Age-specific frequencies of antibodies to Escherichia coli verocytotoxins (Shiga toxins) 1 and 2 among urban and rural populations in southern Ontario.

In 173 urban residents and 232 rural dairy-farm residents (age range, 0-70 years) who were stratified for age, the frequency of antiverocytotoxin 2 antibodies (VT2 Abs) (frequency in urban residents, 46%; frequency in rural residents, 65%) was significantly higher than that of antiverocytotoxin 1 antibodies (VT1 Abs) (frequency in urban residents, 12%; frequency in rural residents, 39%) (P< or =.001). The frequency of VT2 Abs (93%) was also significantly higher than that of VT1 Abs (50%) in 14 patients with hemolytic uremic syndrome (HUS) associated with verocytotoxin-producing Escherichia coli (VTEC) strains that expressed both toxins. In urban residents, the frequency of both antibodies tended to decrease between the first and the second decades of life, and it then increased until the fifth decade of life, before, in the case of VT2 Abs, decreasing again. This pattern, which inversely reflects the age-related incidence of HUS, is consistent with a role for antiverocytotoxin antibodies in protective immunity. In dairy-farm residents, peak frequencies of antibodies to both toxins occurred during the first decade of life and remained elevated for 3 decades before decreasing, a pattern consistent with frequent exposure to bovine VTEC from an early age.

Long versus standard initial steroid therapy for children with the nephrotic syndromeA report from the Southwest Pediatric Nephrology Study Group.

A retrospective cohort study was conducted by the Southwest Pediatric Nephrology Study Group (SPNSG) to address whether a longer initial course of corticosteroids in patients with idiopathic nephrotic syndrome (INS) provides superior protection against relapse without increased adverse effects. In order to be included in the evaluation, patients with INS must have responded to an initial steroid course, either standard or long regimen as defined here, and completed at least 1 year of follow-up. The standard regimen consisted of prednisone 2.0+/-0.3 mg/kg per day or 60+/-10 mg/m(2) per day for 28+/-4 days, followed by alternate-day prednisone for 4-12 weeks. The long regimen consisted of daily prednisone 2.0+/-0.3 mg/kg per day or 60+/-10 mg/m(2) per day for 42+/-6 days, followed by alternate-day prednisone for 6-14 weeks. The primary outcome measure was relapse of NS within 12 months of discontinuing the initial course of prednisone. There were 151 children who met the criteria for the study; 82 received the standard regimen and 69 the long regimen. The two groups did not differ in age, race, blood pressure, serum albumin, or serum cholesterol prior to the initial steroid course. The cumulative prednisone dose was 49% higher in the long regimen group than in the standard regimen group. Relapse within 12 months was reported in 72.5% of patients who received the long regimen versus 84.1% of those who received the standard regimen. The odds ratio for relapse within 12 months was 0.496 (95% confidence interval 0.22, 1.088), long versus standard regimen. This did not reach statistical significance ( chi(2)=3.058, P=0.08). The odds ratio of experiencing at least one side effect was 3.76, long relative to standard regimen ( n=133, P<0.001). Our data suggest that prolongation of the steroid treatment for the initial episode of steroid-sensitive NS may have a beneficial effect, but at the cost of increased side effects. However, definitive conclusions are limited by the retrospective design of the study and the number of patients. This may have caused failure to achieve statistical significance on the basis of a type II error.

Varicella vaccination in children with nephrotic syndrome: a report of the Southwest Pediatric Nephrology Study Group.

OBJECTIVE: To evaluate the safety and immunogenicity of varicella vaccine in children with nephrotic syndrome, including those taking low-dose, alternate-day prednisone. STUDY DESIGN: Prospective, open-label, multicenter clinical trial of varicella vaccine in a 2-dose regimen in US and Canadian children (12 months to <18 years) with nephrotic syndrome. Varicella Zoster Virus (VZV) antibody levels were measured after the first and second vaccine dose and yearly for 2 years. Patients were monitored for adverse reactions to vaccine, exposure to varicella, dermatomal zoster, and chickenpox. RESULTS: Twenty-nine children, mean age 4.9 (SD 1.9) years, 45% receiving every-other-day steroids, received 2 vaccine doses. All patients seroconverted and had VZV antibody levels considered protective against breakthrough varicella (>or=5 gpELISA units) after 2 doses. At 2-year follow-up, all patients retained detectable antibody, and 91% (21 of 23) had levels >or=5 gpELISA units. There were no adverse events associated with vaccination. CONCLUSIONS: Varicella vaccine was generally well tolerated and highly immunogenic in children with nephrotic syndrome, including those on low-dose, alternate-day prednisone.

Effective removal of methotrexate by high-flux hemodialysis.

The purpose of the present study was to examine the clearance of methotrexate (MTX) by high-flux hemodialysis (HD) in pediatric oncology patients. We present three patients who experienced nephrotoxicity and prolonged exposure to toxic MTX concentrations following high-dose infusions during treatment for osteogenic sarcomas. Each patient was successfully treated with high-flux HD, followed by carboxypeptidase G2 (CPDG2) in two cases. Minimal systemic toxicity occurred. We review the literature and discuss guidelines for early and aggressive treatment for this complication of high-dose MTX therapy. Clinically important removal of MTX depends upon prompt initiation of HD after detection of nephrotoxicity and delayed clearance of MTX. Therapy is indicated in cases where compassionate use of CPDG(2) may not be available, or while awaiting its delivery.

Antibodies to intimin and Escherichia coli secreted proteins A and B in patients with enterohemorrhagic Escherichia coli infections.

Enterohemorrhagic Escherichia coli produce an attaching and effacing lesion upon adhering to the intestinal epithelium. Bacterial factors involved in this histopathology include the intimin adhesin and E. coli secreted proteins (Esps) A and B. In this study we investigated the serum antibody responses to recombinant E. coli O157:H7 intimin, EspA, and EspB by immunoblotting. Canadian patients with O157:H7 infection (n=10), Swedish patients with O157:H7 (n=21), non-O157 (n=18), or infection from which the serotype was not available (n=3), and asymptomatic household members (n=25) were studied and compared with Canadian (n=20) and Swedish controls (n=52). In Canadian patients, IgG antibodies to intimin, EspA, and EspB were analyzed, in Swedish patients and their household members IgA, IgG, and IgM antibodies to EspA and EspB were studied. Patients and household members mounted an antibody response to the antigens. Significantly more patients developed an acute response to EspB compared with controls (P<0.01 Canadian patients, P<0.0001 Swedish patients). EspB IgA, IgG, and IgM had a specificity of 100%, 86%, and 86%, positive predictive value of 100%, 83%, and 81%, and sensitivity of 57%, 69%, and 63%, respectively, and appear to be an appropriate assay for the detection of EHEC infection. In cases of hemolytic uremic syndrome or hemorrhagic colitis this assay may be useful when a fecal strain has not been isolated, or in epidemics of non-O157 infection.