The Regulation Of Th1/Th2 In Contact Sensitisation Due To Paraphenylenediamine On Skin

Objective:Allergic contact dermatitis(ACD)in dye is a delayed-type hypersensitivity(DTH)induced by T cells,and sometimes delayed subtype of typeⅠincluded rarely.It has been a difficult and common problem for both consumer and dermatologist.Nowadays the use of dye is fashionable,but for covering the white hair only.The patients with allergic contact dermatitis in dye are more and more. Unfortunately,now our strategy for these patients is to avoid the allergen only.Thus they will suffer from the psychologic deseases and the loss of their confidences. Paraphenylenediamine(PPDA)is the wellknown allergen in dye.Our aim is to find the relationship of dose-response and the natural turnover course induced by PPDA. Finding a few immunol markers and a safe method to dye are also our expectation. Assessing the sensitivity feature of PPDA-ACD in human skin by patch test.Methods:1.We induce DTH on skin in guinea pigs.Six concentrations of PPDA(C1 0.1%,C2 0.25%,C3 0.5%,C4 1.0%,C5 1.5%C6 2.0%)were applied on the back of the guinea pigs,and the skin response was read at 2hr(D1),24hr(D2)and 48hr(D3) after the patches' removal.A modified procedure based on the Buehler Test was used. Occlusion was carried out once a week and repeated for 8 weeks.2.We took the same method as described above.First,the test continued 6 weeks with a concentration of 0.75%.Then,the sensitized guinea pigs were devided into two groups,A and B,1.5% for group A for 2 weeks and 0.75%for group B for 6 weeks,respectively.Last,the group A was devided into two groups again,a1 and a2,1.5%for group a1 and 0.75% for group a2 for 4 weeks.Skin biopsies were made at week 0,6,8,12 and detected the contents of IL-10,IL-12 and IL-1a by ELISA.Finally,group 1 represented the concentration 0.75-1.5-1.5,group 2 0.75-1.5-0.75,group 3 0.75-0.75-0.75.3.Patch test was made to assess the sensitivity feature of PPDA in human.Results:1.The response of group C1 is low and the largest response percent(LRP) 17.9%occurred at week(W)6.The response of C2 is higher than C1'and the LRP 53.6%at week 7,C3 76.7%at W 7,C4 96.2%at W 5,C5 85.7%and C6 92.6% at W4.The strongest response(≥4)of C1 is absent,which of C2 23.5%occurred at W7,C3 6.7%at W6,C4 15.4%at W6,C5 10.7%at W6 and C6 is absent as C1.All dose-response curves subsidised from the peak of the response.2.The skin contents of IL-10(pg/g)reached the peak at W6 and the difference is significant (P＜0.05),which decreased at W8 and which of group 1 is lower than group 2 at W12. The skin contents of IL-12(pg/g)at W6 is higher than W0 and the difference is significant(P＜0.05),which of W8 is higher than W6 and which of group 1 is higher than group 2.The differences of IL-1A between the four time points aren't significant. 3.The positive percent is 1.8%and the strongest response percent is 2.2%in 48H patch test(48H-PT),3.8%and 3.4%in 24H-PT.The percent of the response which performance is peak at D2 is 11.5%in 24H-PT,6.7%in 48H-PT and the difference is significant(P＜0.05).The percent of the response which performance is peak at D3 is 15.2%in 48H-PT,8.2%in 24H-PT and the difference is significant(P＜0.05).The percent of the response which performance of D3 is stronger than D2' is 17.0%in 48H-PT,9.1%in 24H-PT and the difference is significant(P＜0.05).The percent of the response which performance of D3 is lower than D2' is 8.5%in 48H patch test, 12.5%in 24H one.Conclusion:1.The dose-response curves and time point curves of all groups reflect the immunoregulation in DTH.2.The immunoreaction easily inclines to Th2 in low dose group than the high one.IL-10 is an early suppression cytokine.The balance between IL-10 and IL-12 is related to the immunoregulation.3.The results of the human test are consistent with the animal test'.The PPDA-CS in human also shows off the immunoregulation.