RESUMEN
AIMS: Vancomycin is frequently used in critically ill children in whom the drug pharmacokinetics are significantly altered as a result of changes in renal clearance and volume of distribution. Therapeutic drug monitoring (TDM) is recommended to achieve vancomycin trough concentrations between 10 and 20 mg/L. In this study we reviewed vancomycin dosing, TDM and treatment outcomes in paediatric and neonatal intensive care unit patients. METHODS: We reviewed the medical records of all patients receiving intravenous vancomycin in a tertiary paediatric and neonatal intensive care unit over a 10-month period. Demographic, vancomycin dosing, TDM and drug-related adverse effects data were collected. RESULTS: In total, 115 children received 126 courses of vancomycin and had at least 1 TDM blood sample taken at steady state. In only 38/126 (30%) courses was the target concentration (10-20 mg/L) achieved at the initial steady state trough sample. Of the 88 courses that had initial trough concentrations outside the target range, the dose was adjusted in only 49 (56%). Overall, minimum doses of 30 mg/kg/day in neonates with a corrected gestational age of <35 weeks, and 50 mg/kg/day in older children, were required to achieve target vancomycin concentrations. Vancomycin-attributable nephrotoxicity occurred in 10/126 (8%) courses and there were no episodes of red man syndrome. CONCLUSION: In critically ill children, individualised dosing is needed. In the absence of Bayesian model-based dosing, in children with normal renal function, empiric vancomycin doses of at least 30 mg/kg/day in neonates of <35 weeks corrected gestational age, and 50 mg/kg/day in older children, should be considered. Optimisation of TDM practices through the development of protocols, ideally built into electronic medical records, should be considered.
Asunto(s)
Antibacterianos/administración & dosificación , Cálculo de Dosificación de Drogas , Monitoreo de Drogas/estadística & datos numéricos , Enfermedades Renales/epidemiología , Sepsis/tratamiento farmacológico , Vancomicina/administración & dosificación , Administración Intravenosa , Adolescente , Factores de Edad , Antibacterianos/efectos adversos , Antibacterianos/farmacocinética , Niño , Preescolar , Enfermedad Crítica/terapia , Relación Dosis-Respuesta a Droga , Femenino , Edad Gestacional , Humanos , Lactante , Recien Nacido Extremadamente Prematuro , Recién Nacido , Unidades de Cuidado Intensivo Neonatal/estadística & datos numéricos , Riñón/efectos de los fármacos , Enfermedades Renales/inducido químicamente , Masculino , Registros Médicos/estadística & datos numéricos , Estudios Retrospectivos , Vancomicina/efectos adversos , Vancomicina/farmacocinéticaRESUMEN
Murine natural killer (NK) cells are regulated by the interaction of Ly49 receptors with major histocompatibility complex class I molecules (MHC-I). Although the ligands for inhibitory Ly49 were considered to be restricted to classical MHC (MHC-Ia), we have shown that the non-classical MHC molecule (MHC-Ib) H2-M3 was a ligand for the inhibitory Ly49A. Here we establish that another MHC-Ib, H2-Q10, is a bona fide ligand for the inhibitory Ly49C receptor. H2-Q10 bound to Ly49C with a marginally lower affinity (â¼5 µm) than that observed between Ly49C and MHC-Ia (H-2K(b)/H-2D(d), both â¼1 µm), and this recognition could be prevented by cis interactions with H-2K in situ To understand the molecular details underpinning Ly49·MHC-Ib recognition, we determined the crystal structures of H2-Q10 and Ly49C bound H2-Q10. Unliganded H2-Q10 adopted a classical MHC-I fold and possessed a peptide-binding groove that exhibited features similar to those found in MHC-Ia, explaining the diverse peptide binding repertoire of H2-Q10. Ly49C bound to H2-Q10 underneath the peptide binding platform to a region that encompassed residues from the α1, α2, and α3 domains, as well as the associated ß2-microglobulin subunit. This docking mode was conserved with that previously observed for Ly49C·H-2K(b) Indeed, structure-guided mutation of Ly49C indicated that Ly49C·H2-Q10 and Ly49C·H-2K(b) possess similar energetic footprints focused around residues located within the Ly49C ß4-stand and L5 loop, which contact the underside of the peptide-binding platform floor. Our data provide a structural basis for Ly49·MHC-Ib recognition and demonstrate that MHC-Ib represent an extended family of ligands for Ly49 molecules.