Nicotine modulates molecules of the innate immune response in epithelial cells and macrophages during infection with M. tuberculosis.

Smoking increases susceptibility to becoming infected with and developing tuberculosis. Among the components of cigarette smoke, nicotine has been identified as the main immunomodulatory molecule; however, its effect on the innate immune system is unknown. In the present study, the effect of nicotine on molecules of the innate immune system was evaluated. Lung epithelial cells and macrophages were infected with Mycobacterium tuberculosis (Mtb) and/or treated with nicotine. The results show that nicotine alone decreases the expression of the Toll-like receptors (TLR)-2, TLR-4 and NOD-2 in all three cell types, as well as the production of the SP-D surfactant protein in type II pneumocytes. Moreover, it was observed that nicotine decreases the production of interleukin (IL)-6 and C-C chemokine ligand (CCL)5 during Mtb infection in epithelial cells (EpCs), whereas in macrophages derived from human monocytes (MDMs) there is a decrease in IL-8, IL-6, tumor necrosis factor (TNF)-α, IL-10, CCL2, C-X-C chemokine ligand (CXCL)9 and CXCL10 only during infection with Mtb. Although modulation of the expression of cytokines and chemokines appears to be partially mediated by the nicotinic acetylcholine receptor α7, blocking this receptor found no effect on the expression of receptors and SP-D. In summary, it was found that nicotine modulates the expression of innate immunity molecules necessary for the defense against tuberculosis.

Regulatory T-cell subsets in response to specific Mycobacterium tuberculosis antigens in vitro distinguish among individuals with different QTF and TST reactivity.

Regulatory T cells (Tregs), a subset of CD4+ T cells related with immune regulation, have been associated with active and latent tuberculosis infection (LTBI). Treg frequencies were evaluated by multicolor flow cytometry (FC) in peripheral blood mononuclear cells (PBMCs) stimulated with mycobacterial antigens ESAT-6, CFP-10, and TB7.7 to assess their capacity to distinguish subjects with different reactivity to the QuantiFERON-TB® Gold In-Tube (QFT-IT) test and the tuberculin skin test (TST). Increased frequencies of CD4+CD25highCD39+ cells were found for the [TST+, QTF+] compared with the [TST+, QTF-] group. Also, higher frequencies were observed for the [TST+, QTF+] compared with the [TST+, QTF-] and [TST-, QTF-] groups in CD4+CD25highFoxp3+ and CD4+CD25highCD39+Foxp3+ populations. Receiver operating characteristics (ROC curve) analysis confirmed these discriminating results. QFT-IT and TST quantitative values correlated with several Treg population frequencies.

Analysis of Th1, Th17 and regulatory T cells in tuberculosis case contacts.

We have hypothesized that individuals infected with Mycobacteriumtuberculosis that exhibit different patterns of immune reactivity in serial interferon (IFN)-γ release assays (IGRA's) correspond to different status within the immune spectrum of latent tuberculosis (TB). Accordingly, we analyzed the possible association between the consistent results (negative or positive) in an IGRA test and relevant immune parameters, mainly the levels of Th1 and Th17 lymphocytes and T regulatory (Treg) cells in the peripheral blood of TB case contacts. We found that individuals with a persistently positive IGRA showed increased levels of Th1 and Th17 lymphocytes upon in vitro stimulation with MTB antigens. In addition, a significant increase in the proportion of CD4+CTLA-4+ and CD4+Foxp3+ cells was detected in assays with blood samples from these individuals. Our data support that different immune phenotypes can be identified into the spectrum of latent TB, by combining different parameters of immune reactivity against MTB.

Increased frequency of CD14+HLA-DR-/low cells in type 2 diabetes patients with poor glycemic control.

AIMS: Type 2 diabetes (T2DM) is associated with alterations of the immune response and T2DM patients have an increased risk for infections and certain sorts of cancers. Although CD14+HLA-DR-/low cells have emerged as important mediators of immunosuppression in several pathologies, including cancer and non-malignant diseases, the presence of these cells in T2DM is not fully characterized. METHODS: In this study, we evaluated the frequency of CD14+HLA-DR-/low cells in non-obese T2DM patients and their association with glycemic control. Peripheral blood mononuclear cells were isolated from healthy controls (HC, n = 24) and non-obese T2DM patients (n = 25), the population was evaluated by flow cytometry, and an analysis of correlation between cell frequencies and clinical variables was performed. RESULTS: CD14+HLA-DR-/low monocytes were expanded in patients with T2DM compared to HC regardless of weight. Among the subjects with T2DM, the frequency of CD14+HLA-DR-/low was higher in patients with poor glycemic control (HbA1c > 9%) compared to those with better glycemic control (HbA1c < 9%) and, positively correlated with the years since the diagnosis of T2DM, the age of the patients and the glycemic index. CONCLUSIONS: An increased frequency of CD14+HLA-DR-/low cells in the blood of T2DM patients was recorded. The influence of hyperglycemia seems to be independent of obesity, but related to glycemic control and age.

B regulatory cells associated with changes in biochemical and inflammatory parameters in normal-glycemic individuals, pre-diabetes and T2DM patients.

AIM: To determine the percentages of (CD19 + CD24 + CD38+, CD19 + CD24 + CD27+, CD19 + IL-10+)-Breg cells, IL-17 single and IL-17+/IFN-γ double producers T cells and IFN-γ+ T cells, in normal-glycemic individuals, prediabetes and T2DM patients, and to analyze the association of Breg cells with metabolic parameters of T2DM. METHODS: percentages of Breg cells, IL-17+ and IL-17 + IFN-γ+ T cells, IFN-γ+ T cells and IL-10 were determined by flow cytometry. IL-6 levels were evaluated by ELISA assay. RESULTS: increased IL-6 levels, IL-17+ and IL-17 + IFN-γ+ T cells and a diminution of IL-10 levels and CD19 + IL-10+ cells in T2DM patients were observed. We found that CD19 + CD24 + CD27+ cells and CD19 + CD24 + CD38+ cells were increased in T2DM patients. The percentages of CD19 + CD24 + CD38+ cells were associated with HOMA-B, TyG index, HDL and cholesterol values. In normal-glycemic individuals, CD19 + CD24 + CD27+ cells were inversely associated to triglycerides and TyG index. In prediabetes patients, CD19 + CD24 + CD38+ cells were inversely related with cholesterol and LDL. Finally, CD19 + CD24 + CD38+ cells were inversely related with HDL values in T2DM patients. CONCLUSION: Our results suggest that increased percentages of IL-17 single and IL-17/IFN-γ double producers T cells in T2DM patients may be a consequence of the initial CD19 + IL-10+ cells reduction. Furthermore, dyslipidemia could play an important role in percentages and activity of B regulatory cells.

Identification of putative miRNA biomarkers in early rheumatoid arthritis by genome-wide microarray profiling: A pilot study.

Despite the existing research, the etiology of rheumatoid arthritis (RA), an autoimmune disease remains poorly understood with early and accurate diagnosis difficult to achieve. MicroRNAs (miRNAs) play an important role in biological processes as modulators of transcription and translation. Previous studies have demonstrated a downregulation of several genes in early RA stages and in addition, miRNAs may serve as early biomarkers of subclinical changes in early RA. When comparing the four groups (ANOVA P < 0.01, fold change > 4), we found 253 differentially expressed miRNAs. Of these, 97 miRNAs were identified as overexpressed in early rheumatoid arthritis. The validation of miRNA microarray expression was performed in a set by RT-qPCR and showed strong agreement with microarray expression data. The putative targets of overexpressed microRNAs in early RA were significantly enriched in apoptosis, tolerance loss and Wnt pathways. Moreover, ROC analysis showed values of AUC 0.76 and P < 0.05 for miR 361-5p, identifying this miRNA as a potential biomarker of disease. We identified specific microRNAs associated with early rheumatoid arthritis and proposed them as early biomarkers of disease. Our results provide novel insight into immune disease physiopathology and describe unreported microRNAs in RA with potential for clinical use.

Transcriptional signature associated with early rheumatoid arthritis and healthy individuals at high risk to develop the disease.

BACKGROUND: Little is known regarding the mechanisms underlying the loss of tolerance in the early and preclinical stages of autoimmune diseases. The aim of this work was to identify the transcriptional profile and signaling pathways associated to non-treated early rheumatoid arthritis (RA) and subjects at high risk. Several biomarker candidates for early RA are proposed. METHODS: Whole blood total RNA was obtained from non-treated early RA patients with <1 year of evolution as well as from healthy first-degree relatives of patients with RA (FDR) classified as ACCP+ and ACCP- according to their antibodies serum levels against cyclic citrullinated peptides. Complementary RNA (cRNA) was synthetized and hybridized to high-density microarrays. Data was analyzed in Genespring Software and functional categories were assigned to a specific transcriptome identified in subjects with RA and FDR ACCP positive. Specific signaling pathways for genes associated to RA were identified. Gene expression was evaluated by qPCR. Receiver operating characteristic (ROC) analysis was used to evaluate these genes as biomarkers. RESULTS: A characteristic transcriptome of 551 induced genes and 4,402 repressed genes were identified in early RA patients. Bioinformatics analysis of the data identified a specific transcriptome in RA patients. Moreover, some overlapped transcriptional profiles between patients with RA and ACCP+ were identified, suggesting an up-regulated distinctive transcriptome from the preclinical stages up to progression to an early RA state. A total of 203 pathways have up-regulated genes that are shared between RA and ACCP+. Some of these genes show potential to be used as progression biomarkers for early RA with area under the curve of ROC > 0.92. These genes come from several functional categories associated to inflammation, Wnt signaling and type I interferon pathways. CONCLUSION: The presence of a specific transcriptome in whole blood of RA patients suggests the activation of a specific inflammatory transcriptional signature in early RA development. The set of overexpressed genes in early RA patients that are shared with ACCP+ subjects but not with ACCP- subjects, can represent a transcriptional signature involved with the transition of a preclinical to a clinical RA stage. Some of these particular up-regulated and down-regulated genes are related to inflammatory processes and could be considered as biomarker candidates for disease progression in subjects at risk to develop RA.

Interleukin levels in cerebrospinal fluid from children with neurocysticercosis.

No information about the levels of pro-inflammatory interleukins has been described in children with neurocysticercosis (NCC). The levels of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-5, IL-6, and IL-12 in the cerebrospinal fluid from children with NCC were determined by enzyme-linked immunosorbent assay (ELISA). Twelve children with NCC, six with active and six with inactive disease, and six children without NCC were studied. TNF-alpha was undetectable in CSF from controls and five children with inactive NCC, whereas the levels were significantly higher (median 22.1 pg/ml; P = 0.008) in all children with active NCC. Levels of IL-6 were low in active and inactive NCC patients but two subjects with active subarachnoid disease had high levels. IL-5 and IL-12 were not detected. This study shows that high levels of TNF-alpha are present in CSF from children with active NCC. IL-6 levels are higher when infection occurs in the subarachnoid space.

Giardia lamblia: isoenzyme analysis of 19 axenic strains isolated from symptomatic and asymptomatic patients in Mexico.

Infection of the small intestine of humans with the parasitic protozoon Giardia lamblia may have an asymptomatic course, or it may produce acute or chronic diarrhoea. In order to establish if the different clinical outcome of giardiasis in children could be due, at least partially, to strain differences, 19 isolates from asymptomatic and symptomatic cases studied in Mexico City were cultured under axenic conditions and the isoenzyme electrophoretic patterns of 10 different enzymes were compared. Strains from carriers and from symptomatic cases of giardiasis were equally amenable to isolation and axenization. Isoenzyme electrophoresis demonstrated remarkable homogeneity in 7 enzyme patterns for all 19 isolates, except for phosphoglucomutase, for which 3 different zymodemes were found. Therefore, these isolates of G. lamblia, obtained from a single geographical location, tended to be genetically homogeneous. In addition, there were no consistent zymodeme differences between isolates from symptomatic and asymptomatic human infections.

Interleukin mRNA changes in mast cells stimulated by TSL-1 antigens.

In this work we analyzed by RT-PCR, the mRNA changes for IL-4, IL-10, TNF and IFN (induced by TSL-1 antigens in a rat mast cell line (HRMC) with mucosal characteristics. The data obtained showed an increase of 65 and 52% in mRNA expression for IL-4 and TNF respectively and a decrease of 59 and 55% in mRNAs for IFN gamma and IL-10. Our results suggest that TSL-1 antigens induce the release from MC of regulatory molecules, such as IL-4 by an IgE independent mechanism. Our data also provides important information related to the ability of MC to participate not only in the effector phase against the infectious agents, but also in the orchestration of the immune response by the host against parasites.

Isolation and axenization of Giardia lamblia isolates from symptomatic and asymptomatic patients in Mexico.

Infection of the small intestine of humans with the parasitic protozoan Giardia lamblia may have an asymptomatic course, or else, may produce acute or chronic diarrhea. In order to establish if the different clinical outcome of giardiasis in children could be due, at least partially, to strain differences, isolates from asymptomatic and symptomatic cases studied in Mexico City during 1986 and 1987 were cultured under axenic conditions. With modifications of available methods for the isolation of G. lamblia from cysts in stools, we obtained 19 axenic isolates: 5 from symptomatic patients and 14 from asymptomatic cyst carriers. The isolation procedure involved: (1) concentration and cleaning of cysts through centrifugation in sucrose gradients; (2) excystment induction in acid solution; (3) culture in modified TYI-S-33 medium, and (4) axenization of isolates using ceftriaxone and Amphotericin B. Results indicate that isolates from carriers and from symptomatic cases of giardiasis are equally amenable to isolation and axenization. The Giardia isolates obtained are being studied to analyze differences in isoenzyme pattern, antigenicity, and molecular markers.

The effect of iron on the expression of cytokines in macrophages infected with Mycobacterium tuberculosis.

Iron is known to play an important role in different bacterial infections and, in particular, in their development. One example is infection with Mycobacterium tuberculosis where iron contributes to growth and survival of the bacteria within the host cell. The majority of studies performed on tuberculosis have focused on the direct effect of iron on bacterial growth; however, little is known about how iron modifies the mycobacterial-host interaction. In order to address this, we have investigated the effect of iron on intracellular growth of M. tuberculosis in J774 macrophages and the molecular mechanisms that are affected during this interaction. We observed that iron modifies intracellular growth of the mycobacteria and that their growth kinetics was modified from that observed for the extracellular situation in the presence of iron. Similarly, when iron was present during the infection, there was a reduced release of tumour necrosis factor-alpha and it was related to a higher number of bacilli inside the host cell and low expression of interleukin-1 (IL-1) and IL-6 mRNA. Hence, this work demonstrates that iron, besides promoting mycobacterial growth, also regulates the relationship between macrophage and bacteria.

Use of receiver operating characteristic curves to assess the performance of a microdilution assay for determination of drug susceptibility of clinical isolates of Mycobacterium tuberculosis.

The aim of this study was to apply receiver operating characteristic (ROC) analysis to the microplate Alamar blue assay, a recently developed alternative for drug susceptibility testing of mycobacteria. As this is a quantitative assay, its performance can be determined by ROC analysis, in which the area under the ROC curve represents a summary of test performance (the higher the area, the better the test's performance). Sixty isolates of Mycobacterium tuberculosis were tested by the microcolorimetric assay against six twofold dilutions of streptomycin, isoniazid, rifampin, and ethambutol. For each isolate, the susceptibility pattern was simultaneously established by the agar proportion method, the result of which represented the gold standard value for the ROC analysis. The critical concentration, area under the curve, and P value for each drug were determined by ROC curve analysis. The results of the assay were obtained in an average of 8 days of incubation. The performance of the assay was excellent for all four drugs: the area under the curves was >0.97, the P values were 0.000, and sensitivity was 94%, specificity 97%, predictive value for resistance >/=92%, predictive value for susceptibility 97%, and test efficiency 97%. According to ROC analysis, the microplate Alamar blue assay is a reliable method for determination of drug-susceptibility. Rapidity and cost efficiency are two additional qualities that make this test an excellent alternative for the drug susceptibility testing of Mycobacterium tuberculosis. The ROC curve analysis is a robust statistical approach for evaluating the performance of new quantitative methods for determination of drug sensitivity of Mycobacterium tuberculosis isolates.