PBMS cells from SJS/TEN

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are life-threatening adverse drug reactions characterized by massive epidermal necrosis, in which the specific danger signals involved remain unclear. Here we show that blister cells from skin lesions of SJS-TEN primarily consist of cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells, and both blister fluids and cells were cytotoxic. Gene expression profiling identified granulysin as the most highly expressed cytotoxic molecule, confirmed by quantitative PCR and immunohistochemistry. Granulysin concentrations in the blister fluids were two to four orders of magnitude higher than perforin, granzyme B or soluble Fas ligand concentrations, and depleting granulysin reduced the cytotoxicity. Granulysin in the blister fluids was a 15-kDa secretory form, and injection of it into mouse skin resulted in features mimicking SJS-TEN. Our findings demonstrate that secretory granulysin is a key molecule responsible for the disseminated keratinocyte death in SJS-TEN and highlight a mechanism for CTL- or NK cell—mediated cytotoxicity that does not require direct cellular contact. Blood samples were obtained from 5 different patients with SJS/TEN. The peripheral blood mononuclear cells (PBMCs) were isolated from the whole blood samples by Ficoll-Isopaque (Pharmacia Fine Chemicals) density gradient centrifugation. Total RNA from PBMC was isolated using the RNeasy kit (Qiagen). The 28S and 18S ribosomal RNA peak ratios were determined using microfluidics technology (Agilent). RNA was subjected to reverse transcription using the Superscript II kit (Invitrogen), and the cleaned cRNA was then hybridized to an Affymetrix human genome U133 plus 2.0 array.