The lack of either IRF9, or STAT2, has surprisingly little effect on human natural killer cell development and function.

Analysis of genetically defined immunodeficient patients allows study of the effect of the absence of specific proteins on human immune function in real-world conditions. Here we have addressed the importance of type I interferon signalling for human NK cell development by studying the phenotype and function of circulating NK cells isolated from patients suffering primary immunodeficiency disease due to mutation of either the human interferon regulatory factor 9 (IRF9) or the signal transducer and activator of transcription 2 (STAT2) genes. IRF9, together with phosphorylated STAT1 and STAT2, form a heterotrimer called interferon stimulated gene factor 3 (ISGF3) which promotes the expression of hundreds of IFN-stimulated genes that mediate antiviral function triggered by exposure to type I interferons. IRF9- and STAT2-deficient patients are unable to respond efficiently to stimulation by type I interferons and so our experiments provide insights into the importance of type I interferon signalling and the consequences of its impairment on human NK cell biology. Surprisingly, the NK cells of these patients display essentially normal phenotype and function.

Genetics of inborn errors of immunity: Diagnostic strategies and new approaches to CNV detection.

BACKGROUND: Genetic diagnosis of inborn errors of immunity (IEI) is complex due to the large number of genes involved and their molecular features. Missense variants have been reported as the most common cause of IEI. However, the frequency of copy number variants (CNVs) may be underestimated since their detection requires specific quantitative techniques. At this point, the use of Next Generation Sequencing (NGS) is acquiring relevance. METHODS: In this article, we present our experience in the genetic diagnosis of IEI based on three diagnostic algorithms that allowed the detection of single nucleotide variants (SNVs) and CNVs. Following this approximation, 703 index cases were evaluated between 2014 and 2021. Sanger sequencing, MLPA, CGH array, breakpoint spanning PCR or a customized NGS-based multigene-targeted panel were performed. RESULTS: A genetic diagnosis was reached in 142 of the 703 index cases (20%), 19 of them presented deletions as causal variants. Deletions were also detected in 5 affected relatives and 16 healthy carriers during the family studies. Additionally, we compile, characterize and present all the CNVs detected by our diagnostic algorithms, representing the largest cohort of deletions related to IEI to date. Furthermore, three bioinformatic tools (LACONv, XHMM, VarSeq™) based on NGS data were evaluated. VarSeq™ was the most sensitive and specific bioinformatic tool; detecting 21/23 (91%) deletions located in captured regions. CONCLUSION: Based on our results, we propose a strategy to guide the molecular diagnosis that can be followed by expert and non-expert centres in the field of IEI.

Trends in cord blood banking.

BACKGROUND: Umbilical cord blood (UCB) is a source of hematopoietic precursor cells for transplantation. The creation of UCB banks in 1992 led to the possibility of storing units of UCB for unrelated transplants. The distribution of cell contents in historical inventories is not homogenous and many units are not, therefore, suitable for adults. The aim of this study was to analyse our UCB bank inventory, evaluate the units released for transplantation and calculate the cost of the current process per unit of UCB stored. METHODS: Three study periods were defined. In the first period, from January 1996 to January 2006, the total nucleated cell (TNC) count acceptable for processing was 4-6×10(8) and a manual processing system was used. In the second period, from October 2006 to July 2010, processing was automated and the acceptable TNC count varied from 8-10×10(8). In the third period, from January 2009 to June 2010, an automated Sepax-BioArchive procedure was used and the accepted initial TNC count was >10×10(8). Within each period the units were categorised according to various ranges of cryopreserved TNC counts in the units: A, >16.2×10(8); B1, from 12.5-16.1×10(8); B2, from 5.2-12.4×10(8); and C, <5.1×10(8). RESULTS: The third period is best representative of current practices, with homogenous TNC acceptance criteria and automated processing. In this period 15.7% of the units were category A and 25.5% were category B. Overall, the mean TNC count of units released for transplantation was 14×10(8) (range, 4.6×10(8) to 36.5×10(8)). The cost of the processed UCB in 2009 was 720.41 euros per unit. CONCLUSION: An UCB bank should store units of high-quality, in terms of the TNC count of units issued for transplantation, have a training programme to optimise the selection of donors prior to delivery, use similar volume reduction systems and homogenous recovery indices, express its indicators in the same units, use validated analytical techniques, and bear in mind ethnic minorities.