Characterization of the molecular composition and in vitro regenerative capacity of platelet-based bioproducts and related subfractions.

The use and demand of platelet-based bioproducts in regenerative medicine is steadily increasing. However, it is very difficult to establish the real clinical benefits of these therapies, as the lack of characterization and detailed production methods of platelet-based bioproducts persists in the literature and precludes cross-study comparisons. We characterized the molecular composition and in vitro regenerative capacity of platelet-rich plasma (PRP) produced in a closed-system. Furthermore, we performed a parallel characterization on different PRP subfractions (plasma and plasma-free platelet lysate), identifying that the fractions containing platelet-derived cargo exert the most potent regenerative capacity. This observation led us to develop a method to obtain a platelet secretome highly enriched in growth factors, free of plasma and cellular components (PCT/IB2022/057936), with the aim of establishing a superior bioproduct. The molecular characterization of secretomes revealed agonist-dependent differences, which correlates with beneficial grades of regenerative capacity. Importantly, secretomes showed general superiority to PRP in vitro. We discuss the variables influencing the bioproduct quality (inter-donor variation, platelet source and processing methods). Finally, we propose that the characteristics of secretomes circumvents certain limitations of PRP (autologous vs allogeneic), and envision that optimizing post-processing protocols (nanoencapsulation, lyophilization), would allow their clinical application even beyond regenerative medicine. STATEMENT OF SIGNIFICANCE: The use and demand of platelet-based bioproducts in regenerative medicine is steadily increasing. However, it is very difficult to establish the real clinical benefits of these therapies, or to improve/personalize them, as the lack of characterization of the bioproducts and their production methods is a constant in the literature, reason that precludes cross-study comparisons. In the present manuscript, we provide a comprehensive molecular and functional characterization of platelet-based bioproducts and subfractions, including platelet rich plasma, plasma fractions and platelet secretomes produced with a methodology developed by our group. Our results show that the molecular composition of each fraction correlates with its regenerative capacity in vitro. Thus, a rigorous characterization of platelet-derived bioproducts will potentially allow universal use, customizing and new applications.

Effects of IFIH1 rs1990760 variants on systemic inflammation and outcome in critically ill COVID-19 patients in an observational translational study.

Background: Variants in IFIH1, a gene coding the cytoplasmatic RNA sensor MDA5, regulate the response to viral infections. We hypothesized that IFIH1 rs199076 variants would modulate host response and outcome after severe COVID-19. Methods: Patients admitted to an intensive care unit (ICU) with confirmed COVID-19 were prospectively studied and rs1990760 variants determined. Peripheral blood gene expression, cell populations, and immune mediators were measured. Peripheral blood mononuclear cells from healthy volunteers were exposed to an MDA5 agonist and dexamethasone ex-vivo, and changes in gene expression assessed. ICU discharge and hospital death were modeled using rs1990760 variants and dexamethasone as factors in this cohort and in-silico clinical trials. Results: About 227 patients were studied. Patients with the IFIH1 rs1990760 TT variant showed a lower expression of inflammation-related pathways, an anti-inflammatory cell profile, and lower concentrations of pro-inflammatory mediators. Cells with TT variant exposed to an MDA5 agonist showed an increase in IL6 expression after dexamethasone treatment. All patients with the TT variant not treated with steroids survived their ICU stay (hazard ratio [HR]: 2.49, 95% confidence interval [CI]: 1.29-4.79). Patients with a TT variant treated with dexamethasone showed an increased hospital mortality (HR: 2.19, 95% CI: 1.01-4.87) and serum IL-6. In-silico clinical trials supported these findings. Conclusions: COVID-19 patients with the IFIH1 rs1990760 TT variant show an attenuated inflammatory response and better outcomes. Dexamethasone may reverse this anti-inflammatory phenotype. Funding: Centro de Investigación Biomédica en Red (CB17/06/00021), Instituto de Salud Carlos III (PI19/00184 and PI20/01360), and Fundació La Marató de TV3 (413/C/2021).

Patients with severe COVID-19 often need mechanical ventilation to help them breathe and other types of intensive care. The outcome for many of these patients depends on how their immune system reacts to the infection. If the inflammatory response triggered by the immune system is too strong, this can cause further harm to the patient. One gene that plays an important role in inflammation is IFIH1 which encodes a protein that helps the body to recognize viruses. There are multiple versions of this gene which each produce a slightly different protein. It is possible that this variation impacts how the immune system responds to the virus that causes COVID-19. To investigate, Amado-Rodríguez, Salgado del Riego et al. analyzed the IFIH1 gene in 227 patients admitted to an intensive care unit in Spain for severe COVID-19 between March and December 2020. They found that patients with a specific version of the gene called TT experienced less inflammation and were more likely to survive the infection. Physicians typically treat patients with moderate to severe COVID-19 with corticosteroid drugs that reduce the inflammatory response. However, Amado-Rodríguez, Salgado del Riego et al. found that patients with the TT version of the IFIH1 gene were at greater risk of dying if they received corticosteroids. The team then applied the distribution of IFIH1 variants among different ethnic ancestries to data from a previous clinical trial, and simulated the effects of corticosteroid treatment. This 'mock' clinical trial supported their findings from the patient-derived data, which were also validated by laboratory experiments on immune cells from individuals with the TT gene. The work by Amado-Rodríguez, Salgado del Riego et al. suggests that while corticosteroids benefit some patients, they may cause harm to others. However, a real-world clinical trial is needed to determine whether patients with the TT version of the IFIH1 gene would do better without steroids.

Defining a Methylation Signature Associated With Operational Tolerance in Kidney Transplant Recipients.

Operational tolerance after kidney transplantation is defined as stable graft acceptance without the need for immunosuppression therapy. However, it is not clear which cellular and molecular pathways are driving tolerance in these patients. We performed genome-wide analysis of DNA methylation in peripheral blood mononuclear cells from kidney transplant recipients with chronic rejection and operational tolerance from the Genetic Analysis of Molecular Biomarkers of Immunological Tolerance (GAMBIT) study. Our results showed that both clinical stages diverge in 2737 genes, indicating that each one has a specific methylation signature associated with transplant outcome. We also observed that tolerance is associated with demethylation in genes involved in immune function, including B and T cell activation and Th17 differentiation, while in chronic rejection it is associated with intracellular signaling and ubiquitination pathways. Using co-expression network analysis, we selected 12 genomic regions that are specifically hypomethylated or hypermethylated in tolerant patients. Analysis of these genes in transplanted patients with low dose of steroids showed that these have a similar methylation signature to that of tolerant recipients. Overall, these results demonstrate that methylation analysis can mirror the immune status associated with transplant outcome and provides a starting point for understanding the epigenetic mechanisms associated with tolerance.

Genetic contribution of endoplasmic reticulum aminopeptidase 1 polymorphisms to liver fibrosis progression in patients with HCV infection.

The endoplasmic reticulum aminopeptidase ERAP1 regulates innate and adaptive immune responses, trimming peptides and loading onto HLA class I molecules. Coding single nucleotide polymorphisms within ERAP1 are associated with autoimmune diseases, viral infections, and cancer development. Our purpose was to analyze the influence of ERAP1 variants on fibrogenesis in hepatitis C virus (HCV)-infected patients. A range of ERAP1 polymorphisms were genotyped in 722 unrelated Caucasian patients diagnosed with chronic HCV from two Spanish cohorts. Patients were classified according to their fibrosis stage. Paraffin-embedded tissue microarrays were constructed to assess ERAP1 expression (HCV = 38; alcoholic = 20) by immunohistochemistry. A statistical algorithm was applied to derive a fibrogenesis prediction model. The ERAP1 variants rs30187/T (K528, pc < 0.001) and rs27044/G (Q730, pc < 0.001) were related with severe fibrosis. These results were validated in the two independent cohorts. Furthermore, patients with the rs30187/T allele had stronger ERAP1 protein expression than those with the rs30187/C (p < 0.05). The statistical model showed that patients with rs30187 C/T and T/T genotypes took 15.58 years (median) to develop advanced fibrosis, but this value was 32.08 years in patients carrying C/C genotype (p < 0.005). ERAP1 variants may influence the clinical course of fibrogenesis in HCV-infected patients. These polymorphisms could be exploited as constitutive new markers of fibrosis evolution. The results highlight the possibility of using modulators of ERAP1 to generate a protective immune response against chronic HCV infection. KEY MESSAGES: What is known Several ERAP1 polymorphisms are associated with autoimmune diseases and cancer. ERAP1 trims peptides to HLA class I presentation. What is new here ERAP1 polymorphisms are associated with fibrogenesis. The ERAP1 polymorphisms genotype could help us in clinical management of patients. Potential translational impact The use of modulators of ERAP1 could generate a protective response depending on SNPs.

A Single Nucleotide Polymorphism in the Il17ra Promoter Is Associated with Functional Severity of Ankylosing Spondylitis.

The aim of this study was to identify new genetic variants associated with the severity of ankylosing spondylitis (AS). We sequenced the exome of eight patients diagnosed with AS, selected on the basis of the severity of their clinical parameters. We identified 27 variants in exons and regulatory regions. The contribution of candidate variants found to AS severity was validated by genotyping two Spanish cohorts consisting of 180 cases/300 controls and 419 cases/656 controls. Relationships of SNPs and clinical variables with the Bath Ankylosing Spondylitis Disease Activity and Functional Indices BASDAI and BASFI were analyzed. BASFI was standardized by adjusting for the duration of the disease since the appearance of the first symptoms. Refining the analysis of SNPs in the two cohorts, we found that the rs4819554 minor allele G in the promoter of the IL17RA gene was associated with AS (p<0.005). This variant was also associated with the BASFI score. Classifying AS patients by the severity of their functional status with respect to BASFI/disease duration of the 60th, 65th, 70th and 75th percentiles, we found the association increased from p60 to p75 (cohort 1: p<0.05 to p<0.01; cohort 2: p<0.01 to p<0.005). Our findings indicate a genetic role for the IL17/ILRA axis in the development of severe forms of AS.

Diversity of killer cell immunoglobulin-like receptor (KIR) genotypes and KIR2DL2/3 variants in HCV treatment outcome.

The aim of this study was to analyse the distribution of KIR haplotypes and the KIR2DL2/3 alleles in chronic HCV-infected patients in order to establish the influence on the response to pegylated interferon plus ribavirin classical treatment. The alleles study of previously associated KIR2DL2/3 showed that KIR2DL2*001 was more frequent in non-SVR (NSVR) (42.2% vs. 27.5%, p<0.05) and KIR2DL3*001 was associated with sustained viral response (SVR) (41.6% vs. 61.2%, p<0.005). The KIR2DL3*001-HLA-C1 association was also significant (24.5% vs. 45.7%, p<0.001). From the frequencies of KIR obtained, 35 genotypes were assigned on the basis of previous studies. The centromeric A/A genotype was more frequent in SVR (44.1% vs. 34.5%, p<0.005) and the centromeric B/B genotype was found to be significantly more frequent in NSVR (20.9% vs. 11.2%, p<0.001). The logic regression model showed the importance of KIR genes in predicting the response to combined treatment, since the positive predictive value (PPV) was improved (from 55.9% to 75.3%) when the analysis of KIR was included in addition to the IFNL3 rs12979860 polymorphism. The study of KIR receptors may be a powerful tool for predicting the combined treatment response in patients with chronic HCV infection in association with the determination of IFNL3 polymorphism.

Autoantibodies against MHC class I polypeptide-related sequence A are associated with increased risk of concomitant autoimmune diseases in celiac patients.

BACKGROUND: Overexpression of autologous proteins can lead to the formation of autoantibodies and autoimmune diseases. MHC class I polypeptide-related sequence A (MICA) is highly expressed in the enterocytes of patients with celiac disease, which arises in response to gluten. The aim of this study was to investigate anti-MICA antibody formation in patients with celiac disease and its association with other autoimmune processes. METHODS: We tested serum samples from 383 patients with celiac disease, obtained before they took up a gluten-free diet, 428 patients with diverse autoimmune diseases, and 200 controls for anti-MICA antibodies. All samples were also tested for anti-endomysium and anti-transglutaminase antibodies. RESULTS: Antibodies against MICA were detected in samples from 41.7% of patients with celiac disease but in only 3.5% of those from controls (P <0.0001) and 8.2% from patients with autoimmune disease (P <0.0001). These antibodies disappeared after the instauration of a gluten-free diet. Anti-MICA antibodies were significantly prevalent in younger patients (P <0.01). Fifty-eight patients with celiac disease (15.1%) presented a concomitant autoimmune disease. Anti-MICA-positive patients had a higher risk of autoimmune disease than MICA antibody-negative patients (P <0.0001; odds ratio = 6.11). The risk was even higher when we also controlled for age (odds ratio = 11.69). Finally, we found that the associated risk of developing additional autoimmune diseases was 16 and 10 times as high in pediatric patients and adults with anti-MICA, respectively, as in those without. CONCLUSIONS: The development of anti-MICA antibodies could be related to a gluten-containing diet, and seems to be involved in the development of autoimmune diseases in patients with celiac disease, especially younger ones.

Patrones de expression de los ligandos de NKG2D en la mucosa intestinal de pacientes con enfermedad celiaca / NKG2D ligands expression patterns in gut mucosa from patients with coeliac disease

Introducción La interacción de MIC/NKG2D participa en la respuesta de los linfocitos intraepiteliales (LIE) en la enfermedad celíaca (EC). El objetivo de este estudio fue investigar la expresión, en la mucosa intestinal de pacientes con EC, de los ligandos de NKG2D (MICA, MICB), de la IL-15 y del receptor NKG2D, y relacionarla con la severidad del daño. Pacientes y métodos Seleccionamos biopsias intestinales de 20 pacientes con EC y de cinco controles sanos. Todos los pacientes resultaron positivos para anticuerpos anti-transglutaminasa 2 y para HLA-DQ2 o HLA-DQ8. Los pacientes fueron divididos en dos grupos según el grado de deterioro de la mucosa: diez con daño leve y otros 10 con daño grave (denominados MMD y SMD, respectivamente). En todos ellos se analizó la expresión de MICA, MICB, NKG2D y IL-15 a nivel de ARN mensajero, y en el caso de MICA se completó el estudio analizando su expresión por inmunohistoquímica. Resultados Se observó sobreexpresión de MICA y MICB en biopsias de pacientes celíacos en relación con los controles sanos (p<0.001). Sin embargo, la expresión fue notablemente mayor en el grupo de pacientes MMD que en aquellos del grupo SMD (p<0.001). Los niveles de receptor NKG2D y IL-15 también fueron mayores en pacientes que en controles, pero no se encontró relación con la gravedad de la lesión de la mucosa. Conclusiones Nuestros resultados sugieren que los ligandos de NKG2D pueden desempeñar un papel importante durante el inicio del proceso inflamatorio en las primeras etapas del desarrollo de la enfermedad celíaca (AU)

Introduction The activating MICA/NKG2D interaction is involved in the response of intraepithelial lymphocytes (IELs) in coeliac disease (CD). The aim of this study was to investigate the expression of NKG2D ligands (MICA, MICB), IL-15 and NKG2D receptor in gut mucosa of CD patients, and the correlation with the severity of histological damage. Patients and methods Intestinal biopsies from 20 CD patients and five healthy controls were selected. All patients were positive for anti-transglutaminase 2 antibodies and for DQ2 or DQ8. Patients were divided into two groups according to their grade of mucosal impairment: ten each with mild and severe mucosal damage (MMD and SMD, respectively). The expression of proposed genes was determined at mRNA level. MICA expression was also determined by immunohistochemistry. Results Overexpression of MICA and MICB was observed in biopsies from coeliac patients compared to healthy controls (P<0.001). Nevertheless, the expression was considerably higher in the group of patients with MMD (P<0.0001) than in those with SMD. The levels of NKG2D receptor and IL-15 were also higher in patients than in controls, but no relationship with the severity of the mucosal lesion was found. Conclusions Our results suggest that NKG2D ligands may play an important role during the onset of the inflammatory process in the early stages of the development of coeliac disease (AU)

Immune systems evolution.

Animals and plants have a complex and effective immune system that protect them from invading microorganisms. The mechanisms of immunity are evolutionarily selected throughout host-pathogen interaction to be tolerant to self-antigens and to recognize nonself molecular patterns. Plants and animals share a germ line encoded diversity of receptors capable of nonself recognition. Somatic rearranging of immunological receptors emerges at early stages of vertebrate evolution, allowing these animals to generate an almost unlimited diversity of receptors. Nevertheless, this recombinational system came with a high price: The potential for self-reactivity. In this chapter we will discuss the differences and the striking similarities of the immune mechanisms across different taxa in the context of evolution and the selective pressures that favoured the development of the adaptive immune system and the lymphoid organs.

Immunology and the challenge of transplantation.

Transplantation of tissues or organs between individuals who are not genetically related often leads to rejection by the recipient. The human genes responsible for this process are located on the short arm of the chromosome 6 and are called Major Histocompatibility Complex (MHC). Six main loci have been identified in the human MHC: HLA-A, HLA-B and HLA-C belong to the HLA class I, while HLA-DP, HLA-DQ and HLA-DR belong to HLA class II. The physiological function of MHC molecules is to present peptides to the T cells. Indeed, they are integral components of the ligands that recognise most T cells, since the receptor of the T cell (TCR) has specificity for complexes of foreign antigenic peptides, and self-MHC molecules. Thus the proteins of the MHC are responsible for the body being able to distinguish between its own and foreign cells, known as self-tolerance and consequently are the proteins which determine the evolution of transplants. The special case of foreign MHC antigen recognition is known as allorecognition and consists of the capacity of T cells to recognise peptide/MHC complexes with which they have not been in contact during the process of maturation in the thymus. There are two mechanisms of allorecognition, direct and indirect; both can lead to rejection of the transplant. Direct recognition prevails during the first few weeks or months after transplantation, and is caused by the APCs of the donor. These cells start disappearing from the transplanted organ and indirect recognition becomes important. There is evidence that the indirect pathway is sufficient to mediate both acute and chronic rejection. In this chapter we will describe fundamental aspects of the MHC system, as well as, specifically, its involvement in the allogenic response of the immune system against organ transplants.

Mobilization and homing of hematopoietic stem cells.

Hematopoietic stem cells (HSC) are a population of precursor cells that posses the capacity for self-renewal and multilineage differentiation. In the bone marrow (BM), HSCs warrant blood cell homeostasis, but at the same time a stable pool of functional cells must be constantly maintained. For this, HSCs constitute a model in which subpopulations of quiescent and active adult stem cells co-exist in the same tissue, in specific microenvironment called stem-cell "niches." These microenvironments keep the stem cells at quiescent (osteoblastic niche) for its self-renewal and activate the stem cells (vascular niche) for proliferation and/or injury repair, maintaining a dynamic balance between self-renewal and differentiation. HSC reside in the bone marrow but can be forces into the blood, a process termed mobilization used clinically to harvest large number of cells for transplantation. At the same time, homing to the BM is necessary to optimize cell engraftment. Here, we summarize current understanding of HSC niche characteristics, and the physiological and pathological mechanisms that guide HSC mobilization both within the BM and to distant niches in the periphery. Mobilization and Homing are mirror process depending on an interplay between chemokines, chemokine receptors, intracellular signaling, adhesion moleculas and proteases. The interaction between SDF-1/CXCL12 and its receptor CXCR4 is critical to retain HSCs within the bone marrow. Current mobilization strategies used in clinic, mainly G-CSF cytokine, are well tolerated but often produce suboptimal number of collected HSCs. Novel agents (AMD3100, stem cell factor, GROßT.) are being developed to enhance the mobilization to modify the signaling into the niche and boost the stem cell harvest, increasing the number of HSCs available for the transplant.

A predictive model of treatment outcome in patients with chronic HCV infection using IL28B and PD-1 genotyping.

BACKGROUND & AIMS: The advent of new chronic hepatitis C virus (HCV) therapies requires characterization of patients in order to predict adequate treatment. A good candidate marker is Programmed Cell Death-1 (PD-1) which is involved in progression of HCV infection. The aim of this study was to analyse the effect of several single nucleotide polymorphisms of PD-1 gene and several previously associated factors (IL28B and KIR receptors) on treatment responses. METHODS: 407 HCV chronic infected patients treated with PEG-IFN-α and ribavirin were recruited and classified according to their response to treatment. They were genotyped for PD-1 and IL28B polymorphisms, killer immunoglobulin-like receptors (KIR) and HLA genes. A multivariate logistic regression analysis and a Chi-squared Automatic Interaction Detector (CHAID) prediction model of response included these and other clinical parameters. RESULTS: Our results showed that PD-1.3/A allele was significantly associated with sustained virological response (SVR) in a multivariate logistic regression analysis (p<0.01, OR=2.57). Additionally, IL28B C/C genotype was the most significant predictor of an SVR to treatment in all HCV genotypes (74.5%). In IL28B C/C patients, the presence of PD-1.3/A allele increased the probability of an SVR to 93.3%. Moreover, when this analysis was made only with patients infected by HCV-1, the predictive value of IL28B C/C genotype with PD-1.3/A allele was 90%. CONCLUSIONS: PD-1.3/A allele is associated with SVR to treatment and notably increases the predictive value of IL28B C/C genotype. Both markers in conjunction could be a useful tool, more relevant than HCV genotype in some cases, in clinical practice.

Relationship between functional ability in older people, immune system status, and intensity of response to CMV.

Shorter survival in the elderly has been associated with deterioration of the immune system and also with functional disability. To analyze the relationship between functional and immune impairment in older individuals, we studied 100 elderly who lived in a nursing home, were age matched, and grouped according to their functional status. We characterized cell subpopulations by flow cytometry, quantified TREC by RT-PCR, and measured the T-cell proliferation and activation response (IFN-γ by ELISPOT, CD69) against anti-CD3 and CMV. Specific antibody titers against influenza virus and CMV were determined by ELISA. Individuals with worse functional status had significantly higher levels of NK cells and fewer B cells. These poorly functioning elders also had a significantly lower proportion of CD4+ T cells, increased CD8+ T cells, and a decreased CD4/CD8 ratio. TREC levels in CD4+ T cells were significantly lower in individuals with a high disability. Lower TREC levels correlated with a lower frequency of naïve T-cell subpopulations (CD45RA+CCR7+) and higher percentages of effector cells (CD45RA-CCR7-). The functionally impaired group had lower anti-CD3 responses, but gradually increased responses against CMV. Similarly, the higher CMV titers were found in elderly with worse functional status. On the contrary, the functional response in vivo, and the titer of antibodies generated after vaccination against influenza virus, was higher in individuals with better performance status. In summary, we concluded that the functional decline of elderly individuals was clearly associated with the aging of their immune system, and the intensity of the response to CMV.

Interaction between ERAP1 and HLA-B27 in ankylosing spondylitis implicates peptide handling in the mechanism for HLA-B27 in disease susceptibility.

Ankylosing spondylitis is a common form of inflammatory arthritis predominantly affecting the spine and pelvis that occurs in approximately 5 out of 1,000 adults of European descent. Here we report the identification of three variants in the RUNX3, LTBR-TNFRSF1A and IL12B regions convincingly associated with ankylosing spondylitis (P < 5 × 10(-8) in the combined discovery and replication datasets) and a further four loci at PTGER4, TBKBP1, ANTXR2 and CARD9 that show strong association across all our datasets (P < 5 × 10(-6) overall, with support in each of the three datasets studied). We also show that polymorphisms of ERAP1, which encodes an endoplasmic reticulum aminopeptidase involved in peptide trimming before HLA class I presentation, only affect ankylosing spondylitis risk in HLA-B27-positive individuals. These findings provide strong evidence that HLA-B27 operates in ankylosing spondylitis through a mechanism involving aberrant processing of antigenic peptides.

Fine mapping of a major histocompatibility complex in ankylosing spondylitis: association of the HLA-DPA1 and HLA-DPB1 regions.

OBJECTIVE: To investigate the potential association of major histocompatibility complex (MHC) markers other than HLA-B27 with ankylosing spondylitis (AS). METHODS: A total of 603 patients with AS and 542 healthy control subjects, all of whom were HLA-B27 positive, were selected for this study based on clinical criteria. First, high-density genotyping across the MHC region (2,360 single-nucleotide polymorphisms [SNPs]) was performed in a cohort of 191 patients and 241 control subjects. After a fine-mapping study, 5 SNPs from the HLA-DPA1/DPB1 region were validated in a second cohort of 412 patients with AS and 301 healthy control subjects. RESULTS: Seventeen SNPs located within or near the HLA-DPA1 and HLA-DPB1 loci showed association with AS (P = 1.38 × 10⁻5 to 0.05). In addition, multimarker tests, both linkage disequilibrium and sliding windows, showed association of some groups of adjacent SNPs within the HLA-DPA1/DPB1 region with AS (P = 1.0 × 10⁻4 to 3.96 × 10⁻7). We validated the association by genotyping 5 SNPs from the DPA1/DPB1 region in an additional cohort and obtained P values from 6.42 × 10⁻5 to 0.01 in the analysis of the combined cohorts. Subtyping analysis of HLA-DPA1 and HLA-DPB1 showed that HLA-DPA1*01:03, A1*02:01, and B1*13:01 were the subtypes most susceptible to AS. CONCLUSION: HLA markers and linkage disequilibrium blocks near HLA-DPA1 and HLA-DPB1 are statistically associated with AS. We identified a region located around the HLA-DPA1 and HLA-DPB1 loci associated with AS, another region within the MHC that is different from HLA-B27.

Inflammation and matrix remodeling during repair of ventilator-induced lung injury.

High-pressure ventilation triggers different inflammatory and matrix remodeling responses within the lung. Although some of them may cause injury, the involvement of these mediators in repair is largely unknown. To identify mechanisms of repair after ventilator-induced lung injury (VILI), mice were randomly assigned to baseline conditions (no ventilation), injury [90 min of high-pressure ventilation without positive end-expiratory pressure (PEEP)], repair (injury followed by 4 h of low-pressure ventilation with PEEP), and ventilated controls (low-pressure ventilation with PEEP for 90 and 330 min). Histological injury and lung permeability increased during injury, but were partially reverted in the repair group. This was accompanied by a proinflammatory response, together with increases in TNF-α and IFN-γ, which returned to baseline during repair, and a decrease in IL-10. However, macrophage inflammatory protein-2 (MIP-2) and matrix metalloproteinases (MMP)-2 and -9 increased after injury and persisted in being elevated during repair. Mortality in the repair phase was 50%. Survivors showed increased cell proliferation, lower levels of collagen, and higher levels of MIP-2 and MMP-2. Pan-MMP or specific MMP-2 inhibition (but not MIP-2, TNF-α, or IL-4 inhibition) delayed epithelial repair in an in vitro wound model using murine or human alveolar cells cultured in the presence of bronchoalveolar lavage fluid from mice during the repair phase or from patients with acute respiratory distress syndrome, respectively. Similarly, MMP inhibition with doxycycline impaired lung repair after VILI in vivo. In conclusion, VILI can be reverted by normalizing ventilation pressures. An adequate inflammatory response and extracellular matrix remodeling are essential for recovery. MMP-2 could play a key role in epithelial repair after VILI and acute respiratory distress syndrome.

Differences between pediatric and adult celiac disease.

INTRODUCTION: Celiac disease (CD) is a common autoimmune condition (involves 1-2% of the general population) that develops at any age in life but manifests differently in children and adults. OBJECTIVES: To analyze clinical differences in disease expression between both groups, as well as findings at the time of diagnosis. METHODS: A retrospective study of a series of patients diagnosed with CD during childhood (< 14 years) versus a series of adult patients (> 14 years). RESULTS: a total of 187 patients were included, of which 43 were children and 144 were adults. Among clinical manifestations in children classic presentation forms predominated -34 patients(79%) versus 20 adult patients (14%) (p < 0.001) (OR = 23.4;95% CI: 9.8-56.1). In contrast, atypical forms were predominant in the latter, and anemia was the most common finding in 61 patients (42%) versus 8 pediatric patients (19%) (p < 0.01). Adults had a greater diagnostic delay with a mean 10 ± 9 years versus 1 ± 2 years in children (p < 0.001). In adults, we found a higher frequency of associated autoimmune diseases (24.3 versus 9.3% in children) (p < 0.05). Regarding serum markers, TGt-2 was more commonly positive among children (88%) as compared to adults (31%) (p < 0.001); (OR = 21.4: 95% CI: 7.2-63.6). We found similar results with regard to the presence of villous atrophy, which was more common in children (95%) than in adults (33%) (p < 0.001) (OR = 41.0;95% CI: 9.5-76.7). As regards genetic markers, DQ2 was somewhat more common in children (97.7%) than in adults (90.3%) whereas DQ8 wasless common in children (2.3%) than in adults (9.7%), with no significant differences between groups. Patients negative for both markers were not included. CONCLUSIONS: Pediatric CD has clear differences when compared to adult CD, with classic forms predominating in the former, who also display a higher occurrence of positive serology and villous atrophy, and less diagnostic delay. In contrast, atypical forms predominate in the adult, with a lower occurrence of positive serology and milder histological forms. In these patients associated autoimmune conditions are more common and diagnostic delay is longer.

Diferencias entre la enfermedad celiaca infantil y del adulto / Diferences between pediatric and adult celiac disease

Introducción: la enfermedad celiaca (EC) es un proceso frecuente (afecta al 1-2% en población general), de naturaleza autoimmune, que aparece a cualquier edad de la vida, pero que se presenta de forma diferente en el niño que en el adulto. Objetivos: analizar las diferencias clínicas en las formas de expresión de la enfermedad entre ambos grupos, así como los hallazgos al momento del diagnóstico. Métodos: estudio retrospectivo de una serie de pacientes diagnosticados, en la infancia (< 14 años), frente a una serie de adultos (> 14 años). Resultados: se incluyeron un total de 187 pacientes, de los cuales 43 eran niños y 144 adultos. En las manifestaciones clínicas de los niños, predominaron las formas de presentación clá - sicas, 34 casos (79%) frente a los adultos 20 casos (14%) (p < 0,001) (OR = 23,4; IC-95%: 9,8-56,1). Por el contrario, en estos predominaron las formas atípicas, siendo la anemia el hallazgo más frecuente en 61 casos (42%) frente a 8 casos (19%) en los niños (p < 0,01). En los adultos existía un mayor retraso diagnóstico con una media de 10 ± 9 años, frente a los niños, que es de 1 ± 2 años (p < 0,001). Encontramos en los adultos una mayor frecuencia de enfermedades autoinmunes asociadas (24,3%), frente al 9,3% en niños (p < 0,05). Respecto a los marcadores serológicos, la TGt-2 fue más frecuentemente positiva en los niños (88%), que en los adultos (31%) (p < 0,001); (OR = 21,4: IC-95%: 7,2-63,6). Resultados similares encontramos en relación con la presencia de atrofia vellositaria, que estuvo presente más frecuentemente en los niños (95%) que en los adultos (33%) (p < 0,001) (OR = 41,0; IC-95%: 9,5-76,7). Respecto a los marcadores genéticos, el DQ2 fue algo más frecuente en niños (97,7%) que en adultos 90,3%, y el DQ8 ocurrió al contrario, siendo menos frecuente en niños (2,3%) que en adultos (9,7%), no encontrando diferencias entre ambos grupos. No se incluyeron pacientes negativos para ambos marcadores(AU)

Introduction: celiac disease (CD) is a common autoimmune condition (involves 1-2% of the general population) that develops at any age in life but manifests differently in children and adults. Objectives: to analyze clinical differences in disease expression between both groups, as well as findings at the time of diagnosis. Methods: a retrospective study of a series of patients diagnosed with CD during childhood (< 14 years) versus a series of adult patients (> 14 years). Results: a total of 187 patients were included, of which 43 were children and 144 were adults. Among clinical manifestations in children classic presentation forms predominated –34 patients (79%) versus 20 adult patients (14%) (p < 0.001) (OR = 23.4; 95% CI: 9.8-56.1). In contrast, atypical forms were predominant in the latter, and anemia was the most common finding in 61 patients (42%) versus 8 pediatric patients (19%) (p < 0.01). Adults had a greater diagnostic delay with a mean 10 ± 9 years versus 1 ± 2 years in children (p < 0.001). In adults, we found a higher frequency of associated autoimmune diseases (24.3 versus 9.3% in children) (p < 0.05). Regarding serum markers, TGt-2 was more commonly positive among children (88%) as compared to adults (31%) (p < 0.001); (OR = 21.4: 95% CI: 7.2-63.6). We found similar results with regard to the presence of villous atrophy, which was more common in children (95%) than in adults (33%) (p < 0.001) (OR = 41.0; 95% CI: 9.5-76.7). As regards genetic markers, DQ2 was somewhat more common in children (97.7%) than in adults (90.3%) whereas DQ8 was less common in children (2.3%) than in adults (9.7%), with no significant differences between groups. Patients negative for both markers were not included(AU)