Christof Senger

Impaired NLRP3 inflammasome activity during fetal development regulates IL-1β production in human monocytes.

Interleukin‐1β (IL‐1β) production is impaired in cord blood monocytes. However, the mechanism underlying this developmental attenuation remains unclear. Here, we analyzed the extent of variability within the Toll‐like receptor (TLR)/NLRP3 inflammasome pathways in human neonates. We show that immature low CD14 expressing/CD16pos monocytes predominate before 33 weeks of gestation, and that these cells lack production of the pro‐IL‐1β precursor protein upon LPS stimulation. In contrast, high levels of pro‐IL‐1β are produced within high CD14 expressing monocytes, although these cells are unable to secrete mature IL‐1β. The lack of secreted IL‐1β in these monocytes parallels a reduction of NLRP3 induction following TLR stimulation resulting in a lack of caspase‐1 activity before 29 weeks of gestation, whereas expression of the apoptosis‐associated speck‐like protein containing a CARD and function of the P2×7 receptor are preserved. Our analyses also reveal a strong inhibitory effect of placental infection on LPS/ATP‐induced caspase‐1 activity in cord blood monocytes. Lastly, secretion of IL‐1β in preterm neonates is restored to adult levels during the neonatal period, indicating rapid maturation of these responses after birth. Collectively, our data highlight important developmental mechanisms regulating IL‐1β responses early in gestation, in part due to a downregulation of TLR‐mediated NLRP3 expression. Such mechanisms may serve to limit potentially damaging inflammatory responses in a developing fetus.

Rituximab Treatment in a Child with Rosai-Dorfman Disease and Systemic Lupus Erythematosus

To the Editor: Rosai-Dorfman disease (RDD) is a rare disorder in childhood. The association of RDD and systemic lupus erythematosus (SLE) is very rare, with only 2 previously reported cases, and neither of these in a child1,2. We describe a child who presented with histopathology-confirmed RDD, and developed SLE 3 years later. A 7-year-old boy of Canadian First Nations background presented at age 4 years to the pediatric hematology/oncology clinic with a 3-month history of asymptomatic, bilateral massive lymphadenopathy involving the cervical, supraclavicular, mediastinal, hilar, and axillary lymph nodes. He has a healthy fraternal twin, and there is no family history of connective tissue diseases. The lymphadenopathy failed to respond to a course of antibiotics. Laboratory tests showed mild microcytic hypochromic anemia with lymphopenia [white blood cells (WBC) 6.29 x 109/l, hemoglobin 103 g/l, mean corpuscular volume 74.3 fl, mean corpuscular hemoglobin 23.5 pg/cell, platelets 262 x 109/l, lymphocytes 0.63 x 109/l, absolute neutrophil count 4.98 x 109/l) and high erythrocyte sedimentation rate, 63 mm/h. Serial chest radiographs showed persistent nonprogressive large bilateral mediastinal, hilar, right infrahilar, and paratracheal lymphadenopathy (Figure 1). Computed tomography scan showed adenopathy, airway narrowing, and atelectasis as well as superior vena cava displacement (Figure … Address correspondence to Dr. Alqanatish; E-mail: jqanatish{at}hotmail.com

New insights into the neuropathogenesis of molybdenum cofactor deficiency

BACKGROUND Molybdenum cofactor deficiency (MOCOD) is a rare, progressive neurodegenerative disorder caused by sulphite oxidase enzyme deficiency. The neuropathological findings are consistent with a toxic insult to the brain that causes severe neuronal loss, reactive astrogliosis and spongiosis. The mechanisms responsible for these changes are unknown. METHODS The case is a male infant with MOCOD who died at nine months of age from pneumonia. At autopsy, a complete neuropathological examination was performed including conventional immunohistochemical staining. In addition, brain sections were stained cytochemically with shikata and orcein which stain for disulphide bonds. The elemental composition of cortical cells was then analyzed in the scanning electron microscope using backscatter electron imaging and energy dispersive X-ray spectrometry. RESULTS Neurons demonstrated cytoplasmic staining with shikata and orcein cytochemically when compared to control sections. Energy dispersive X-ray spectrometry analysis of these neurons confirmed the presence of excess sulphur and unexpectedly revealed excess magnesium accumulation. None of these findings was found in an age-matched control. CONCLUSIONS In MOCOD we found abnormal accumulation of sulphur and magnesium in neurons. It is postulated that sulphur-containing compound(s) that are formed as a result of MOCOD cause excitotoxic neuronal injury in the presence of excess magnesium.

Hierarchical Maturation of Innate Immune Defences in Very Preterm Neonates

Background: Preterm neonates are highly vulnerable to infection. Objectives: To investigate the developmental contribution of prematurity, chorioamnionitis and antenatal corticosteroids (ANS) on the maturation of neonatal microbial pathogen recognition responses. Methods: Using standardized protocols, we assayed multiple inflammatory cytokine responses (IL-1β, IL-6, TNF-α and IL-12/23p40) to three prototypic Toll-like receptor (TLR) agonists, i.e. TLR4 (lipopolysaccharide), TLR5 (flagellin) and TLR7/8 (R848), and to the non-TLR retinoic acid-inducible gene I (RIG-I)-like receptor agonist, in cord blood mononuclear cells from neonates born before 33 weeks of gestation and at term. Results: TLR responses develop asynchronously in preterm neonates, whereby responses to TLR7/8 were more mature and were followed by the development of TLR4 responses, which were also heterogeneous. Responses to TLR5 were weakest and most immature. Maturity in TLR responses was not influenced by sex. Overall, we detected no significant contribution of ANS and chorioamnionitis to the developmental attenuation of either TLR or RIG-I responses. Conclusions: The maturation of anti-microbial responses in neonates born early in gestation follows an asynchronous developmental hierarchy independently of an exposure to chorioamnionitis and ANS. Our data provide an immunological basis for the predominance of specific microbial infections in this age group.

Diffuse Angiopathy in Adams-Oliver Syndrome Associated With Truncating DOCK6 Mutations

Adams‐Oliver syndrome (AOS) is a rare malformation syndrome characterized by the presence of two anomalies: aplasia cutis congenita of the scalp and transverse terminal limb defects. Many affected individuals also have additional malformations, including a variety of intracranial anomalies such as periventricular calcification in keeping with cerebrovascular microbleeds, impaired neuronal migration, epilepsy, and microcephaly. Cardiac malformations can be present, as can vascular dysfunction in the forms of cutis marmorata telangiectasia congenita, pulmonary vein stenoses, and abnormal hepatic microvasculature. Elucidated genetic causes include four genes in different pathways, leading to a model of AOS as a multi‐pathway disorder. We identified an infant with mild aplasia cutis congenita and terminal transverse limb defects, developmental delay and a severe, diffuse angiopathy with incomplete microvascularization. Whole‐genome sequencing documented two rare truncating variants in DOCK6, a gene associated with a type of autosomal recessive AOS that recurrently features periventricular calcification and impaired neurodevelopment. We highlight an unexpectedly high frequency of likely deleterious mutations in this gene in the general population, relative to the rarity of the disease, and discuss possible explanations for this discrepancy.

Somatic mosaicism for the p.His1047Arg mutation in PIK3CA in a girl with mesenteric lipomatosis

We describe a patient who presented with a localized growth of mature fat tissue, which was surgically removed. MRI imaging identified diffuse increase in visceral adipose tissue. Targeted deep sequencing of the resected tissue uncovered a p.H1047R variant in PIK3CA, which was absent in blood. This report expands the phenotypic spectrum of mosaic PIK3CA mutations.

Abnormal liver transaminases and conjugated hyperbilirubinemia at presentation of acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is the most common malignancy in childhood. While hepatitis is a well‐known complication during the treatment phase of ALL, the association of abnormal liver biochemistries at initial presentation of leukemia is poorly described. The aim of this study is to examine the prevalence and assess the clinical impact of hepatitis at diagnosis in children with ALL.

Successful approach to treatment of Helicobacter bilis infection in X-linked agammaglobulinemia.

Helicobacter bilis, an unusual cause of chronic infections in patients with X-linked agammaglobulinemia (XLA), is notoriously difficult to diagnose and eradicate. Based on the limited number of cases reported worldwide, we highlight the typical features of H. bilis infection in XLA and provide a rational and successful approach to diagnosis and treatment of this challenging infection.

The role of angiogenesis in the transformation of plexiform neurofibroma into malignant peripheral nerve sheath tumors in children with neurofibromatosis type 1.

Purpose The role of angiogenesis in the transformation of peripheral neurofibroma (PNF) to malignant peripheral nerve sheath tumor (MPNST) in neurofibromatosis type 1 (NF1) remains elusive and forms the objective of this study. Experimental Design Archival tissue from 5 children with NF1 and PNF, who developed MPNST between the ages of 8 and 15 years were analyzed for differences in microvasculature. The role of proangiogenic growth factors such as Vascular Endothelial Growth Factor (VEGF), and its receptors Flk-1 and Flt-1, and vessel maturity, defined as von Willebrand factor (vWf), α-smooth muscle actin+ (SMA+), were evaluated by immuno-histochemistry. Results A qualitative evaluation of the vasculature showed predominantly α-SMA+/vWf+ more stable vessels in PNF, and an irregular meshwork of α-SMA−/vWf+ endothelial cells structures in MPNST. In NF and PNF tumor cells were VEGF−, in contrast to VEGF+ tumor cells in MPNST. If present, the VEGF stain was confined mainly to the perivascular spaces in PNF, unlike the mainly stromal VEGF stain in MPNST. VEGF receptors also manifested a tumor stage-specific pattern. Flk-1 and Flt-1 were restricted to the mature, well-formed vasculature in PNF, but exhibited a diffuse pattern in MPNST. Conclusion Our study provides a rare opportunity to document consistent and histologically detectable differences in the vascular organization of PNF and MPNST. It permits a pair-wise evaluation of the malignant conversion of benign PNF into its malignant counterpart, in the same patients. The phenotypic variations and characteristics of the vessels in these tumors are consistent with the idea that a strong proangiogenic drive contributes to the progressive growth in MPNST.

Pre- and postnatal findings in a boy with duplication of the bladder and intestine: report and review.

We describe a boy with a septated bladder and dilated bowel loop found on prenatal ultrasonography. Subsequent prenatal MRI diagnosed a probable caudal duplication anomaly. Postnatal investigations and surgical findings confirmed duplication of bladder, urethra, and bowel from distal ileum to rectum. This is the first reported case of combined bladder and colon duplication suspected antenatally with thorough imaging investigations including fetal MRI. While diagnosis of bladder duplication has been described, prenatal diagnosis of intestinal duplication has not been documented previously. This report of prenatal imaging with surgical and pathological correlation contributes to our detailed understanding of the spectrum of anatomy seen in caudal duplication anomaly.