Title: Chemicals and Multiple Chemical Sensitivity (MCS)

Abstract

The Multiple Chemical Sensitivity (MCS) is a chronic disease with recurrent symptoms affecting multiple organs and systems, reproducible in response to exposure to low levels of chemical substances, which are not related to each other from a molecular point of view, a much lower concentration that those generally tolerated by the general population. The Symptoms improve or disappear when the triggers are removed (Consensus Report Of Chicago, USA 2001). MCS has an incidence between 2,5% and 12,6% in the population (Caress SM 2003-2004, Mooser 1987, Hausteiner 2005). Exposure the xenobiotic substances causes hyperactivation of NMDA receptor (Pall 2002, 2003, 2007, 2008, 2013), which trigger a vicious circle of NO/ONOO aggravated by increase of oxidative stress and pro inflammatory cytokines and reduced production of ATP. MCS patients often have olfactory disorders: 18F-FDG PET/TC Study, carried out first with a neutral stimulation, then with a pure stimulation, show anomalies of cerebral perfusion in patients with MCS, compared to the normal population (Chiaravalloti 2015). A recent regression analysis showed that patients with MCS have a higher incidence of mutation of the enzymes of Phase I (Cytochrome P450 2D6, 2C9, 2C19) and Phase II (GST, PON, SOD, NOS, UGT), involved in xenobiotic detoxification (Micarelli, Cormano 2019). Exposure to xenobiotic compounds and impaired functioning of Phase I and II enzymes can therefore cause bioaccumulation within living organism. The study of adducts on leukocyte DNA, carried out on 187 MCS patients of the Reference Center for Prevention, Diagnosis and Treatment of MCS of Policlinico Umberto I in Rome, showed the presence of 91 adduced genes, 72 xenobiotic substances such as heavy metals, pesticides, herbicides, insecticides, VOCs, derivatives of Petrol and exhaust gas.