Differential expression of interferon-induced genes and other tissue-based biomarkers in acute graft-versus-host disease vs. lupus erythematosus in skin

Background: In both acute graft-versus-host disease (GVHD) and lupus erythematosus (LE), the patient's own tissues are subjected to immunological assault via complex mechanisms influenced by interferon (IFN) and other cytokines. Although not typically confused clinically, these entities have overlapping histopathological findings in the skin. Aim: To assess whether GVHD can be differentiated from LE using molecular methods on skin specimens. Methods: We developed a quantitative reverse transcription PCR assay based on previously identified tissue-based biomarkers of cutaneous GVHD, and compared gene expression in GVHD with that in LE. Results: Both entities showed robust expression of IFN-induced genes and of genes encoding proteins involved in antigen presentation, cell signalling and tissue repair. Levels of gene expression differed significantly in GVHD compared with LE, particularly those of IFN-induced genes such as MX1, OAS3, TAP1 and STAT3 (P < 0.01). Three logistic regression models could differentiate the two entities with a high degree of certainty (receiver operating characteristic area under the curve of 1.0). Conclusion: The study demonstrates the feasibility of distinguishing between microscopically similar inflammatory dermatoses using tissue-based molecular techniques.