New findings of a lamina densa in relation to plasma cells.

In an ultrastructural study of oral lesions in lichen planus, it was found that some plasma cells have an associated lamina densa. Subsequently, similar appearances have been found in pemphigus vulgaris, in the inflammatory cell infiltrates in dental granulomas and cysts and in a patient with Ehlers-Danlos syndrome. The lamina densa was mainly present adjacent to those parts of the membrane of the plasma cell that were invested with fibrillar connective tissue. The lamina was similar in thickness and electron density to that surrounding Schwann cells and endothelial cells. It is believed that lamina densa has not previously been reported in relation to plasma cells. It is of interest that in all other situations in which lamina densa has been described, the cells are considered to be part of the normal cell population of the tissue, whereas plasma cells are not regarded as part of the resident population of connective tissue.