Simultaneous analysis of the local and systemic immune responses in mice to study the occupational asthma mechanisms induced by chromium and platinum.

As a result of industrial development, increased exposure to platinum and chromium compounds and the subsequent development of occupational asthma (OA) has been reported. Although specific IgE antibodies, an indicator of allergic asthma, against chromium and platinum have been detected in workers with OA, the immunopathological mechanisms involved in this disease are not fully understood. To better understand these complex mechanisms, the local and systemic immune responses were simultaneously analyzed in mice sensitized and challenged three, four, or five times with sodium hexachloroplatinate (Pt salt) and with potassium dichromate (Cr salt) via the respiratory route. Dinitrochlorobenzene (DNCB) and anhydride trimellitic (TMA) were included in this study as reference compounds that induce Th1 and Th2 responses respectively. All the compounds studied may provoke pulmonary sensitization. In the Pt salt-treated mice with a significant increase in local Th2 cytokine production, the increase in IgE and mucus production and in eosinophil number had a positive correlation with the number of challenges (r=0.942, 0.976, and 0.978 respectively), whereas in the Cr salt-treated mice with no local increase in Th2 cytokines, the increase in IgE production and eosinophil numbers had an inverse correlation with the number of challenges (r=-0.895 and -0.999 respectively). The Th2-dominated response induced by Pt salt was very close to that induced by TMA and may thrive after the fifth challenge, probably due to the constancy of the significant decrease in IFN-γ level in the spleens. The results of the present work may increase our understanding of the immunopathological mechanisms of OA induced by platinum and chromium, and emphasize the advantage of simultaneously analyzing local and systemic immune response when studying respiratory allergy.