Management of well appearing infants born to afebrile mothers with inadequate GBS prophylaxis: A retrospective comparison of the three approaches recommended by the COFN.

BACKGROUND: There are three different approaches set forth by the Committee on the Fetus and Newborn (COFN) for managing asymptomatic neonates born to mothers with inadequate intrapartum antibiotic prophylaxis (IAP) for early-onset Group B Strep (GBS) infection. The first approach is that of categorical risk factor assessments, and recommends that asymptomatic infants born to afebrile mothers with inadequate IAP for GBS be monitored with clinical observation for 36-48 hours. The second approach recommends serial physical examinations and vital signs for 36-48 hours to closely monitor changes in clinical condition for all patients. The Kaiser Permanente EOS risk calculator (SRC) is an example of the third approach, a multivariate risk assessment, and it takes into consideration several perinatal risk factors. This multivariate risk assessment then provides recommendations for reassessment and management based on presume risk of the infant developing or having Early Onset Sepsis (EOS). The aim of our study was to compare these three recently published recommendations from the COFN for the management of asymptomatic neonates born to afebrile mothers with inadequate IAP for GBS. STUDY DESIGN: This is a retrospective study of asymptomatic neonates with gestational age ≥35 weeks born to afebrile mothers with indicated inadequate IAP for GBS between April 2017 and July 2020. Management recommendations of the SRC were compared to the recommendations of categorical risk assessment and risk assessment based on clinical condition. RESULTS: A total of 7,396 infants were born during the study period, 394 (5.3%. to mothers with inadequate IAP. Recommendations for these infants according to both the categorical risk factor guideline and the clinical condition guideline include extended, close observation. However, the SRC recommended routine newborn care for 99.7%.f these infants. None of the infants developed EOS. CONCLUSION: The SRC recommend routine neonatal care without enhanced and prolonged observation for nearly all asymptomatic infants born to afebrile mothers with inadequate IAP. As none of the infants in this cohort had EOS, further studies in a larger cohort are needed to establish the safety of SRC in neonates born to mothers with inadequate IAP.

Management of infants born to mothers with chorioamnionitis: A retrospective comparison of the three approaches recommended by the committee on fetus and newborn.

BACKGROUND: Based on the most recently published recommendations from the Committee on the Fetus and Newborn (COFN), three approaches currently exist for the use of risk factors to identify infants who are at increased risk of early-onset sepsis (EOS). Categorical risk factor assessments recommend laboratory testing and empiric antibiotic therapy for all infants born to mothers with a clinical diagnosis of chorioamnionitis. Risk assessments based on clinical condition recommend frequent examinations and close vital sign monitoring for infants born to mothers with chorioamnionitis. The Kaiser Permanente EOS risk calculator (SRC) is an example of the third approach, multivariate risk assessments. The aim of our study was to compare the three risk stratification approaches recommended by the COFN for management of chorioamnionitis-exposed infants. METHODS: Retrospective study of 1,521 infants born ≥35 weeks to mothers with chorioamnionitis. Management recommendations of the SRC were compared to the recommendations of categorical risk assessment and risk assessment based on clinical condition (CCA). RESULTS: Hypothetical application of SRC and CCA resulted in 79.6% and 76.8-85.1% respectively fewer infants allocated empiric antibiotic therapy. While CCA recommended enhanced observation for all chorioamnionitis-exposed infants, SRC recommended routine care without enhanced observation in 44.3% infants. For the six infants (0.39%) with EOS, SRC and CCA recommended empiric antibiotics only for three symptomatic infants. CONCLUSION: The SRC and CCA can reduce antibiotic use but potentially delay antibiotic treatment. The SRC does not recommend enhanced observation with frequent and prolonged vital signs for >44% of chorioamnionitis-exposed infants.

Utility of measuring direct bilirubin at first 72 h of age in neonates admitted to the neonatal intensive care unit.

OBJECTIVE: To assess the utility of measuring direct bilirubin (DB) during the first 72 h of life in infants admitted to the neonatal intensive care unit (NICU). STUDY DESIGN: Infants born between May 2006 and June 2013, and admitted to the NICU were included. Abnormal DB was defined as: DB level⩾1 mg dl-1 with a corresponding TB of ⩽5 mg dl-1 or DB level >20% of the corresponding TB>5 mg dl-1. RESULTS: The DB levels were measured in 3715 infants during the first 72 h of life. Sixty-three infants (1.7%) had abnormal DB. In a number of infants with potentially treatable diseases (biliary atresia and choledochal cyst), the only abnormal finding was a mildly elevated DB (1 to 2 mg dl-1) during the first 3 days of life. In 22 infants (35%), the cause for high DB was unknown (16%) or not investigated (19%). CONCLUSIONS: Routine measurement of DB in neonates admitted to NICU may be helpful in identifying potentially treatable causes of cholestasis.

CD4 is expressed by epidermal Langerhans' cells predominantly as covalent dimers.

Langerhans' cells (LC) of skin are CD4 expressing, dendritic, antigen-presenting cells, that are essential for activation of primary immune responses and are productively infected by HIV. We have shown previously that lymphocytes and monocytes express CD4 both as monomers and covalently linked homodimers. In those cells the 55-kDa monomer structure predominates. LC in un-fractionated human epidermal cell (EC) suspension also expresses both forms of CD4, but in EC the dimer form is predominant. Because isolation of LC into single cell suspension by trypsin, as is routinely used for LC isolation, degrades CD4, a systematic study for an alternate procedure for LC isolation was performed. Thus it was found that collagenase blend F treatment can efficiently release LC into suspension, under conditions of only minimal degradation of control soluble recombinant CD4 or CEM-T4 or THP-1 cell CD4, or importantly of LC surface CD4. SDS-PAGE immunoblotting of purified LC extracted from EC by collagenase confirmed CD4 structure as predominantly 110-kDa dimers, with only minimal 55-kDa monomers. The suitability of LC prepared thus for functional studies was demonstrated with binding of functional ligand HIV gp120. It remains to be determined, however, why tissue embedded LC express mainly CD4 dimers, but single-celled blood lymphocytes and monocytes mainly monomers.

Direct evidence for native CD4 oligomers in lymphoid and monocytoid cells.

CD4 is expressed by T lymphocytes and monocytes and is generally considered a monomer even though its structure was originally modelled on the REI Bence-Jones homodimer. However, native CD4 was demonstrated as both monomer and dimers of 55 and 110 kDa in lymphoid and monocytoid cells by immunoprecipitation and immunoblotting after solubilization with alkylating (iodoacetamide) or reducing (dithiothreitol, 2-mercaptoethanol) reagents. Full reduction yielded only the 55-kDa monomeric form. Purified CD4 oligomers from CEM-T4 cells were also resolved as homodimers by MALDI-Tof mass fingerprinting after tryptic digestion. Cell treatment with the membrane impermeable, free-thiol reactive, 5,5'-dithiobis-2-nitrobenzoic acid enhanced cell surface CD4 dimers and tetramers. The interaction sites producing dimerization were probably in the D4 domain as OKT4 inhibited self association of recombinant CD4 (rCD4). Oligomerization of rCD4 by glutathione and thioredoxin indicates that thiol exchange interactions were responsible. Enhanced CD4 dimer expression was also observed after PMA (20 ng/ml) activation of THP-1 cells. These findings demonstrate that different quaternary forms of CD4 such as monomers, homodimers and tetramers are expressed by T lymphocytes and monocytes/macrophages.

Analysis of recombinant and native CD4 by one- and two-dimensional gel electrophoresis.

Knowledge of CD4 conformation within the membranes of human lymphoid and monocytoid cells is essential for a clear understanding of its function as a ligand for major histocompatibility complex II (MHC) molecules in T cell activation and for gp120 in human immunodeficiency virus (HIV) infection. The charge and structure of native (nCD4) and soluble recombinant CD4 (rCD4) were examined by one- and two-dimensional (2-DE) electrophoresis antigen mapping and silver staining. Recombinant CD4 was partitioned by nonequilibrium pH gradient electrophoresis (NEPHGE) and revealed a number of differentially charged 44 kDa species (pI > 9.5). Biotinylation (4 h, room temperature) of rCD4 yielded a single labelled species on sodium dodedyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with an increased apparent molecular mass to 50 kDa, consistent with a maximal incorporation of approximately 18 molecules of biotin per rCD4 molecule. The milder biotinylation (15 min, 4 degrees C) of cell-(CEM-T4, THP-1) expressed CD4 was not accompanied by any apparent alteration in molecular weight, nor abrogation of CD4 antigenicity. This was determined by isolation of nCD4 by immunoprecipitation and SDS-PAGE immunoblotting, using anti-CD4 mAbs (leu3a, OKT4A, Q4120, T4, OKT4, Q425) and by flow cytometry (leu4a, T4). The immunoprecipitation of full-length native CD4 from lymphoid MT2 and CEM-T4 cell extracts, however, revealed both monomeric and higher-order CD4 antigen complexes by immunoblotting. These studies describe the biotinylation, 1-DE and 2-DE of CD4 preparations, and indicate the capacity of CD4 of lymphocytes to form complexes which may influence CD4 conformation and epitope availability.