HMGB1 and toxic epidermal necrolysis: Interestingly, for the first time, we have shown that blister‐fluid levels of HMGB1 in patients with SJS/TEN were 55‐fold higher than in serum, indicating that voiding of HMGB1 from the keratinocytes in the epidermis is likely to contribute to the significantly elevated blister fluid levels (Fig. 3).