Deletion of Ptch1 in epithelial cells causes the B- and T-cell defects. (A) Characteristic histologic appearance in skin of MxPtch1^Δ/Δ mice. (B) Quantitative RT-PCR for Gli1 mRNA expression in skin from MxPtch1^Δ/Δ mice. Mean plus SD from 3 mice of each genotype. (C) Characteristic histologic changes in skin of K14Ptch1^Δ/Δ mice. (D) Numbers of pre-BII cells and (E) thymocytes in K14Ptch1 mice. Analyses were performed at 4 to 6 weeks of age. Mean plus SD from 5 mice of each genotype. (F) Numbers of LKS cells in BM from K14Ptch1 mice. Mean plus SD from 7 mice of each genotype. (G) Numbers of osteoblasts along femoral shaft of K14Ptch1 mice. Mean plus SD from 3 mice of each genotype. (H) Quantitative RT-PCR for TSLP mRNA expression in thymus and skin of control (Ptch^fl/fl) and MxPtch1-null (Δ/Δ) mice. Results were normalized for HPRT and expressed as the mean plus SD (arbitrary units [AU]) from 3 mice of each genotype. (I) Serum TSLP levels in MxPtch1^Δ/Δ mice (n = 4) and K14Ptch1^Δ/Δ mice (n = 4). Serum TSLP levels in control Ptch1^fl/fl mice (n = 8) were below the detectable limit of the immunoassay (4 pg/mL).