Assessment of Autoimmune Responses Associated with Asbestos Exposure in Libby, Montana, USA Jean C. Pfau, Jami J. Sentissi, Greg Weller, and Elizabeth A. Putnam Center for Environmental Health Sciences, Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana, USA Abstract Systemic autoimmune responses are associated with certain environmental exposures, including crystalline particles such as silica. Positive antinuclear antibody (ANA) tests have been reported in small cohorts exposed to asbestos, but many questions remain regarding the prevalence, pattern, and significance of autoantibodies associated with asbestos exposures. The population in Libby, Montana, provides a unique opportunity for such a study because of both occupational and environmental exposures that have occurred as a result of the mining of asbestos-contaminated vermiculite near the community. As part of a multifaceted assessment of the impact of asbestos exposures on this population, this study explored the possibility of exacerbated autoimmune responses. Age- and sex-matched sets of 50 serum samples from Libby and Missoula, Montana (unexposed) , were tested for ANA on HEp-2 cells using indirect immunofluorescence. Data included frequency of positive tests, ANA titers, staining patterns, and scored fluorescence intensity, all against known controls. Serum immunoglobulin A (IgA) , rheumatoid factor, and antibodies to extractable nuclear antigen (ENA) were also tested. The Libby samples showed significantly higher frequency of positive ANA and ENA tests, increased mean fluorescence intensity and titers of the ANAs, and higher serum IgA, compared with Missoula samples. In the Libby samples, positive correlations were found between ANA titers and both lung disease severity and extent of exposure. The results support the hypothesis that asbestos exposure is associated with autoimmune responses and suggests that a relationship exists between those responses and asbestos-related disease processes. Key words: asbestos, ANA, environmental autoimmunity, immunotoxicology. Environ Health Perspect 113:25-30 (2005) . doi:10.1289/ehp.7431 available via http://dx.doi.org/ [Online 30 September 2004] Address correspondence to J.C. Pfau, Center for Environmental Health Sciences, Department of Biomedical and Pharmaceutical Sciences, Skaggs 154, University of Montana, Missoula, MT 59812 USA. Telephone: (406) 243-4529. Fax: (406) 243-2807. E-mail: jean.pfau@umontana.edu We thank the subjects, families, and the Center for Asbestos Related Diseases Clinic in Libby, MT ; R. Hamilton [Center for Environmental Health Sciences (CEHS) biostatistics], C. Noonan (CEHS epidemiology) , and M. Fritzler, University of Calgary (rheumatology) for their expertise ; and T. Larson, Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry, for Tremolite Asbestos Registry data. This work was supported by National Institutes of Health grants ES-04804 (J.C.P.) and ES-11676 (E.A.P.) and National Research Service Award ES-11249 (J.C.P.) . The authors declare they have no competing financial interests. Received 16 July 2004 ; accepted 30 September 2004. The full version of this article is available for free in HTML or PDF formats. |