NOS2 mRNA expression by RISH in acral and nonacral samples. (a) Quantification of NOS2 RISH in normal acral skin (n = 9), HPE (n = 12), PP (n = 8), nonacral psoriasis (n = 10), and MFPP (n = 8) following the scoring system in Table 3. (b–d) Representative NOS2 RISH (red) in PP (b), HPE (c), and MFPP (d) tissues. Middle lines represent medians; upper and lower ends of the boxes represent IQRs; whiskers represent values within 1.5 × IQR. Each point represents an individual case. Bar = 200 μm. HPE, hyperkeratotic palmoplantar eczema; IQR, interquartile range; MFPP, mycosis fungoides palmaris et plantaris; NAP, nonacral psoriasis; NL, normal acral skin; PP, palmoplantar psoriasis; RISH, RNA in situ hybridization.