Toxicology and Applied Pharmacology

Occupational exposure is a factor closely related to few immune system diseases. An association between occupational exposures of inhaled dust, and auto-immunity, was postulated as early XXe century. Genetic factors exist and affect the development of systemic autoimmune disease in certain individuals. But occupational factors could also play a substantial role. The objective was to explore the potential association between dust and airborne hairdresser's exposure inducing autoimmune diseases, more specially Systemic Lupus Erythematous (SLE).The study investigated the relationship of occupational dust inhalation exposure in hairdressing salons, and onset of SLE. Cases were defined as, those who reported having SLE, with clinical and biological confirmation. Cases were more likely to have been exposed to Hairdressing Dust Inhalation Exposure (HDIE), than other people without the disease. Onset of SLE appears in a close temporal relationship with HDIE. The development of symptoms of fatigue, myalgia, arthralgia, dysesthesias of the hands and feet and skin problems, appeared to be linked to HDIE. Moreover, increase positive autoantibodies have been observed, followed by a decrease, after cessation of HDIE. These biomarkers were dependant of HDIE. SLE may be caused by a large number of chemically unrelated agents under circumstances of exposure, which were prolonged and frequent. Agents implicated in

triggering or accelerating SLE were mercury, iodine, vinyl chloride, and crystalline silica, possibly included in hairdressing products. But, it is difficult to infer correctly the exact agent because hairdressing products are made of many chemicals and mixtures. It is important to underline that dust itself has adjuvant effects. In conclusion, mechanism and epidemiology linking HDIE to development of SLE, are not well known. But these findings support the hypothesis that HDIE is frequently associated with SLE.