
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