Thursday, July 14, 2016
Micronutrient Deficiencies Associated with Failed Immune Response to Pathogens
During pregnancy, the hepatitis E virus (HEV) can cause spontaneous abortions, stillbirths, and hepatic failure. Large HEV outbreaks have been documented in regions of South Asia and Africa. In Bangladesh, 1 in 10 maternal and neonatal deaths is attributed to hepatitis. Micronutrient deficiencies may increase the risk of HEV infection during pregnancy.
A new prospective cohort study published in the American Journal of Tropical Medicine and Hygiene evaluated the effect of maternal micronutrient status on immunological health and the risk of HEV infection during pregnancy and through the early postpartum (PP) period.
The study conducted in Bangladesh included 1100 pregnant women who were administered 15 vitamin and mineral supplements or an iron and folic acid supplement. Blood samples were collected before supplementation, during the 3rd month, and at 3 months after childbirth. The blood samples that were positive for anti-HEV IgG were further tested to identify whether seroconversion occurred in the pregnancy. Seroconversion is the time taken for the specific antibody to develop and become detectable in the blood. Women whose blood samples did not contain HEV at postpartum were taken as the control group. The levels of plasma cytokine and nutrients such as vitamins A, E, and D were measured; plasma zinc, copper, and selenium levels were also measured. Women who developed antibody responses to HEV were referred to as seroconverters.
Seroconverters had high concentrations of both pro- and anti-inflammatory cytokines throughout pregnancy, which was associated with immune system dysfunction and a consequent increase in the risk of HEV infection and, possibly, other infections. Seroconverters had reduced circulating selenium, and a higher incidence of vitamin D deficiency and anaemia compared to the control group. Optimal vitamins A and D levels are essential to maintaining healthy anti-inflammatory Th2 cytokines, while zinc, iron, vitamin E, copper, and selenium are necessary for Th1 cytokine levels.
According to the findings of the study, deficiencies of micronutrients may lead to a dysregulated appearance of cytokines and a dysfunction of immunity, increasing the risk of HEV infection. Nutrient supplementation during pregnancy may enhance micronutrient levels; this may reduce the risk of HEV later in pregnancy or the postpartum period.
News source - Kmush BL, Labrique A, Li W, Klein SL, Schulze K, Shaikh S, Ali H, Engle RE, Wu L, Purcell RH, Mehra S. The association of cytokines and micronutrients with hepatitis e virus infection during pregnancy and the postpartum period in rural Bangladesh. The American journal of tropical medicine and hygiene. 2016 Jan 6;94(1):203-11.,