In preterm neonates the immune system is thought to be less developed at birth, but very little is known about the actual size of lymphocyte subpopulations, and even less about the maturation of these subpopulations during the first months after a premature birth. To evaluate the development of lymphocyte subpopulations in preterm infants during the first 3 months after birth, we performed a prospective longitudinal study in two hospitals in the Netherlands. Preterm neonates (n = 38) of all post‐menstrual ages were included and blood samples were taken from cord blood, and at 1 week, 6 weeks, and 3 months. Lymphocyte subpopulations were measured by four‐colour flow cytometry. The data were compared with follow‐up data obtained in healthy term neonates (n = 8), and with single samples from school age children (n = 5) and adults (n = 5). Overall, we found a similar pattern of post‐natal development of lymphocyte subpopulations in the term and preterm infants. Both B lymphocytes and helper and cytotoxic T lymphocytes mainly consist of naive cells at birth and during the 3 months of follow‐up in all neonatal age groups. So, the preterm immune system seems to be able to generate an outburst of naive T and B lymphocytes from the thymus and bone marrow within the same time span after the start of post‐natal antigenic stimulation from the environment as the term immune system, but, with lower post‐menstrual age, the absolute counts of naive helper T lymphocytes are lower.

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We describe a patient with invasive pulmonary aspergillosis on extracorporeal membrane oxygenation therapy in which therapeutic drug monitoring and individualization of therapy by measuring voriconazole plasma concentrations were performed.

Congenital diaphragmatic hernia (CDH) is a disorder of the development of the lung and diaphragm and is associated with pulmonary hypoplasia and pulmonary hypertension. Denys-Drash syndrome (DDS) is a well-known syndrome caused by several different germline mutations in the WT1-gene. CDH in DDS is rare. We present the third case of CDH with clinical features of DDS and the same, rare Arg366His mutation in the WT1-gene, as reported in the other two known cases. This report provides additional evidence that WT1 mutations can result in diaphragmatic hernia.

Background: Congenital chylothorax (CC) is a severe congenital disorder characterized by the collection of chyle in the pleural space. Recent case reports suggest that the use of octreotide in the treatment of CC may be useful. Objective: To evaluate the effect of octreotide on pleural effusions in CC. Methods: Hospital records of 7 patients with a CC, who were admitted to the Neonatal Intensive Care Unit of the Radboud University Nijmegen Medical Centre between 2006 and 2010 and were treated with octreotide, were retrospectively evaluated. Results: There was no clear and consistent effect of octreotide treatment on pleural effusions. Pleural effusions eventually decreased in all patients after reaching a dose of 5–6 µg/kg/min, but this could also reflect the natural history of CC. Out of 7 patients, 4 were diagnosed with persistent pulmonary hypertension of the newborn. No other known side effects of octreotide were found. There was a mortality rate of 30%. Conclusions: No clear and consistent effect of octreotide was identified. Pulmonary hypertension was a common problem in this patient group. It is not clear whether or not this was caused or maintained by octreotide treatment. A randomized controlled trial is needed to investigate the safety and usefulness of octreotide. Until then, clinicians should be careful in using octreotide, especially when persistent pulmonary hypertension is present.