Identification of responsible volatile chemicals that induce hypersensitive reactions to multiple chemical sensitivity patients.

Multiple chemical sensitivity (MCS) has become a serious problem as a result of airtight techniques in modern construction. The mechanism of the MCS, however, has not been clarified. Responsible chemicals and their exposure levels for patient's hypersensitive reactions need to be identified. We measured the exposure of 15 MCS patients to both carbonyl compounds and volatile organic compounds (VOCs) that may induce hypersensitive reactions. The exposures of those not suffering from MCS (non-MCS individuals) were also measured at the same time. To characterize the chemicals responsible for MCS symptoms, we applied a new sampling strategy for the measurement of carbonyls and VOCs using active and passive sampling methods. The results of our study clearly demonstrated that the chemicals responsible for such hypersensitive reactions varied from patient to patient. Moreover, the concentrations during hypersensitive symptoms, which were apparent in some of the MCS patients, were far below both the WHO and the Japanese indoor guidelines. The average exposure levels of MCS patients within a 7-day period were lower than those of paired non-MCS individuals except for a few patients who were exposed to chemicals in their work places. This result indicates that the MCS patients try to keep away from exposures to the chemical compounds that cause some symptoms.