Nucleic Acid Testing for Diagnosis of Perinatally Acquired Hepatitis C Virus Infection in Early Infancy.

BACKGROUND: Most US children with perinatal hepatitis C virus (HCV) exposure fail to receive the recommended anti-HCV antibody test at age ≥18 months. Earlier testing for viral RNA might facilitate increased screening, but sensitivity of this approach has not been established. We hypothesized that modern HCV-RNA RT-PCR platforms would adequately detect infected infants. METHODS: Nationwide Children's Hospital electronic health records from 1/1/2008 to 30/6/2018 were reviewed to identify perinatally exposed infants tested by HCV-RNA RT-PCR at age 2-6 months. Diagnostic performance was determined using a composite case definition: (1) infected children had positive repeat HCV-RNA testing or positive anti-HCV at age ≥24 months; (2) uninfected children lacked these criteria and had negative anti-HCV at age ≥18 months. RESULTS: 770 perinatally exposed infants underwent HCV-RNA testing at age 2-6 months. Of these, 28 (3.6%) tested positive; viremia was confirmed in all who underwent repeat testing (n = 27). Among 742 infants with negative HCV-RNA results, 226 received follow-up anti-HCV testing at age ≥18 months, of whom 223 tested negative. Three children had low-positive anti-HCV results at age 18-24 months that were negative upon retesting after age 24 months, possibly indicating waning maternal antibodies. Using the composite case definitions, early HCV-RNA screening demonstrated sensitivity of 100% (87.5-100%, Wilson-Brown 95% CI) and specificity of 100% (98.3-100%). CONCLUSIONS: Modern HCV-RNA RT-PCR assays have excellent sensitivity for early diagnosis of perinatally acquired infection and could aid HCV surveillance given the substantial loss to follow-up at ≥18 months of age.

Clinical use of a simultaneous HPLC assay for indinavir, saquinavir, ritonavir and nelfinavir in children and adults.

PROTEASE INHIBITOR TDM: This study examines the importance of therapeutic drug monitoring (TDM) of protease inhibitors (PI) in adults and children infected with the human immunodeficiency virus (HIV). Pediatric patients were included because information in this population is limited. A high performance liquid chromatographic (HPLC) assay measured indinavir, saquinavir, ritonavir and nelfinavir simultaneously in 0.2 mL of plasma. Initially, the reliability, sensitivity and specificity of the assay were verified in stored samples of plasma from adult patients who had been receiving PIs. Non-detectable concentrations (ND) were <25-50 ng/mL. In 96 out of 293 stored samples from adult patients, selected randomly, concentrations of PIs were ND. In a second prospective study of 10 adults (9 mothers and one father, aged 24-42 years) and 15 children (2.9-18 years) ND levels of PI were observed frequently (27% or 4 out of 15 pediatric subjects). In the latter study, drug-drug interactions, dosing errors, noncompliance and other important problems were identified and corrected. Routine monitoring and interpretation of PI concentrations (TDM) may improve the management of adult and pediatric patients infected with HIV, especially in those who fail to respond, develop adverse effects or viral resistance, or lack compliance.

Clinical use of a simultaneous HPLC assay for indinavir, saquinavir, ritonavir, and nelfinavir in children and adults.

Protease inhibitor (PI) monitoring may improve the care of human immunodeficiency virus (HIV)-infected patients; however, pediatric data are limited. A high-performance liquid chromatographic (HPLC) assay developed for the simultaneous determination of indinavir, ritonavir, saquinavir, and nelfinavir in 0.2 mL of plasma was used to quantify PI concentrations in HIV patients. The reliability, sensitivity, and specificity of the assay were first verified in stored adult samples. Later, blood collected prospectively from patients aged 2.9 to 42 years of age (10 adults aged 24 to 42 and 15 children aged 2.9 to 18 years) was tested. Nondetectable (below 25-50 ng/mL) concentrations (ND) were found in 33% of adult samples and 24% of pediatric samples. Four patients taking from 13.7 to 28 mg/kg/d of ritonavir (mean of 21.3) had concentrations ranging from ND to 11.4 microg/mL, quite different from predicted values. Correctable, important clinical problems including drug-drug interactions, drug administration problems, and confirmed noncompliance were identified and corrected using modern therapeutic drug monitoring (TDM) techniques. Routine PI monitoring and interpretation (TDM) could improve the care of adult and pediatric HIV patients; especially in patients who do not respond as expected to treatment, develop viral resistance or toxicity, and have questionable compliance.