Ultrastructural lupus band test in the skin of MRL mice.

The ultrastructural localization of immunoglobulin deposits in the dermoepidermal junction of MRL/l mice was examined using immunoperoxidase staining. All specimens that showed positive findings at the basement membrane zone of the skin on light microscopy had reaction products at the sub-basal laminar area when observed by electron microscopy. In the skin that had no distinct eruptions or which was distant from the lesions, the reaction products were distributed mostly just beneath the basal lamina in fine to course granular deposits. In the lesional skin, they formed a rather uniformly granular pattern among the irregularly arranged collagen fibrils and increased fine fibrillar amorphous material under the highly infolded basal lamina. Some of the reaction products were located just on the collagen fibrils and some appeared to be related to the free basal lamina. From the perspective of immunoelectron microscopy, the skin eruptions of MRL/l mice may serve as a good dermatological model of human systemic lupus erythematosus.