IL-10 and TGF-ß unbalanced levels in neutrophils contribute to increase inflammatory cytokine expression in childhood obesity.

PURPOSE: Obesity is a multifactorial disease, associated with metabolic disorders, chronic low-grade inflammation, and impaired immunity. This study aimed to evaluate the childhood obesity-associated effects on neutrophil activation and cytokine production. METHODS: We evaluated activation and recognition markers and cytokine production in neutrophils from the peripheral blood of children with obesity and normal weight using multicolor flow cytometry. RESULTS: We demonstrate a higher frequency of neutrophils in childhood obesity group (CO) compared to normal-weight group (NW). Our data showed that neutrophils from CO group are capable of antigen recognition and presentation through higher expression of TLR-4 (CD284) and HLA-DR in comparison with neutrophils from NW. On the other hand, neutrophils from CO group are faulty to deliver co-stimulatory signals, through lower expression of co-stimulatory molecules. We showed an increased expression of IL-6, IL-1ß, IL-12, and TNF, and decreased expression of IL-8 and IL-10 by neutrophils from CO compared to NW, while TGF-ß is equivalently expressed in neutrophils from both groups. Despite this, we observed that TGF-ß/inflammatory cytokine ratio was significantly higher than the IL-10/inflammatory cytokine ratio only in CO group. Our analysis showed obesity altering the correlation profile for the expression of co-stimulatory, recognition, and activation molecules, as well as for cytokines by neutrophils, suggesting an association between lower IL-10 expression and inflammation in childhood obesity. CONCLUSIONS: The unbalance between the ratio of IL-10 and TGF-ß expressions, the IL-10 lower expression, and changes in correlation profile seem to contribute with an inefficient regulation of inflammatory cytokine expression in childhood obesity. However, these changes still not may be considered the sole mechanism that directs inflammation during childhood obesity, once other molecules, pathways, and cells should be evaluated.

Collaborative study to establish World Health Organization international reference reagents for dengue virus Types 1 to 4 RNA for use in nucleic acid testing.

BACKGROUND: Dengue is the most important reemerging mosquito-borne viral disease worldwide. Caused by dengue virus (DENV), a member of the genus Flavivirus in the Flaviviridae family, dengue can be asymptomatic (approx. 80% of cases) or symptomatic, ranging from a flu-like illness known as dengue fever, to a life-threatening form called severe dengue. DENV is primarily transmitted from human to human through the bite of mosquitoes of the genus Aedes; however, it is also transmissible by transfusion of blood and blood components and by solid organ transplant. Nucleic acid test (NAT) assays are considered the most appropriate approach for blood donor screening for recent DENV infections, but there is no Food and Drug Administration-approved assay for the screening of blood for DENV. STUDY DESIGN AND METHODS: An international collaborative study was conducted to assess the suitability of reference reagent (RR) candidates for DENV Types 1 to 4 RNA for use in NAT-based assays. RESULTS: Two sets of RR candidates were prepared for each DENV type, one liquid frozen (Set 1) and one lyophilized (Set 2). A total of 28 laboratories from 20 countries agreed to participate in the study, of which 21 submitted the results for qualitative and/or quantitative assessments. CONCLUSION: The World Health Organization has established the lyophilized materials as international RRs for DENV RNA with a unitage of 13,500, 69,200, 23,400, and 33,900 units/mL for DENV-1 to -4, respectively.

The role of interleukin 17-mediated immune response in Chagas disease: High level is correlated with better left ventricular function.

Interleukin 17A (IL-17A) has been associated with protective rather than pathogenic response in Chagas disease (ChD). However, it is not established whether or not IL-17A-mediated immune response is correlated with patient's left ventricular (LV) function in ChD. To address this question we have gathered cardiac functional parameters from ChD patients and analysed the possible relationship between their plasma IL-17A levels and LV function. Plasma IL-17A levels were measured by BD Cytometric Bead Array (CBA) in 240 patients with positive specific serology for Trypanosoma cruzi (T. cruzi) grouped as indeterminate (IND) and Chagas cardiomyopathy (CARD) forms. The levels of IL-17A in ChD patients were compared with 32 healthy individuals, mean age of 39 years, 50% male, that were also included as a control group (non-infected [NI]). The overall mean age of ChD patients was 46 years and 52% were male. The IND group included 95 asymptomatic patients, with ages ranging from 27 to 69 years (mean of 43 years), and 42.1% of them were male. The CARD group included 145 patients, which 58.6% were male, with ages ranging from 23 to 67 years (mean of 49). The IND group presented substantially higher levels of IL-17A, median of 26.16 (3.66-48.33) as compared to both the CARD group, median of 13.89 (3.87-34.54) (P <0.0001), and the NI group, median of 10.78 (6.23-22.26) (P <0.0001). The data analysis demonstrated that the IND group comprises a significantly greater proportion (P <0.001) of high IL-17A producers (52.6%, 50 of 95 subjects) than do the other groups. A significant direct correlation was verified between IL-17A levels and cardiac function expressed by LV ejection fraction (LVEF), LV diastolic diameter (LVDd), and body surface area (BSA)-indexed LVDd as well as ratio of the early diastolic transmitral flow velocity to early diastolic mitral annular velocity (E/e') in both groups. We demonstrated that plasma IL-17A levels has an accurate sensitivity and specificity to predict heart failure in serology-positive patients and might be a useful parameter to distinguish patients with or without cardiac impairment. This study indicates a consistent relationship between high expression of IL-17A and better LV in human chronic ChD. Our data raise the possibility that IL-17A plays an important immunomodulatory role in the chronic phase of ChD and might be involved in protection against myocardial damage.

Differential Expression of Matrix Metalloproteinases 2, 9 and Cytokines by Neutrophils and Monocytes in the Clinical Forms of Chagas Disease.

Dilated cardiomyopathy, the most severe manifestation in chronic phase of Chagas disease, affects about 30% of patients and is characterized by myocardial dysfunction and interstitial fibrosis due to extracellular matrix (ECM) remodeling. ECM remodeling is regulated by proteolytic enzymes such as matrix metalloproteinases (MMPs) and cytokines produced by immune cells, including phagocytes. We evaluated by flow cytometry the expression of MMP-2, MMP-9, IL-1ß, TNF-α, TGF-ß and IL-10 by neutrophils and monocytes from patients with indeterminate (IND) and cardiac (CARD) clinical forms of Chagas disease and non-infected individuals (NI), before and after in vitro stimulation with Trypanosoma cruzi antigens. Our results showed an important contribution of neutrophils for MMPs production, while monocytes seemed to be involved in cytokine production. The results showed that neutrophils and monocytes from IND and CARD patients had higher intracellular levels of MMP-2 and MMP-9 than NI individuals. On the other hand, T. cruzi derived-antigens promote a differential expression of MMP-2 and MMP-9 in patients with Chagas disease and may regulate MMPs expression in neutrophils and monocytes, mainly when a cardiac alteration is not present. Our data also showed that in the presence of T. cruzi derived-antigens the production of cytokines by neutrophils and monocytes, but mainly by monocytes, may be intensified. Correlation analysis demonstrated that MMP-2 had a positive correlation with IL-10 and a negative correlation with IL-1ß, whereas MMP-9 showed a negative correlation with IL-10. We also observed that IND patients presented a greater percentage of high producer cells of regulatory molecules when compared to CARD patients, indicating a different pattern in the immune response. Our data suggest that MMPs and cytokines produced by neutrophils and monocytes are important contributors for cardiac remodeling and may be an interesting target for new biomarker research.

Chronic Low-Grade Inflammation in Childhood Obesity Is Associated with Decreased IL-10 Expression by Monocyte Subsets.

Chronic low-grade inflammation is related to the development of comorbidities and poor prognosis in obesity. Monocytes are main sources of cytokines and play a pivotal role in inflammation. We evaluated monocyte frequency, phenotype and cytokine profile of monocyte subsets, to determine their association with the pathogenesis of childhood obesity. Children with obesity were evaluated for biochemical and anthropometric parameters. Monocyte subsets were characterized by flow cytometry, considering cytokine production and activation/recognition molecules. Correlation analysis between clinical parameters and immunological data delineated the monocytes contribution for low-grade inflammation. We observed a higher frequency of non-classical monocytes in the childhood obesity group (CO) than normal-weight group (NW). All subsets displayed higher TLR4 expression in CO, but their recognition and antigen presentation functions seem to be diminished due to lower expression of CD40, CD80/86 and HLA-DR. All subsets showed a lower expression of IL-10 in CO and correlation analyses showed changes in IL-10 expression profile. The lower expression of IL-10 may be decisive for the maintenance of the low-grade inflammation status in CO, especially for alterations in non-classical monocytes profile. These cells may contribute to supporting inflammation and loss of regulation in the immune response of children with obesity.

Distribution of Dengue Virus Types 1 and 4 in Blood Components from Infected Blood Donors from Puerto Rico.

BACKGROUND: Dengue is a mosquito-borne viral disease caused by the four dengue viruses (DENV-1 to 4) that can also be transmitted by blood transfusion and organ transplantation. The distribution of DENV in the components of blood from infected donors is poorly understood. METHODS: We used an in-house TaqMan qRT-PCR assay to test residual samples of plasma, cellular components of whole blood (CCWB), serum and clot specimens from the same collection from blood donors who were DENV-RNA-reactive in a parallel blood safety study. To assess whether DENV RNA detected by TaqMan was associated with infectious virus, DENV infectivity in available samples was determined by culture in mosquito cells. RESULTS: DENV RNA was detected by TaqMan in all tested blood components, albeit more consistently in the cellular components; 78.8% of CCWB, 73.3% of clots, 86.7% of sera and 41.8% of plasma samples. DENV-1 was detected in 48 plasma and 97 CCWB samples while DENV-4 was detected in 21 plasma and 31 CCWB samples. In mosquito cell cultures, 29/111 (26.1%) plasma and 32/97 (32.7%) CCWB samples were infectious. A subset of samples from 29 donors was separately analyzed to compare DENV viral loads in the available blood components. DENV viral loads did not differ significantly between components and ranged from 3-8 log10 PCR-detectable units/ml. CONCLUSIONS: DENV was present in all tested components from most donors, and viral RNA was not preferentially distributed in any of the tested components. Infectious DENV was also present in similar proportions in cultured plasma, clot and CCWB samples, indicating that these components may serve as a resource when sample sizes are limited. However, these results suggest that the sensitivity of the nucleic acid tests (NAT) for these viruses would not be improved by testing whole blood or components other than plasma.

Epidemiological Scenario of Dengue in Brazil.

Dengue is the most important reemerging mosquito-borne viral disease worldwide. It is caused by any of four Dengue virus types or serotypes (DENV-1 to DENV-4) and is transmitted by mosquitoes from the genus Aedes. Ecological changes have favored the geographic expansion of the vector and, since the dengue pandemic in the Asian and Pacific regions, the infection became widely distributed worldwide, reaching Brazil in 1845. The incidence of dengue in Brazil has been frequently high, and the number of cases in the country has at some point in time represented up to 60% of the dengue reported cases worldwide. This review addresses vector distribution, dengue outbreaks, circulating serotypes and genotypes, and prevention approaches being utilized in Brazil.