Association Between Atopic Dermatitis And Meteorological Factors And Correlation Study Between Serum HMGB1 Expression And Th17/Treg Balance

Background and objective: Atopic dermatitis(AD)is the leading burden of of all skin diseases,increasing prevalence of AD has further increased the health burden and economic burden.Environmental factors are closely associated with the onset of AD,as an essential part of the natural exposure environment,meteorological factors are involved in the occurrence and development of.Many studies have explored the association between meteorological factors and atopic dermatitis.however,the results are inconsistent.Given the results are conflicting,the link remains unclear.Previous epidemiological studies were conducted mainly in humid regions,studies in semi-arid areas are lacking.The study explored the exposure-response association between meteorological factors and AD outpatient visits effects of meteorological factors on AD in Lanzhou,China.Method: The daily cases of AD outpatient visits came from electronic medical record system of three large tertiary hospitals in Lanzhou.Daily meteorological data during the study period were collected from the China Meteorological Data Network(http://data.cma.cn).Daily average concentrations for air pollutants were collected from the Lanzhou Environmental Protection Bureau.We established a time series of AD outpatient visits,meteorological factors and air pollutants.Spearman correlation analysis between meteorological factors and air pollutants was applied to determine which of factors would be incorporated in the model.A Poisson generalized linear regression model combined with a distributed lag non-linear model(DLNM)was used to analyze data.Results: A total of 72,955 populations visit outpatient clinics for AD from 2013 to 2019.Extremely high or low temperature,extremely high diurnal temperature range(DTR),extremely low relative humidity(RH),and extremely high wind speed(WS)increased the risk of outpatient visits for AD.Extremely high wind speed had greater influences on outpatient visits for AD,with maximum cumulative risks of 3.281(95%CI: 2.948,3.653)at lag 0–21,respectively.Subgroup stratified analyses showed that females and children aged 0–14 years were more vulnerable.At lag0-21,RR values of extremely low temperature,extremely high temperature,extremely high DTR,extremely low RH,and extremely high WS affect females were 0.993(95% CI: 0.884,1.114),1.143(95% CI: 1.025,1.275),1.536(95% CI: 1.136,2.333),1.485(95% CI:1.323,1.667))and 3.651(95% CI: 3.140,4.245),respectively.RR values of extremely low temperature,extremely high temperature,extremely high DTR,extremely low RH,and extremely high WS affect children aged 0–14 years were 1.279(95% CI: 1.028,1.511),1.528(95% CI: 1.300,1.795),1.661(95% CI: 1.183,2.333),1.597(95% CI:1.362,1.872))and 3.966(95% CI: 3.257,4.831),respectively.Conclusion: The effect of meteorological factors on AD outpatient visits is nonlinear and lagged in Lanzhou.Extremely high or low temperatures,extremely high DTR,extremely low RH,and extremely high WS increased the risk of outpatient visits for AD.Background and objective: Atopic dermatitis(AD)is a chronically relapsing inflammatory skin disease.The etiology of AD is complex and still poorly understood,immune imbalance is the critical link in the pathogenesis of AD.Th17/Treg imbalance may participate in the pathogenesis of AD.Studies have suggested that high-mobility group box(HMGB1)might participate in the regulation of Th17/Treg balance in various inflammatory diseases.However,the relationship between HMGB1 and the imbalance of Th17/Treg in AD has not yet been reported.The present study explored whether there is a correlation between serum HMGB1 levels and Th17/Treg imbalance in patients with AD and clarified the role of HMGB1 in the immune balance of AD..Method: 30 patients with AD from April 27,2022,to September 14,2022,admitted to the dermatology outpatient clinic were enrolled,20 normal healthy people were gathered from child health department and the medical examination center of our hospital as the control group.We stratified patients into mild,moderate,and severe based on the scoring severity of AD(SCORAD)score.Peripheral venous blood was collected.IL-17 and IL-10 concentrations were detected by ELISA,the frequencies of Th17 and Treg cells were detected by flow cytometry.Serum HMGB1、IL-17、IL-10、the frequencies of Th17 and treg cells were compared using Mann-Whitney U between AD patients and healthy controls.The Spearman rank correlation was used to assess correlation between HMGB1 and IL-17、IL-10、the frequencies of Th17 and treg cells.Results: Serum levels of IL-10 and IL-17 A [5.52ng/m L(3.35-8.91),28.2pg/m L(14.00-112.96)] in AD patients were higher compared to healthy control [3.71pg/ml(1.39-6.66),20.50 pg/ml(11.05-29.36)](P < 0.05).HMGB1 and the percentage of peripheral eosinophils were significantly higher in patients with severe than with mild to moderate AD [9.21ng/m L(5.09-13.22)vs 4.58 ng/m L(1.80-7.49),3.30%(4.65%-7.05%)vs 2.40%(1.20%-3.38%),P<0.05].The percentages of Th17 cells and the ratio of Th17 to Treg cells [(3.59±1.57)%,0.78(0.53-1.07)] were significantly higher than healthy control [(1.98±0.75)%,0.31(0.25-0.45)](P<0.001).The percentages of Treg cells(4.80±2.20)% lower than healthy control(6.03±1.94)%(P<0.05).The levels of serum HMGB1 were positively correlated with the percentage of Th17 cells 、 Th17/Treg and IL-17A(r=0.537,0.370 and 0.388).There was no obvious relation between HMGB1 and the percentage of Th17 cells and IL-10.Conclusion: The serum levels of HMGB1 in AD patients was elevated compared to healthy control.HMGB1 was significantly higher in patients with severe than with mild to moderate AD.The levels of serum HMGB1 were positively correlated with the percentage of Th17 cells、Th17/Treg and IL-17 A.We speculate that HMGB1 could regulate Th17 differentiation to promote the development of AD.