Maternal immunization with ovalbumin prevents neonatal allergy development and up-regulates inhibitory receptor FcγRIIB expression on B cells

Abstract Background Preconception allergen immunization prevents neonatal allergen sensitization in mice by a complex interaction between regulatory cells/factors and antibodies. The present study assessed the influence of maternal immunization with ovalbumin (OVA) on the immune response of 3 day-old and 3 week-old offspring immunized or non-immunized with OVA and evaluated the effect of IgG treatment during fetal development or neonatal period. Results Maternal immunization with OVA showed increased levels of FcγRIIb expression in splenic B cells of neonates, which were maintained for up to 3 weeks and not affected by additional postnatal OVA immunization. Maternal immunization also exerted a down-modulatory effect on both IL-4 and IFN-γ-secreting T cells and IL-4 and IL-12- secreting B cells. Furthermore, immunized neonates from immunized mothers showed a marked inhibition of antigen-specifc IgE Ab production and lowered Th2/Th1 cytokine levels, whereas displaying enhanced FcγRIIb expression on B cells. These offspring also showed reduced antigen-specific proliferative response and lowered B cell responsiveness. Moreover, in vitro evaluation revealed an impairment of B cell activation upon engagement of B cell antigen receptor by IgG from OVA-immunized mice. Finally, in vivo IgG transference during pregnancy or breastfeeding revealed that maternal Ab transference was able to increase regulatory cytokines, such as IL-10, in the prenatal stage; yet only the postnatal treatment prevented neonatal sensitization. None of the IgG treatments induced immunological changes in the offspring, as it was observed for those from OVA-immunized mothers. Conclusion Maternal immunization upregulates the inhibitory FcγRIIb expression on offspring B cells, avoiding skewed Th2 response and development of allergy. These findings contribute to the advancement of prophylactic strategies to prevent allergic diseases in early life.

Prevalence of the metabolic syndrome using two proposed definitions in a Japanese-Brazilians community

Metabolic Syndrome (MetS) is associated with increased risk of morbi-mortality, thus the characterization of the population magnitude of this syndrome is critical for allocating health care. However, prevalence estimates of MetS in the same population could differ depending on the definition used. Therefore, we compared the prevalence of the MetS using definitions proposed by: National Cholesterol Education Panel Revised (NCEP) and International Diabetes Federation (IDF) 2009 in a Japanese-Brazilians community (131 individuals, age 57 ± 16 years, 1st and 2nd generation). All individuals went through a clinical and laboratorial evaluation for assessment of weigh, height, waist circumference, blood pressure, triglycerides, HDL-cholesterol and fasting plasma glucose. The prevalence of MetS was 26.7% (n = 35) and 37.4% (n = 49) under the NCEP and IDF definitions, respectively. Despite higher blood pressure measurements, waist circumference and serum triglyceride levels and lower HDL cholesterol levels (p < 0.01), individuals identified with MetS did not show increased blood glucose levels. IDF definition classified 14 individuals (10.7%) with MetS that were not classified under the NCEP and 35 individuals were identified with MetS by both criteria. We observed, in this group, more severe lipid disorders, compared to individuals identified only under the IDF definition, and the BMI and waist circumference (p = 0.01; p = 0.006, respectively) were lower. In conclusion, the IDF revised criteria, probably because of the ethnic specific values of waist circumference, was able to identify a larger number of individuals with MetS. However, our data suggesting that additional studies are necessary to define best MetS diagnostic criteria in this population.