Global surface ultraviolet radiation intensity may modulate the clinical and immunologic expression of autoimmune muscle disease

Abstract

Objective. To determine if geoclimatic factors may influence the nature and frequency of dermatomyositis (DM), polymyositis, and associated autoantibodies around the world.Methods. We assessed, in the first global evaluation of these conditions, the relationship between 13 geoclimatic variables that may modulate disease and the relative proportion of DM and its associated autoantibody anti-Mi-2, directed against an SNF2-superfamily helicase associated with the nucleosome remodeling and histone acetylation and deacetylation complex, in a global myositis population. Altogether, 919 consecutive patients from populations at 15 locations were studied.Results. Univariate and multivariate analyses demonstrated that of the variables evaluated, surface ultraviolet (UV) radiation intensity (irradiance) most strongly contributed to the relative proportion of DM and was strongly related to the proportion of anti-Mi-2 autoantibodies (weighted r ‫؍‬ 0.939, P < 4 ؋ 10 -7 and weighted r ‫؍‬ 0.69, P ‫؍‬ 0.02, respectively). Published ethnogeographic immunogenetic allele frequencies imply that the striking differences in the proportion of DM-and DM-specific autoantibodies observed around the world are not the result of inherent global variations in known genetic risk factors.Conclusion. These data suggest that UV radiation exposure may modulate the clinical and immunologic expression of an autoimmune disease in different populations around the world.

UV Radiation Regulates Mi-2 through Protein Translation and Stability

“…Moreover, UV radiation exposure has been linked to an increased risk of developing DM and Mi-2 autoantibodies (18). Herein, we investigated the role of UV radiation on the regulation of Mi-2 protein.…”

“…Global epidemiological studies suggest that UV exposure increases the risk for development of DM as well as Mi-2-specific autoantibodies (18). We hypothesized a relationship between UV radiation and the regulation of the Mi-2 protein in the cellular context of these photosensitive rashes.…”

“…A study investigating global surface UV intensity and the development of DM showed a statistically significant association of UV intensity with the frequency of disease (18). Even more interesting was a similar relationship between UV intensity and DM patients expressing Mi-2 autoantibodies.…”

“…Recent evidence suggests that exposure to ultraviolet (UV) radiation may be an important risk factor for the disease as well as development of Mi-2 autoimmunity (18). A study investigating global surface UV intensity and the development of DM showed a statistically significant association of UV intensity with the frequency of disease (18).…”

Dermatomiosite

“…5 As lesões cutâneas e musculares são agravadas pelo sol. 24 Fototestes, entretanto, não reproduzem as lesões cutâneas, sendo o espectro de luz que causa as manifestações clínicas ainda desconhecido. 25 Segundo Hengstman et al, 26 uma das prováveis causas da DM é a radiação ultravioleta B.…”