Antigen-specific B cells direct T follicular-like helper cells into lymphoid follicles to mediate Mycobacterium tuberculosis control.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a global cause of death. Granuloma-associated lymphoid tissue (GrALT) correlates with protection during TB, but the mechanisms of protection are not understood. During TB, the transcription factor IRF4 in T cells but not B cells is required for the generation of the TH1 and TH17 subsets of helper T cells and follicular helper T (TFH)-like cellular responses. A population of IRF4+ T cells coexpress the transcription factor BCL6 during Mtb infection, and deletion of Bcl6 (Bcl6fl/fl) in CD4+ T cells (CD4cre) resulted in reduction of TFH-like cells, impaired localization within GrALT and increased Mtb burden. In contrast, the absence of germinal center B cells, MHC class II expression on B cells, antibody-producing plasma cells or interleukin-10-expressing B cells, did not increase Mtb susceptibility. Indeed, antigen-specific B cells enhance cytokine production and strategically localize TFH-like cells within GrALT via interactions between programmed cell death 1 (PD-1) and its ligand PD-L1 and mediate Mtb control in both mice and macaques.

Human anti-N1 monoclonal antibodies elicited by pandemic H1N1 virus infection broadly inhibit HxN1 viruses in vitro and in vivo.

Neuraminidase (NA) is one of the two influenza virus surface glycoproteins, and antibodies that target it are an independent correlate of protection. However, our current understanding of NA antigenicity is incomplete. Here, we describe human monoclonal antibodies (mAbs) from a patient with a pandemic H1N1 virus infection in 2009. Two mAbs exhibited broad reactivity and inhibited NA enzyme activity of seasonal H1N1 viruses circulating before and after 2009, as well as viruses with avian or swine N1s. The mAbs provided robust protection from lethal challenge with human H1N1 and avian H5N1 viruses in mice, and both target an epitope on the lateral face of NA. In summary, we identified two broadly protective NA antibodies that share a novel epitope, inhibited NA activity, and provide protection against virus challenge in mice. Our work reaffirms that NA should be included as a target in future broadly protective or universal influenza virus vaccines.

Publisher Correction: Group 3 innate lymphoid cells mediate early protective immunity against tuberculosis.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Group 3 innate lymphoid cells mediate early protective immunity against tuberculosis.

Tuberculosis is the leading cause of death by an infectious disease worldwide1. However, the involvement of innate lymphoid cells (ILCs) in immune responses to infection with Mycobacterium tuberculosis (Mtb) is unknown. Here we show that circulating subsets of ILCs are depleted from the blood of participants with pulmonary tuberculosis and restored upon treatment. Tuberculosis increased accumulation of ILC subsets in the human lung, coinciding with a robust transcriptional response to infection, including a role in orchestrating the recruitment of immune subsets. Using mouse models, we show that group 3 ILCs (ILC3s) accumulated rapidly in Mtb-infected lungs and coincided with the accumulation of alveolar macrophages. Notably, mice that lacked ILC3s exhibited a reduction in the accumulation of early alveolar macrophages and decreased Mtb control. We show that the C-X-C motif chemokine receptor 5 (CXCR5)-C-X-C motif chemokine ligand 13 (CXCL13) axis is involved in Mtb control, as infection upregulates CXCR5 on circulating ILC3s and increases plasma levels of its ligand, CXCL13, in humans. Moreover, interleukin-23-dependent expansion of ILC3s in mice and production of interleukin-17 and interleukin-22 were found to be critical inducers of lung CXCL13, early innate immunity and the formation of protective lymphoid follicles within granulomas. Thus, we demonstrate an early protective role for ILC3s in immunity to Mtb infection.

Dendritic cells drive profibrotic inflammation and aberrant T cell polarization in systemic sclerosis.

OBJECTIVES: SSc is a devastating autoimmune disease characterized by fibrosis and obliterative vasculopathy affecting the skin and visceral organs. While the processes mediating excessive extracellular matrix deposition and fibroblast proliferation are clear, the exact link between autoimmunity and fibrosis remains elusive. Th17 cells have been proposed as critical drivers of profibrotic inflammation during SSc, but little is known about the immune components supporting their pathogenic role. Our aim was to determine cytokine responses of stimulated monocyte-derived dendritic cells (Mo-DCs) and to determine how they influence T-cell cytokine production in SSc. MATERIAL AND METHODS: Dendritic cells (DCs) activate and shape T cell differentiation by producing polarizing cytokines. Hence, we investigated the cytokine responses of monocyte-derived DCs (Mo-DCs) from patients with limited cutaneous SSc (lcSSc), diffuse cutaneous SSc (dcSSc) and healthy controls (HCs) after stimulation with toll-like receptor (TLR) agonists. Also, using co-culture assays, we analysed T cell subpopulations after contact with autologous TLR-activated Mo-DCs. RESULTS: In general, we observed an increased production of Th17-related cytokines like IL-1ß, IL-17F, IL-21 and IL-22 by SSc compared with HC Mo-DCs, with variations between lcSSc vs dcSSc and early- vs late-stage subgroups. Noticeably, we found a significant increment in IL-33 production by Mo-DCs in all SSc cases regardless of their clinical phenotype. Strikingly, T cells displayed Th2, Th17 and dual Th2-Th17 phenotypes after exposure to autologous TLR-stimulated Mo-DCs from SSc patients but not HCs. These changes were pronounced in individuals with early-stage dcSSc and less significant in the late-stage lcSSc subgroup. CONCLUSIONS: Our findings suggest that functional alterations of DCs promote immune mechanisms favouring the aberrant T cell polarization and profibrotic inflammation behind clinical SSc heterogeneity.

Comprehensive Immunologic Evaluation of Bronchoalveolar Lavage Samples from Human Patients with Moderate and Severe Seasonal Influenza and Severe COVID-19.

Infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) or seasonal influenza may lead to respiratory failure requiring intubation and mechanical ventilation. The pathophysiology of this respiratory failure is attributed to local immune dysregulation, but how the immune response to viral infection in the lower airways of the human lung differs between individuals with respiratory failure and those without is not well understood. We used quantitative multiparameter flow cytometry and multiplex cytokine assays to evaluate matched blood and bronchoalveolar lavage (BAL) samples from control human subjects, subjects with symptomatic seasonal influenza who did not have respiratory failure, and subjects with severe seasonal influenza or SARS-CoV-2 infection with respiratory failure. We find that severe cases are associated with an influx of nonclassical monocytes, activated T cells, and plasmablast B cells into the lower airways. Cytokine concentrations were not elevated in the lower airways of moderate influenza patients compared with controls; however, 28 of 35 measured cytokines were significantly elevated in severe influenza, severe SARS-CoV-2 infection, or both. We noted the largest elevations in IL-6, IP-10, MCP-1, and IL-8. IL-1 family cytokines and RANTES were higher in severe influenza infection than severe SARS-CoV-2 infection. Interestingly, only the concentration of IP-10-correlated between blood and BAL during severe infection. Our results demonstrate inflammatory immune dysregulation in the lower airways during severe viral pneumonia that is distinct from lower airway responses seen in human patients with symptomatic, but not severe, illness and suggest that measurement of blood IP-10 concentration may predict this unique dysregulation.

Expression of Surfactant Protein D Distinguishes Severe Pandemic Influenza A(H1N1) from Coronavirus Disease 2019.

The differentiation between influenza and coronavirus disease 2019 (COVID-19) could constitute a diagnostic challenge during the ongoing winter owing to their clinical similitude. Thus, novel biomarkers are required to enable making this distinction. Here, we evaluated whether the surfactant protein D (SP-D), a collectin produced at the alveolar epithelium with known immune properties, was useful to differentiate pandemic influenza A(H1N1) from COVID-19 in critically ill patients. Our results revealed high serum SP-D levels in patients with severe pandemic influenza but not those with COVID-19. This finding was validated in a separate cohort of mechanically ventilated patients with COVID-19 who also showed low plasma SP-D levels. However, plasma SP-D levels did not distinguish seasonal influenza from COVID-19 in mild-to-moderate disease. Finally, we found that high serum SP-D levels were associated with death and renal failure among severe pandemic influenza cases. Thus, our studies have identified SP-D as a unique biomarker expressed during severe pandemic influenza but not COVID-19.

Impaired Cellular Immune Responses During the First Week of Severe Acute Influenza Infection.

BACKGROUND: Cellular immune responses are not well characterized during the initial days of acute symptomatic influenza infection. METHODS: We developed a prospective cohort of human subjects with confirmed influenza illness of varying severity who presented within a week after symptom onset. We characterized lymphocyte and monocyte populations as well as antigen-specific CD8+ T-cell and B-cell responses from peripheral blood mononuclear cells using flow cytometry and enzyme-linked immunospot assays. RESULTS: We recruited 68 influenza-infected individuals on average 3.5 days after the onset of symptoms. Three patients required mechanical ventilation. Influenza-specific CD8+ T-cell responses expanded before the appearance of plasmablast B cells. However, the influenza-specific CD8+ T-cell response was lower in infected subjects than responses seen in uninfected control subjects. Circulating populations of inflammatory monocytes were increased in most subjects compared with healthy controls. Inflammatory monocytes were significantly reduced in the 3 subjects requiring mechanical ventilation. Inflammatory monocytes were also reduced in a separate validation cohort of mechanically ventilated patients. CONCLUSIONS: Antigen-specific CD8+ T cells respond early during acute influenza infection at magnitudes that are lower than responses seen in uninfected individuals. Circulating inflammatory monocytes increase during acute illness and low absolute numbers are associated with very severe disease.

Mycobacterium tuberculosis HN878 Infection Induces Human-Like B-Cell Follicles in Mice.

Specific spatial organization of granulomas within the lungs is crucial for protective anti-tuberculosis (TB) immune responses. However, only large animal models such as macaques are thought to reproduce the morphological hallmarks of human TB granulomas. In this study, we show that infection of mice with clinical "hypervirulent" Mycobacterium tuberculosis (Mtb) HN878 induces human-like granulomas composed of bacilli-loaded macrophages surrounded by lymphocytes and organized localization of germinal centers and B-cell follicles. Infection with laboratory-adapted Mtb H37Rv resulted in granulomas that are characterized by unorganized clusters of macrophages scattered between lymphocytes. An in-depth exploration of the functions of B cells within these follicles suggested diverse roles and the activation of signaling pathways associated with antigen presentation and immune cell recruitment. These findings support the use of clinical Mtb HN878 strain for infection in mice as an appropriate model to study immune parameters associated with human TB granulomas.

Inflammatory chemokine profiles and their correlations with effector CD4 T cell and regulatory cell subpopulations in cutaneous lupus erythematosus.

We compared the chemokine/receptor expression in skin biopsies of discoid (SLE/DLE) and subacute lupus (SLE/SCLE) and correlated it with tissue and circulating effector CD4 T cells/regulatory cells. Skin biopsies and peripheral blood from 9 active SLE/DLE patients, 9 SLE/SCLE patients, 5 control SLE patients without cutaneous lesions and 10 control healthy donors were included. Clinical skin activity was measured by Cutaneous Lupus Erythematosus Disease Area and Severity Index scoring, and systemic activity was measured by a modified SLEDAI-2K excluding the cutaneous items. Pain and pruritus were evaluated by a 10-point visual analogue scale. To determine the frequencies of CXCL-10/CXCR3-, CCL2/CCR2-, CCL17/CCR4-, CCL20/CCR6-, CCL27/CCR10-, CXCL8/CXCR1-, CXCL13/CXCR5-, IL-22-, CD4/IL-17A-, CD4/IL-4-, CD4/IFN-γ-, CD123/IDO-, CD25/Foxp3-, and CD20/IL-10-expressing cells, double immunostaining procedures were performed. Circulating CD4+/CD161-/IL-22+, CD4+/CD161+/IL-17+, CD4+/CD25-/IL-4+, CD4+/CD25-/IFN-γ+, CD4+/CD25hi/Foxp3+, CD3+/CD19+/CD38hi/IL-10+, and CD123+/CD196+/IDO + cells were analyzed by flow cytometry. RESULTS: In the tissue, CXCL10, CXCR5, and CCL20 expression and IL-22+, CD4+/IL-17+, CD4+/IFN-γ + and CD123+/IDO + cell percentages were increased in SLE/DLE versus SLE/SCLE. Circulating CD4+/CD161-/IL-22+, CD4+/CD161+/IL-17+, CD4+/CD25-/IFN-γ+, CD19+/CD38hi/IL-10 + and CD123+/CD196+/IDO + cell percentages were higher in SLE/DLE versus SLE/SCLE. In the tissue, we found positive correlations between CXCR3 and CD4+/IL-17 + cells; CCR2 and CD4+/IFN-γ + cells; and CCR10 and CD123+/IDO + cells in the SLE/DLE patients and between CXCL13 and CD20+/IL-10 + cells in the SLE/SCLE patients. In the peripheral blood, we determined positive correlations between CXCR5 and CD4+/CD25-/IFN-γ + cells; CCL17 and CD4+/CD161-/IL-22 + cells; and CCL17 and CD4+/CD161+/IL-17 + cells in the SLE/DLE patients and between CXCR5 and CD3+/CD19+/CD38hi/IL-10 + cells; CCR2 and CD4+/CD25hi/Foxp3 + cells; and CXCR1 and CD4+/CD25hi/Foxp3 + cells in the SLE/SCLE patients. Positive correlations between the pain score and the expression of CCL2 and CCR6 expression were found in the SLE/SCLE patients. In conclusion, the correlations between the expression of chemokines/receptors and subpopulations of effector/regulatory cells showed differential responses among the cutaneous pathologies.

Dysregulated expression of hypoxia-inducible factors augments myofibroblasts differentiation in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an age-related, progressive and lethal disease, whose pathogenesis is associated with fibroblasts/myofibroblasts foci that produce excessive extracellular matrix accumulation in lung parenchyma. Hypoxia has been described as a determinant factor in its development and progression. However, the role of distinct members of this pathway is not completely described. METHODS: By western blot, quantitative PCR, Immunohistochemistry and Immunocitochemistry were evaluated, the expression HIF alpha subunit isoforms 1, 2 & 3 as well, as their role in myofibroblast differentiation in lung tissue and fibroblast cell lines derived from IPF patients. RESULTS: Hypoxia signaling pathway was found very active in lungs and fibroblasts from IPF patients, as demonstrated by the abundance of alpha subunits 1 and 2, which further correlated with the increased expression of myofibroblast marker αSMA. In contrast, HIF-3α showed reduced expression associated with its promoter hypermethylation. CONCLUSIONS: This study lends further support to the involvement of hypoxia in the pathogenesis of IPF, and poses HIF-3α expression as a potential negative regulator of these phenomena.

MicroRNA Expression in Cutaneous Lupus: A New Window to Understand Its Pathogenesis.

BACKGROUND: The role of miRNAs in the pathogenesis of cutaneous lupus has not been studied. OBJECTIVE: It was to assess the levels of a selected panel of circulating miRNAs that could be involved in the regulation of the immune response, inflammation, and fibrosis in cutaneous lupus. METHODS: It was a cross-sectional study. We included 22 patients with subacute (SCLE) and 20 with discoid (DLE) lesions, and 19 healthy donors (HD). qRT-PCR for miRNA analysis, flow cytometry in peripheral blood, and skin immunohistochemistry were performed to determine the distribution of CD4 T cells and regulatory cells and their correlation with circulating miRNAs. RESULTS: miR-150, miR-1246, miR-21, miR-23b, and miR-146 levels were downregulated in SCLE vs. HD. miR-150, miR-1246, and miR-21 levels were downregulated in DLE vs. HD. miR-150, miR-1246, and miR-21 levels were downregulated in DLE γ + with miR-1246 in SCLE, whereas CD123+/CD196+/IDO+ cells were positively associated with miR-150 in DLE. In the tissue, CD4+/IL-4+ and CD20+/IL-10+ cells were positively associated with miR-21 and CD4+/IFN-γ + with miR-1246 in SCLE, whereas CD123+/CD196+/IDO+ cells were positively associated with miR-150 in DLE. In the tissue, CD4+/IL-4+ and CD20+/IL-10+ cells were positively associated with miR-21 and CD4+/IFN-ß, thyroid hormone, and cancer signaling pathways were shared between miR-21, miR-31, miR-23b, miR-146a, miR-1246, and miR-150. CONCLUSIONS: A downregulation of miR-150, miR-1246, and miR-21 in both CLE varieties vs. HD. miR-150, miR-1246, and miR-21 levels were downregulated in DLE.

Epigenetics in non-small cell lung carcinomas.

OBJECTIVE: To perform a systematic review of the main epigenetic aberrations involved in non-small cell lung carcinomas' (NSCLC) diagnosis, progression, and therapeutics. MATERIALS AND METHODS: We performed a systematic review of the scientific literature on lung cancer epigenetics, focusing on NSCLC. RESULTS: Several advances in the molecular study of classical epigenetic mechanisms and massive studies of lung cancer epigenome have contributed relevant new evidence revealing that various molecular complexes are functionally influencing genetic-epigenetic and transcriptional mechanisms that promote lung tumorigenesis (initiation, promotion, and progression), and are also involved in NSCLC therapyresistance mechanisms. CONCLUSIONS: Several epigenetic complexes and mechanisms must be analyzed and considered for the design of new and efficient therapies, which could be fundamental to develop an integrated knowledge to achieve a comprehensive lung cancer personalized medicine.

OBJETIVO: Realizar una revisión sistemática y estructurada de las principales aberraciones epigenéticas involucradas en el diagnóstico, progresión y terapia del cáncer pulmonar de células no pequeñas (CPCNP). MATERIAL Y MÉTODOS: Revisión sistemática de literatura científica sobre epigenética del cáncer pulmonar del grupo CPCNP. RESULTADOS: El estudio de los diversos mecanismos epigenéticos y su impronta epigenética en el epigenoma del cáncer pulmonar han arrojado nuevas evidencias a nivel biológico, biomédico y médico-clínico del impacto que los mecanismos epigenéticotranscripcionales promueven de manera activa y reversible sobre los procesos de tumorigénesis, progresión histopatológica y mecanismos de resistencia a la terapia oncológica pulmonar. CONCLUSIONES: Deben analizarse diferentes complejos y mecanismos epigenéticos para el estudio y diseño de esquemas nuevos y eficaces de terapia epigenética, los cuales podrían ser fundamentales para desarrollar un conocimiento integral en el desarrollo de la medicina personalizada en el cáncer pulmonar del grupo CPCNP.

Genetic Differentiation in a Sample from Northern Mexico City Detected by HLA System Analysis: Impact in the Study of Population Immunogenetics.

The major histocompatibility complex is directly involved in the immune response, and thus the genes coding for its proteins are useful markers for the study of genetic diversity, susceptibility to disease (autoimmunity and infections), transplant medicine, and pharmacogenetics, among others. The polymorphism of the system also allows researchers to use it as a proxy for population genetics analysis, such as genetic admixture and genetic structure. In order to determine the immunogenetic characteristics of a sample from the northern part of Mexico City and to use them to analyze the genetic differentiation from other admixed populations, including those from previous studies of Mexico City population, we analyzed molecular typing results of donors and patients from the Histocompatibility Laboratory of the Central Blood Bank of the Centro Médico Nacional La Raza selected according to their geographic origin. HLA-A, -B, -DRB1, and -DQB1 alleles were typed by polymerase chain reaction with sequence-specific primers. Allelic and haplotype frequencies, as well as population genetics parameters, were obtained by maximum likelihood methods. The most frequent haplotypes found were HLA-A*02/-B*39/-DRB1*04/-DQB1*03:02P, HLA-A*02/-B*35/-DRB1*04/-DQB1*03:02P, HLA-A*68/-B*39/-DRB1*04/-DQB1*03:02P, and HLA-A*02/-B*35/-DRB1*08/-DQB1*04. Importantly, the second most frequent haplotype found in our sample (HLA-A*02/-B*35/-DRB1*04/-DQB1*03:02P) has not been previously reported in any mixedancestry populations from Mexico but is commonly encountered in Native American human groups, which can reflect the impact of migration dynamics in the genetic conformation of the northern part of Mexico City, and the limitations of previous studies with regard to the genetic diversity of the analyzed groups. Differences found in haplotype frequencies demonstrated that large urban conglomerates cannot be analyzed as one homogeneous entity but, rather, should be understood as a set of structures in which social, political, and economical factors influence their genesis and dynamics.

A transcriptome-based model of central memory CD4 T cell death in HIV infection.

BACKGROUND: Human central memory CD4 T cells are characterized by their capacity of proliferation and differentiation into effector memory CD4 T cells. Homeostasis of central memory CD4 T cells is considered a key factor sustaining the asymptomatic stage of Human Immunodeficiency Virus type 1 (HIV-1) infection, while progression to acquired immunodeficiency syndrome is imputed to central memory CD4 T cells homeostatic failure. We investigated if central memory CD4 T cells from patients with HIV-1 infection have a gene expression profile impeding proliferation and survival, despite their activated state. METHODS: Using gene expression microarrays, we analyzed mRNA expression patterns in naive, central memory, and effector memory CD4 T cells from healthy controls, and naive and central memory CD4 T cells from patients with HIV-1 infection. Differentially expressed genes, defined by Log2 Fold Change (FC) ≥ |0.5| and Log (odds) > 0, were used in pathway enrichment analyses. RESULTS: Central memory CD4 T cells from patients and controls showed comparable expression of differentiation-related genes, ruling out an effector-like differentiation of central memory CD4 T cells in HIV infection. However, 210 genes were differentially expressed in central memory CD4 T cells from patients compared with those from controls. Expression of 75 of these genes was validated by semi quantitative RT-PCR, and independently reproduced enrichment results from this gene expression signature. The results of functional enrichment analysis indicated movement to cell cycle phases G1 and S (increased CCNE1, MKI67, IL12RB2, ADAM9, decreased FGF9, etc.), but also arrest in G2/M (increased CHK1, RBBP8, KIF11, etc.). Unexpectedly, the results also suggested decreased apoptosis (increased CSTA, NFKBIA, decreased RNASEL, etc.). Results also suggested increased IL-1ß, IFN-γ, TNF, and RANTES (CCR5) activity upstream of the central memory CD4 T cells signature, consistent with the demonstrated milieu in HIV infection. CONCLUSIONS: Our findings support a model where progressive loss of central memory CD4 T cells in chronic HIV-1 infection is driven by increased cell cycle entry followed by mitotic arrest, leading to a non-apoptotic death pathway without actual proliferation, possibly contributing to increased turnover.

Circulating levels of miR-150 are associated with poorer outcomes of A/H1N1 infection.

BACKGROUND: Overproduction of pro-inflammatory cytokines and chemokines is frequently associated with severe clinical manifestations in patients infected with influenza A/H1N1 virus. Micro-RNAs (miRNAs) are highly conserved small non-coding RNA molecules that post-transcriptionally regulate gene expression and are potential biomarkers and therapeutic targets in different inflammatory conditions. METHODS: We studied the circulating and miRNA profiles in critically ill A/H1N1 patients, A/H1N1 patients with milder disease, asymptomatic housemates and healthy controls. Cytokine, chemokine and growth factors that were potential targets of differentially expressed miRNAs were assessed. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment and interactome analysis of these miRNAs were also performed. RESULTS: Critically ill patients exhibited a significant over-expression of circulating miR-150 (p<0.005) when compared to patients with milder disease. miR-29c, miR-145 and miR-22 were differentially expressed in patients with severe A/H1N1 disease whereas miR-210, miR-126 and miR-222 were downregulated in individuals exposed to the A/H1N1 virus. Significant correlations (p<0.05) between circulating levels of miR-150 with IL-1ra, IL-2, IL-6, CXCL8, IFN-γ, CXCL10 and G-CSF were detected, particularly in critically ill patients. CONCLUSION: The up-regulation of miR-150 is associated with poorer outcomes of A/H1N1 infection. The differential expression of miRNAs related with immune processes in severe A/H1N1 disease supports the potential role of these miRNAs as biomarkers of disease progression.

Serum surfactant protein D (SP-D) is a prognostic marker of poor outcome in patients with A/H1N1 virus infection.

INTRODUCTION: Surfactant protein D (SP-D) plays an important role in the innate responses against pathogens and its production is altered in lung disorders. METHODS: We studied the circulating levels of SP-D in 37 patients with acute respiratory distress syndrome due to the A/H1N1 virus infection and in 40 healthy controls. Cox logistic regression models were constructed to explore the association of SP-D levels and risk of death. RESULTS: Mortality rate after a 28-day was 32.42 %. Significant higher levels of SP-D were detected in A/H1N1 patients with fatal outcome (p < 0.05). After adjusting for confounding variables, levels of SP-D ≥250 ng/mL were associated with increased the risk of death (HR = 8.27, 95 % CI 1.1-64.1, p = 0.043). CONCLUSIONS: Our results revealed that higher circulating levels of SP-D are associated with higher mortality risk in critically ill A/H1N1 patients. SP-D might be a predictive factor of poor outcomes in viral pneumonia.

Analysis of heat shock protein 70 gene polymorphisms Mexican patients with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease of unknown etiology. Genetic variation within different major histocompatibility complex (MHC) loci contributes to the susceptibility to IPF. The effect of 70 kDa heat shock proteins (HSP70) gene polymorphisms in the susceptibility to IPF is unknown. The aim of this study was to explore the association between HSP70 polymorphisms and IPF susceptibility in the Mexican population. METHODS: Four HSP70 single nucleotide polymorphisms (SNPs) were evaluated using real time PCR assays in 168 IPF patients and 205 controls: +2763 C>T of HSPA1L (rs2075800), +2437 of HSP HSPA1L A>G (rs2227956), +190 of HSPA1A G>C (rs1043618) and +1267 of HSPA1B G>A (rs1061581). RESULTS: The analysis of the recessive model revealed a significant decrease in the frequency of the genotype HSPA1B AA (rs1061581) in IPF patients (OR = 0.27, 95 % CI = 0.13-0.57, Pc = 0.0003) when compared to controls. Using a multivariate logistic regression analysis in a codominant model the HSPA1B (rs1061581) GA and AA genotypes were associated with a lower risk of IPF compared with GG (OR = 0.22, 95 % CI = 0.07-0.65; p = 0.006 and OR = 0.17, 95 % CI = 0.07-0.41; p = <0.001). Similarly, HSPA1L (rs2227956) AG genotype (OR = 0.34, 95 % CI = 0.12-0.99; p = 0.04) and the dominant model AG + GG genotypes were also associated with a lower risk of IPF (OR = 0.24, 95 % CI = 0.08-0.67; p = 0.007). In contrast, the HSPA1L (rs2075800) TT genotype was associated with susceptibility to IPF (OR = 2.52, 95 % CI = 1.32-4.81; p = 0.005). CONCLUSION: Our findings indicate that HSPA1B (rs1061581), HSPA1L (rs2227956) and HSPA1 (rs1043618) polymorphisms are associated with a decreased risk of IPF.

The role of leptin in the development of pulmonary neutrophilia in infection and acute lung injury.

OBJECTIVES: One of the hallmarks of severe pneumonia and associated acute lung injury is neutrophil recruitment to the lung. Leptin is thought to be up-regulated in the lung following injury and to exert diverse effects on leukocytes, influencing both chemotaxis and survival. We hypothesized that pulmonary leptin contributes directly to the development of pulmonary neutrophilia during pneumonia and acute lung injury. DESIGN: Controlled human and murine in vivo and ex vivo experimental studies. SETTING: Research laboratory of a university hospital. SUBJECTS: Healthy human volunteers and subjects hospitalized with bacterial and H1N1 pneumonia. C57Bl/6 and db/db mice were also used. INTERVENTIONS: Lung samples from patients and mice with either bacterial or H1N1 pneumonia and associated acute lung injury were immunostained for leptin. Human bronchoalveolar lavage samples obtained after lipopolysaccharide-induced lung injury were assayed for leptin. C57Bl/6 mice were examined after oropharyngeal aspiration of recombinant leptin alone or in combination with Escherichia coli- or Klebsiella pneumoniae-induced pneumonia. Leptin-resistant (db/db) mice were also examined using the E. coli model. Bronchoalveolar lavage neutrophilia and cytokine levels were measured. Leptin-induced chemotaxis was examined in human blood- and murine marrow-derived neutrophils in vitro. MEASUREMENTS AND MAIN RESULTS: Injured human and murine lung tissue showed leptin induction compared to normal lung, as did human bronchoalveolar lavage following lipopolysaccharide instillation. Bronchoalveolar lavage neutrophilia in uninjured and infected mice was increased and lung bacterial load decreased by airway leptin administration, whereas bronchoalveolar lavage neutrophilia in infected leptin-resistant mice was decreased. In sterile lung injury by lipopolysaccharide, leptin also appeared to decrease airspace neutrophil apoptosis. Both human and murine neutrophils migrated toward leptin in vitro, and this required intact signaling through the Janus Kinase 2/phosphatidylinositol-4,5-bisphosphate 3-kinase pathway. CONCLUSIONS: We demonstrate that pulmonary leptin is induced in injured human and murine lungs and that this cytokine is effective in driving alveolar airspace neutrophilia. This action appears to be caused by direct effects of leptin on neutrophils.

Obesity and pro-inflammatory mediators are associated with acute kidney injury in patients with A/H1N1 influenza and acute respiratory distress syndrome.

BACKGROUND: The obesity has been shown to increase the severity of A/H1N1 infection and the development of acute respiratory distress syndrome (ARDS) and organ involvement. METHODS: Circulating levels of C-peptide, insulin, glucagon, leptin, acute phase reactants (procalcitonin, C-reactive protein, tissue plasminogen activator, and serum amyloids A and P), were measured in samples from 32 critically ill patients with A/H1N1 virus infection, 17 of whom had ARDS complicated by acute kidney injury (AKI) and 15 of whom had ARDS but did not develop AKI. RESULTS: Patients with ARDS and AKI (ARDS/AKI) had higher BMI and higher levels of C-peptide, insulin, leptin, procalcitonin and serum amyloid A compared to those ARDS patient who did not develop AKI. Adjusting for confounding variables using logistic regression analysis, higher levels of C-peptide (>0.75 ng/mL) (OR=64.8, 95% CI = 2.1-1980, p = 0.0006) and BMI>30 Kg/m(2) (OR = 42.0, 95% CI = 1.2-1478, p = 0.04) were significantly associated with the development of AKI in ARDS patients. CONCLUSION: High levels of C-peptide and BMI>30 kg/m(2) were associated with the development of AKI in ARDS patients due to A/H1N1 infection. These metabolic/obesity indicators, together with the profiles of pro-inflammatory acute phase proteins, may be important links between obesity and poor outcomes in A/H1N1 09 infection.