RESUMO
OBJECTIVE: To assess the effect of individual exposure, in real-time, to traffic-related pollutants on serum interleukin levels of childhood-onset lupus erythematous systemic (c-SLE) patients. METHODS: A longitudinal and observational design was conducted in 12 repeated measures of serum samples and clinical evaluations (totaling 108 measurements) of c-SLE patients over 30 consecutive months. Real-time, individual exposure to fine particles (PM2.5) and nitrogen dioxide (NO2) was measured with portable monitors. Generalized estimating equation was used to evaluate the association between exposure to PM2.5 and NO2 and the following serum cytokine levels on the 7 days preceding clinical assessment and serum collection: MCP1, IL-6, IL-8, IL-10, IL-17, IFN-alpha, and TNF-alpha. Disease activity and other risk factors were also controlled. RESULTS: An interquartile range (IQR) increase in PM2.5 daily concentration was significantly associated with increased levels of TNF-alpha on the third, fourth, and seventh day after exposure; IL-10 on the third and fourth day after exposure; IL-17 on the third and seventh day after exposure; and INF-alpha on the third day after exposure (p < 0.05). An IQR increase in 7-day moving average of PM2.5 was associated with a 6.2 pg/mL (95% CI: 0.5; 11.8; p = 0.04) increase in serum IFN-alpha level. An unexpected significant association was observed between an IQR increase in NO27-day cumulative concentration and a decrease of 1.6 pg/mL (95% CI: -2.6; -0.7; p < 0.001) in serum IL-17. CONCLUSION: Real-time exposure to PM2.5 prospectively associated with increased serum TNF-alpha, INF-alpha, IL-10, and IL-17 levels in c-SLE patients.