Unexpected effects on the immune system are revealed by a gene study on tetrabromobisphenol A.

Tetrabromobisphenol A (TBBPA) is a potent flame retardant used in numerous appliances and is a major pollutant in households and ecosystems. It is the most widely used Bromophenolic flame retardant (BFR). TBBPA was thought to account for over 60% of all BFR production globally in 2004, with the yearly production in the United States, Japan, and Israel reaching about 170,000 tonnes. 

TBBPA is produced in large quantities, and as a result, it has been found in both terrestrial and aquatic environments as well as in air and inhaled dust. It has been demonstrated to have an impact on thyroid signaling, neurodevelopment, and the hypothalamic-pituitary-gonadal axis in vertebrates. Particularly at the level of transcriptome reprogramming, the molecular phenotype brought on by TBBPA exposure is only sketchily defined. 

TBBPA influences a significant number of genes, according to research from the National Museum of Natural History in Paris that applied a systems biology method to analyse experimental data on rodent stem cells. Surprisingly, they also discovered the following "hotspots of action": 

1. at the level of immune system operations  

2. at the level of neural development indicators  

The most well-known effects are related to its neurotoxicity and its impact on reproduction and the hypothalamo-pituitary-gonadal axis. Three weeks old mice exposed through maternal milk of mothers fed with high doses of TBBPA resulted in neurological and behavioral alterations. TBBPA also affects the nervous system. A high throughput toxicity test of a bank of 84 compounds identified TBBPA as a selective toxicant targeting dopaminergic neurons of midbrain-like tissues grown as organoids. 

TBBPA has the ability to impair not just the homeostatic balance of multiple endocrine pathways and neural development, but also the primary system defending body integrity from aggressors and the potential to cause cancer, hence Norway has asked Echa to designate it as a substance of very high concern (SVHC). In accordance with the Community Rolling Action Plan (Corap) of the EU, Denmark is also testing the drug for endocrine-disrupting characteristics.