SUMMARY Antibodies to DNA and chromatin drive autoimmunity in systemic lupus erythematosus (SLE). Null mutations and hypomorphic variants of the secreted deoxyribonuclease DNASE1L3 are linked to familial and sporadic SLE, respectively. We report that DNASE1L3-deficient mice rapidly develop autoantibodies to DNA and chromatin, followed by an SLE-like disease. Circulating DNASE1L3 is produced by dendritic cells and macrophages, and its levels inversely correlate with anti-DNA antibody response. DNASE1L3 is uniquely capable of digesting chromatin in microparticles released from apoptotic cells. Accordingly, DNASE1L3-deficient mice and human patients have elevated DNA levels in plasma, particularly in circulating microparticles. Murine and human autoantibody clones and serum antibodies from human SLE patients bind to DNASE1L3-sensitive chromatin on the surface of microparticles. Thus, extracellular micro-particle-associated chromatin is a potential self-antigen normally digested by circulating DNASE1L3. The loss of this tolerance mechanismcan contribute to SLE, and its restoration may represent a therapeutic opportunity in the disease.

It was demonstrated that although the Tel Hashomer criteria were successful in diagnosing the FMF patients in childhood, its specificity was definitely low in children. The new set of criteria has a high sensitivity and specificity for the diagnosis of FMF and is practical to use on an everyday basis.

No abstract

Objective. Hypocomplementemic urticarial vasculitis syndrome (HUVS) is characterized by recurrent urticaria along with dermal vasculitis, arthritis, and glomerulonephritis. Systemic lupus erythematosus (SLE) develops in >50% of patients with HUVS, although the pathogenesis is unknown. The aim of this study was to identify the causative DNA mutations in 2 families with autosomal-recessive HUVS, in order to reveal the pathogenesis and facilitate the laboratory diagnosis.Methods. Autozygosity mapping was combined with whole-exome sequencing.Results. In a family with 3 affected children, we identified a homozygous frameshift mutation, c.289_ 290delAC, in DNASE1L3. We subsequently identified another homozygous DNASE1L3 mutation leading to exon skipping, c.320؉4delAGTA, in an unrelated family. The detected mutations led to loss of function, via either nonsense-mediated messenger RNA decay or abolished endonuclease activity, as demonstrated by a plasmid nicking assay.Conclusion. These results show that HUVS is caused by mutations in DNASE1L3, encoding an endonuclease that previously has been associated with SLE.

Herein the results of a multicenter study from the Turkish Pediatric Kidney Transplantation Study Group are reported. The aims of this study were to compare the quality of life (QoL) scores of Turkish children who are dialysis patients (DP), renal transplant recipients (TR), and age-matched healthy controls and to compare child-self and parent-proxy scores. The Turkish versions of the Kinder Lebensqualität Fragebogen (KINDL(R)) questionnaires were used as a QoL measure. The study group consisted of 211 children and adolescents with chronic kidney disease (CKD) (139 TR and 72 DP aged between 4-18 years; 13.7 +/- 3.5 years) from 11 university hospitals, 129 parents of these patients, 232 age-matched healthy children and adolescents (aged between 4-18 years; 13.1+/-3.5 years) and 156 of their parents. Patients with CKD had lower scores in all subscales except for physical well-being than those in the control group. TR had higher scores in physical well-being, self-esteem, friends' subscales, and total scores than DP. Child-self scores were lower than parent-proxy scores, especially in CKD, DP, and control groups. Concordance between parent-proxy and child-self reports in the TR, DP, CKD, and control groups was only moderate for the majority of subscales (r = 0.41-0.61). It was concluded that parent-proxy scores on the QoL were not equivalent to child-self scores and that evaluating both children's and parents' perspectives were important. Additionally, psychosocial counseling is crucial not only for patients with CKD but also for their parents.

Urofacial syndrome (UFS) (or Ochoa syndrome) is an autosomal-recessive disease characterized by congenital urinary bladder dysfunction, associated with a significant risk of kidney failure, and an abnormal facial expression upon smiling, laughing, and crying. We report that a subset of UFS-affected individuals have biallelic mutations in LRIG2, encoding leucine-rich repeats and immunoglobulin-like domains 2, a protein implicated in neural cell signaling and tumorigenesis. Importantly, we have demonstrated that rare variants in LRIG2 might be relevant to nonsyndromic bladder disease. We have previously shown that UFS is also caused by mutations in HPSE2, encoding heparanase-2. LRIG2 and heparanase-2 were immunodetected in nerve fascicles growing between muscle bundles within the human fetal bladder, directly implicating both molecules in neural development in the lower urinary tract.

Acute and chronic renal impairment are important complications after HSCT. A prospective study was conducted to investigate the glomerular renal function in children who received allogeneic HSCT from matched related donors. Non-radiation conditioning regimens were used in all but one patient. CrCl and serial measurements of serum creatinine were evaluated prior to HSCT, within the first 100 days and one yr after. AKI was defined as at least a 1.5-fold rise in pre-HSCT serum creatinine within the first 100 days and classified as grade 1 to 3 according to the new definition criteria proposed by "AKI Network." Fifty-seven patients were enrolled in the study and 24 patients (42%) had AKI. CsA, amphotericin B, and SOS were found as risk factors for AKI. One yr after HSCT five patients (10%) had CKD and none of them required dialysis. None of the parameters were found as a predictor for CKD. We conclude that AKI is an important complication of HSCT. Careful monitoring of renal function, minimizing the use of nephrotoxic medication, prophylaxis, and effective treatment of SOS might be effective preventive measures to decrease the incidence of AKI.

Colchicine is the standard treatment in familial Mediterranean fever (FMF) patients. New treatment strategies are needed in FMF patients who were unresponsive to colchicine therapy or who had developed amyloidosis. The aim of this study was to present clinical-laboratory features and treatment responses of pediatric FMF patients that were treated with anti-IL-1 therapies. Files of patients who had been followed in our department with diagnosis of FMF were retrospectively evaluated. Patients that have been receiving anti-IL-1 therapies (anakinra or canakinumab) were included to the study. All patients were interpreted with respect to the demographic data, clinical and laboratory features of the disease, genetic analysis of MEFV mutations and treatment responses. Among 330 currently registered FMF patients, 13 patients were included to the study. Seven of them received anti-IL-1 therapy due to colchicine resistance and 6 due to FMF-related amyloidosis (1 of them with nephrotic syndrome, 2 with chronic kidney disease, 3 with renal transplantation). In all treated patients, attacks completely disappeared or decreased in frequency; partial remission occured in nephrotic syndrome patient; and their life quality improved. Anti-IL-1 therapies can be successfully used in colchicine-resistant FMF patients and patients with amyloidosis during childhood and adolescent period without major side effects.