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In Argentina, more than 3 million people suffer from asthma, with numbers rising. When asthma patients acquire viral infections which, in turn, trigger the asthmatic response, they may develop subsequent bacterial infections, mainly by Streptococcus (S.) pneumoniae. This encapsulated Gram+ bacterium has been considered historically a T cell-independent antigen. Nevertheless, several papers describe the role of T cells in the immune response to S. pneumoniae. We evaluated the response to S. pneumoniae and compared it to the response to Mycobacterium (M.) tuberculosis, a different type of bacterium that requires a T helper type 1 ( Th1) response, in cells from atopic asthmatic children, to compare parameters for the same individual under exacerbation and in a stable situation whenever possible. We studied asthma patients and a control group of age-matched children, evaluating cell populations, activation markers and cytokine production by flow cytometry, and cytokine concentration in serum and cell culture supernatants by enzyme-linked immunosorbent assay ( ELISA). No differences were observed in γδ T cells for the same patient in either situation, and a tendency to lower percentages of CD4+ CD25hi T cells was observed under stability. A significantly lower production of tumour necrosis factor ( TNF)-α and a significantly higher production of interleukin ( IL)-5 was observed in asthma patients compared to healthy individuals, but no differences could be observed for IL-4, IL-13 or IL-10. A greater early activation response against M. tuberculosis, compared to S. pneumoniae, was observed in the asthmatic patients' cells. This may contribute to explaining why these patients frequently acquire infections caused by the latter bacterium and not the former. [ABSTRACT FROM AUTHOR]

Background: In yellow fever (YF) endemic areas, measles, mumps, and rubella (MMR), and YF vaccines are often co-administered in childhood vaccination schedules. Because these are live vaccines, we assessed potential immune interference that could result from co-administration. Methods: We conducted an open-label, randomized non-inferiority trial among healthy 1-year-olds in Misiones Province, Argentina. Children were randomized to one of three groups (1:1:1): Co-administration of MMR and YF vaccines (MMR1YF1), MMR followed by YF vaccine four weeks later (MMR1YF2), or YF followed by MMR vaccine four weeks later (YF1MMR2). Blood samples obtained pre-vaccination and 28 days post-vaccination were tested for immunoglobulin G antibodies against measles, mumps, and rubella, and for YF virus-specific neutralizing antibodies. Non-inferiority in seroconversion was assessed using a -5% non-inferiority margin. Antibody concentrations were compared with Kruskal-Wallis tests. Results: Of 851 randomized children, 738 were correctly vaccinated, had ≥ 1 follow-up sample, and were included in the intention-to-treat population. Non-inferior seroconversion was observed for all antigens (measles seroconversion: 97.9% in the MMR1YF1 group versus 96.3% in the MMR1YF2 group, a difference of 1.6% [90% CI -1.5, 4.7]; rubella: 97.9% MMR1YF1 versus 94.7% MMR1YF2, a difference of 3.3% [-0.1, 6.7]; mumps: 96.7% MMR1YF1 versus 97.9% MMR1YF2, a difference of -1.3% [-4.1, 1.5]; and YF: 96.3% MMR1YF1 versus 97.5% YF1MMR2, a difference of -1.2% [-4.2, 1.7]). Rubella antibody concentrations and YF titers were significantly lower following co-administration; measles and mumps concentrations were not impacted. Conclusion: Effective seroconversion was achieved and was not impacted by the co-administration, although antibody levels for two antigens were lower. The impact of lower antibody levels needs to be weighed against missed opportunities for vaccination to determine optimal timing for MMR and YF vaccine administration. Trial Registration: The study was retrospectively registered in ClinicalTrials.gov (NCT03368495) on 11/12/2017. [ABSTRACT FROM AUTHOR]

Background: Inflammation has been associated with increased morbidity and mortality in HIV-positive patients. We compared inflammatory biomarkers with dual therapy using lopinavir/ritonavir plus lamivudine (LPV/r+3TC) versus triple therapy using LPV/r plus two nucleoside reverse transcriptase inhibitors (LPV/r+2NRTIs) in treatment-naïve HIV-positive adults. Methods: This was a substudy among Argentinian participants in the randomized trial GARDEL. We measured hsCRP, IL-6, MCP-1, TNF, D-dimer and sCD14 from plasma collected at baseline, week 24 and week 48. Generalized estimating equations with an identity/logit link were used to model the average impact of dual versus triple therapy on each biomarker over time, controlling for baseline levels. Additional models estimated the average effect of virologic suppression on biomarker levels over time, adjusting for age, sex, and baseline CD4 count. Results: Of 191 trial participants enrolled in Argentina, 172 had baseline and follow-up measurements and were included. Median (IQR) age was 35.5 (28.5, 45) years and CD4 cell count was 310 (219, 414) cells/mm3. Dual therapy was not associated with significantly different biomarker levels over 48 weeks relative to triple therapy. Virologic suppression was associated with statistically significant decreases in MCP-1, TNF and D-dimer levels and an unexpected increase in sCD14 levels. No change was observed in hsCRP or the proportion of participants with undetectable IL-6 levels. Conclusions: In addition to having virologic non-inferiority, LPV/r+3TC dual therapy is generally associated with similar inflammatory biomarker levels over 48 weeks compared to LPV/r+2NRTIs triple therapy in treatment-naïve adults. Further study of dual treatment regimens is warranted. [ABSTRACT FROM AUTHOR]

Leukotrienes (LTs) produced from arachidonic acid by the action of 5-lipoxygenase (5-LO) are classical mediators of inflammatory responses. However, studies published in the literature regarding these mediators are contradictory and it remains uncertain whether these lipid mediators play a role in host defense against the fungal pathogen Paracoccidioides brasiliensis. To determine the involvement of LTs in the host response to pulmonary infection, wild-type and LT-deficient mice by targeted disruption of the 5-lipoxygenase gene (knockout mice) were studied following intratracheal challenge with P. brasiliensis yeasts. The results showed that infection is uniformly fatal in 5-LO-deficient mice and the mechanisms that account for this phenotype are an exacerbated lung injury and higher fungal pulmonary burden. Genetic ablation or pharmacological inhibition of LTs resulted in lower phagocytosis and fungicidal activity of macrophages in vitro, suggesting that deficiency in fungal clearance seems to be secondary to the absence of activation in 5-LO−/− macrophages. Exogenous LTB4 restored phagocytosis and fungicidal activity of 5-LO−/− macrophages. Moreover, P. brasiliensis killing promoted by LTB4 was dependent on nitric oxide (NO) production by macrophages. Taken together, these results reveal a fundamental role for 5-LO-derived LTB4 in the protective response to P. brasiliensis infection and identify relevant mechanisms for the control of fungal infection during the early stages of the host immune response. Author Summary: Paracoccidioidomycosis is a deep mycosis that is endemic in Latin America, mostly affecting rural workers of Argentina, Colombia, Venezuela and Brazil. Paracoccidioides brasiliensis infection is acquired upon the inhalation of airborne propagules derived from the saprophytic mycelium form of the fungus. Once in the lungs, P. brasiliensis converts to its parasitic yeast form and interacts with alveolar macrophages. This phagocytic cell is specialized in secreting cytokines, lipid mediators, and microbicidal molecules that control the fungal growth. Among the lipid mediators generated by macrophages, 5-LO-derived leukotrienes play an important role in lung innate immunity and are known to be important for neutrophil recruitment and activation. Here, we evaluated whether leukotrienes are involved in the immune response in a murine model of P. brasiliensis infection. 5-LO-deficient mice exhibited high mortality, severe lung pathogenesis and increased fungal burden in the lungs, associated with less activation of macrophages, resulting in lower phagocytosis and P. brasiliensis killing. These results reveal for the first time that endogenous production of leukotrienes, especially LTB4, is important for assembling a protective immune response of the host against P. brasiliensis. [ABSTRACT FROM AUTHOR]