Fig. 4

HDM re-challenge initiated a lymphocyte response in the BAL and lungs and HDM specific IgE responses in serum. A BAL numbers of ILC2, B and CD4+ T regulatory cells, peaked at 3 days post HDM re-challenge. TH2 cells were only present in numbers at 7 days post HDM re-challenge, (n = 4 per time-point for saline controls and 6 for HDM re-challenged group). B Lung lymphocyte responses either peaked at day 3 post HDM re-challenge (ILC2 and TH2 cells) whereas B and T regulatory cell numbers remained constant and did not resolve, (n = 4 per time-point for saline controls and 6 for HDM re-challenged group). C HDM-specific IgE was detectable in significant amounts at day 7 in the serum of HDM re-challenged mice coinciding with sustained numbers of CD19⁺ B cells in both BAL and lung (n = 7 in saline groups and 9 in HDM re-challenged groups per time-point). *p < 0.05, **p < 0.01, ***p < 0.001 compared to saline