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 is 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 (n = 525). 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 tlgE, but not tIgA. The association with tIgG was mainly apparent n boys (p for interaction = 0.055), in whom each doubling of maternal U-As was related to an increase in tIgG by 28 mg/dL. The associations s at 9 years with tIgG and tIgE were evident in underweight children (p for interaction <0.032). 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 (beta)= -0.16; 95% confidence interval (CI): -0.33, 0.01; p = 0.064 and (beta = -0.12; 95% CI: -0.27, -0.029; p = 0.113, 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.