IL17A and Ito hypomelanosis: The median[IQR] plasma IL-17 levels in the IPA and non-IPA groups were 15.05 [10.00, 20.46]pg./ml and 7.72[4.33,13.79] ng/ml, respectively, the difference was statistically significant (P<0.001); Similarly, the median level of IL-17 in the BALF of the IPA group was significantly higher than that in the control group (25.71[21.76,29.12]pg./mL vs. 11.56[8.03,22.27]pg./mL, P<0.001).