Transient bullous dermolysis of the newborn. Retention of anchoring fibril- and basal lamina-like structures in keratinocytes and evidence of collagenolysis.

In a freshly induced blister from transient bullous dermolysis of the newborn, we found in epidermal basal cells structures similar to anchoring fibrils and lamina densa, often in combination. In the upper dermis, collagenolysis and phagocytosis of degenerated collagen fragments were observed. It is concluded that the stellate inclusions previously reported in this disease are prematurely assembled anchoring fibrils and lamina densa. A disturbance of delivery mechanism of precursor materials for anchoring fibrils and lamina densa may cause the deficiency of these structures which are essential for the integrity of dermo-epidermal adhesion. The presence of many normal anchoring fibrils and lamina densa in perilesional skin and their prompt degeneration after rupture of the inclusions previously led us to conclude that lytic enzymes are involved in the formation of blisters in this disease. The new finding of collagen phagocytosis in the lesional dermis seemed to support this contention.