Cutaneous lupus erythematosus (CLE) is an autoimmune disease characterized by inflammation of the skin. Healthy skin is maintained by proliferation and differentiation of basal progenitor cells, and supra-basal transient amplifying (TA) cells. Senescence is a state of cell cycle arrest, inducible by various triggers including inflammation, and characterized by p16 and p21 expression. This study evaluates senescence marker expression by cells in the epidermal basal and supra-basal layers in CLE patients, compared with other inflammatory dermatoses and unaffected skins.
Senescence markers p16 and p21 expression in the epidermal basal and supra-basal layers in lesions from age-matched CLE patients (n=20), 7 other conditions with dermoepidermal junction (DEJ) infiltration (n=22), 9 dermatoses without EDJ infiltration (n=27), and unaffected skins (n=3) was examined by immunohistochemistry.
Significantly more p16+ and p21+ cells in basal and supra-basal layers were detected by immunohistochemistry in age-matched CLE skin lesions and other dermatoses with DEJ infiltration, compared to those without and to unaffected skin biopsies (p<0.05). p16+ cell number correlated with p21+ cells in the basal (R=0.45, p<0.0001) and supra-basal (R=0.47, p<0.0001) layers. p16+ cells were more frequently found in the basal layer, and p21+ cells conversely in the supra-basal layer (p<0.0001). p16+ and p21+ cells in CLE lesions did not differ from other dermatoses with DEJ infiltration (p>0.05).
DEJ infiltration may play a role in development of skin progenitor/TA cell senescence. Progenitor and TA cells in skin lesions of patients with CLE may be regeneratively dysfunctional, as a consequence of senescence.