Chronic methyl mercury poisoning may trigger endemic pemphigus foliaceus “fogo selvagem”

In endemic pemphigus foliaceus (EPF) or “fogo selvagem” the epidemiological evidence shows that all the described outbreaks occur on the banks of rivers where there is mercury contamination from alluvium gold mining and deforestation.Pathophysiological evidence shows a similarity to pemphigus induced by sulphydryl (SH−) drugs that act by denaturing cadherins at the desmosomal level, which are the pemphigus antigens. The sulfhydryl radical (SH−) call also thiol or mercaptans from the SH-drugs, act at the level of SH-groups of cystein as would the methyl mercury from the contaminated animals and fish in the diet of humans from endemic areas of pemphigus foliaceus. The methyl mercury would join the SH-groups from the cysteines amino acids from cadherin proteins in the skin. The autoimmune disease would only be triggered in genetically susceptible individuals with human leukocyte antigen HLA-DRB 1 haplotypes, just as Brown-Norway (BN) rats which are susceptible to develop Th2-dependent autoimmunity induced by metals. Immunological evidence from all the seroepidemiological studies could also be explained by binding mechanism of the methyl mercury to the SH-groups from the cysteines in the desmosomal cadherins proteins. The conclusion is that chronic methyl mercury poisoning is the most likely trigger of endemic pemphigus foliaceus “fogo selvagem”. To reduce the contamination of methyl mercury in the animals of the polluted rivers is pertinent to the design of campaigns and education programs with the population. Implement reforestation and biological control measures like phytoremediation technologies using decontaminant plants to decrease the methylation, and the process of biomagnifications of the methyl mercury in the Latin-America EPF foci.