Down regulation of IL-8 and IL-6 in human limbal epithelial cells cultured with human dialyzable leukocyte extracts

Introduction: Human Limbal Epithelial Cells (hLEC) are stem cells that give rise to corneal epithelium. After corneal damage, hLEC produce large amounts of IL-8 and IL-6, inducing inflammation in cornea and conjunctiva. Despite inflammation is necessary to repair the ocular surface since this process may be potentially harmful and could lead to corneal opacity. Ophthalmic infectious diseases have been treated with human dialyzable leukocyte extracts (hDLE). Clinical observations in hDLE-treated patients, have suggested an apparent control of ocular inflammatory injuries, without changes in the re-epithelialization process. Objective: To determine the inflammatory cytokine profile in supernatants (SN) of hLEC cultured with hDLE. Methods: hLEC were obtained from cadaver donors. hDLE were added to the hLEC cultures, and SN were collected at different times (1h, 3h, 6h, and 24h). IL-1β, IL-6, IL-8, IL-12p70 and TNF-α were measured in SN with cytometric bead arrays. Results: The majority of isolated cells were CK19+/vimentin+/p63+, indicating that cultured-cells were limbal epithelial stem cells. Limbal cells responded to hDLE by diminishing the secretion of IL-8 and IL-6. Secretion of IL-8 and IL-6 was down-regulated significantly at 24h of culture with hDLE. Interestingly, hDLE did not induce secretion of IL-1 β, TNF-α, and IL-12p70 in hLEC at any evaluated times. Conclusions: hDLE down-regulates secretion of IL-8 and IL-6 without induction of IL-1 β, TNF-α, and IL-12p70 in hLEC. Our results provide a basis to understand some clinical effects, related to control ocular inflammation, that have been observed in patients treated with hDLE.