Transient anti-cytokine autoantibodies superimpose the hyperinflammatory response in Kawasaki disease and multisystem inflammatory syndrome in children: a comparative cohort study on correlates of disease.

BACKGROUND: Children with SARS-CoV-2 related Multisystem Inflammatory Syndrome in Children (MIS-C) often present with clinical features that resemble Kawasaki disease (KD). Disease severity in adult COVID-19 is associated to the presence of anti-cytokine autoantibodies (ACAAs) against type I interferons. Similarly, ACAAs may be implicated in KD and MIS-C. Therefore, we explored the immunological response, presence of ACAAs and disease correlates in both disorders. METHODS: Eighteen inflammatory plasma protein levels and seven ACAAs were measured in KD (n = 216) and MIS-C (n = 56) longitudinally by Luminex and/or ELISA. Levels (up to 1 year post-onset) of these proteins were related to clinical data and compared with healthy paediatric controls. FINDINGS: ACAAs were found in both patient groups. The presence of ACAAs lagged behind the inflammatory plasma proteins and peaked in the subacute phase. ACAAs were mostly directed against IFN-γ (>80%) and were partially neutralising at best. KD presented with a higher variety of ACAAs than MIS-C. Increased levels of anti-IL-17A (P = 0·02) and anti-IL-22 (P = 0·01) were inversely associated with ICU admission in MIS-C. Except for CXCL10 in MIS-C (P = 0·002), inflammatory plasma proteins were elevated in both KD and MIS-C. Endothelial angiopoietin-2 levels were associated with coronary artery aneurysms in KD (P = 0·02); and sCD25 (P = 0·009), angiopoietin-2 (P = 0·001), soluble IL-33-receptor (ST2, P = 0·01) and CXCL10 (P = 0·02) with ICU admission in MIS-C. INTERPRETATION: Markers of endothelial activation (E-selectin, angiopoietin-2), and innate and adaptive immune responses (macrophages [CD163, G-CSF], neutrophils [lipocalin-2], and T cells [IFN-γ, CXCL10, IL-6, IL-17]), are upregulated in KD and MIS-C. ACAAs were detected in both diseases and, although only partly neutralising, their transient presence and increased levels in non-ICU patients may suggest a dampening role on inflammation. FUNDING: The Kawasaki study is funded by the Dutch foundation Fonds Kind & Handicap and an anonymous donor. The sponsors had no role in the study design, analysis, or decision for publication.

Inflammatory responses in SARS-CoV-2 associated Multisystem Inflammatory Syndrome and Kawasaki Disease in children: An observational study.

Multisystem Inflammatory Syndrome in Children (MIS-C) is a severe inflammatory disease in children related to SARS-CoV-2 with multisystem involvement including marked cardiac dysfunction and clinical symptoms that can resemble Kawasaki Disease (KD). We hypothesized that MIS-C and KD might have commonalities as well as unique inflammatory responses and studied these responses in both diseases. In total, fourteen children with MIS-C (n=8) and KD (n=6) were included in the period of March-June 2020. Clinical and routine blood parameters, cardiac follow-up, SARS-CoV-2-specific antibodies and CD4+ T-cell responses, and cytokine-profiles were determined in both groups. In contrast to KD patients, all MIS-C patients had positive Spike protein-specific CD3+CD4+ T-cell responses. MIS-C and KD patients displayed marked hyper-inflammation with high expression of serum cytokines, including the drug-targetable interleukin (IL)-6 and IFN-γ associated chemokines CXCL9, 10 and 11, which decreased at follow-up. No statistical differences were observed between groups. Clinical outcomes were all favourable without cardiac sequelae at 6 months follow-up. In conclusion, MIS-C and KD-patients both displayed cytokine-associated hyper-inflammation with several high levels of drug-targetable cytokines.

Bone mineral density in children and adolescents with Prader-Willi syndrome: a longitudinal study during puberty and 9 years of growth hormone treatment.

CONTEXT: Longitudinal data on bone mineral density (BMD) in children and adolescents with Prader-Willi Syndrome (PWS) during long-term GH treatment are not available. OBJECTIVE: This study aimed to determine effects of long-term GH treatment and puberty on BMD of total body (BMDTB), lumbar spine (BMDLS), and bone mineral apparent density of the lumbar spine (BMADLS) in children with PWS. DESIGN AND SETTING: This was a prospective longitudinal study of a Dutch PWS cohort. PARTICIPANTS: Seventy-seven children with PWS who remained prepubertal during GH treatment for 4 years and 64 children with PWS who received GH treatment for 9 years participated in the study. INTERVENTION: The children received GH treatment, 1 mg/m(2)/day (≅ 0.035 mg/kg/d). MAIN OUTCOME MEASURES: BMDTB, BMDLS, and BMADLS was measured by using the same dual-energy x-ray absorptiometry machine for all annual measurements. RESULTS: In the prepubertal group, BMDTB standard deviation score (SDS) and BMDLSSDS significantly increased during 4 years of GH treatment whereas BMADLSSDS remained stable. During adolescence, BMDTBSDS and BMADLSSDS decreased significantly, in girls from the age of 11 years and in boys from the ages of 14 and 16 years, respectively, but all BMD parameters remained within the normal range. Higher Tanner stages tended to be associated with lower BMDTBSDS (P = .083) and a significantly lower BMADLSSDS (P = .016). After 9 years of GH treatment, lean body mass SDS was the most powerful predictor of BMDTBSDS and BMDLSSDS in adolescents with PWS. CONCLUSIONS: This long-term GH study demonstrates that BMDTB, BMDLS, and BMADLS remain stable in prepubertal children with PWS but decreases during adolescence, parallel to incomplete pubertal development. Based on our findings, clinicians should start sex hormone therapy from the age of 11 years in girls and 14 years in boys unless there is a normal progression of puberty.

High activity of fatty acid oxidation enzymes in human placenta: implications for fetal-maternal disease.

As the human fetus and placenta are considered to be primarily dependent on glucose oxidation for energy metabolism, the cause of the remarkable association between severe maternal pregnancy complications and the carriage of a fetus with an inborn error of mitochondrial long-chain fatty acid oxidation (FAO) has remained obscure. We analysed human term placenta and chorionic villus samples for the activities of a variety of enzymes involved in FAO, and compared the results with those obtained in human liver. All enzymes were found to be expressed, with a very high activity of two enzymes involved in the metabolism of long-chain fatty acids (CPT2 and VLCAD), whereas the activity of medium-chain acyl-CoA dehydrogenase (MCAD) was found to be low, when compared to liver. These results suggest that fatty acid oxidation may play an important role in energy generation in human placenta, and that a deficiency in the placental oxidation of long-chain FAO may result in placental dysfunction, thus causing gestational complications.