Background The pathogenesis of psoriasis vulgaris is attributed to an immune dysregulation of T lymphocytes, and psoriatic plaques result from interactions between keratinocytes and T lymphocytes. Objective To decipher the impact of keratinocyte-T lymphocyte interactions on cell survival during active cutaneous psoriasis by using a new in vitro model of psoriasis. Methods Cocultures of psoriatic or healthy keratinocytes were performed with normal human blood T lymphocytes. Apoptosis was detected by flow cytometry after labeling cells with annexin V and propidium iodide. Results Psoriatic keratinocytes were significantly more efficient than healthy keratinocytes in enhancing T lymphocyte survival. Conclusion Our in vitro model is pertinent to understanding the immunopathogenesis of psoriasis and to discovering new pharmacological targets.