The Complement System as a Biomarker of Environmental Pollutants as Toxic Agents: A Focus on Polybrominated Diphenyl Ethers (PBDEs) Exposure

Polybrominated diphenyl ethers (PBDEs) were the most widely used brominated flame retardants worldwide in recent decades. Due to their ubiquity in the environment and toxicity, PBDEs have posed great threat to both ecosystems and human health. PBDEs are commonly detected in aquatic ecosystems, causing bioaccumulation in fish tissues. In humans, food consumption (fish for example) and absorption of house dust are the major pathways of PBDEs exposure. Human and fish exposure to PBDEs are related to neurodevelopmental impairment, hepatotoxicity, metabolic, endocrine, and carcinogenic disruptions, as well immunological suppression. Among the components of the immune system, the complement system that plays a functional bridge between innate and adaptive immune responses has been evaluated after PBDE exposure in humans, mice, and fishes. Since its central role in immune response, the complement has risen as an important immunological indicator that may be used as biomarkers to monitor the effects of PDBEs exposure.