TAC, MMF and MP are used in pediatric kidney tx. The cytochrome P450 (CYP)3A5 enzyme appears to play a role in TAC metabolism. The aims of this study were to investigate CYP3A5 polymorphism's effect on TAC dosing and the age dependency of TAC dosing by testing blood concentrations, and the interaction between steroids and TAC during the first year after tx. Genomic DNA was extracted and amplified with specific primers. CYP3A5 alleles were confirmed by direct sequencing of PCR products on an automated AB13100 capillary sequencer. We studied 48 renal transplant patients (age at tx 12±0.5yr, 22 boys) receiving TAC, MMF, MP. Of these, 79% were CYP3A5*3/*3 (non-expressers homozygotes) and 21% were CYP3A5*1/*3 (expressers). TAC trough levels were 7.1±0.4ng/mL in CYP3A5*3/*3 patients and 6.5±0.7ng/mL in CYP3A5*1/*3 group (p=0.03). CYP3A5*1/*3 patients had lower levels of dose-adjusted TAC (36.7±5.8ng/mL/mg/kg/day) to achieve target blood concentration and required higher daily dose per weight (0.21±0.03mg/kg/day) than CYP3A5*3/*3 patients, 72.4±8.0ng/mL/mg/kg/day and 0.13±0.01mg/kg/day (p<0.001). Prepubertal patients with different CYP3A5 polymorphisms required significant higher TAC doses and achieved lower dose-normalized concentration compared with pubertal patients. Both TAC dose and adjusted-dose correlated with daily MP dose in CYP3A5*1*3 (r: 0.4, p<0.03 and r: 0.4, p<0.03) and in CYP3A5*3*3 (r: 0.6, p<0.01 and r: 0.47, p<0.001) patients. CYP3A5 polymorphism performed before tx could contribute to a better individualization of TAC therapy. The higher TAC dose in prepubertal patients and the pharmacological interactions between MP and TAC may not be fully explained by different CYP3A5 polymorphisms.

SummaryHaemolytic uraemic syndrome (HUS) is characterized by haemolytic anaemia, thrombocytopenia and acute renal failure. We studied the activation state of classical and alternative pathways of complement during the acute phase of Shiga toxin-associated HUS by performing a prospective study of 18 patients and 17 age-matched healthy controls to evaluate C3, C3c, C4, C4d, Bb and SC5b-9 levels. SC5b-9 levels were increased significantly in all patients at admission compared to healthy and end-stage renal disease controls, but were significantly higher in patients presenting with oliguria compared to those with preserved diuresis. C3 and C4 levels were elevated significantly at admission in the non-oliguric group when compared to controls. No significant differences were found for C4d values, whereas factor Bb was elevated in all patients and significantly higher in oliguric patients when compared to both controls and non-oliguric individuals. A positive and significant association was detected when Bb formation was plotted as a function of plasma SC5b-9 at admission. Bb levels declined rapidly during the first week, with values not significantly different from controls by days 3 and 5 for non-oligurics and oligurics, respectively. Our data demonstrate the activation of the alternative pathway of complement during the acute phase of Stx-associated HUS. This finding suggests that complement activation may represent an important trigger for the cell damage that occurs during the syndrome.

We demonstrate here increased levels of OS during the acute phase of HUS, with peak plasma lipid peroxidation values well above those registered in ESRD individuals, and suggest a connection between OS and the clinical course of HUS.

Allograft function and metabolic effects of four treatment regimens, namely, methylprednisone (MP) standard dose (MP-STD), deflazacort (DFZ), MP-late steroid withdrawal (MP-LSW), and MP-very low dose (MP-VLD), were evaluated in prepubertal patients. MP was decreased by month 4 post-transplantation to 0.2 mg/kg/day in MP-STD and DFZ patients and to <0.1 mg/kg/day in MP-LSW and MP-VLD patients. Starting in month 16 post-transplant, MP was switched to DFZ in the DFZ group and totally withdrawn in the MP-LSW group. Creatinine clearance diminished in the MP-STD and MP-LSW groups from 77 +/- 6 to 63 +/- 6 ml/min/1.73 m(2)and from 103 +/- 5 to 78 +/- 3 ml/min/1.73 m(2), respectively (p < 0.01 and p < 0.001, respectively). Height increased >0.5 SDS only in the MP-LSW and MP-VLD groups. The body mass index and fat body mass for height-age increased only in the MP-STD patients (p < 0.05 and p < 0.01, respectively). Fat body mass decreased in the DFZ group (p < 0.05), total cholesterol and LDL-cholesterol increased in the MP-STD group, while LDL-cholesterol and total cholesterol/HDL-cholesterol ratio decreased in the DFZ group (p < 0.01). Lumbar spine bone mineral density (BMD) for height-age showed an increase in the MP-LSW and MP-VLD groups (p < 0.01). Our data suggest that MP-LSW and MP-VLD strategies improve linear growth, BMD, the peripheral distribution of fat, and preservation of the bone-muscle unit and maintain the normal lipid profile. The MP-LSW patients had a concerning rate of acute rejections and graft function deterioration in prepubertal patients.

Studies are increasingly recognizing health‐related quality of life (HRQOL) as a key pediatric outcome in both clinical and research settings and an essential health outcome measure to assess the effectiveness of medical treatment. However, it has not yet been studied among the healthy siblings of kidney transplant recipients. The aim of this study, therefore, is to examine HRQOL among this population. We asked the following three groups to complete a validated measure of HRQOL among children (KIDSCREEN‐52): siblings of children who had received kidney transplants (n = 50), kidney transplant recipients (n = 43), and a healthy control group (n = 84). We found that siblings of kidney transplant patients exhibited lower scores for financial resources and autonomy than kidney transplant recipients. They also served lower on physical well‐being, financial resources, autonomy, and parent relations/home life than the control group. However, they scored higher on social acceptance than kidney transplant recipients. Our study underscores the importance of assessing HRQOL in families including a child diagnosed with a chronic illness. Siblings require social and psychological support to promote coping and adaptation.