With the aim to individuate alleles that may reflect a higher susceptibility to the disease, in the present study we analyzed the HLA allele frequency distribution in a group of 99 Italian patients ...affected by a severe or extremely severe form of COVID‐19. After the application of Bonferroni's correction for multiple tests, a significant association was found for HLA‐DRB1*15:01, ‐DQB1*06:02 and ‐B*27:07, after comparing the results to a reference group of 1017 Italian individuals, previously typed in our laboratory. The increased frequencies observed may contribute to identify potential markers of susceptibility to the disease, although controversial results on the role of single HLA alleles in COVID‐19 patients have been recently reported.
Allogeneic hematopoietic stem cell transplantation (HSCT) represents a curative treatment for many patients with hematological malignant or non-malignant disorders. Evaluation of potential donors for ...HSCT includes a rigorous assessment of the human leukocyte antigens (HLA) match status of family members, and the identification of suitable unrelated donors. Genes encoding transplantation antigens are placed both within and outside the major histocompatibility complex (MHC). The human MHC is located on the short arm of chromosome 6 and contains a series of genes encoding two distinct types of highly polymorphic cell surface glycoproteins. Donors for HSCT are routinely selected based on the level of matching for HLA-A, -B, -C, -DRB1, and -DQB1 loci. However, disease relapse, graft-versus-host-disease, and infection remain significant risk factors of morbidity and mortality. In the same breath, in high-risk patients, graft-versus-leukemia effects inherent in HLA mismatching play a substantial immunological role to limit the recurrence of post-transplant disease. The definition of a suitable donor is ever changing, shaped not only by current typing technology, but also by the specific transplant procedure. Indeed, a more complete understanding of permissible HLA mismatches and the role of Killer Immunoglobulin-like receptors' genes increases the availability of HLA-haploidentical and unrelated donors.
Luminex-based technology has been applied to discriminate between the different Human Leukocyte Antigens (HLA) alleles. The typing method consists in a reverse-SSO assay: Target DNA is PCR-amplified ...using biotinylated group-specific primers. A single PCR reaction is used for each HLA locus. The biotinylated PCR product is chemically denatured using a pH change and allowed to rehybridize to complementary DNA probes conjugated to microspheres. These beads are characterized by two internal fluorescent dyes that create a unique combination of color, make them identifiable. Washes are performed to eliminate any additional PCR product that does not exactly match the sequence detected by the probe. The biotinylated PCR product bound to the microsphere is labelled with streptavidin conjugated with R-phycoerythrin (SAPE). A flow analyzer identifies the fluorescent intensity SAPE on each microsphere. Software is used to assign positive or negative reactions based on the strength of the fluorescent signal. The assignment of the HLA typing is based on positive and negative probe reactions compared with published HLA gene sequences. Recently kits characterized by an extensive number of probes/beads designed to potentially reduce the number of ambiguities or to directly lead to an allele level typing, have been made available.
This section brings together the files of some of the most important Italian archives where valuable documentation on theatre photography is preserved: indispensable places for research, repositories ...of a precious collective memory. The detailed description of the fonds and archives of these institutions should remind us how important it is to continue to preserve, protect and promote the object of photography, which is often neglected and not 'treated', i.e. protected and catalogued, as it should be for the benefit of the History of the Performing Arts and studies on the art of photography. Keywords: Photography, Italian archives, Iconography, Theatre, Actors.
IL‐10‐producing CD4+ type 1 regulatory T (Tr1) cells, defined based on their ability to produce high levels of IL‐10 in the absence of IL‐4, are major players in the induction and maintenance of ...peripheral tolerance. Tr1 cells inhibit T‐cell responses mainly via cytokine‐dependent mechanisms. The cellular and molecular mechanisms underlying the suppression of APC by Tr1 cells are still not completely elucidated. Here, we defined that Tr1 cells specifically lyse myeloid APC through a granzyme B (GZB)‐ and perforin (PRF)‐dependent mechanism that requires HLA class I recognition, CD54/lymphocyte function‐associated antigen (LFA)‐1 adhesion, and activation via killer cell Ig‐like receptors (KIRs) and CD2. Notably, interaction between CD226 on Tr1 cells and their ligands on myeloid cells, leading to Tr1‐cell activation, is necessary for defining Tr1‐cell target specificity. We also showed that high frequency of GZB‐expressing CD4+ T cells is detected in tolerant patients and correlates with elevated occurrence of IL‐10‐producing CD4+ T cells. In conclusion, the modulatory activities of Tr1 cells are not only due to suppressive cytokines but also to specific cell‐to‐cell interactions that lead to selective killing of myeloid cells and possibly bystander suppression.
Various immunotherapies for the treatment of type 1 diabetes are currently under investigation. Some of these aim to rescue the remaining beta cells from autoimmune attack caused by the disease. ...Among the strategies employed, p53 has been envisaged as a possible target for immunomodulation. We studied the possible effect of p53 activation on Treg subsets and Treg/Teff balance in type 1 diabetes patients' PBMC. Upon p53 activation, we observed an increase in CD8+ Treg and activated CD8+ Teff whilst CD8+ Teff cells significantly decreased in healthy PBMC when stimulated with anti-CD3/CD28. No effect was detected on percentages of CD4+ Treg, while a reduction was seen in CD4+ Teff cells and an increase in activated CD4+ Teff cells. In patients' PBMC, upon p53 activation followed by 6 days of anti-CD3/CD28 stimulation, CD8+ Treg and activated CD8+ Teff were increased while CD8+ Teff were decreased. No differences were detected in the CD4+ counterparts. CD8+ Teff PD1+, CD8+ Teff PD1low were increased upon p53 activation in type 1 diabetics compared to controls while CD8+ Teff PD1high were increased in both groups. The same increased percentages were detected for CD4+ counterparts. CD4+ Treg PD1high cells were decreased in diabetics upon p53 activation at day 6 of anti-CD3/CD28 stimulation. In conclusion, a Teff dysregulation is observed upon p53 activation suggesting that molecules promoting p53 cannot be used for therapy in type 1 diabetics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Human leukocyte antigen (HLA) genes play a key role in the immune response to infectious diseases, some of which are highly prevalent in specific environments, like malaria in sub‐Saharan Africa. ...Former case–control studies showed that one particular HLA‐B allele, B*53, was associated with malaria protection in Gambia, but this hypothesis was not tested so far within a population genetics framework. In this study, our objective was to assess whether pathogen‐driven selection associated with malaria contributed to shape the HLA‐B genetic landscape of Africa. To that aim, we first typed the HLA‐A and ‐B loci in 484 individuals from 11 populations living in different environments across the Sahel, and we analysed these data together with those available for 29 other populations using several approaches including linear modelling on various genetic, geographic and environmental parameters. In addition to relevant signatures of populations’ demography and migrations history in the genetic differentiation patterns of both HLA‐A and ‐B loci, we found that the frequencies of three HLA alleles, B*53, B*78 and A*74, were significantly associated with Plasmodium falciparum malaria prevalence, suggesting their increase through pathogen‐driven selection in malaria‐endemic environments. The two HLA‐B alleles were further identified, by high‐throughput sequencing, as B*53:01:01 (in putative linkage disequilibrium with one HLA‐C allele, C*04:01:01:01) and B*78:01 in all but one individuals tested, making them appropriate candidates to malaria protection. These results highlight the role of environmental factors in the evolution of the HLA polymorphism and open key perspectives for functional studies focusing on HLA peptide‐binding properties.
Type 1 diabetes is an autoimmune disease, in which pancreatic β cells are destroyed by autoreactive T cells in genetically predisposed individuals. Serum beta cell autoantibody specificities have ...represented the mainstay for classifying diabetes as autoimmune-mediated and for stratifying risk in first-degree relatives. In recent years, approaches were attempted to solve the difficult issue of detecting rare antigen-specific autoreactive T cells and their significance to etiopathogenesis such as the use of the MHC multimer technology. This tool allowed the specific detection of increased percentages of GAD65 autoreactive T cells by means of HLA A*02:01 GAD65 AA 114-122 pentamers in newly diagnosed diabetics. Here we provide evidence that GAD65 AA 114-122 pentamers can depict a GAD65 AA114-122 peptide expandable population of functionally and phenotypically skewed, preliminary characterized CD3-CD8dullCD56+ 'memory-like' NK cells in PBMC of newly diagnosed diabetics. Our data suggest that the NK cell subset could bind the HLA class I GAD65 AA 114-122 pentamer through ILT2 inhibitory receptor. CD107a expression revealed increased degranulation of CD3-CD8dullCD56+ NK cells in GAD65 AA 114-122 and FLU peptide expanded peripheral blood mononuclear cells of diabetics following GAD65 AA 114-122 peptide HLA A*02:01 presentation in respect to the unpulsed condition. CD107a expression was enriched in ILT2 positive NK cells. As opposite to basal conditions where similar percentages of CD3-CD56+ILT2+ cells were detected in diabetics and controls, CD3-CD56+CD107a+ and CD3-CD56+ILT2+CD107a+ cells were significantly increased in T1D PBMC either GAD65 AA 114-122 or FLU peptides stimulated after co-culture with GAD65 AA 114-122 pulsed APCs. As control, healthy donor NK cells showed similar degranulation against both GAD65 AA 114-122 pulsed and unpulsed APCs. The pathogenetic significance of the CD3-CD8dullCD56+ 'memory-like NK cell subset' with increased response upon secondary challenge in diabetics remains to be elucidated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The 17th International HLA and Immunogenetics Workshop (IHIW) organizers conducted a Pilot Study (PS) in which 13 laboratories (15 groups) participated to assess the performance of the various ...sequencing library preparation protocols, NGS platforms and software in use prior to the workshop. The organizers sent 50 cell lines to each of the 15 groups, scored the 15 independently generated sets of NGS HLA genotyping data, and generated “consensus” HLA genotypes for each of the 50 cell lines. Proficiency Testing (PT) was subsequently organized using four sets of 24 cell lines, selected from 48 of 50 PS cell lines, to validate the quality of NGS HLA typing data from the 34 participating IHIW laboratories. Completion of the PT program with a minimum score of 95% concordance at the HLA-A, HLA-B, HLA-C, HLA-DRB1 and HLA-DQB1 loci satisfied the requirements to submit NGS HLA typing data for the 17th IHIW projects. Together, these PS and PT efforts constituted the 17th IHIW Quality Control project. Overall PT concordance rates for HLA-A, HLA-B, HLA-C, HLA-DPA1, HLA-DPB1, HLA-DQA1, HLA-DQB1, HLA-DRB1, HLA-DRB3, HLA-DRB4 and HLA-DRB5 were 98.1%, 97.0% and 98.1%, 99.0%, 98.6%, 98.8%, 97.6%, 96.0%, 99.1%, 90.0% and 91.7%, respectively. Across all loci, the majority of the discordance was due to allele dropout. The high cost of NGS HLA genotyping per experiment likely prevented the retyping of initially failed HLA loci. Despite the high HLA genotype concordance rates of the software, there remains room for improvement in the assembly of more accurate consensus DNA sequences by NGS HLA genotyping software.
PDF
