Heterogeneous JunB expression within lesional psoriatic skin. Immune reactivity of a monoclonal antibody against JunB within a psoriatic lesion. (a) Distinct anti JunB reactivity of a parakeratotic lesion. JunB expression is observed throughout all epidermal layers (left side, arrow), whereas it is reduced on the right side of the lesion (see arrow). (b) A different area of the same lesion. A virtual absence of nuclear reactivity is seen in basal keratinocytes, whereas strong nuclear activity is detected in the upper suprabasal epidermal layers ((a) and (b) arrows).