Cell renewal in discoid lupus erythematosus.

Cell proliferation has been evaluated in four patients with discoid lupus erythematosus after in vivo incorporation of tritiated thymidine. Numerous epidermal cells are in S phase or in mitosis. The acceleration of cell renewal is paralleled by a shortening of the transit time of completely differentiating keratinocytes. Remodellings of the vascular belt are evidenced by the labeling of many endothelial cells. There is no sign of lymphoblastic transformation in the dermis since the mononuclear infiltrate remains unlabeled.