Membrane cofactor protein (MCP; CD46) is a widely expressed transmembrane complement regulator. Like factor H it inhibits complement activation by regulating C3b deposition on targets. Factor H mutations occur in 10 -20% of patients with hemolytic uremic syndrome (HUS). We hypothesized that MCP mutations could predispose to HUS, and we sequenced MCP coding exons in affected individuals from 30 families. MCP mutations were detected in affected individuals of three families: a deletion of two amino acids (D237͞S238) in family 1 (heterozygous) and a substitution, S206P, in families 2 (heterozygous) and 3 (homozygous). We evaluated protein expression and function in peripheral blood mononuclear cells from these individuals. An individual with the D237͞S238 deletion had reduced MCP levels and Ϸ50% C3b binding compared with normal controls. Individuals with the S206P change expressed normal quantities of protein, but demonstrated Ϸ50% reduction in C3b binding in heterozygotes and complete lack of C3b binding in homozygotes. MCP expression and function was evaluated in transfectants reproducing these mutations. The deletion mutant was retained intracellularly. S206P protein was expressed on the cell surface but had a reduced ability to prevent complement activation, consistent with its reduced C3b binding and cofactor activity. This study presents further evidence that complement dysregulation predisposes to development of thrombotic microangiopathy and that screening patients for such defects could provide informed treatment strategies.

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.

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Primary peritonitis is a well-described infectious complication of nephrotic syndrome. Current data on the true incidence of peritonitis and efficacy of preventive pneumococcal vaccination are not clear in this group of children. In this nationwide study, among a total of 268 patients with an initial diagnosis of steroid sensitive nephrotic syndrome, eight episodes of primary peritonitis were detected in seven patients during 5 years. All eight attacks of peritonitis occurred in the relapse period. Seven of these peritonitis episodes occurred in the first 2 years of nephrotic syndrome, three of them during the first attack. One patient had two attacks with a 6-month interval. Only two of the patients were steroid sensitive, while four of them were steroid dependent, and one was steroid resistant at the diagnosis of peritonitis. The causing microorganism was identified in three patients (Streptococcus hemolyticus, Streptococcus pneumoniae, and alpha-hemolytic Streptococcus). Incidence of peritonitis (2.6%) in our series was not high when compared with previous reports. None of the patients had been immunized against pneumococcus before or after the peritonitis attack. It raises the question if the vaccine is necessary for every child with steroid sensitive nephrotic syndrome. However, we suggest that immunization against pneumococcus is not indicated in children with steroid-responsive nephrotic syndrome (NS) and should be reserved for the small number of children who have steroid-dependent or steroid-resistant NS.

Familial Mediterranean fever is characterized by recurrent polyserositis episodes associated with fever. However, the clinical spectrum of this disease has been expanded recently and myalgia is now a frequently recognized component. Protracted febrile myalgia syndrome was first described in patients with familial Mediterranean fever in 1994. This syndrome is characterized by severe paralyzing myalgia, high fever, abdominal pain, diarrhea, arthritis/arthralgia, and transient vasculitic rashes mimicking Henoch-Schonlein purpura. Recently, we evaluated 6 patients with the clinical picture of protracted febrile myalgia syndrome in our clinic. One of them was a patient with known familial Mediterranean fever, but the others were subsequently diagnosed to have familial Mediterranean fever by mutational analyses. Thus, introduction of genetic analysis would possibly change the diagnostic criteria for familial Mediterranean fever. In addition, all 6 patients presented in the spring months when streptococcal infections are at their peak rate and 3 of them had elevated ASO levels indicating that streptococci could be one of the agents triggering protracted febrile myalgia syndrome.

We evaluated the predictors of renal scar in children with urinary tract infections (UTIs) having primary vesicoureteral reflux (VUR). Data of patients who were examined by dimercaptosuccinic acid (DMSA) scintigraphy between 1995 and 2005 were evaluated retrospectively. Gender, age, reflux grade, presence/development of scarring, breakthrough UTIs, and resolution of reflux, were recorded. The relation of gender, age and VUR grade to preformed scarring and the relation of gender, age, VUR grade, presence of preformed scarring, number of breakthrough UTIs and reflux resolution to new scarring were assessed. There were 138 patients [male/female (M/F) 53/85]. Multivariate analysis showed that male gender [odds ratio (OR) 2.5], age > or = 27 months in girls (OR 4.2) and grades IV-V reflux (OR 12.4) were independent indicators of renal scarring. On the other hand, only the presence of previous renal scarring was found to be an independent indicator for the development of new renal scar (OR 13.4). In conclusion, while the most predictive variables for the presence of renal scarring among children presenting with a UTI were male gender, age > or = 27 months in girls, and grades IV-V reflux, the best predictor of new scar formation was presence of previous renal scarring.

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