Current treatment strategies for severe acute GVHD and TEN differ. In North America, high-dose IVIG frequently is used as first-line systemic therapy, while high-dose systemic corticosteroids rarely are used.13 Studies have demonstrated successful use of anti–TNF-α drugs for the treatment of TEN.3,4 Moreover, etanercept has shown to effectively inhibit lymphotoxin α.14 Similarly, TNF inhibition in the management of steroid-refractory acute GVHD has been successful.1 These studies coupled with the underlying immune mechanisms that both diseases share encouraged initiating a trial of anti–TNF-α therapy in our patients.
Patient 1 merits further discussion because he was both a 100% donor chimera as well as a carrier of an human leukocyte antigen susceptibility candidate allele to TMP-SMX. Historical features of his presentation are consistent with either steroid-refractory GVHD or TEN superimposed on acute GVHD. His initial presentation of the more typical macular exanthem of cutaneous acute GVHD was both biopsy proven and supported by clinical improvement with steroid therapy, which was later followed by a robust blistering mucocutaneous presentation approximately 3 weeks after the administration of TMP-SMX and 1 week after initiating voriconazole that improved with IVIG and etanercept.
It is difficult to determine if TEN represents a continuum or result of the underlying drivers of acute GVHD vs a drug reaction. Although there is insufficient evidence to establish a clear-cut diagnosis of TEN, these cases illustrate the need for better diagnostic techniques to allow differentiation between TEN and grade 4 acute GVHD, and in the context of uncertainty, TNF-α inhibition poses a viable therapeutic strategy for these 2 often lethal conditions. Our cases do unequivocally indicate the benefit of this therapeutic modality, add to the current body of literature supporting the use of TNF-α inhibitors in patients such as ours without an official TEN diagnosis, and may guide future investigative efforts.