Extracorporeal membrane oxygenation (ECMO) is a therapy that ensures adequate tissue oxygen delivery in patients suffering cardiac and/or respiratory failure that are unresponsive to conventional therapy During ECMO, it is common to see a decrease in urine output that may be associated with acute renal failure. In this context, continuous renal replacement therapy (CRRT) should be considered. Our aim is to evaluate a pioneer experience in Latin America, related to the use of CRRT in a group of neonatal-pediatric patients during ECMO. We conducted a retrospective review of patients treated with ECMO at our institution between May 2003 and May 2005. Twelve infants were treated with ECMO, six of them also underwent CRRT. The main reasons for CRRT initiation were fluid overload and progressive azotemia. Observed complications were clots in the filter and excessive ultrafiltration. CRRT was successful in fluid management and solute clearance in all patients. Discharge survival rate was 83%, all of them with normal renal function. Concurrent CRRT with ECMO is technically feasible and efficacious in the management of fluid overload and solute clearance. We report the first experience with these therapies in a Latin American neonatal-pediatric ECMO program associated with the Extracorporeal Life Support Organization.

The Nephrology Branch of the Chilean Pediatric Society has greatly influenced the development of government health plans regarding the management and care of patients under 18 years with chronic renal failure (CRF). In order to assess the status of children with CRF in Chile up to 1996, a questionnaire was sent to all pediatric nephrologists in charge of those children. The total sample was of 227 patients under 18 years, giving a national prevalence of 42.5 and an incidence of 5.7 per million inhabitants; of these patients, 50.7% were male, 58.6% over 10 years and 15% younger than 5 years. The most frequent etiologies of CRF were: obstructive uropathy, 18.1%; hypo/dysplasia, 16.7%; reflux nephropathy, 16.7%; and glomerulopathies, 16.3%. Although 48% of patients were on conservative medical treatment, 42.2% of these were in end-stage renal disease, 22.9% were on dialysis, and 29.1% had undergone renal transplantation. Of the dialysis group, 75% were on peritoneal dialysis. Of the transplanted children, 78.8% had normal renal function, but 16.7% returned to dialysis. Three-year graft survival and patient survival were 68% and 94%, respectively.

Nuclear factor kappa-B subunit 2 (NF-κB2/p100/p52), encoded by NFKB2 (MIM: 164012) belongs to the NF-κB family of transcription factors that play a critical role in inflammation, immunity, cell proliferation, differentiation and survival. Heterozygous C-terminal mutations in NFKB2 have been associated with early-onset common variable immunodeficiency (CVID), central adrenal insufficiency and ectodermal dysplasia. Only two previously reported cases have documented decreased natural killer (NK) cell cytotoxicity, and little is known about the role of NF-κB2 in NK cell maturation and function. Here we report a 13-year-old female that presented at 6 years of age with a history of early onset recurrent sinopulmonary infections, progressive hair loss, and hypogamaglobulinemia consistent with a clinical diagnosis of CVID. At 9 years of age she had cytomegalovirus (CMV) pneumonia that responded to ganciclovir treatment. Functional NK cell testing demonstrated decreased NK cell cytotoxicity despite normal NK cell numbers, consistent with a greater susceptibility to systemic CMV infection. Research exome sequencing (ES) was performed and revealed a novel de novo heterozygous nonsense mutation in NFKB2 (c.2611C>T, p.Gln871 * ) that was not carried by either of her parents. The variant was Sanger sequenced and confirmed to be de novo in the patient. At age 12, she presented with a reactivation of the systemic CMV infection that was associated with severe and progressive nephrotic syndrome with histologic evidence of pedicellar effacement and negative immunofluorescence. To our knowledge, this is the third NF-κB2 deficient patient in which an abnormal NK cell function has been observed, suggesting a role for non-canonical NF-κB2 signaling in NK cell cytotoxicity. NK cell function should be assessed in patients with mutations in the non-canonical NF-κB pathway to explore the risk for systemic viral infections that may lead to severe complications and impact patient survival. Similarly NF-κB2 should be considered in patients with combined immunodeficiency who have aberrant NK cell function. Further studies are needed to characterize the role of NF-κB2 in NK cell cytotoxic function.

A 2-year-old boy had a severe cytomegalovirus (CMV) infection with multi-organ involvement, while on maintenance therapy for acute lymphoblastic leukemia. The patient was treated with intravenous gancyclovir, with a marked improvement in his clinical status, with the exception of a progressive deterioration of the renal function. He also developed hemolytic anemia and thrombocytopenia, suggesting a diagnosis of atypical hemolytic uremic syndrome (HUS). A percutaneous renal biopsy showed lesions consistent with HUS, but no evidence of CMV infection. The patient had a good clinical outcome with no evidence of renal sequelae. We report a rare association of CMV infection and HUS in the pediatric age-group, which suggests a possible cause-effect relationship that deserves further evaluation.