Publications by authors named "Jojanneke Heidema"

Background: There is a lack of evidence on oral amoxicillin pharmacokinetics and exposure in neonates with possible serious bacterial infection (pSBI). We aimed to describe amoxicillin disposition following oral and intravenous administration and to provide dosing recommendations for preterm and term neonates treated for pSBI.

Methods: In this pooled-population pharmacokinetic study, 3 datasets were combined for nonlinear mixed-effects modeling.

View Article and Find Full Text PDF

Background: Switching from intravenous antibiotic therapy to oral antibiotic therapy among neonates is not yet practised in high-income settings due to uncertainties about exposure and safety. We aimed to assess the efficacy and safety of early intravenous-to-oral antibiotic switch therapy compared with a full course of intravenous antibiotics among neonates with probable bacterial infection.

Methods: In this multicentre, randomised, open-label, non-inferiority trial, patients were recruited at 17 hospitals in the Netherlands.

View Article and Find Full Text PDF

Objectives: While physicians are often confronted with immunoglobulin A (IgA) deficiency in children with recurrent infections, the clinical relevance of this finding is unclear. Large-scale studies examining the significance of IgA deficiency in children are hampered by differences in techniques for measuring IgA and the physiological increase of IgA with age. Both result in a variety of reference values used for diagnosing IgA deficiency.

View Article and Find Full Text PDF

We present a case of a 10-year-old girl diagnosed with Sydenham's chorea. Despite treatment with haloperidol and valproic acid for 2 weeks and antibiotics for 5 days, her symptoms continued to worsen. She became severely impaired in daily functioning, as she could barely speak or walk, experienced major feeding difficulties and required help with all daily activities.

View Article and Find Full Text PDF

An 8-year-old boy presented with a fever, headache, maculopapular rash and painful joints after a vacation in Morocco. He had an eschar on his arm. Under the presumed diagnosis of rickettsiosis he was treated with doxycycline after which his fever subsided.

View Article and Find Full Text PDF

A neonate presented with hypoplasia of the abdominal wall muscles after fetal ascites due to anemia caused by an intra-uterine infection with parvovirus B19. Because this is an extremely rare complication, pathogenesis and prognosis are currently unclear.

View Article and Find Full Text PDF

We determined the dynamics of CD8(+) T cells specific for influenza virus and respiratory syncytial virus in blood and tracheostoma aspirates of children during the course of respiratory infections. We showed that during localized respiratory infections the ratio of activated effector CD8(+) T cells to resting memory/naive CD8(+) T cells in peripheral blood increased significantly. Furthermore, the number of effector/memory T cells specific for respiratory viruses declined in blood and increased in the airways, suggesting that these T cells redistributed from blood to airways.

View Article and Find Full Text PDF

A protective role for CD8+ T cells during viral infections is generally accepted, but little is known about how CD8+ T cell responses develop during primary infections in infants, their efficacy, and how memory is established after viral clearance. We studied CD8+ T cell responses in bronchoalveolar lavage (BAL) samples and blood of infants with a severe primary respiratory syncytial virus (RSV) infection. RSV-specific CD8+ T cells with an activated effector cell phenotype: CD27+CD28+CD45RO+CCR7-CD38+HLA-DR+Granzyme B+CD127- could be identified in BAL and blood.

View Article and Find Full Text PDF

Background: We investigated respiratory syncytial virus (RSV)-specific CD8(+) memory T cell responses in healthy control participants (n=31) and in patients with chronic obstructive pulmonary disease (COPD) (n=9), with respect to frequency, memory phenotype, and proliferative requirements.

Methods: The properties of RSV-specific CD8(+) T cells were analyzed by use of RSV tetramers. The proliferative requirements of RSV-specific CD8(+) T cells were analyzed by culture of peripheral-blood mononuclear cells with RSV peptide in combination with distinct cytokines.

View Article and Find Full Text PDF

CD4 T cells play a crucial role during virus infections by producing antiviral cytokines and by regulating humoral and cellular immune responses. Unfortunately however, exaggerated CD4 T cell responses can cause significant immune-mediated disease as was observed during RSV infections in children previously vaccinated with a formalin-inactivated virus in the 1960s. It has been observed that vaccination with the G protein of RSV tends to prime mice for a similar Th2-mediated enhanced disease.

View Article and Find Full Text PDF

CD8(+) T lymphocytes play a major role in the clearance of respiratory syncytial virus (RSV) infections. To be able to study the primary CTL response in RSV-infected children, epitopes presented by a set of commonly used HLA alleles (HLA-A1, -A3, -B44 and -B51) were searched for. Five epitopes were characterized derived from the matrix (M), non-structural (NS2) and second matrix (M2) proteins of RSV.

View Article and Find Full Text PDF