CD4 and toxic epidermal necrolysis: However, it is difficult to draw convincing conclusions from their results because they were conducted with a single drug only (Grl-ELISA, sensitivity 86% in SJS/TEN) [22] or in a single center (Grl in CD3+CD4+, sensitivity 56% in SJS/TEN; IL-4-ELISpot, sensitivity 90% in DRESS) [20,26,42] and, until now, an overall number of tested individuals has generally been small.