Humoral Immunity in Arsenic-Exposed Children in Rural Bangladesh: Total Immunoglobulins and Vaccine-Specific Antibodies

BACKGROUND: Early-life arsenic exposure has been associated with reduced cell-mediated immunity, but little is known about its effects on humoral immunity. OBJECTIVE: We evaluated whether prenatal and childhood arsenic exposure was associated with humoral immune function in school-aged children. METHODS: Children born in a prospective mother–child cohort in rural Bangladesh were immunized with measles, mumps, and rubella (MMR) vaccines at 9 years of age ([Formula: see text]). Arsenic exposure was assessed in urine (U-As), from mothers during pregnancy and their children at 4.5 and 9 years of age. Total IgG (tIgG), tIgE, tIgA, and MMR-specific IgG concentrations were measured in plasma using immunoassays. RESULTS: Arsenic exposure was positively associated with child tIgG and tIgE, but not tIgA. The association with tIgG was mainly apparent in boys (p for [Formula: see text]), in whom each doubling of maternal U-As was related to an increase in tIgG by [Formula: see text]. The associations of U-As at 9 years with tIgG and tIgE were evident in underweight children (p for interaction [Formula: see text]). Childhood arsenic exposure tended to impair mumps-specific vaccine response, although the evaluation was complicated by high preimmunization titers. Postimmunization mumps–specific IgG titers tended to decrease with increasing U-As at 4.5 and 9 years of age [regression coefficient [Formula: see text]; 95% confidence interval (CI): [Formula: see text] , 0.01; [Formula: see text] and [Formula: see text]; 95% CI: [Formula: see text] , [Formula: see text]; [Formula: see text] , respectively) in 25% children with the lowest preexisting mumps-specific IgG titers. CONCLUSIONS: Arsenic exposure increased tIgG and tIgE in plasma, and tended to decrease mumps-specific IgG in children at 9 years of age. https://doi.org/10.1289/EHP318