Nesrin Besbas

Guideline for the investigation and initial therapy of diarrhea-negative hemolytic uremic syndrome.

This guideline for the investigation and initial treatment of atypical hemolytic uremic syndrome (HUS) is intended to offer an approach based on opinion, as evidence is lacking. It builds on the current ability to identify the etiology of specific diagnostic sub-groups of HUS. HUS in children is mostly due to infection, enterohemorrhagic Escherichia coli (EHEC), Shigella dysenteriae type 1 in some geographic regions, and invasive Streptococcus pneumoniae. These sub-groups are relatively straightforward to diagnose. Their management, which is outside the remit of this guideline, is related to control of infection where that is necessary and supportive measures for the anemia and acute renal failure. A thorough investigation of the remainder of childhood HUS cases, commonly referred to as “atypical” HUS, will reveal a risk factor for the syndrome in approximately 60% of cases. Disorders of complement regulation are, numerically, the most important. The outcome for children with atypical HUS is poor, and, because of the rarity of these disorders, clinical experience is scanty. Some cases of complement dysfunction appear to respond to plasma therapy. The therapeutic part of this guideline is the consensus of the contributing authors and is based on limited information from uncontrolled studies. The guideline proposes urgent and empirical plasmapheresis replacement with whole plasma fraction for the first month after diagnosis. This should only be undertaken in specialized pediatric nephrology centers where appropriate medical and nursing skills are available. The guideline includes defined terminology and audit points so that the early clinical effectiveness of the strategy can be evaluated.

Mutation frequency of Familial Mediterranean Fever and evidence for a high carrier rate in the Turkish population

Familial Mediterranean Fever (FMF) is a recessive disorder characterised by episodes of fever and neutrophil-mediated serozal inflammation. The FMF gene (MEFV) was recently identified and four common mutations characterised. The aim of this study was to determine the carrier rate in the Turkish population and the mutation frequency in the clinically diagnosed FMF patients. We found a high frequency of carriers in the healthy Turkish population (20%). The distribution of the five most common MEFV mutations among healthy individuals (M694V 3%, M680I 5%, V726A 2%, M694I 0% and E148Q 12%) was significantly different (P<0.005) from that found in patients (M694V 51.55%, M680I 9.22%, V726A 2.88%, M694I 0.44% and E148Q 3.55%).

An international consensus approach to the management of atypical hemolytic uremic syndrome in children

Atypical hemolytic uremic syndrome (aHUS) emerged during the last decade as a disease largely of complement dysregulation. This advance facilitated the development of novel, rational treatment options targeting terminal complement activation, e.g., using an anti-C5 antibody (eculizumab). We review treatment and patient management issues related to this therapeutic approach. We present consensus clinical practice recommendations generated by HUS International, an international expert group of clinicians and basic scientists with a focused interest in HUS. We aim to address the following questions of high relevance to daily clinical practice: Which complement investigations should be done and when? What is the importance of anti-factor H antibody detection? Who should be treated with eculizumab? Is plasma exchange therapy still needed? When should eculizumab therapy be initiated? How and when should complement blockade be monitored? Can the approved treatment schedule be modified? What approach should be taken to kidney and/or combined liver–kidney transplantation? How should we limit the risk of meningococcal infection under complement blockade therapy? A pressing question today regards the treatment duration. We discuss the need for prospective studies to establish evidence-based criteria for the continuation or cessation of anticomplement therapy in patients with and without identified complement mutations.

Familial Mediterranean fever in children: report of a large series and discussion of the risk and prognostic factors of amyloidosis

Abstract Familial Mediterranean fever (FMF) is a genetically transmitted disease characterized by recurrent attacks of fever and serositis. The most important complication of this disease is the development of amyloidosis. We present our analysis of 425 FMF patients without and 180 with amyloidosis (123 FMF having amyloidosis type I and 57 FMF having amyloidosis type II). The male/female ratio was higher in the amyloidosis population (111/69) when compared to the FMF population (225/200) (P = 0.048). Consanguinity rate was the same among FMF and amyloidosis groups. However, a family history of amyloidosis was significantly more frequent in the amyloidosis group (P = 0.00001). Multivariate analysis has revealed that in FMF patients, the presence of a family history of amyloidosis plus consanguinity has a 6.04 fold increased risk of amyloidosis (P < 0.0001). The 5-year chronic renal failure free survival was 43.1% and 18.7% in type I and type II amyloidosis, respectively. The time interval to develop chronic renal failure after the development of amyloidosis was 4.8 in type I and 3.0 years in type II, respectively. We found ten cases of Henoch-Schönlein Purpura and nine of polyarteritis nodosa among our patients. The significance of the association between FMF and vasculitis awaits to be clarified. Among the FMF patients put on colchicine therapy (435), only 10 (2.3%) have developed amyloidosis confirming that this drug protects from amyloidosis. Conclusion Since the presence of a familial history of amyloidosis has been defined as the most important risk factor in the development of amyloidosis, we suggest that additional genetic factors may be operative in the development of amyloidosis.

The Role of Cytokines in Henoch Schonlein Purpura

Serum levels of tumor necrosis factor (TNF) and interleukin(IL-1) were studied in 20 HSP patients, in the acute phase and after remission, by ELISA technique. Skin biopsies obtained during the acute phase both from a lesion and from unaffected skin, as well as during remission, were immunostained for TNF, IL-1, and IL-6. The mean age of the patients was 9.8 (5-13). Mean serum TNF levels during the acute phase and remission were 14.0 +/- 8.9 pg/ml, and 6.8 +/- 2.4 pg/ml, respectively (p < 0.05). Serum TNF levels in patients with renal involvement (18.8 +/- 10.2 pg/ml) were significantly higher than in those without (10.8 +/- 6.5 pg/ml) (p < 0.05). Serum levels of IL-1 in the acute phase and remission were undetectable. All specimens showed leukocytoclastic vasculitis. Immunohistochemical studies revealed TNF, and a less intense IL-1 and IL-6 staining in the nucleated epidermal layer, with a granular, intracellular pattern. Staining was significantly increased in the affected skin during the acute phase. These results suggest that TNF, IL-1, and IL-6 may play a role as a mediator of inflammation in HSP.

E148Q is a disease-causing MEFV mutation: a phenotypic evaluation in patients with familial Mediterranean fever

Background: Familial Mediterranean fever (FMF) is one of the periodic fever syndromes. It is common among Turks, Jews, Arabs, and Armenians. Several mutations in the MEFV gene, including E148Q, have been identified as causing this disease. It has been suggested that the E148Q mutation is the mildest mutation and some reports have questioned its disease association. Objective: To evaluate the phenotypic features of the patients with E148Q mutation. Subjects: 26 patients homozygous for E148Q, 10 compound heterozygous for E148Q, and eight complex cases were assessed. Results: Although four of the 26 patients with E148Q/E148Q were asymptomatic at the time of evaluation, abdominal pain was seen in 77% of the patients, fever in 66%, arthralgia in 50%, arthritis in 15.4%, and vomiting in 23.8%. Compound heterozygotes and complex cases had a higher frequency of abdominal pain, fever, arthralgia, arthritis, myalgia, and chest pain than subjects who were homozygous for E148Q, but none of these symptoms reached statistical significance. None of our patients had amyloidosis but two with E148Q/E148Q had a family history of amyloidosis and one had rapidly progressive glomerulonephritis secondary to vasculitis, which progressed to chronic renal failure. Conclusions: Patients homozygous for E148Q have a heterogeneous clinical presentation. Most are symptomatic and colchicine treatment is required in these patients.

DGKE Variants Cause a Glomerular Microangiopathy That Mimics Membranoproliferative GN

Renal microangiopathies and membranoproliferative GN (MPGN) can manifest similar clinical presentations and histology, suggesting the possibility of a common underlying mechanism in some cases. Here, we performed homozygosity mapping and whole exome sequencing in a Turkish consanguineous family and identified DGKE gene variants as the cause of a membranoproliferative-like glomerular microangiopathy. Furthermore, we identified two additional DGKE variants in a cohort of 142 unrelated patients diagnosed with membranoproliferative GN. This gene encodes the diacylglycerol kinase DGKε, which is an intracellular lipid kinase that phosphorylates diacylglycerol to phosphatidic acid. Immunofluorescence confocal microscopy demonstrated that mouse and rat Dgkε colocalizes with the podocyte marker WT1 but not with the endothelial marker CD31. Patch-clamp experiments in human embryonic kidney (HEK293) cells showed that DGKε variants affect the intracellular concentration of diacylglycerol. Taken together, these results not only identify a genetic cause of a glomerular microangiopathy but also suggest that the phosphatidylinositol cycle, which requires DGKE, is critical to the normal function of podocytes.

Implications of certain genetic polymorphisms in scarring in vesicoureteric reflux: Importance of ace polymorphism

Polymorphisms of the renin-angiotensin system (RAS) have been shown to affect renal prognosis in a number of diseases. We examined the influence of deletion (D) and insertion (I) polymorphism in the angiotensin I-converting enzyme (ACE) gene and the other polymorphic markers of RAS, and that of plasminogen-activator inhibitor-1 (PAI-1) on renal scarring in reflux nephropathy. Ninety-four children with third- or fourth-degree reflux were the subject of the study. They were stratified into two groups according to the technetium-99m-dimercaptosuccinic acid (DMSA) findings: the first group consisted of 41 patients with no scar formation. In the second group (n = 53), there was significant scar formation in the refluxing units. ACE levels, ACE gene, angiotensin-1 receptor (AT1) A1166C, angiotensinogen (ATG) M235T, and PAI-1 4G/5G polymorphisms were studied. In the second group with scarred kidneys, 18 patients had decreased renal function. The frequency of patients homozygous for the D allele was significantly greater in the second group with scar formation in the refluxing units compared with the first group of patients (P < 0.005). On multivariate analysis, the DD genotype was the only factor that had a significant impact on renal scar formation, introducing a 4.9-fold risk (P < 0.05, 95% confidence interval). We were unable to find any correlation with the presence ofDD genotype and hypertension, decreased renal function, proteinuria, or sex of the patient. DDgenotype correlated with the serum ACE levels (P < 0.005). AT1and ATGpolymorphisms and PAI-1 polymorphism did not correlate with scar formation or any of the parameters. This study provides evidence that the DDgenotype of ACE may be a genetic susceptibility factor contributing to adverse renal prognosis in reflux nephropathy; namely, scar formation. The role of the synergism between the aforementioned genetic polymorphisms can be enlightened with larger patient groups, possibly through multicenter studies.

The significance of antineutrophil cytoplasmic antibody in microscopic polyangitis and classic polyarteritis nodosa

AIMS To describe the distribution and features of classic polyarteritis nodosa (PAN) and microscopic polyarteritis (MPA) and the importance of antineutrophil cytoplasmic antibody (ANCA) in childhood PAN. METHODS Classic PAN was diagnosed in 15 patients based on the presence of aneurysms on angiography in 10 patients and of necrotising vasculitis in medium sized arteries in five. MPA was diagnosed in 10 patients, based on characteristic findings at renal biopsy in six and by the presence of small sized necrotising arteritis in four. Serum ANCA was detected initially by indirect immunofluorescence (IIF) followed by an immunoassay for myeloperoxidase (MPO) in each case. RESULTS The median age of the patients with classic PAN and MPA was 12 (range 8–17) and 9.5 (range 5–14) respectively. None of the patients with classic PAN had renal failure. Six of the patients with MPA presented with renal failure; four progressed to chronic renal failure. Clinically evident pulmonary–renal syndrome was present in three of the 10 patients with MPA. IIF for ANCA in classic PAN was negative in nine, showed mild staining patterns in six, and in one MPO-ELISA was mildly increased. IIF for ANCA in MPA revealed very strong perinuclear ANCA staining in nine and atypical staining in one. In MPA, median MPO-ELISA level was 42.5 EU/ml (range 20–250). Treatment of childhood PAN was satisfactory with effective treatment; however relapses did occur. CONCLUSION ANCA is useful in the diagnosis and follow up of MPA.

Renal involvement in polyarteritis nodosa: evaluation of 26 Turkish children

Abstract Renal involvement is common in childhood polyarteritis nodosa (PAN). We report a retrospective analysis of the presentation and clinical course of 26 patients with PAN and renal involvement. The mean age was 9.3 years (range 1–14 years) and there were 12 boys and 14 girls. Renal symptoms at presentation were as follows: 3 had isolated proteinuria, 9 had nephritic syndrome, 2 had nephritic and nephrotic components, and 10 had renal failure with one of the above features. Two patients with isolated hypertension were diagnosed by angiography and classified as classical PAN. Patients either received prednisone p.o. alone (n=9), or prednisone plus cyclophosphamide p.o. (n=11), or pulse steroids with prednisone p.o. and cyclophosphamide (n=2); 4 did not receive any treatment. Patients who were given cyclophosphamide had a significantly better outcome than those who did not. We suggest that oral cyclophosphamide therapy and corticosteroids are effective in the treatment of PAN. The overall 1-year and 5-year survival rates of the patients were 72.5% and 60%, respectively. In conclusion, renal disease is a serious manifestation of PAN necessitating prompt and aggressive treatment.