Immunohistochemical evaluation of toxic epidermal necrolysis treated with human intravenous immunoglobulin

Abstract

Aim: Toxic epidermal necrolysis (TEN) is a severe drug reaction characterized by massive epidermal cell death. The authors of the current study and others have noted improved outcomes in TEN patients treated with human intravenous immunoglobulin (IVIG), purportedly due to its ability to inhibit the fas/fas-ligand (Fas-L) apoptotic pathway, but published case series evaluating TEN through the use of immunohistochemical antibody stains for Fas and Fas-L before and after IVIG treatment are lacking. The authors hypothesized that due to IVIG's ability to arrest the evolution of TEN, expression of Fas/Fas-L on keratinocytes would be decreased or absent following IVIG treatment.

Methods: Ten patients diagnosed with TEN underwent biopsies of their lesions prior to and five days after treatment with IVIG. Seven post-treatment biopsies were of sufficient quality to undergo evaluation.

Results: All ten pretreatment biopsies had Fas and Fas-L expression by immunohistochemistry, while six out of seven (85.7%) post-treatment biopsies failed to demonstrate Fas or Fas-L expression. One of seven post-treatment biopsies stained positive for Fas and Fas-L.

Conclusion: This reduced immunohistochemical expression of apoptotic markers may represent IVIG inhibition of the pathogenic mechanism of TEN. Alternatively reduced Fas and Fas-L may be a feature of reepithelialization in TEN, or characteristic of rapidly proliferating epidermis.