Regulatory function of factor-XIIIa-positive dendrocytes in incipient toxic epidermal necrolysis and graft-versus-host reaction - A hypothesis

Background: Lymphocyte-poor graft-versus-host-reaction (GVHR) and toxic epi dermal necrolysis (TEN) share some histological resemblance. In both diseas es; factor-XIIIa-positive dendrocytes show some morphological changes, prob ably as a response to altered cytokine environment. Objective: To study the ultrastructural aspect of boosted dendrocytes in GVHR and TEN. Methods: Si xty GVHR and 25 TEN lesions were examined using immunohistochemistry. Among them, 6 dendrocyte-rich cases of each disease were studied by electron mic roscopy. Results: Dendrocyte activation with enlarged endoplasmic reticulum , and collagen fiber and mast cell granule phagocytosis were evidenced in b oth diseases. Depletion in dendrocytes was only encountered in a few GVHR c ases exhibiting specifically a sclerotic aspect in the superficial dermis. Conclusion: Factor-XIIIa-positive dendrocytes probably play a role in the r egulation of the connective tissue remodeling that may accompany epidermal destruction.