Analysis of a Cluster of Cases of Wegener Granulomatosis

Abstract

Wegener granulomatosis is a chronic inflammatory autoimmune disease of unknown etiology. The sporadic occurrence, lack of familial or genetic associations, and rising incidence suggest possible exposure to environmental agents as causative for this disease. The objective of this study was to examine possible environmental triggers of Wegener granulomatosis. While conducting an environmental survey of potential precipitants of Wegener granulomatosis on a cohort of patients seen at Doylestown Hospital and at the University of Pennsylvania, we identified a cluster of cases in the Dublin, Pennsylvania, region. Through hospital records and patient contacts, we located 7 cases diagnosed in a 3-year period within a 10-mile radius of an Environmental Protection Agency (EPA) Superfund toxic waste site. The radius of inclusion represents a population of approximately 50,000 individuals. Assuming complete ascertainment of cases--which is unlikely given the methods used to acquire patients--the prevalence is 2- to 4-fold greater than the expected rate of 3 per 100,000. We identified toxins at or above "action level" within the demarcated geographic region using published data from the EPA. Furthermore, we queried patients regarding their particular chemical exposures. These patients with Wegener granulomatosis were possibly exposed to high levels of trichloroethylene (TCE), vinyl chloride, methyl tertiary-butyl ether (MTBE), dichloroethene (DCE), and chromic acid from several industrial waste sites within the area. Additionally, these patients reported a total of greater than 30 possible exposures, including the aforesaid chemical contaminants. Three of 5 patients whose water source is known had well water that exposed them to industrial runoff and necessitated EPA intervention. This data, along with other epidemiologic studies, suggest possible toxic exposures as potentially correctable risk factors for Wegener granulomatosis. We encourage clinicians to seek data that suggests an unusual environmental exposure and to solicit information that might implicate an industrial source for these exposures.