A pilot study comparing histological and immunophenotypic patterns in stage 4 skin graft vs host disease from toxic epidermal necrolysis

Background Stage 4 skin graft‐versus‐host disease (GVHD) is associated with poor prognosis and high mortality rates. Clinical and histologic similarities with toxic epidermal necrolysis (TEN) make it difficult to distinguish between these 2 life‐threatening conditions. Methods A retrospective cohort study was conducted from a tertiary referral center. Skin biopsies were obtained from 11 patients who developed stage 4 skin GVHD and 11 patients who developed TEN between 2005 and 2012. The CD8+/CD4+ T lymphocyte ratios were assessed in lesional skin specimens. Results Average CD8+and CD4+ cell counts co‐expressing CD3 were 126.29 (range 86.42‐173.06) and 84.60 (29.87‐197.20) for stage 4 skin GVHD patients, and 61.97 (45.79‐146.67) and 7.65 (0.00‐39.50) for TEN patients, respectively. Immunohistochemical studies of stage 4 skin GVHD and TEN skin demonstrated average CD8+/CD4+ ratios of 1.78 (range 0.69‐3.09) and 7.33 (1.16‐12.3), respectively (P = .013). Conclusions Stage 4 skin GVHD and TEN are processes with cytotoxic profiles. TEN is notable for a greater relative depletion of CD4+ T lymphocytes compared with stage 4 skin GVHD, while stage 4 skin GVHD tends to be more inflammatory than TEN. These data suggest an immunohistologic method by which these 2 entities may be distinguished.