Mast cells control the expansion and differentiation of IL-10-competent B cells

The discovery of B cell subsets with regulatory properties, dependent on IL-10 production, has expanded our view on the mechanisms that control inflammation. Regulatory B cells acquire the ability to produce IL-10 in a stepwise process: first, they become IL-10 competent, a poised state in which B cells are sensitive to trigger signals but do not actually express the Il-10 gene; then, when exposed to appropriate stimuli, they start producing IL-10. Even if the existence of IL-10-competent B cells is now well established, it is not yet known how different immune cell types cross talk with B cells and affect IL-10-competent B cell differentiation and expansion. Mast cells (MCs) contribute to the differentiation and influence the effector functions of various immune cells, including B lymphocytes. In this study, we explored whether MCs could play a role in the expansion of IL-10-competent B cells and addressed the in vivo relevance of MC deficiency on the generation of these cells. We show that MCs can expand IL-10-competent B cells, but they do not directly induce IL-10 production; moreover, the absence of MCs negatively affects IL-10-competent B cell differentiation. Noteworthy, our findings reveal that the CD40L/CD40 axis plays a significant role in MC-driven expansion of IL-10-competent B cells in vitro and highlight the importance of MC CD40L signaling in the colon.

Rethinking the role of immunoglobulin E and its high-affinity receptor: new insights into allergy and beyond

Immunoglobulin E (IgE) and its high-affinity receptor (FcεRI) are well-known participants in the allergic response. The interaction of allergens with FcεRI-bound IgE antibodies is an essential step in mast cell/basophil activation and the subsequent release of allergic mediators. It is known that the affinity of the interaction between an IgE antibody and an allergen may differ, raising the question of whether FcεRI can decipher these differences. If so, do the cellular and physiological outcomes vary? Are the molecular mechanisms initiated by FcεRI similarly under low- or high-affinity interactions? Could the resulting inflammatory response differ? Recent discoveries summarized herein are beginning to shed new light on these important questions. What we have learned from them is that IgE and FcεRI form a complex regulatory network influencing the inflammatory response in allergy and beyond.

Characteristics of the built environment in relation to objectively measured physical activity among Mexican adults, 2011

INTRODUCTION

The built environment correlates of physical activity are documented in high-income countries but have yet to be studied among Mexican adults. Our objectives were to assess the associations between characteristics of the built environment and physical activity among adults in Cuernavaca, Mexico, and to examine potential moderation by perceived park and neighborhood safety.

METHODS

We conducted a population-based study of adults in Cuernavaca, Mexico, in 2011 (N = 677). Participants wore Actigraph GT3X accelerometers for 7 days. We used geographic information systems (GIS) to generate 500-m- and 1-km-buffer-based measures of net residential density, proportion of commercial land use, land-use mix, connectivity, walkability, and number of parks and transit routes. We also obtained data on distance to the nearest park with GIS. Perceived neighborhood and park safety were self-reported. We created quartile-based categories for all built environment characteristics and ran linear regression models to estimate the association between each characteristic and total weekly moderate-to-vigorous physical activity (MVPA) and MVPA within 10-minute bouts.

RESULTS

Walkability was inversely related to total weekly minutes of MVPA (1-km buffer, -46.9 [standard error, 20.0]; P = .03) and weekly minutes of MVPA within bouts (500-m buffer, -31.5 [12.9]; P = .02). The number of transit routes in the 500-m buffer was inversely related to total weekly minutes of MVPA (-23.8 [10.6]; P = .04). Perception of park safety moderated the association between physical activity and having a park intersect the 500-m buffer.

CONCLUSION

Our findings contrast with those from high-income countries, suggesting that environmental programs and policies to increase physical activity in Mexican cities cannot be adapted from high-income countries without considering the local context.

Hermansky-Pudlak syndrome. Overview of clinical and molecular features and case report of a new HPS-1 variant

Hermansky-Pudlak syndrome (HPS) is a rare, autosomal recessive disorder affecting lysosome-related organelles (LRO), including dense platelet granules. HPS causes oculocutaneous hypopigmentation, bleeding diathesis and granulomatous colitis or pulmonary fibrosis. To date, there is no curative treatment and the clinical management depends on the severity of symptoms. A prompt diagnosis of HPS patients could improve their quality of life and clinical management. However, the absence of a specific platelet function test, the wide molecular heterogeneity, and the lack of phenotype-genotype correlations hamper the rapid diagnosis. Nine subtypes of HPS have been identified as a result of mutations in nine genes that codify for proteins involved in formation and shuttle of the LRO. The molecular characterization of patients and knowledge derived from animal models of HPS contribute to the understanding of biogenesis and function of the LRO. This paper describes a patient with a novel homozygous nonsense mutation causing HPS and provides a review of the literature focusing on recent advances in the molecular characterization and physiopathology of HPS.

Obesity Prevention in Latin America

In Latin American countries, obesity prevalence has increased significantly as a result of rapid urbanization and an improvement in socioeconomic conditions. We report the prevalence of overweight and/or obesity and prevention efforts in five countries: Mexico, Colombia, Brazil, Peru, and Chile. In children, the highest and lowest rates of obesity are found in Chile (23 % in 6-year-olds) and Peru (1.8 % in those <5 years), respectively. In adults, Mexico and Chile present similar high rates of obesity (around 35 %), whereas in Brazil and Colombia, the rates are around 20 % and 16.5 %, respectively. In general, the highest prevalence occurs in low-income women. Every country has developed initiatives to target obesity, from the government to the private sector and academia, mainly at the health sector and school settings. Food labeling is being addressed, but has not been implemented yet. Two interventions are described, a community-based in Mexico and a school-based in Chile. Because the increase in chronic diseases, especially diabetes, has paralleled that of obesity, effective prevention efforts are urgently needed.

Uso Combinado del Método Cualitativo y del Metanálisis en el Enfoque Diagnóstico de la Diarrea Infecciosa

Objetivo: Comparar la utilidad diagnóstica de pruebas índice en la identificación de la diarrea invasiva. Métodos: Combinación de análisis cualitativo y cuantitativo (metanálisis). Identificación de datos y selección de los estudios: De 2603 referencias identificadas vía MEDLINE (1970 -1994), listas de referencia y por correspondencia con expertos en el campo, 81 cumplieron los requerimientos de selección preestablecidos. De éstas, 25 contenían datos suficientes para un metanálisis adicional. Extracción de datos: En la revisión cualitativa, un autor extrajo información amplia sobre la utilidad diagnóstica de las pruebas índice y sobre las características metodológicas de los estudios. En el metanálisis, todos los datos de los artículos seleccionados fueron extraídos por un investigador, en tanto otro verificó su exactitud. Se calculó la tasa de verdaderos positivos (TPR) y de falsos positivos (FPR), a partir de cada tabia de contingencia de 2 x 2. Utilizando el método de transformación logística y regresión lineal ponderada de cuadrados mínimos, se elaboró curvas resumen de las característícas operativas del receptor (SROC), para determinar la utilidad diagnóstica comparativa de las pruebas. Resultados del análisis de datos: El enfoque cualitativo no restrictivo identificó problemas metodológicos que fueron evaluados adicionalmente en el estudio cuantitativo. En el metanálisis, la graficación de TPR contra FPR, como curvas SROC, demostró puntos dispersos, indicando heterogeneidad. La curva de lactoferrina fecal mostró el mayor rendimiento y la de leucocitos fecales el menor rendimiento. Conclusiones: La lactoferrina fecal es la prueba con mayor utilidad diagnóstica en la identificación de la diarrea invasiva. Se propone la utilización del enfoque combinado cualitativo y metanalítico como un método adecuado de evaluación de la utilidad de pruebas diagnósticas, tanto en la práctica clínica como en el proceso general de análisis de decisiones.

[Pneumatosis cystoides intestinalis: a case report and review of the literature]

Pneumatosis cystoides intestinalis features the presence of subserum or submucous cysts with gas in the intestinal wall. Its prevalence is 0.03%, although it has increased in the past decades due to a greater use of colonoscopy in everyday medical practice. Though there are several theories about its origin and many associated diseases were reported, its pathogenesis still remains uncertain. It is generally diagnosed as a finding in an imaging test. The treatment depends on the severity of the associated disease and symptoms. We report the case of a 59-year-old woman, heavy smoker, with no other clinical conditions who took a medical consultation due to abdominal bloating. She underwent a screening colonoscopy which detected the existence of cysts on the colonic wall. Afterwards, a computed tomography was performed and showed apical lung bullae, gas in a colonic wall segment, and ascitis associated to a big anexial tumor. She underwent a cytoreductive surgery, confirming the presence of advanced ovary neoplasm. The endoscopic biopsy confirmed the diagnosis of penumatosis cystoides intestinalis. We report these case because it is a rare entity which requires uncommon management and treatment guidelines.

Autoreactive IgE is prevalent in systemic lupus erythematosus and is associated with increased disease activity and nephritis

The presence of autoantibodies in systemic lupus erythematosus, particularly those of the IgG subclass, have long been associated with disease onset and activity. Here we explored the prevalence of autoreactive IgE in SLE and its relevance to disease in French (n = 79) and United States (US) (n = 117) cohorts with a mean age of 41.5 ± 12.7 and 43.6 ± 15.3 years and disease duration of 13.5 ± 8.5 and 16.6 ± 11.9 years, respectively. Our findings show that approximately 65% of all SLE subjects studied produced IgE antibodies to the seven autoantigens tested. This positivity was increased to almost 83% when only those subjects with active disease were considered. SLE subjects who were positive for anti-dsDNA, -Sm, and -SSB/La -specific IgE showed a highly significant association in the levels of these antibodies with disease activity similar to that of the corresponding IgG's. A strong association of IgE autoantibodies with active nephritis was also found in the combined cohort analysis. A test of the predictive value of autoreactive IgE's and IgGs for disease activity (SLE Disease Activity Index (SLEDAI) ≥ 4) revealed that the best predictors were dsDNA-specific IgE and IgG, and that the age of an SLE subject influenced this predictive model. The finding argue that the overall levels of IgE autoantibodies, independently or in combination with IgG autoantibodies, may serve as indicators of active disease.

Molecular editing of cellular responses by the high-affinity receptor for IgE

Cellular responses elicited by cell surface receptors differ according to stimulus strength. We investigated how the high-affinity receptor for immunoglobulin E (IgE) modulates the response of mast cells to a high- or low-affinity stimulus. Both high- and low-affinity stimuli elicited similar receptor phosphorylation; however, differences were observed in receptor cluster size, mobility, distribution, and the cells' effector responses. Low-affinity stimulation increased receptor association with the Src family kinase Fgr and shifted signals from the adapter LAT1 to the related adapter LAT2. LAT1-dependent calcium signals required for mast cell degranulation were dampened, but the role of LAT2 in chemokine production was enhanced, altering immune cell recruitment at the site of inflammation. These findings uncover how receptor discrimination of stimulus strength can be interpreted as distinct in vivo outcomes.

Family history of coronary heart disease and the incidence and progression of coronary artery calcification: Multi-Ethnic Study of Atherosclerosis (MESA)

OBJECTIVE

We evaluated family history as a predictor of incident and progressive coronary artery calcium (CAC) using data from the Multi-Ethnic Study of Atherosclerosis (MESA).

BACKGROUND

MESA is a multi-center prospective study of 6814 asymptomatic individuals. The relationship between family history of coronary heart disease (CHD) and CAC incidence or progression has not been described previously.

METHODS

A total of 5099 participants had detailed information about family history of CHD (late versus premature and parental versus sibling history). The mean time between CAC scans was 3.1 ± 1.3 years. The association of late versus premature family history was assessed against CAC change using multivariate regression model adjusted for demographics and cardiac risk factors.

RESULTS

A family history of premature CHD was associated with an odds ratio (OR) of 1.55 (p < 0.01) for incident development of CAC after adjusting for risk factors and demographics. A premature family history was associated with 14.4 units (p < 0.01) greater volume scores compared to those with no family history in similarly adjusted models by median regression analysis. A combined parental and sibling family history was associated with the greatest incidence and progression in demographic-adjusted models. Caucasians demonstrated the most consistent predictive relationship between family history of premature CHD and incidence (p < 0.01) and progression (p < 0.05) of CAC, though no significant interaction with ethnicity was noted.

CONCLUSIONS

Family history of premature CHD is associated with enhanced development and progression of subclinical disease, independent of other risk factors, in a multiethnic, population-based study.

Contribution of formative research to design an environmental program for obesity prevention in schools in Mexico City

OBJECTIVE

This paper describes the methods and key findings of formative research conducted to design a school-based program for obesity prevention.

MATERIALS AND METHODS

Formative research was based on the ecological model and the principles of social marketing. A mixed method approach was used. Qualitative (direct observation, indepth interviews, focus group discussions and photo-voice) and quantitative (closed ended surveys, checklists, anthropometry) methods were employed.

RESULTS

Formative research key findings, including barriers by levels of the ecological model, were used for designing a program including environmental strategies to discourage the consumption of energy dense foods and sugar beverages.

CONCLUSION

Formative research was fundamental to developing a context specific obesity prevention program in schools that seeks environment modification and behavior change.