Congenital deficiency reveals critical role of ISG15 in skin homeostasis

Ulcerating skin lesions are manifestations of human ISG15 deficiency, a type I interferonopathy. However, chronic inflammation may not be their exclusive cause. We describe two siblings with recurrent skin ulcers that healed with scar formation upon corticosteroid treatment. Both had a homozygous nonsense mutation in the ISG15 gene, leading to unstable ISG15 protein lacking the functional domain. We characterized ISG15(-/-) dermal fibroblasts, HaCaT keratinocytes, and human induced pluripotent stem cell-derived vascular endothelial cells. ISG15-deficient cells exhibited the expected hyperinflammatory phenotype, but also dysregulated expression of molecules critical for connective tissue and epidermis integrity, including reduced collagens and adhesion molecules, but increased matrix metalloproteinases. ISG15(-/-) fibroblasts exhibited elevated ROS levels and reduced ROS scavenger expression. As opposed to hyperinflammation, defective collagen and integrin synthesis was not rescued by conjugation-deficient ISG15. Cell migration was retarded in ISG15(-/-) fibroblasts and HaCaT keratinocytes, but normalized under ruxolitinib treatment. Desmosome density was reduced in an ISG15(-/-) 3D epidermis model. Additionally, there were loose architecture and reduced collagen and desmoglein expression, which could be reversed by treatment with ruxolitinib/doxycycline/TGF-beta 1. These results reveal critical roles of ISG15 in maintaining cell migration and epidermis and connective tissue homeostasis, whereby the latter likely requires its conjugation to yet unidentified targets

Allele-Level KIR Genotyping of More Than a Million Samples: Workflow, Algorithm, and Observations

The killer-cell immunoglobulin-like receptor (KIR) genes regulate natural killer cell activity, influencing predisposition to immune mediated disease, and affecting hematopoietic stem cell transplantation (HSCT) outcome. Owing to the complexity of the KIR locus, with extensive gene copy number variation (CNV) and allelic diversity, high-resolution characterization of KIR has so far been applied only to relatively small cohorts. Here, we present a comprehensive high-throughput KIR genotyping approach based on next generation sequencing. Through PCR amplification of specific exons, our approach delivers both copy numbers of the individual genes and allelic information for every KIR gene. Ten-fold replicate analysis of a set of 190 samples revealed a precision of 99.9%. Genotyping of an independent set of 360 samples resulted in an accuracy of more than 99% taking into account consistent copy number prediction. We applied the workflow to genotype 1.8 million stem cell donor registry samples. We report on the observed KIR allele diversity and relative abundance of alleles based on a subset of more than 300,000 samples. Furthermore, we identified more than 2,000 previously unreported KIR variants repeatedly in independent samples, underscoring the large diversity of the KIR region that awaits discovery. This cost-efficient high-resolution KIR genotyping approach is now applied to samples of volunteers registering as potential donors for HSCT. This will facilitate the utilization of KIR as additional selection criterion to improve unrelated donor stem cell transplantation outcome. In addition, the approach may serve studies requiring high-resolution KIR genotyping, like population genetics and disease association studies

Negative thermal expansion in the Kondo system Ce_xLa_1−xAl₂

Measurements of the thermal expansion, α(T), between 0.05 and 370 K are reported for the Kondo system CexLa1−xAl2 with 0.07 ⩽ x ⩽ 1. As the most intriguing result we find for all samples a negative α(T) anomaly at sufficiently low temperatures. Our data suggest this anomaly to be a single-ion property. A natural explanation is furnished by a local Fermi-liquid picture

Thermal expansion of La_1−x Ce_xB₆ single crystals

The single-ion Kondo effect in La1−x CexB6 (0 0.8, whereas antiferromagnetic order seems to exist for x ≳ 0.5

Thermal expansion study of magnetic phase transitions in Kondo-lattice systems

High precision measurements of the thermal expansion coefficient, α(T), of the Kondo lattice systems CeAl2 and CeB6 reveal the coexistence of two second-order phase transitions at the Néel temperaturesT N =3.9 K and 2.35 K, respectively. These results are discussed with regard to the complex antiferromagnetic order known from neutron diffraction experiments on both compounds. For CeIn3, a Kondo lattice with simpler magnetic structure, only one discontinuity in α(T) occurs atT N ≃10 K