Peripheral blood mononuclear cells from severe asthmatic children release lower amounts of IL-12 and IL-4 after LPS stimulation.

INTRODUCTION: Asthma is an inflammatory disorder of the airways associated with bronchial hyperresponsiveness, airway obstruction, and increased mucus production, with a predominance of type 2 immune response (Th2). According to the hygiene hypothesis, exposure to environmental bacterial lipopolysaccharide (LPS) may induce a type 1 immune response (Th1), modulating the development of asthma. OBJECTIVE: In this study we investigated cytokine production by peripheral blood mononuclear cells (PBMC) from children and adolescents with severe asthma, in response to LPS stimulation in vitro. MATERIALS AND METHODS: 26 children were selected: 13 severe asthmatics and 13 healthy controls, aged between 5 and 18 years. They were evaluated through routine medical history, physical examination and lung function test to diagnose severe asthma. Allergy status was confirmed by skin prick test and specific IgE assay. We collected blood samples to analyse in vitro LPS-induced cytokines release by PBMC. RESULTS: PBMC from severe asthmatic children produced lower levels of IL-12p70 in basal conditions and after 12 and 24h stimulation with LPS compared to healthy controls. PBMC from severe asthmatic children produced lower levels of IL-4 after 24h LPS stimulation compared to healthy controls. PBMC from severe asthmatic children produced more levels IL-17 and IL-10 after stimulus with LPS compared to healthy controls. The release of IFN-γ, IL-5 and TNF-α by PBMC from severe asthmatic children was similar to healthy controls. CONCLUSION: Our results demonstrate that LPS directly influence the cytokine profile of PBMC in children with severe asthma. These observations may be potentially helpful in developing new treatment strategies.

BAY 41-2272, a soluble guanylate cyclase agonist, activates human mononuclear phagocytes.

BACKGROUND AND PURPOSE: Phagocyte function is critical for host defense against infections. Defects in phagocytic function lead to several primary immunodeficiencies characterized by early onset of recurrent and severe infections. In this work, we further investigated the effects of BAY 41-2272, a soluble guanylate cyclase (sGC) agonist, on the activation of human peripheral blood monocytes (PBM) and THP-1 cells. EXPERIMENTAL APPROACH: THP-1 cells and PBM viability was evaluated by methylthiazoletetrazolium assay; reactive oxygen species production by lucigenin chemiluminescence; gene and protein expression of NAPDH oxidase components by qRT-PCR and Western blot analysis, respectively; phagocytosis and microbicidal activity by co-incubation, respectively, with zymosan and Escherichia coli; and cytokine release by elisa. KEY RESULTS: BAY 41-2272, compared with the untreated group, increased spreading of monocytes by at least 35%, superoxide production by at least 50%, and gp91(PHOX) and p67(PHOX) gene expression 20 to 40 times, in both PBM and THP-1 cells. BAY 41-2272 also augmented phagocytosis of zymosan particles threefold compared with control, doubled microbicidal activity against E. coli and enhanced the release of TNF-α and IL-12p70 by both PBM and THP-1 cells. Finally, by inhibiting sGC with ODQ, we showed that BAY 41-2272-induced superoxide production and phagocytosis is not dependent exclusively on sGC activation. CONCLUSIONS AND IMPLICATIONS: In addition to its ability to induce vasorelaxation and its potential application for therapy of vascular diseases, BAY 41-2272 was shown to activate human mononuclear phagocytes. Hence, it is a novel pro-inflammatory drug that may be useful for controlling infections in the immunocompromised host.

Antibody response to pneumococcal capsular polysaccharide vaccine in Down syndrome patients.

The majority of children with Down syndrome (DS) tend to have frequent bacterial infections including recurrent respiratory infections. Our objective was to evaluate the production of antibodies to pneumococcal polysaccharide antigens after active immunization in DS subjects. IgG antibodies to pneumococcal serotypes (1, 3, 6B, 9V, and 14) were measured before and 6 weeks after immunization with a 23-valent pneumococcal vaccine (Pneumo23, Pasteur-Merrieux) in 6- to 13-year-old DS children (N = 17) and in aged-matched normal controls (N = 30). An adequate response was defined as a 4-fold increase over baseline or a post-immunization level of specific pneumococcal serotype antibody > or = 1.3 microg/mL. After immunization, all DS children had an increase in post-immunization levels against all serotypes analyzed. A 4-fold or more increase was observed in all DS children concerning serotypes 1 and 14, in 90% of subjects for serotypes 3 and 9V, and in 65% for serotype 6B. Regarding this increase, 8 of the 17 DS children had an adequate response to all serotypes analyzed, 8/17 patients to 4 serotypes and 1/17 to 3 serotypes. However, when we compared post-immunization levels between DS children and controls, we observed lower levels in the former group (P < 0.05) for all serotypes except serotype 3. We conclude that pneumococcal polysaccharide immunization could be beneficial for these DS children.

Antibody response to pneumococcal capsular polysaccharide vaccine in Down syndrome patients

The majority of children with Down syndrome (DS) tend to have frequent bacterial infections including recurrent respiratory infections. Our objective was to evaluate the production of antibodies to pneumococcal polysaccharide antigens after active immunization in DS subjects. IgG antibodies to pneumococcal serotypes (1, 3, 6B, 9V, and 14) were measured before and 6 weeks after immunization with a 23-valent pneumococcal vaccine (Pneumo23®, Pasteur-Merrieux) in 6- to 13-year-old DS children (N = 17) and in aged-matched normal controls (N = 30). An adequate response was defined as a 4-fold increase over baseline or a post-immunization level of specific pneumococcal serotype antibody > or = 1.3 æg/mL. After immunization, all DS children had an increase in post-immunization levels against all serotypes analyzed. A 4-fold or more increase was observed in all DS children concerning serotypes 1 and 14, in 90 percent of subjects for serotypes 3 and 9V, and in 65 percent for serotype 6B. Regarding this increase, 8 of the 17 DS children had an adequate response to all serotypes analyzed, 8/17 patients to 4 serotypes and 1/17 to 3 serotypes. However, when we compared post-immunization levels between DS children and controls, we observed lower levels in the former group (P < 0.05) for all serotypes except serotype 3. We conclude that pneumococcal polysaccharide immunization could be beneficial for these DS children.