Hypothesis for Induction and Propagation of Chemical Sensitivity Based on Biopsy Studies
William J. Meggs
Department of Emergency Medicine, East Carolina University School of Medicine, Greenville, North Carolina
Abstract
The reactive airways dysfunction syndrome (RADS), the reactive upper airways dysfunction syndrome (RUDS), the sick building syndrome (SBS), and the multiple chemical sensitivity syndrome (MCS) are overlapping disorders in which there is an intolerance to environmental chemicals. The onset of these illnesses is often associated with an initial acute chemical exposure. To understand the pathophysiology of these conditions, a study of the nasal pathology of individuals experiencing these syndromes was undertaken. Preliminary data indicate that the nasal pathology of these disorders is characterized by defects in tight junctions between cells, desquamation of the respiratory epithelium, glandular hyperplasia, lymphocytic infiltrates, and peripheral nerve fiber proliferation. These findings suggest a model for a relationship between the chronic inflammation seen in these conditions and an individual's sensitivity to chemicals. A positive feedback loop is set up: the inflammatory response to low levels of chemical irritants is enhanced due to the observed changes in the epithelium, and the epithelial changes are propagated by the inflammatory response to the chemicals. This model, combined with the concept of neurogenic switching, has the potential to explain many aspects of RADS, RUDS, SBS, and MCS in a unified way. -- Environ Health Perspect 105(Suppl 2):473-478 (1997)
Key words: rhinitis, asthma, sick building syndrome, multiple chemical sensitivity syndrome, reactive airways dysfunction syndrome, reactive upper airways dysfunction syndrome, neurogenic inflammation, neurogenic switching
This paper is based on a presentation at the Conference on Experimental Approaches to Chemical Sensitivity held 20-22 September 1995 in Princeton, New Jersey. Manuscript received at EHP 6 March 1996; manuscript accepted 10 October 1996.
The author thanks Drs. Tarik Elsheik, W. James Metzger, Marcus Albernaz, and Richard M. Bloch for their ongoing support and collaboration. This research was supported by the North Carolina Chapter of the American Lung Association.
Address correspondence to Dr. W.J. Meggs, Room 4W54, Brody Building, Department of Emergency Medicine, East Carolina University School of Medicine, Greenville, NC 27858. Telephone: (919) 816-2954. Fax: (919) 816-3589.
Abbreviations used: ETS, environmental tobacco smoke; MCS, multiple chemical sensitivity; RADS, reactive airways dysfunction syndrome; RUDS, reactive upper airways dysfunction syndrome; SBS, sick building syndrome; VIP, vasoactive intestinal polypeptide.
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Last Update: March 18, 1997