Ultraviolet radiation-induced cytokines promote mast cell accumulation and matrix metalloproteinase production: potential role in cutaneous lupus erythematosus

Abstract

Objective: To examine the role of mast cells (MCs), cytokines, and matrix metalloproteinases (MMPs) following ultraviolet B (UVB) radiation in cutaneous lupus erythematosus (CLE).

Methods: Immunohistochemistry was used to determine the presence of MCs and the expression of MMP-1, MMP-9, interleukin (IL)-15, and CCL5/RANTES in skin from patients with CLE. Human keratinocytes were exposed to varying doses of UVB and supernatants were collected and assessed for IL-15, CCL5, MMP-1, and MMP-9 by protein assays. MC migration was determined against supernatants from UVB-treated keratinocytes.

Results: MCs in the skin of patients with CLE were significantly increased. MMP-1 and MMP-9 expression was abundant in these lesions. Intense reactivity for IL-15 and CCL5 was found in skin, particularly in epidermal keratinocytes, from patients with CLE. UVB irradiation induced IL-15, CCL5, MMP-1, and MMP-9 production from keratinocytes in a dose- and time-dependent manner. Supernatants obtained from UVB-treated keratinocytes induced MC migration, which was attenuated by anti-IL-15 and anti-CCL5 neutralizing antibodies. IL-15 induced MC-derived MMP production.

Conclusions: Our results indicate that MCs and MMPs may play a role in the skin inflammation in CLE. MC recruitment as well as MMP production may be perpetuated by UV irradiation through locally released mediators.

Acknowledgements

We thank Professor Steven Kossard and Micheal Konopka from the Skin and Cancer Foundation Australia for providing some of the skin specimens.