Abstract
Electrohypersensitivty (EHS) and multiple chemical sensitivity (MCS) are new worldwide emerging neurologic disorders in the framework of sensitivity-related environmental pathology. We have recently extended and confirmed our previous observation showing that EHS and MCS share clinically identical symptoms and may co-exist as a unique, common, sensitivity-related neurologic syndrome in 25% of the cases. There is presently no published biological study of these disorders, except the one we have previously published as preliminary. In the present study, we show that EHS and MCS and the combined syndrome share identical biochemical changes. More precisely, by measuring levels of peripheral blood and urine molecular biomarkers in a cohort of 2,018 consecutive cases, we show that both disorders and the combined syndrome can be objectively characterized, in about 90% of the cases, by a decrease in the production of 6-hydroxymelatonin sulfate in urine, while in 30-50% they are characterized by increased levels of histamine and of heat shock proteins (HSP) 27 and/or 70, and of protein S100B and nitrotyrosine in the peripheral blood. Increased levels of histamine and HSP are indicators of low grade inflammation while increased levels of protein S100B and nitrotyrosine are indicators of blood-brain barrier disruption/opening. In addition, we show that in about 15% of the cases anti-myelin autoantibodies can be detected in the peripheral blood, accounting for the occurrence of an autoimmune response. Sensitivity, specificity and reproducibility of the biochemical tests are discussed, as well as the role of these indicators used as biomarkers for the diagnosis and follow-up of patients. We also discuss cases with undetectable biological change for which they can be nevertheless diagnosed by cerebral neurotransmitters analysis in urine and brain imaging. On the basis of these biological data it is suggested that EHS and/or MCS are new brain disorders, generated via a common etiopathogenic mechanism.