In another region of the clustered "etiome", CTLA4 (cytotoxic T-lymphocyte antigen 4) and TNF were clustered with immune-mediated processes such as thyroiditis, viral hepatitis vaccines, and immunizations, and more distant similarity with a myriad of environmental pollutants, such as toluenes, air pollution, polymers, and even silicones (Figure 3B). This evidence concerns the gene CTLA4 and viral hepatitis.