Renal amyloidosis in children

bDMARD can prevent the progression of AA amyloidosis to end-stage renal disease

INTRODUCTION

AA amyloidosis (AA) can be the consequence of any chronic inflammatory disease. AA is associated with chronic inflammatory diseases (cid+AA), autoinflammatory syndromes (auto+AA) or AA of unknown origin or idiopathic AA (idio+AA). The major organ manifestation is renal AA that can progress to end-stage renal disease (ESRD) and multiple organ failure.

MATERIALS AND METHODS

This study is a monocentric retrospective analysis of the renal outcome and survival of patients with cid+AA (n=34), auto+AA (n=24) and idio+AA (n=25) who were treated with cytokine-inhibiting biological disease-modifying antirheumatic drugs (bDMARDs).

RESULTS

83 patients with renal AA were identified and followed for a mean observational period of 4.82 years. C reactive protein (CRP), serum amyloid alpha and proteinuria were significantly reduced with bDMARD therapy. Progression to ESRD was prevented in 60% (cid+AA), 88% (auto+AA) and 81% (idio+AA) of patients. Tocilizumab was given to 34 patients with cid+AA and idio+AA and was more effective in reducing CRP and progression to ESRD and death compared with other bDMARDs.

CONCLUSIONS

bDMARDs reduce systemic inflammation in various diseases, leading to a reduction of proteinuria and prevention of ESRD. Importantly, tocilizumab was more effective than other bDMARDs in controlling systemic inflammation in patients with chronic inflammatory diseases and idiopathic AA, leading to better renal and overall survival.

IL-1 Inhibitors in the Treatment of Familial Mediterranean Fever: Treatment Indications and Clinical Features in a Large Real-World Cohort

Background: The accruing evidence about the efficacy of anti-IL-1 agents in Familial Mediterranean Fever (FMF) patients led to their widespread off-label use. Therefore, identifying precise indications and clinical characteristics of IL-1i-warranting patients are important. This study investigated the clinical characteristics and treatment indications of patients with FMF requiring interleukin 1 inhibition therapy (IL-1i). Methods: Hospital records of FMF patients attending a tertiary care center at the Department of Rheumatology, University of Health Sciences, Basaksehir Cam and Sakura City Hospital were retrospectively analyzed. Data on symptoms and disease manifestations, age of symptom onset, time to diagnosis, MEFV variants, type of treatment, and their indications were collected. Results: Between June 2020 and March 2023, 312 FMF patients were identified. The mean age at the onset of symptoms was 14.0, and the mean time to diagnosis was 11.9 years. In total, 87.1% of patients were receiving colchicine monotherapy, while the remaining 11.8% warranted IL-1i. Clinical symptoms and flare manifestations did not show a significant difference between the two groups. However, patients receiving IL-1i started having symptoms at younger age (11.5 vs. 14.5, p = 0.042) and time to diagnosis was longer (18.2 vs. 11.0, p < 0.01). M694V homozygosity was more common in patients receiving IL-1i. Indications for patients receiving IL-1i were colchicine resistance (8.0%), secondary amyloidosis (5.1%), and colchicine intolerance (2.2%). Conclusions: This study shows that a subset of FMF patients, particularly those with a more severe phenotype with an earlier disease onset and M694V homozygosity, require IL-1i treatment despite the overall good efficacy and tolerability of colchicine, primarily due to colchicine resistance, intolerance, or complications such as amyloidosis.

The pyrin inflammasome, a leading actor in pediatric autoinflammatory diseases

The activation of the pyrin inflammasome represents a highly intriguing mechanism employed by the innate immune system to effectively counteract pathogenic agents. Despite its key role in innate immunity, pyrin has also garnered significant attention due to its association with a range of autoinflammatory diseases (AIDs) including familial Mediterranean fever caused by disruption of the MEFV gene, or in other genes involved in its complex regulation mechanisms. Pyrin activation is strictly dependent on homeostasis-altering molecular processes, mostly consisting of the disruption of the small Ras Homolog Family Member A (RhoA) GTPases by pathogen toxins. The downstream pathways are regulated by the phosphorylation of specific pyrin residues by the kinases PKN1/2 and the binding of the chaperone 14-3-3. Furthermore, a key role in pyrin activation is played by the cytoskeleton and gasdermin D, which is responsible for membrane pores in the context of pyroptosis. In addition, recent evidence has highlighted the role of steroid hormone catabolites and alarmins S100A8/A9 and S100A12 in pyrin-dependent inflammation. The aim of this article is to offer a comprehensive overview of the most recent evidence on the pyrin inflammasome and its molecular pathways to better understand the pathogenesis behind the significant group of pyrin-related AIDs.

Effectiveness of Colchicine or Canakinumab in Japanese Patients with Familial Mediterranean Fever: A Single-Center Study

Background: To investigate the clinical features of Japanese patients with Familial Mediterranean Fever (FMF), we evaluated the frequency of attacks, treatment responses, and adverse effects in 27 patients with FMF treated with colchicine or canakinumab in a real-world clinical setting. Methods: We retrospectively reviewed 27 Japanese patients with FMF treated at our institute between April 2012 and June 2023. All patients were diagnosed with FMF according to the Tel-Hashomer criteria. We performed genetic analyses of the MEFV gene using targeted next-generation sequencing. The clinical response was monitored through the number of attacks, and inflammatory markers were monitored through the C-reactive protein (CRP), and serum amyloid A (SAA) concentrations. Colchicine resistance was defined as the presence of at least one attack/month despite administration of the maximum tolerated dose of colchicine for at least 6 months, and C-reactive protein and serum amyloid A levels above the normal range between attacks. Results: A total of 27 patients diagnosed with FMF were enrolled in this study and the median follow-up period was 36.4 months. The median attack frequency was 1.0 (interquartile range: 0.33-1.0) every 3 months before treatment initiation. All the patients (n = 27) were treated with colchicine. Among the 27 patients, 20 (71.8%) showed a clinical response and 7 (25.9%) showed an incomplete response with sufficient doses of colchicine (n = 5) and non-sufficient doses (n = 2). Two patients on non-sufficient doses were unable to increase colchicine to the maximum dose due to diarrhea and liver dysfunction. All seven patients achieved a reduction in attack frequency after the initiation of canakinumab. No serious adverse events associated with canakinumab treatment were observed. In these seven patients with colchicine-resistant FMF (crFMF), the MEFV exon 10 variant was not detected, and the absence ratio of the MEFV variant was significantly higher compared to those without crFMF. Conclusions: Colchicine was effective in 71.8% (20/27) of Japanese patients with FMF; however, the remaining patients (7/27) had crFMF. Canakinumab effectively controlled febrile attacks in crFMF, even in the absence of pathogenic MEFV exon 10 variants.

Renal involvement in monogenic autoinflammatory diseases: A narrative review

Autoinflammatory diseases (AIDs) are mostly caused by dysfunctions in single genes encoding for proteins with a prominent role in the regulation of innate immunity, such as complement factors, inflammasome components, tumour necrosis factor (TNF)-α, and proteins belonging to type I-interferon (IFN) signalling pathways. Due to the deposition of amyloid A (AA) fibrils in the glomeruli, unprovoked inflammation in AIDs frequently affects renal health. In fact, secondary AA amyloidosis is the most common form of amyloidosis in children. It is caused by the extracellular deposition of fibrillar low-molecular weight protein subunits resulting from the degradation and accumulation of serum amyloid A (SAA) in numerous tissues and organs, primarily the kidneys. The molecular mechanisms underlying AA amyloidosis in AIDs are the elevated levels of SAA, produced by the liver in response to pro-inflammatory cytokines, and a genetic predisposition due to specific SAA isoforms. Despite the prevalence of amyloid kidney disease, non-amyloid kidney diseases may also be responsible for chronic renal damage in children with AIDs, albeit with distinct characteristics. Glomerular damage can result in various forms of glomerulonephritis with distinct histologic characteristics and a different underlying pathophysiology. This review aims to describe the potential renal implications in patients with inflammasomopathies, type-I interferonopathies, and other rare AIDs in an effort to improve the clinical course and quality of life in paediatric patients with renal involvement.

Intrinsic Kidney Pathology in Children and Adolescents Following COVID-19 Vaccination: A Systematic Review

Global COVID-19 vaccination programs for children and adolescents have been developed with international clinical trial data confirming COVID-19 mRNA vaccine safety and efficacy for the pediatric population. The impact of COVID-19 vaccination in the kidneys is thought to be explained by a complex immune-mediated relationship between the two, although the pathophysiological mechanisms of how COVID-19 vaccination potentially induces kidney pathology are not presently well known. Whilst intrinsic kidney pathologies following COVID-19 vaccination have been reported in adults, such cases are only being recently reported with greater frequency in children and adolescents. Conforming to the PRISMA checklist, we conducted a systematic review of the current literature to provide an overview on the range of intrinsic kidney pathologies that have been reported following COVID-19 vaccination in children and adolescents. All English language research articles published on or before 30 June 2022 reporting new-onset or relapsed intrinsic kidney pathology in children or adolescents (≤18 years) following COVID-19 vaccination were selected for qualitative analysis. Out of 18 cases from the 13 published articles selected, there were 10 cases of IgA nephropathy (1 case of rapidly progressive glomerulonephritis requiring acute hemodialysis), 5 cases of minimal change disease (MCD), 1 case of concurrent MCD/tubulointerstitial nephritis (TIN) and 2 cases of TIN. There is no indication currently to avoid vaccination, unless specific circumstances exist, as the benefits of COVID-19 vaccination far outweigh its risks. Concluding the findings from our systematic review based on preliminary evidence, potential adverse effects to the kidney from COVID-19 vaccination affects a small number of children and adolescents among the many who have been vaccinated. There remains good reason at present to support vaccination of children and adolescents with a greater morbidity status, such as those living with preexisting chronic kidney disease. Close observation of all children and adolescents receiving COVID-19 vaccination is recommended, particularly in those with preceding intrinsic kidney pathology to identify risks of relapsed disease.

Amyloidosis in a Patient With Congenital Neutropenia Because of G6PC3 Deficiency

Glucose-6-phosphatase catalytic subunit 3 (G6PC3) deficiency is a recently identified form of congenital neutropenia associated with developmental anomalies. The severity of neutropenia and the clinical spectrum are highly variable. Aside from infectious complications and extrahematologic features, inflammatory bowel disease and autoinflammatory complications are less frequently observed manifestations. However, amyloidosis has never been reported in G6PC3 deficiency. Here, we present a 12-year-old patient with incidentally discovered neutropenia because of the p.E65A (c.194A>C) variant of the G6PC3 gene. He had recurrent aphthae and abdominal pain episodes, and developed nephrotic-range proteinuria, amyloidosis, and end-stage renal failure during follow-up.

The effectiveness of anti-interleukin-1 therapy on subclinical inflammation parameters during the attack-free period in familial Mediterranean fever patients: A case-control study

Background/aim

Anti IL-1 therapy is useful in suppressing attacks in FMF patients with colchicine resistance, however, it is not certain whether subclinical inflammation can sufficiently be inhibited with anti-IL-1 therapy in FMF patients with amyloidosis.

Materials and methods

Forty-six FMF patients receiving anti-interleukin-1 therapy and 36 healthy control patients were compared in terms of laboratory parameters. Also, FMF patients were further divided into two groups; those with amyloidosis and those without it, and these subgroups were compared to each other in terms of clinical and laboratory findings.

Results

In comparison between the FMF and healthy control groups, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) level, and red cell distribution width (RDW) level were detected to be higher and hemoglobin level lower in the patient group. Within the FMF patient group, the ESR, CRP, fibrinogen, RDW, and NLR values were significantly higher in the subgroup with amyloidosis in comparison to the subgroup without amyloidosis.

Conclusion

Anti-interleukin-1 therapy could not fully suppress the subclinical inflammatory parameters when compared to healthy individuals.

Intrinsic Kidney Pathology Following COVID-19 Infection in Children and Adolescents: A Systematic Review

Introduction: COVID-19 infections resulting in pathological kidney manifestations have frequently been reported in adults since the onset of the global COVID-19 pandemic in December 2019. Gradually, there have been an increased number of COVID-19-associated intrinsic kidney pathologies in children and adolescents reported as well. The pathophysiological mechanisms between COVID-19 and the onset of kidney pathology are not fully known in children; it remains a challenge to distinguish between intrinsic kidney pathologies that were caused directly by COVID-19 viral invasion, and cases which occurred as a result of multisystem inflammatory syndrome due to the infection. This challenge is made more difficult in children, due to the ethical limitations of performing kidney biopsies to reach a biopsy-proven diagnosis. Although previous systematic reviews have summarized the various pathological kidney manifestations that have occurred in adults following acute COVID-19 infection, such reviews have not yet been published for children and adolescents. We describe the results of a systematic review for intrinsic kidney pathology following COVID-19 infection in children and adolescents. Methods: A systematic literature search of published data up until 31 October was completed through the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Research articles reporting new-onset or relapsed intrinsic kidney pathology in children or adolescents (≤18 years) following acute COVID-19 infection were included for qualitative review. COVID-19 infection status was defined by a positive result from a RT-PCR, or nuclear antibody testing. Only full-text articles published in the English language were selected for review. Results: Twenty-nine cases from fifteen articles were included in the qualitative synthesis of this systematic review. Nephrotic syndrome, as an umbrella condition, appeared as the most frequently observed presentation (20 cases) with disease remission noted in all cases with steroid treatment. Other cases included numerous glomerulonephritides, such as acute necrotizing glomerulonephritis, MPO vasculitis and collapsing glomerulopathy, and thrombotic microangiopathies, such as aHUS. For patients with transplanted kidneys, T-cell-mediated rejection and mild tubular interstitial infiltration were noted following testing positive for COVID-19. There were no mortalities reported in any of the included cases, although two patients remained dialysis dependent at hospital discharge. Conclusion: This systematic review highlights the various intrinsic pathological kidney manifestations in children and adolescents as a result of acute COVID-19 infection. The clinical timeline and presentation of these cases support the mechanistic hypothesis between COVID-19 infection and the onset of intrinsic kidney pathologies within this context. The progressive introduction of vaccination programs for children and adolescents may hopefully reduce the severity of COVID-19-associated illnesses, and pathological kidney manifestations in this population.

Monogenic Autoinflammatory Diseases: State of the Art and Future Perspectives

Systemic autoinflammatory diseases are a heterogeneous family of disorders characterized by a dysregulation of the innate immune system, in which sterile inflammation primarily develops through antigen-independent hyperactivation of immune pathways. In most cases, they have a strong genetic background, with mutations in single genes involved in inflammation. Therefore, they can derive from different pathogenic mechanisms at any level, such as dysregulated inflammasome-mediated production of cytokines, intracellular stress, defective regulatory pathways, altered protein folding, enhanced NF-kappaB signalling, ubiquitination disorders, interferon pathway upregulation and complement activation. Since the discover of pathogenic mutations of the pyrin-encoding gene MEFV in Familial Mediterranean Fever, more than 50 monogenic autoinflammatory diseases have been discovered thanks to the advances in genetic sequencing: the advent of new genetic analysis techniques and the discovery of genes involved in autoinflammatory diseases have allowed a better understanding of the underlying innate immunologic pathways and pathogenetic mechanisms, thus opening new perspectives in targeted therapies. Moreover, this field of research has become of great interest, since more than a hundred clinical trials for autoinflammatory diseases are currently active or recently concluded, allowing us to hope for considerable acquisitions for the next few years. General paediatricians need to be aware of the importance of this group of diseases and they should consider autoinflammatory diseases in patients with clinical hallmarks, in order to guide further examinations and refer the patient to a specialist rheumatologist. Here we resume the pathogenesis, clinical aspects and diagnosis of the most important autoinflammatory diseases in children.

Long-term efficacy and safety of canakinumab in patients with colchicine-resistant familial Mediterranean fever: results from the randomised phase III CLUSTER trial

Objectives

To evaluate the long-term efficacy and safety of canakinumab to treat patients with colchicine-resistant familial Mediterranean fever (crFMF) during Epoch 4 (weeks 41 to 113) of the CLUSTER study.

Methods

Patients received open-label canakinumab 150 or 300 mg, every 4 or 8 weeks during a 72-week period. We evaluated disease activity every 8 weeks using the physician global assessment (PGA) of disease activity, counting the number of flares, and measuring concentrations of C reactive protein (CRP) and serum amyloid A (SAA). Safety was studied by determination and classification of observed adverse events (AEs). We analysed safety and efficacy separately in two subgroups of patients receiving a cumulative dose of less than 2700 mg, or equal or more than 2700 mg.

Results

Of the 61 patients that started the CLUSTER study, 60 entered Epoch 4 and 57 completed it. During the 72-week period, 35/60 (58.3%) patients experienced no flares, and 23/60 (38.3%) had one flare, as compared with a median of 17.5 flares per year reported at baseline. PGA scores indicated no disease activity for the majority of patients throughout the study. Median CRP concentrations were always lower than 10 mg/L, while median SAA concentrations remained over the limit of normal (10 mg/L) but under the 30 mg/L threshold. No new or unexpected AEs were reported.

Conclusion

crFMF patients treated with canakinumab during 72 weeks experienced a minimal incidence of flares and good control of clinical disease activity, with no new safety concerns reported.

Systemic Amyloidosis in a Patient With Familial Mediterranean Fever and Hodgkin Lymphoma: A Case Report

Systemic amyloidosis is a clinical manifestation of the accumulation of amyloid fibrils in tissues because of persistent acute phase elevation and chronic inflammation. Its most common causes are inflammatory diseases and malignancies. Here, we present a 12-year-old girl diagnosed with systemic amyloidosis and Hodgkin lymphoma (HL) who was also previously diagnosed with familial Mediterranean fever (FMF). Despite colchicine treatment for FMF, the patient had a persistent elevation of acute phase reactants and AA-type amyloid deposits were observed in a kidney biopsy. Anakinra, an interleukin-1 antagonist, was added to the treatment. Shortly after the diagnosis of amyloidosis, mediastinal lymphadenopathy was recognized, and she was also diagnosed with HL. A chemotherapy protocol of doxorubicin, bleomycin, vinblastine, and dacarbazine was initiated. After 6 cycles of the chemotherapy and 8 months of the anakinra treatment, no recurrence or residual malignancy was observed and proteinuria was decreased. To the authors' knowledge, this is the first reported case of systemic amyloidosis in the literature associated with both FMF and HL.

Clinicopathological Assessment of Kidney Biopsies in Children with Familial Mediterranean Fever: A Single-Center Experience

OBJECTIVES

Familial Mediterranean fever (FMF) is a monogenic auto-inflammatory disease which might rarely cause glomerulopathy in patients. The aim of this study was to determine the clinical, demographic, and genetic characteristics and type of glomerular lesions in pediatric FMF patients who underwent kidney biopsy.

METHODS

The data of 30 pediatric FMF patients with biopsy-proven glomerulopathy were retrospectively reviewed. Patients were grouped into 2 categories as amyloid nephropathy (AN, n = 16) and non-amyloid nephropathy (N-AN, n = 14).

RESULTS

The mean age at FMF diagnosis was 7.2 ± 3.0 years. The AN group showed higher rates of hypertension, higher levels of 24-h protein excretion and serum creatinine, and lower estimated glomerular filtration rate at the time of kidney biopsy. The rate of ESRD was found to be higher in the AN group (p = 0.011). Mesangioproliferative glomerulonephritis was the most common pathology in the N-AN group (21.4%). The frequency of amyloidosis was significantly higher in patients with homozygous p.M694V mutations than non-homozygous p.M694V mutations (p = 0.039).

CONCLUSIONS

In children with FMF, nephropathy is rare. To our knowledge, this is the first study performed in pediatric FMF patients exploring amyloid and non-amyloid glomerulopathies. Patients with AN had higher rates of proteinuria, lower estimated glomerular filtration rate levels, and higher blood pressure than N-AN patients at the time of biopsy.

Periodic fever syndromes and the autoinflammatory diseases (AIDs)

Innate immune system represents the ancestral defense against infectious agents preserved along the evolution and species; it is phylogenetically older than the adaptive immune system, which exists only in the vertebrates. Cells with phagocytic activity such as neutrophils, macrophages, and natural killer (NK) cells play a key role in innate immunity. In 1999 Kastner et al. first introduced the term “autoinflammation” describing two diseases characterized by recurrent episodes of systemic inflammation without any identifiable infectious trigger: Familial Mediterranean Fever (FMF) and TNF Receptor Associated Periodic Syndrome (TRAPS). Autoinflammatory diseases (AIDs) are caused by self-directed inflammation due to an alteration of innate immunity leading to systemic inflammatory attacks typically in an on/off mode. In addition to inflammasomopathies, nuclear factor (NF)-κB-mediated disorders (also known as Rhelopathies) and type 1 interferonopathies are subjects of more recent studies.

This review aims to provide an overview of the field with the most recent updates (see “Most recent developments in..” paragraphs) and a description of the newly identified AIDs.

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Autoinflammatory diseases are caused by self-directed inflammation.

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Alteration of innate immunity leads to systemic inflammation attacks.

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The autoinflammatory field is exponentially expanding.

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The advances in AIDs have led to new insights into immune system understanding.

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Autoimmunity and autoinflammation features may be simultaneously present.

What's new in autoinflammation?

The pathogenesis of autoinflammatory diseases has shed light on the concept of inflammation in general and on our understanding of the role of the innate immune system. The autoinflammatory diseases have a large spectrum with varying features of inflammation. The most common autoinflammatory diseases are those associated with periodic fevers. The delay in diagnosis of these four common diseases (familial Mediterranean fever, cryopyrin-associated periodic fever syndrome, mevalonate kinase deficiency, and TNF receptor-associated periodic fever syndrome) results in secondary amyloidosis of the kidney. The new work towards classification criteria for these diseases is presented. Recently a group of autoinflammatory diseases that are associated with vasculitis have also been identified. These are stimulators of interferon genes (STING)-associated vasculopathy of infancy (SAVI), which is a monogenic defect associated with excessive activity in interferon alpha and deficiency of adenosine deaminase 2, which is characterized by a polyarteritis nodosa-like picture. These monogenic diseases are now in our differential diagnosis of vasculitides. Secondary amyloidosis is a complication of autoinflammatory diseases. Understanding the inflammatory mechanisms in these diseases has led to the use of targeted biologics for this complication. It is hoped that enlightening the mechanisms underlying these monogenic autoinflammatory diseases will also teach us about the pathways in common diseases.

Chronic inflammation in adult familial Mediterranean fever patients: underlying causes and association with amyloidosis

Background: Chronic inflammation, as determined by persistently elevated acute-phase reactants in attack-free periods, can occasionally be observed in patients with familial Mediterranean fever (FMF) and is suggested to be a risk factor for the development of amyloidosis. We aimed to investigate the underlying causes of chronic inflammation in FMF patients and its association with amyloidosis in long-term follow-up. Method: Electronic medical records of FMF patients who had regular follow-up for ≥ 5 years in our cohort were utilized. As part of routine evaluation, detailed history, physical examination, and pertinent laboratory and radiographic investigations were performed in all patients to determine potential causes of elevated C-reactive protein (CRP) levels. Results: The study included 146 FMF patients who had no evidence of amyloidosis at baseline and had regular follow-up for ≥ 5 years. Thirty-seven patients (25.3%) were found to have chronic inflammation in the disease course. Twenty-five (67.5%) of them had either very frequent attacks or chronic manifestations of disease. In the entire study group, amyloidosis developed in five patients (3.42%) during the 5 year follow-up, four in the FMF with chronic inflammation group (10.8%), and only one of the 109 patients without chronic inflammation (odds ratio 13.09, 95% confidence interval 1.41-121.2). Conclusions: The results suggest that persistently high CRP levels during the attack-free periods may be a strong risk factor for the development of amyloidosis in patients with FMF. The vast majority of FMF patients with chronic inflammation had active FMF.

Secondary, AA, Amyloidosis

Secondary, AA, amyloidosis is a rare systemic complication that can develop in any long-term inflammatory disorder, and is characterized by the extracellular deposition of fibrils derived from serum amyloid A (SAA) protein. SAA is an acute-phase reactant synthetized largely by hepatocytes under the transcriptional regulation of proinflammatory cytokines. The kidney is the major involved organ with proteinuria as first clinical manifestation; renal biopsy is the commonest diagnostic investigation. Targeted anti-inflammatory treatment promotes normalization of circulating SAA levels preventing amyloid deposition and renal damage. Novel therapies aimed at promoting clearance of existing amyloid deposits soon may be an effective treatment approach.

Canakinumab treatment in children with familial Mediterranean fever: report from a single center

Familial Mediterranean fever (FMF), the most common hereditary autoinflammatory disorder is characterized by recurrent episodes of fever, serositis, arthritis. The major long-term result is amyloidosis. Colchicine remains the principle of the treatment; it not only prevents the acute attacks but also prevents the long-term complications such as amyloidosis; 5-10% of the patients are unresponsive to treatment. Recently new therapeutic options as anti-interleukin 1 agents are successfully used for the patients who do not respond to colchicine treatment. In this study, we retrospectively evaluated 11 pediatric colchicine-resistant FMF patients who were treated with canakinumab. Three of the patients had amyloidosis and two had uveitis. Based on our results, we suggest that canakinumab may be a safe and effective therapy in patients who are resistant to colchicine and even in the patients with amyloidosis. We also suggest that canakinumab might be a safe option for the patients with uveitis.

New mosaic tiles in childhood hereditary autoinflammatory disorders

The protean clinical phenotypes of hereditary autoinflammatory disorders (HAID) are caused by abnormal activation of innate immunity and consist of seemingly unprovoked inflammatory flares localized to multiple organs, such as the skin, joints, serosal membranes, gut, and central nervous system. Different mutations in genes implied in activation of the interleukin-1 (IL-1)-structured inflammasome, cytoskeletal signaling and apoptosis contribute to the pathogenesis of different HAID, which mostly start in childhood with self-limited flares unrelated to infectious agents, autoantibody production or autoreactive cells. Though IL-1 remains pivotal in many inflammasome-mediated diseases, other cytokinopathies involving IL-18, nuclear factorκ-B, interferons, and tumor necrosis factor have provided new horizons in the definition of HAID of children: the list of HAID has expanded as a consequence of a better understanding of their pathogenetic molecular mechanisms and also application of new genetic technologies. However, diagnosis of most HAID is clinical and focused on several evidence-based criteria sets: their discrimination remains challenging for unexperienced pediatricians as there are no universally accepted algorithms, and a still relevant number of patients may linger without any clarifying genetic analysis, whose interpretation combined with processing of treatment options should be discussed on a multidisciplinary basis.

Assessment of neutrophil to lymphocyte ratio and mean platelet volume in pediatric familial Mediterranean fever patients

Background:

Blood neutrophil to lymphocyte ratio (NLR) and mean platelet volume (MPV) both have been used as a simple marker of inflammation in many disorders. Here, we aimed to investigate the relationship between NLR, MPV, and familial Mediterranean fever (FMF).

Materials and Methods:

In this retrospective study, the files of FMF patients in pediatric rheumatology outpatient clinic were reviewed. There were 160 participants (68.4%) in the FMF patient group and 74 participants (31.6%) in the control group. Ninety of patients were in attack-free period, and 70 were in attack period.

Results:

The highest values of NLR were found in the patients at attack period. Patients in attack-free period and the participants in control group had similar levels of NLR (1.71 ± 0.83 and 1.91 ± 1.86 respectively) (P = 0.457), and they had lower ratios than the patients did at attack period (4.10 ± 3.11) (P < 0.001 for both). There was no significant difference between MPV values of attack patients (8.35 ± 4.91) and attack-free patients (8.43 ± 1.15) (P = 0.074). MPV values of attack patients and attack-free patients were significantly higher than control group (7.99 ± 0.81) (P < 0.001 for both).

Conclusion:

NLR ratio may indicate FMF attack period. Since there was no significant difference between attack-free patients and control groups, NLR ratio cannot be used as a subclinical inflammation marker. However, NLR could be a useful predictor of inflammation in FMF patients. On the other hand, since our attack and attack-free patients have similar MPV values and both had greater MPV values than control group, we suggest that MPV may be used to show subclinical inflammation.

Serum Amyloid A Level in Egyptian Children with Familial Mediterranean Fever

Background and Objectives. SAA is an acute-phase reactant detected during an FMF attack or other inflammatory conditions. High SAA levels may increase the risk of amyloidosis. The aim of the study is to measure the serum amyloid A (SAA) level in a group of Egyptian children with familial Mediterranean fever (FMF) and study its various correlates, if any. Methods. The study enrolled seventy-one children with FMF. Results. SAA level was high in 78.9% of the studied patients with a mean of 81.62 ± 31.6 mg/L, and CRP was positive in 31% of patients. There was no significant releation between SAA level and any demographic or clinical manifestation. High SAA was more frequent in V726A allele (16.9%) followed by M694V allele (12.3%). Elevated SAA levels were more frequent in patients on low colchicine doses. Forty-five percent (45%) of patients have low adherence to colchicine therapy. Interpretation and Conclusion. High SAA levels were detected two weeks after last FMF attack in a large percentage of Egyptian FMF children. This indicates that subclinical inflammation continues during attack-free periods, and SAA could be used as a marker of it.

The evaluation of renal hemodynamics changes in Familial Mediterranean fever with color Doppler sonography

BACKGROUND

Renal resistive index (RRI) scanned through renal Doppler is a practical marker employed in measuring blood flow in renal and intrarenal arteries and in noninvasive evaluation of renal vascular resistance. We aimed to investigate the renal hemodynamic variations in patients with Familial Mediterranean Fever (FMF).

MATERIAL AND METHODS

Seventy-nine FMF patients and 51 healthy subjects suitable for age and sex were included. Patients were divided into two groups according to their urinary albumin excretion. Fifty-two patients with 0-29 mg/day albuminuria were included in the normoalbuminuric group while 27 patients with 30-299 mg/day albuminuria were included in the microalbuminuric group.

RESULTS

RRI values were higher in patients with FMF compared to the healthy subjects (p < 0.0001). Additionally, RRI values were found to be higher in the microalbuminuric patients group compared to the normoalbuminuric patients group, and RRI values were also higher in normoalbuminuric patients group compared to the control group (p = 0.002, p < 0.0001). The ROC curve analysis suggested that the optimum RRI cutoff value for microalbuminuria in patients was 0.63, sensitivity of 66%, specificity of 60%, and p = 0.013.

CONCLUSION

RRI may be a marker that may be used in assessing resistance to renal blood flow, early renal damage, and progression of renal damage in FMF patients.

Red cell distribution width is associated with albuminuria in adults with familial Mediterranean fever

Systematic inflammation, enhanced oxidative stress, and endothelial dysfunction are important for evolution and progression of renal damage, and they cause an increase in red cell distribution width (RDW). Familial Mediterranean fever (FMF) patients who are in the attack-free period and its relation with albuminuria and performance on assessment of microalbuminuria. One hundred and seventy-seven patients who had been diagnosed in accordance with Tel-hoshmer criteria and were in the attack-free period, and 143 age- and sex-matched healthy individuals were enrolled in our study. RDW values of FMF patients were higher compared with those of the controls (13.85 ± 1.07 and 13.15 ± 0.91, respectively; p < 0.0001). RDW values of FMF patients with microalbuminuria were higher compared with those of FMF patients with normoalbuminuria and the control group (p = 0.002 and p < 0.0001, respectively). RDW values of FMF patients with normoalbuminuria were higher compared with those of the control group (p < 0.0001). We have showed RDW levels are positively correlated with albuminuria (r = 0.185, p = 0.014). When assessing microalbuminuria with RDW in the patients, a cutoff value of 13.85 with sensitivity of 60%, specificity of 62%, and p = 0.002 (area under curve: 0.651, 95% confidence interval 0.563-0.738), was observed according to receiver-operating characteristic curve analysis. Among the various variables associated with albuminuria in multivariate logistic regression analyses, RDW remained an independent predictor of albuminuria (95% confidence interval 0.479-0.942, p = 0.021). RDW may be associated with albuminuria in FMF patients and it can be a predictor of microalbuminuria.

The Relationship Among the Level of Serum Amyloid A, High-Density Lipoprotein and Microalbuminuria in Patients With Familial Mediterranean Fever

BACKGROUND

Serum amyloid A (SAA), which is produced in the liver, acts as an apoprotein of high-density lipoprotein (HDL) accumulation in extracellular matrix of tissues and organs. SAA elevations play a significant role in the development of amyloidosis. Microalbuminuria (MAU) is the early period of amyloidosis in patients with familial Mediterranean fever (FMF). We assessed the association between SAA as an important factor for the development of amyloidosis in patients with FMF and cytokines, HDL, and MAU.

METHODS

A total of 40 FMF patients diagnosed with Tel-Hashomer criteria and making regular follow-up visits at the tertiary referral center from 2012 to 2013 were included in this study, besides 40 age- and sex-matched individuals as controls.

RESULTS

Compared with controls, FMF patients had higher SAA (25.20 ± 45.78 vs. 1.68 ± 0.63 ng/ml; P = 0.002). Also, FMF patients had higher MAU than controls (23.20 ± 39.86 vs. 9.40 ± 5.32 mg/day; P = 0.036). HDL was significantly lower in the patient group than in controls (39.35 ± 10.45 vs. 47.82 ± 15.31 mg/dl; P = 0.023). Interleukin-1 beta (IL-1), IL-6, and tumor necrosis factor alpha (TNF-α) levels were higher in the FMF group than in controls (P < 0.0001, P = 0.009, P = 0.003, respectively).

CONCLUSIONS

Our results suggest that IL-1, IL-6, TNF-α, SAA, and HDL may serve as markers of subclinical inflammation in FMF patients. Due to increased plasma HDL levels, antiinflammatory and antioxidant effects may elevate in FMF patients.

Familial Mediterranean fever: current perspectives

Familial Mediterranean fever (FMF) is the most frequent monogenic autoinflammatory disease, and it is characterized by recurrent attacks of fever and polyserositis. The disease is associated with mutations in the MEFV gene encoding pyrin, which causes exaggerated inflammatory response through uncontrolled production of interleukin 1. The major long-term complication of FMF is amyloidosis. Colchicine remains the principle therapy, and the aim of treatment is to prevent acute attacks and the consequences of chronic inflammation. With the evolution in the concepts about the etiopathogenesis and genetics of the disease, we have understood that FMF is more complicated than an ordinary autosomal recessive monogenic disorder. Recently, recommendation sets have been generated for interpretation of genetic testing and genetic diagnosis of FMF. Here, we have reviewed the current perspectives in FMF in light of recent recommendations.

Observational Study of a French and Belgian Multicenter Cohort of 23 Patients Diagnosed in Adulthood With Mevalonate Kinase Deficiency

The aim of this study was to describe the clinical and biological features of Mevalonate kinase deficiency (MKD) in patients diagnosed in adulthood. This is a French and Belgian observational retrospective study from 2000 to 2014. To constitute the cohort, we cross-check the genetic and biochemical databases. The clinical, enzymatic, and genetic data were gathered from medical records. Twenty-three patients were analyzed. The mean age at diagnosis was 40 years, with a mean age at onset of symptoms of 3 years. All symptomatic patients had fever. Febrile attacks were mostly associated with arthralgia (90.9%); lymphadenopathy, abdominal pain, and skin lesions (86.4%); pharyngitis (63.6%); cough (59.1%); diarrhea, and hepatosplenomegaly (50.0%). Seven patients had psychiatric symptoms (31.8%). One patient developed recurrent seizures. Three patients experienced renal involvement (13.6%). Two patients had angiomyolipoma (9.1%). All but one tested patients had elevated serum immunoglobulin (Ig) D level. Twenty-one patients had genetic diagnosis; most of them were compound heterozygote (76.2%). p.Val377Ile was the most prevalent mutation. Structural articular damages and systemic AA amyloidosis were the 2 most serious complications. More than 65% of patients displayed decrease in severity and frequency of attacks with increasing age, but only 35% achieved remission. MKD diagnosed in adulthood shared clinical and genetic features with classical pediatric disease. An elevated IgD concentration is a good marker for MKD in adults. Despite a decrease of severity and frequency of attacks with age, only one-third of patients achieved spontaneous remission.

Simple markers for subclinical inflammation in patients with Familial Mediterranean Fever

Background

In this study we investigated the potential of neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), mean platelet volume (MPV), and red cell width distribution (RDW) as new inflammatory markers to identify chronic inflammations during symptom-free periods in children diagnosed with Familial Mediterranean Fever (FMF).

Material/Methods

The study included 153 children diagnosed with FMF based on the Tel-Hashomer Criteria, and 90 healthy volunteers. Hospital records were obtained to collect NLR, PLR, MPV, RDW, and FMF scores and the FMF mutation analyses of the patients enrolled in the study. Data on proteinuria were also collected and defined as a protein/creatinine ratio >0.2.

Results

NLR, PLR, MPV, and RDW were significantly higher in symptom-free FMF patients than in the control group. C-reactive protein values also weakly correlated with NLR, PLR, MPV, and RDW, but the correlation was not statistically significant. NLR had the strongest correlation with CRP. The NLR cut-off point to indicate subclinical inflammation in symptom-free FMF patients was calculated to be 1.65.

Conclusions

NLR, PLR, MPV, and RDW are potential subclinical inflammation markers in patients with FMF. NLR, PLR, MPV, and RDW values are higher in patients with FMF during symptom-free periods. NLR was found to be the most reliable marker for subclinical inflammation when compared to PLR, MPV, and RDW. We also found that these markers are not significantly higher in proteinuric patients when compared with levels in non-proteinuric patients.

The hereditary autoinflammatory disorders uncovered

There is a thriving interest in the field of hereditary autoinflammatory disorders (HAID), a gamut of heterogeneous conditions deriving from an aberrant orchestration of innate immunity, unified by the common feature of seemingly unprovoked inflammation, which might be systemic or occur in localized niches of the organism. Recurrent fever and episodic inflammation in the joints, serosal membranes, skin, gut, and other organs are the common denominator of HAID. Mutations in the inflammasome-related genes have been associated with different HAID, showing the intimate link existing between interleukin-1 (IL-1)-structured inflammasome and their pathogenesis. Differential diagnosis of HAID can be challenging, as there are no universally accepted diagnostic protocols, and near half of patients may remain without any genetic abnormality identified. The use of IL-1-antagonists has been associated with beneficial effects in a large number of HAID associated with excessive IL-1 signalling, such as cryopyrin-associated periodic syndromes, familial Mediterranean fever, and deficiency of IL-1 receptor antagonist. This review will discuss about the key-clues of HAID which might guide for an early recognition and drive decisions for treatment.

Retinal and choroidal thickness in children with familial Mediterranean fever

PURPOSE

The aim of the present study was to evaluate retinal and choroidal thicknesses in children with familial Mediterranean fever (FMF).

METHODS

Thirty patients with FMF and 28 healthy controls were included in the study. The thicknesses of the retina and choroid of each subject's right eye were measured at the fovea and horizontal nasal and temporal quadrants at 500-µm intervals to 1500 µm from the foveal center using spectral-domain optic coherence tomography.

RESULTS

Retinal and choroidal thicknesses at the fovea did not differ between groups (p = 0.32 and p = 0.39, respectively). Horizontal nasal and temporal retinal and choroidal thickness measurements at 500-µm intervals to a distance of 1500 µm from the foveal center were also similar between the groups (all p > 0.05).

CONCLUSIONS

The retinal and choroidal thicknesses of children with FMF do not differ from those of age- and sex-matched healthy controls.

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.

Is neutrophil/lymphocyte ratio associated with subclinical inflammation and amyloidosis in patients with familial Mediterranean fever?

Background. The purpose of the present study is to determine the association between neutrophil/lymphocyte ratio and both subclinical inflammation and amyloidosis in familial Mediterranean fever. Methods. Ninety-four patients with familial Mediterranean fever and 60 healthy volunteers were included in the study. Of the patients, 12 had familial Mediterranean fever related amyloidosis. The neutrophil/lymphocyte ratio of the patients was obtained from the hematology laboratory archive. Results. The neutrophil/lymphocyte ratio was significantly higher among persons with familial Mediterranean fever compared to healthy individuals (P < 0.0001). Also, neutrophil/lymphocyte ratio was significantly higher in patients with amyloidosis than in amyloidosis-free patients (P < 0.0001). Since NLR was evaluated in nonamyloid and amyloid stages of the same patient population (type 1 phenotype), we obtained significant statistical differences (1.95 ± 0.30 versus 2.64 ± 0.48, P < 0.05, resp.). With the cutoff value of neutrophil/lymphocyte ratio >2.21 and AUC = 0.734 (P = 0.009), it was a reliable marker in predicting the development of amyloidosis. Conclusion. The neutrophil/lymphocyte ratio, an emerging marker of inflammation, is higher in patients with familial Mediterranean fever in attack-free periods. The neutrophil/lymphocyte ratio may be a useful marker in predicting the development of amyloidosis.

Red cell distribution width and mean platelet volume in amyloidosis

We aimed to determine whether red cell distribution width (RDW) and mean platelet volume (MPV) values differ between patients with reactive amyloid A (AA) amyloidosis due to chronic inflammatory disease and in healthy participants. In this study, 33 patients with AA amyloidosis and 40 age- and sex-matched healthy controls were enrolled. Erythrocyte sedimentation rate (ESR), RDW, platelet count (PLT), and MPV levels were retrospectively obtained from our computerized patient database. We found RDW, ESR, and PLT levels to be significantly higher in patients with AA amyloidosis compared with the controls (P < .0001). Mean platelet volume was significantly lower in patients with amyloidosis (P < .0001). Inflammatory diseases such as AA amyloidosis may demonstrate low MPV and high RDW levels.

Systemic amyloidosis complicating multidrug-resistant tuberculosis in childhood

Multidrug-resistant tuberculosis is increasingly common and is associated with long diagnostic delay and high morbidity. We present a 7-year-old child who developed steroid-resistant nephrotic syndrome while receiving treatment for tuberculosis. Renal biopsy results showed systemic amyloidosis; culture of peritoneal tissue confirmed disseminated multidrug-resistant tuberculosis.

The first case of familial Mediterranean fever associated with renal amyloidosis in Korea

Familial Mediterranean fever (FMF) is an auto-inflammatory disease characterized by periodic episodes of fever and recurrent polyserositis. It is caused by a dysfunction of pyrin (or marenostrin) as a result of a mutation within the MEFV gene. It occurs mostly in individuals of Mediterranean origin; however, it has also been reported in non-Mediterranean populations. In this report, we describe the first case of FMF in a Korean child. As eight-year-old boy presented recurrent febrile attacks from an unknown cause, an acute scrotum and renal amyloidosis. He also showed splenomegaly, lymphadenopathy, pleural effusion, ascites and elevated acute phase reactants. After MEFV gene analysis, he was diagnosed as FMF combined with amyloidosis.